/*
This code includes region comments to collapse code sections in VS Code via the "#region folding for VS Code" extension by maptz
*/

//#region Imports
import { FreeCost } from "./api/Costs";
import { Localization } from "./api/Localization";
import { theory } from "./api/Theory";
import { TextAlignment } from "./api/ui/properties/TextAlignment";
import { Thickness } from "./api/ui/properties/Thickness";
import { Color } from "./api/ui/properties/Color";
import { Theme } from ".api/Settings";
import { LayoutOptions } from "./api/ui/properties/LayoutOptions";
//#endregion

//#region Globals
var id = "sudoku_theory_alpha";
var name = "Sudoku Alpha";
var description = "A minigame theory which allows you to play different difficulties of sudoku (alpha version, still missing a lot of the ultimately planned features)";
var authors = "AfuroZamurai";
var version = 1.7;

var currency;

var easy, medium, hard, expert, omega, devilish;
var difficulty;

/**
 * A board is containing 81 cells, with each cell being the following datastructure (TODO: change to a faster representation)
 * 
 * cell = {
            number: number,
            isGiven: number > 0,
            cornerMarks: [],
            centerMarks: []
        }
 */
var easyBoard, mediumBoard, hardBoard, expertBoard, omegaBoard, devilishBoard;

var easyUndoStack, mediumUndoStack, hardUndoStack, expertUndoStack, omegaUndoStack, devilishUndoStack;
var easyRedoStack, mediumRedoStack, hardRedoStack, expertRedoStack, omegaRedoStack, devilishRedoStack;

var easyTimer, mediumTimer, hardTimer, expertTimer, omegaTimer, devilishTimer;
var easyBestTimer, mediumBestTimer, hardBestTimer, expertBestTimer, omegaBestTimer, devilishBestTimer;
var currentStartTime;

// intentionally almost completed board for testing purposes
var test;
var testBoard;

var testUndoStack;
var testRedoStack;

var testTimer;
var testBestTimer;

const TEST = "Test";
const EASY = "Easy";
const MEDIUM = "Medium";
const HARD = "Hard";
const EXPERT = "Expert";
const OMEGA = "Omega";
const DEVILISH = "Devilish";

const REWARD_TEST = 1;
const REWARD_EASY = 30;
const REWARD_MEDIUM = 150;
const REWARD_HARD = 750;
const REWARD_EXPERT = 2500;
const REWARD_OMEGA = 5000;
const REWARD_DEVILISH = 10000;

const ROWS = 9;
const COLS = 9;
const BOARD_SIZE = ROWS * COLS;
const BOX_SIZE = 3;

const NORMAL_MODE = 0;
const CORNER_MODE = 1;
const CENTER_MODE = 2;

const UNDO_MODE = 0;
const REDO_MODE = 1;

var isPopupOpen = false;

var gameGrid = null;
var hintLabel;
var undoButton;
var redoButton;
var timerLabel;
var bestTimeLabel;

/* Puzzle difficulty for now is defined by the number of givens.
Easy = 47
Medium = 42
Hard = 37
Expert = around 32 (30-33)
Omega = difficult puzzles provided by the user Omega from Discord
Devilish = custom searched puzzles with high challenge
*/
let easyPuzzles = ['094260150700013694681090703109074580503680940020001367945700206830009470000500000',
'528304176371060800000807025103200704089401200040953010230605080004709502065008430',
'603275409049086275200109630050000007700012306816093040930604820020800064408000753',
'900106000000859421251347080045910308030004600790630005823461750000705263507000014',
'008490512009006000750213089500100200821370496040062103096001840400058301185034900',
'507006001010502467480317502690003208803004015102060700060400970758630004934021050',
'050896300104302500863501009280704901010269487900080605530600700021007800070425103',
'007040600516702040300960000030200984009310275704059136401038592208197003060005807',
'070300809300021075108975340512096008830400097040130206450280063020047001789600020',
'100200005098370004002518960041002500706001300280600410315760208604180793879403050',
'600501000827940105130008900412600873000810452000724000070459200260087590954102380',
'005708062003495017800020059540179080030050201608234090154300000089540076720981004',
'030691420806473001004080607908000063240300570367015000509046300403250896080130705',
'208530961070918300039024700380200004001400080402891637023009406800000510714056809',
'048037026207601049301049700013400072600700854400928031700806500009102068006350097',
'000978000064521700897460500600107928051006037078340060480030091100892670020014803',
'207540001503900247980021030002006054746890120351070960400050300100204076025017480',
'001004705007890040024056380050083164413070029680410003205937618098002407006100050',
'062850907105260030489031060093480250214905300050023000840092170500647820000508600',
'010406070573281049960530020048760350026305198050000460007853216031600080005002700',
'009078103341695287700132450807904000410023900026007008000200095090081630600059812',
'865431700190060300407050008500210976710680030326579840904800603080107029000300480',
'873009060926007004045682093010300527708210030600975801084720600007400350301856000',
'403680015002593470756401900609010020104700859075040003921806007500174390000250001',
'800029530002645700904783060020400906706902413500310872690500027030890040070201309',
'291700805856923400004508260067150948015689700000300056579001600003067002002800301',
'608001907053078041027930060406809570810756093005042180300200700079003620081467000',
'700000836002100954605038270540019608020840593908065147453600080200783000871020000',
'430670508950481200008000469109507304240000007560034091000825700604003080875146032',
'703492605805601002406300090008156730001049006000230410080924503062510074500068920',
'630714502050638970008005006746100830093070045810049200500903000027081050361527400',
'752130604008026031100784952503001268017200400280403000900800005374605009005097140',
'906530071080069005005810096678294503503706249490000000320000650769320180000071930',
'576800149403700050208400360000040708080256431002370690309087204001930576760010080',
'702800653060003084008700201005480309304150800280076015903600500800294037140530926',
'873945601051003489009086730406010390307290856900600004100802003702050008060370140',
'531279064002541003070300052100000438097018026450600900640805017210004389709120000',
'430059812006017030189200705070342591013508020200970003840020309000005148001480250',
'106785209400000301289130706768092003051006908900308070817900064004050132020640007',
'009080400314952786060703095480200031692104078700560000906820014803400900007305062',
'200700609800130007065002400502090306079001500480320001603278190027513804158640730',
'050837060610590827070060354030900000724308619006410783000105070087003295240780100',
'864325010037890020520610483001470238000500094943002060015006009470031600206750040',
'701020900420600803389500620000731200008050400150842796804060179010007308600183542',
'000800703070026040280307060304079080007210650521684097439762008600000409710095236',
'007960143200031580004078206851200009600090014903000700700024968428650071160783020',
'250700000809403120407219560970105000008670350043980706600321004714096200092500680',
'014008700958020000276010540720083450065900823809200607082090304100030260643750081',
'500090001604003295709050436071002600902108753035600024000310560047800902056907348',
'983204105652030784001080329300000600067000513090320007516093208034760951700100400',
'960000507705194000084705000300827091400350268020040003012508974547610080803472600',
'913780560605902104020000930060491753007056009009300810091203687308060240046570000',
'020003000300140506041090870408630090902854107753920608684700350007380062000069781',
'500060014090800026600010980029436075004152809103790042078340200016900053030621790',
'048006910700000020010247065859162003071059602400873000002704109500601038084395076',
'038070095509000010270098463600154308005063140003987520057419600820036000906020704',
'803097054017003009025601008000469800700130605096705423089310572200008306304506001',
'453060792009003406761094300000720108000349007302158000500000640200615809698437250',
'009080070800391054403270190006134509041700200385629010098500041067042035004000926',
'003219640010473029400050710940687032082031900070904806060095081098000305504160200',
'600571940508040731001308620900000350057230186012860400035024060009700010874056290',
'402968000001325400936700582070003026394000718600190040069010073840600250507802604',
'102940086684005070750006314010070030000053401003189705948231607005008002201564003',
'200890076010070390060004518035682000702049635649300001500003700300460250498725160',
'008040016590137042000580739819700650632004000704960283105390007040005098083002105',
'930716080165004307040030026006408701000000865873601209600020053397805000251900478',
'845316090193000006260059308408030760009047820301268450704601930000584000012000084',
'302901806061520070400806051603000400708000029940680317134205008290308564500040130',
'013450926600002008050916000560204803200195047479800500087309400900580201305640780',
'080640732720050149930071805002193580318005200600800307007006028293400050005912400',
'040600901718005263056320740890002470070409125004006809060893014485160090039200000',
'984007205206090010053008007401879506020310700005206381047060152500080904009452608',
'740309600800402350309060107002038500014900006638104702207580460450790081100243070',
'800260715700080403325070860032519607070300090598027301907401006050000104604752008',
'605040012028067500400592876030001090796008251250900304069300008300705169080629400',
'005348020003200618070096000401027935096500102007031486020013067700069250608750304',
'523000041861003795400061008080007350054012067609050412005296100938100520010800074',
'690723801850401300007586020065219080083000492000008165040060530030970018928105007',
'136794800580230100970500064051000780800150249009002016690018472403027058000900031',
'059070200804130900160802003415086390080019067970240850008007000632950780790408630',
'040029736006740205020003900653297810071060059800305027300472008480050003765130090',
'401607802003008506065392047007009014084231050900000603256083070300124060109506308',
'050004680000982041184605007807300154306108702001420806018000200470296300039870405',
'560200049071400200004009768027604030300507920459308000010032006603701582742805301',
'002108306093050400000740019316400975004630820050907634030004162560309048427000093',
'507400306900210400431600082280150034640008571000060298870590100104032860006041029',
'007046030903217084040530270030009412100700050089050367002804095008375100076190843',
'062970510400300208395100040020000354950041720007500981034215860080403100506789030',
'600200009907084200520697031400106900000470516196508400701942350050003104348750002',
'968243051040600903520107460004080179007024386036001000602030800410865037085700090',
'824057139500089074001420080407000610300971002200840090059204860082305741103000920',
'734086029920004836056009170107840090083907005549362708305020060600570400000001250',
'460895073097031008583004000342070965006059314015306820020487001008010640100002009',
'000019050409056281201800306002490803093002614148070905980004002027065108600708530',
'028496700000005986000710045819002403740063510000901872650127090087300024290600150',
'010004602604020830008003495820000507300617009060082004159030748432900106780451903',
'007403080200605374048072060000369805900004010405800903876900052102048036530026198',
'596032007804000631300000920403026819009010750160807200940703560052461098008059004',
'820046370600215409004800206740008005050637100106594002098700513501309620362000090',
'097405062300987500500602093002060901954070038680009275879000326405700100013006057']
let mediumPuzzles = ['180520360200600489079480210000700900500001620060008053718962000040070806056034070',
'093006075052040810780203904000030406246807000509024100315000090020071008007002341',
'087000950940070631506900020008201003030050042201034700020009400803467205704510008',
'008020016010005009290036587030850901007490820000001030820049673649000100573012000',
'920057600068400700500903001092108503403020079150009000817005306600070200230684010',
'007063900400592736600000452042309000100254800980070000350701004060900170870645300',
'703094200100630900040008760650200807008015049079000001004380070017450096236001405',
'940003170005614000063207408800175620021309007076008501008000000430506002619040080',
'370920000000730692502410380900867005030000800108200069010004056063100400085672903',
'740130050261040809030082000100405086003000975600803100820716000076008041905020068',
'950032008004000090001040367413256809608100050070004030040067980507009023109020045',
'201070946094600007006400528718030090900184030420900050000018273080020060532006100',
'790054300203067540004081290870000123100038050306020079450002000008009012002870460',
'100847050500920486000063200400000060678005300312780500709250108040109020051030704',
'068430097050209480300010260020708506105002730097100840006024000574086900030000054',
'006503402040160097051029008005002073410900060027651800060084701000200306830700950',
'042095810005000004836047209010080025429050630080064001000809063001076980000002147',
'000908537000003261302060400700805000591076042086190000207504090940007325130080004',
'203605007178240000059870142002007400000108075000060389060520900930004500024096018',
'408053769050009000690000235009001584002074310104068000006300470973402600200080190',
'307400208082936740000027095058600430400070120106003000765004900910062080020005073',
'102900000009042600007186902000001038516030700283507010701050004035419207098020060',
'260071408000500901009040063430659002000480010875003040086214007007068090314000086',
'491300020070001905030869701250008103068100090000020006305700800109486300007903214',
'030806050000400006008052490280040000047093080503081200410968307020170940079304061',
'091800032500001064763050090630200405008509013000376280020190006340705001900000847',
'182006903903028046400100070310080500004000397006075080509607810000802700038409025',
'840007069030904502502680700060071843704800601180000050075020400428300106906008000',
'030680721020000080085071900579106030008950102000807006302560000001398064046002059',
'540076310823000000107920500000614930006200740910350800700190060030068250090402108',
'400301509060090030930050147109065200006832904020149070600000020085670301010008450',
'090003852231900460408720000049005100802130090000009786070080631103604000006070948',
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'297130040008004009010090700025840160600950034380600025046000251800701000139420070',
'704860000290040500106035004040600710670921308302000650930780260508000490000502801',
'090005000060004378801627005042108000370452106508090034000070043903001800784503010',
'080629105300080200600700409007205090023807014061030800400102000075090601190546023',
'000208963309760280286004500007500000198007040030809672060305009072400001040182050',
'000005902320071540001248630070000420860120090500364701710053069030090000040002853',
'036090251918060407072301690301070506049000003000803040694007020080650100007982000',
'805603204060080070300194500093500000178430600502001830930002746004010052050007980',
'604000153103604780070000260496052000037091600802407035005210400000086071380009500',
'080430195004960200000050060410892750075010380806503401007000008300005942920106003',
'030472580801000002000100690015029070089030106307008024742006800050291043190807000',
'002340816800205047069078250901480705005030108300090004108007462070600000506000301',
'007005900160784032300096400200850007015062084800401250970000020500137006081029003',
'140580963690070208803160400302900701008001300904037520000090000209600805570008140',
'026083570785009203030027040100390068040706001209010000070900104010268090300401650',
'059812600020003900108069504075094030001280000940056107704000002003008069206070341',
'000502089000074203502639471156783004030095000809240000008000506400061038907300002',
'192070054500040008006300070654910237008403060023567801001009020409100005070680900',
'320780960609005108841200750400839001000050039000170205530920800710463002006000040',
'900070100071500402320061078006003040000206931500104000060807019180349706003605204',
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'020487030000600400040010809104306098297008040008049001075061302609800500810530906',
'852070410070006290006245000609001802005009001040837609004700003320514007107060084',
'008300700643000018917040520031409002400705380006020090069014870020607040070908036',
'009601030200000050460050708002435980700816240000092516103520000970084000508309170',
'618209405049306701030450000075040019200800304094105870006700182007508090080060000',
'590003006001200705037100089045602010800047500623008900052900007004021653380054090',
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'123070009769420080040090000005300720900804031400050068350007196890130472007006003',
'074300612520180000913200400000073008000691534059002007100726809208400306067000050',
'106000472800000905045300860658037090003146580400890300020609700781503600500080010',
'652000981800002046041896005700000160000705839000341020029070413073524000006003700',
'800701426007500009000024058534870260601200070090010083425683190978002000310000000',
'097530240010000009043607508309008600680050371072400900060240890908016050000780102',
'800000009000718000531062007709050628603480500008600904010806490400001703976204085',
'050640170000530096968201003093724015670000902200100830584000060000005001136907500',
'640180390900654708081900064000200401000003007258740900812070005430020070090006283',
'080650104615030070340807009530020900008100725206900400027040081000590007104208306',
'003659040700180030026340008900830020207090005804205601015008472000520069090700803',
'580410092240807001003905000600702003038009257720384010810070649000600020906000708',
'710920500006100809459803020540700096083409002000500081160008930095001270072300004',
'500962103008307260300500009061890057005210800400703010070620030003005908902108740',
'000100346200709015035480029304060082608502003790018004927051000001090657060800000',
'175008204090105073384702090500200009003070450400000716001390608046001900038050027',
'502061309379000046610300005800054700006102594090706801040205030100079052008000907',
'092047016506208007000090530207006000000300784450170003609803000120760300083910465',
'820601000517000600034820090005706180142980076086130450000570010901000830450300200',
'300206789050009064602470010006010423130000006074083091420000050519740008708095000',
'487903001200007008060021050730506410102708900900002005504019286603205007000600509',
'153792060090053102047800050705200049029000800014968520070000306001309200002004015',
'400108070305002001019406238203800600078009102601527003054203800102600004007004005',
'084965010361720900502000006000000037037416092026530481009184005000270000040053700',
'570000008030015672028407039060040800004709065901603024702154000000900250810036007',
'009004506068251930537960000600410050084502619020800700051003200076000394002080070',
'586700400000052070092003105019304600004510297070289010050608043460930820300007000',
'740610005500790403096350200008070604375080009964023000082530007450000010107049080',
'001090748706400920400820065520004316008030070040069800930572001160000200070310094',
'010206700679081400085009006000030002020147358708900600400013807093002510057804060',
'200087600070000290609210705056008001390641800800530400000076389908054072031090004',
'500910003090370621012008095001504200486720000075093108003200860740006310000000954']
let hardPuzzles = ['060005790758100000903600205124903080306050100000270004082019350500400800000030040',
'000000100020600097046890250200000781050003046609087300103940002000710500005206408',
'063054000001000480500710039002500007006023010800906340000048190038005276100060004',
'006950087007208040043010500081006200200340100060000975050000803432100006000790052',
'070086509604000030020430001405720006092000000703108024010500000509071082047003060',
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'980710500700400800006005000500900400030074000000050020100040089007000100000100004',
'960780500700005000005060000408007900006009800000040030020000050007006209000200001',
'400000008050020040006004900070302000000050700000001030009000400020030050800000006',
'300000002080070010006900000050704000000000008000510070009000300010040080200000006',
'000010007020400080300000500090806000000049060002000000007000100040900020005000003',
'003450000000080060080007005200800100300001900010070004000000020040700001900010600',
'009000003050002060400000700000508020000190000010006000300000900020800050007000004',
'980740500500009070007500000600030000008605700005408300020000003009004800000000010',
'900780500700060900005009000500007800004830000000000020300900700000076019000000050',
'903700500500400600040050080700004006039000400000900070300600700002000000070095001',
'980670000750090600006000000400900050008450700000003004027000030009830500000000001',
'608700900700960500050008000500007400030400000000090020400070800000806001000000050',
'023406000000080000090300400000005008000010070006200900700000050062000300040000001',
'980650400400800600000000070800300960020000030300010005600000000094000300038400006',
'103050000007100006080007100040900060008004300700020000000000092800001400000500010',
'907600500640501700503020000800900400000008050000000008700065094000400070000000600',
'980060500700005080005000004300200000006009400000070023010000040009007800000810095',
'800000004000090030001400700060305000002000000000069050007000100020030090400000008',
'020450009006009000000200400000100000008000013090005200300000078060004500000070000',
'070000000300020050004100600005040020030600400000008009001030040050400700000009008',
'980500600750060090006009000400000005008750060005900080030000200007800030000030001',
'950860700007000060000005009408006900030020040009008600100000090005007100000100006',
'080060500704030600062000070400500900090003085008090006040050800000009000800000001',
'100450700007009030600700000000007003040010900500600000010000098000000002002008300',
'900000002080007040006000100000058070000010000050703000200000600040500030001000009',
'402000001070009020008000600000705090000002000050930000100000800020500030006000004',
'007000004020003010600000800000205000050030090000109000008000007010300020400000601',
'500060700010304000080070000030100000005080900000002040809000007000000020600000509',
'600000008030007040009000100000302070000014000020750000800000009040200050001000600',
'005089000600700000070000900500030002400000010007600500006500800000020003000001040',
'890760500600080900005009000500007800004830000000000020300900600000076001000000050',
'006002000300050700040900000700000108000000040000080037100030005009400000020006000',
'380700600005064000000300000830000700090000030002000001060900800000020050000001004',
'012000000300040000500100030001600050060070008000009600000006900003400020000080007',
'500000009020100070008000300040207000000080000000605010300000800060004020009000005',
'000500008700068000000210000002000040090000300600005001100070006040000020003000900',
'000700900000000030009030806003050060700400000010002000005080090020000000400001005',
'087650400630040700002000060070305080008704500000080007050030800000001009000000000',
'890500600700080050005004000300002140006400090000010000020090005007800060000000003',
'120050000050000006006003000001060008080900070000008400000700800000004090002030005',
'900740500507060900003000070600090420000800000000002001200000059050020046006000200',
'083760500704009080060080700305806200020005000006020000030050800000000010000000007',
'080700600700050020004000007000302000010090000300005090900030010070000008036000400',
'090700600540080070007004000300020500910000000005400080009800060000003002400090100',
'120406000006080002080000000000900050000003400600070001007005090800000300060010007',
'010000002300000040005006700000087900000904000008560000009800500020000001400000030',
'700000009030400060005000200010806000000070000000031080200000700040008030009000005',
'002001000000030040300600700007009005080000020100400600006007003050080000700100900',
'008001000300070900050200000600000409000000050000090730400030007001500000020008000',
'980560700750400900003009000800006000075800090040050800500600400000020008000000010',
'907650400400800500006094070800000000094000600065900080600500800030020000000000001',
'940003600005060040000008500000300020010000075002070400100009200006020004000800000',
'005069000670800000800000600040000030007500900000020001008700500000010020000003004',
'000090000560700000708000500400009030007800900000020001006900700000010040000003002',
'980730500700400900000008030600000000050047600040600009400500200002004005000020001',
'103400000006080003080000040010600008307000000000007200500000090000092500030100004',
'920760500700405900005020000470500600003000080000000000100040050090100046000007100']
let testPuzzles = ['127539468568214793439678251016953824354182976892467315643725189281396547975841632',
'384275619175946823296831574748329165961587032532164798457692381819753246623418957',
'412697835675318429839425167728153694146279583953046712391784256267531948584962371',
'413598672268471395795263418142385769956712843387049521639827154571934286824156937',
'932756148458321976176849235715984623324675819869213054697532481581467392243198567',
'910643258832159467546728913374916825289435176651287394768392541193564782425871639',
'142687539573129864698453721261735948984261357057948612736812495429576183815394276',
'973182654456379218128564379814693725790421836362857491531246987689735142247918563',
'348576192962318745517492386876251934439867251125934867754189623683725410291643578',
'386917524524683971971524368418362795659741830732859416163495287895276143247138659',
'182374596560912748974586321357461982846297135291853674619728453738645219425139867',
'983076254257948631641325789764851923832697415195234867378412596529763148416589372',
'417356298253891764986247351734962185109578432825413976692135847371684529548729613',
'374186259815294736692357814987435621251968473436721598128543067769812345543679182',
'576138249142697385893542716358271964264389157719456032425913678681725493937864521',
'368579124541268793729413856196735402257846931483921675972654318635187249814392567',
'149872356356914287728563914213496578685137429497258631962381745874625193531749062',
'854621937327498651691537248273159864148263795965874123786342519539706482412985376',
'531276849764918325928435761279341658485697132613852974307184296196523487842769513',
'403785162875621493162943857514892376236457918987136245648379521321564789759218634',
'831945726692738451074612983129863574753294168468571392917486235385129647246357819',
'821350769643927815759861432295618374376549128184273596438796251912435687567182943',
'519382647634795281287146953390451876768239514451678392826914735943567128175823469',
'628457931491623785357918624513742869764891253982365417146589372279136548835274106',
'937045128182937546564128973471562389693871254825394761318756492259483617746219835',
'863972154142856793795413268386241975254697831970385642437129586518764329629538417',
'395864712621739548478152396984327651756941023213586479542693187837215964169478235',
'549738261201954378378162954726591483184326597953487612692873145815249736437615829',
'948726351351948672762015948827463519416592783593871426135684297274139865689257134',
'532184679691273845478659213243917586156328794987465132365801427829746351714532968',
'874251936653798214192346758915423687287165493436879125021534869368917542549682371',
'873195462149286735625374189254069317387512694916743528531428976762951843498637251',
'145986237379214586268573914534897621791640853826135749452369178613758492987421365',
'593461278486273519712598630159327486634185927278649351327914865845736192961852743',
'786251943439687512521943867692438751147596238853712694975324186360179425214865379',
'468523179592417368137968542715234986843679215906185734271896453384752691659341827',
'762591834583246791149073652437928165916357428258164973374685219821739546695412387',
'492317568586924713317658294728193456645872931130465872261749385874531629953286147',
'372459681689271543145683729268397154794516832513824967926148375057932416431765298',
'156324789794851632832679415579482361463517298281936547318245976645798123907163854',
'136589742428371695579246813654813279287954361903627584361795428895462137742138956',
'459781632368524197217639845692145783871963524503872916984356271125497368736218459',
'543928176718653429962147583135786294496532718827491365289374651351069847674815932',
'497261853813579624625348179304856912582913467961427385738192546156734298249685731',
'963527418247168593815934672321876945479352861586409327754293186638741259192685734',
'846291357371485269952763814785324196613978542029516783198637425234859671567142938',
'712943568956728134843561972395470681428316795671859243534297816269184357187635429',
'739214685516873904248659317673592841921748536854361279185426793397185462462937158',
'596483127321795864487126935813942576659317480742658319264839751135274698978561243',
'862397145453621790971458326328964517145783962697215483589172634736849251214536879',
'159873246276154398384296715765348921892617504413529867527431689948762153631985472',
'351692784879345261642781359984263175726519843135874926467130592518926437293457618',
'592786341613542978748193625481239756965874132327651894856327419139465087274918563',
'453698721289317456167452893876243905321975684945861372692584137738126549514739268',
'759638241138942675264751839941587326382164597576293418493875162817426950625319784',
'136758924854239176972641035329867451567314298418925367243176589795482613681593742',
'875623194931584762264179583358946271129357648746218359617492835593861427482735016',
'548796132372518694169234875256971348487623519903845726821457963795362481634189257',
'952368741834719562761542398375481609246975813189236475623894157517623984498157236',
'178562943693174852542938671257689134364751298819423567986247315421395786735806429',
'327649815541827936968513247472961058185374629639285174794138562253796481816452793',
'184327596963485712725961380698534127471892635532716849349678251256143978817259463',
'953628174871493625624571389495786231012359468368214597289165743147832956536947812',
'231864597598137462746295813385921674967458031412376985673549128124683759859712346',
'961253784753849261428671359284765193135492670679318425596124837342587916817936542',
'906437251214865937537129684453216798762948315891573426675391842328754169149682573',
'728304159594718632613925874437286915186597423259431768972643581845172396361859247',
'397824516285613947416597832651742389749381605823956471168475293932168754574239168',
'358792461741306295269541783593417826872659134614238579136824957427965318985173642',
'265893741974512368138476592893164275657230814412785936521347689389621457746958123',
'821476395763259184549813276935162748287945631416380529192534867378691452654728913',
'637529481891473265245168397476982153152346879389715642518637924964251738723094516',
'947853126816927435325416879504178692189362547672549381491735268258694713763281954',
'546823971792641853381579426125387649473196285968452307859764132237918564614235798',
'871362594569174328342859716954631287107485639683927451738216945415793862296548173',
'158726934724593168963841725896172543412635897537984216675019482341258679289467351',
'174239658956478231308165497431597862265843179789612345513786924647921583892354716',
'576481329493527681128963547712304865835716492649852173957638214284175936361249758',
'047182356528693147163574892296851734351467289784239561419325678875916423632748915',
'652137984718954632349862517895426173164783259273591468487619025531248796926375841',
'463958127971243856258617493719586342342791685685324971824130769197462538536879214',
'726983415914765238538142697642597183891234576357806924173659842485321769269478351',
'195623487384597261762418395679284153248135976513769842420956738936872514857341629',
'892457163316829547574613928238791456149365782657248319921576804485932671763184295',
'356942187471863529289571346628359714197284635543617892965438271732190468814726953',
'439278156156934872827156934295683417641527398783419265962741583518362749374895601',
'493215768687943215521678349768594123314826957902731684136489572245367891879152436',
'864932751517486239923571486395014627742693518186725943431267895278359164659148372',
'317269450485713269926458317591836724874921635632547981148392576753684192269175843',
'642589317175326498893741526964208731357914682218673954786195243531462879429837165',
'734825961195476832286913574479658213321749685568231749652184397917362408843597126',
'375642981861739254249158673584396712617284395923571468798413526456027139132965847',
'594137286782496351136582974845679123329814567617253498273961845468325719951740632',
'694857123751932486283164579169085734527643918348791265816479352475326891932518647',
'421356798795824316836917245269435871157698423380271659573162984942583167618749532',
'419582763583746912267913845394675128871234596652198374038421657746859231125367489',
'632897415485316729719425836148659372263741958957283641371962584826534107594178263',
'325748196178296435649513278264871359583629741017354682756482913431965827892137564',
'546921380197384526238576941713468259859213674624795138982637415461852793375149862',
'195746832623859174748132956251368749967425381384971265876214593519083427432597618']
//#endregion

var init = () => {
    ///////////////////
    // Setup
    currency = theory.createCurrency("⋆", "\star");

    theory.secondaryEquationHeight = 100;

    ///////////////////
    // Sudoku variables

    // easy
    {
        let getDesc = () => "Easy difficulty (gain " + REWARD_EASY + " ⋆)";
        let getInfo = () => "Open a sudoku with an easy difficulty";
        easy = theory.createUpgrade(0, currency, new FreeCost());
        easy.getDescription = (_) =>getDesc();
        easy.getInfo = (amount) => getInfo();
        easy.bought = (amount) => { 
            easy.level -= amount;
            if (!isPopupOpen) {
                difficulty = EASY;
                showSudokuPopup(EASY);
            }
                
        };
    }

    // medium
    {
        let getDesc = () => "Medium difficulty (gain " + REWARD_MEDIUM + " ⋆)";
        let getInfo = () => "Open a sudoku with a medium difficulty";
        medium = theory.createUpgrade(1, currency, new FreeCost());
        medium.getDescription = (_) =>getDesc();
        medium.getInfo = (amount) => getInfo();
        medium.bought = (amount) => { 
            medium.level -= amount;
            if (!isPopupOpen) {
                difficulty = MEDIUM;
                showSudokuPopup(MEDIUM);
            }
        };
    }

    // hard
    {
        let getDesc = () => "Hard difficulty (gain " + REWARD_HARD + " ⋆)";
        let getInfo = () => "Open a sudoku with a hard difficulty";
        hard = theory.createUpgrade(2, currency, new FreeCost());
        hard.getDescription = (_) =>getDesc();
        hard.getInfo = (amount) => getInfo();
        hard.bought = (amount) => { 
            hard.level -= amount;
            if (!isPopupOpen) {
                difficulty = HARD;
                showSudokuPopup(HARD);
            }
        };
    }

    // expert
    {
        let getDesc = () => "Expert difficulty (gain " + REWARD_EXPERT + " ⋆)";
        let getInfo = () => "Open a sudoku with an expert difficulty";
        expert = theory.createUpgrade(3, currency, new FreeCost());
        expert.getDescription = (_) =>getDesc();
        expert.getInfo = (amount) => getInfo();
        expert.bought = (amount) => { 
            expert.level -= amount;
            if (!isPopupOpen) {
                difficulty = EXPERT;
                showSudokuPopup(EXPERT);
            }
        };
    }

    // omega
    {
        let getDesc = () => "Omega difficulty (gain " + REWARD_OMEGA + " ⋆)";
        let getInfo = () => "Open a sudoku with an omega difficulty";
        omega = theory.createUpgrade(4, currency, new FreeCost());
        omega.getDescription = (_) =>getDesc();
        omega.getInfo = (amount) => getInfo();
        omega.bought = (amount) => { 
            omega.level -= amount;
            if (!isPopupOpen) {
                difficulty = OMEGA;
                showSudokuPopup(OMEGA);
            }
        };
    }

    // devilish
    {
        let getDesc = () => "Devilish difficulty (gain " + REWARD_DEVILISH + " ⋆)";
        let getInfo = () => "Open a sudoku with a devilish difficulty";
        devilish = theory.createUpgrade(5, currency, new FreeCost());
        devilish.getDescription = (_) =>getDesc();
        devilish.getInfo = (amount) => getInfo();
        devilish.bought = (amount) => { 
            devilish.level -= amount;
            if (!isPopupOpen) {
                difficulty = DEVILISH;
                showSudokuPopup(DEVILISH);
            }
        };
    }

    // test
{
    let getDesc = () => "Test difficulty (gain " + REWARD_TEST + " ⋆)";
    let getInfo = () => "Almost solved Sudokus for testing purposes";
    test = theory.createUpgrade(6, currency, new FreeCost());
    test.getDescription = (_) =>getDesc();
    test.getInfo = (amount) => getInfo();
    test.bought = (amount) => { 
        test.level -= amount;
        if (!isPopupOpen) {
            difficulty = TEST;
            showSudokuPopup(TEST);
        }
    };
}
        
    ///////////////
    // Achievements

    // Planned for the full release (or late beta)
}

//#region Theory Code
var tick = (elapsedTime, multiplier) => {
    if (gameGrid && gameGrid.width > 0 && gameGrid.heightRequest < 0) 
        gameGrid.heightRequest = Math.max(gameGrid.width, 0);

    //log("elapsedTime: " + elapsedTime + ", multiplier: " + multiplier + " , elapsedTime * multiplier = " + elapsedTime * multiplier);

    if(currentStartTime != null) {
        updateTimerLabel();
    }
}


var getInternalState = () => {
    // save all difficulty board states and undo/redo stacks
    log("Saving...");

    // Save currently running timer in case of shutdown and reset current start time
    updateTimerInSave();

    var saveArray = [easyBoard, mediumBoard, hardBoard, expertBoard, omegaBoard, devilishBoard, testBoard,
        easyUndoStack, mediumUndoStack, hardUndoStack, expertUndoStack, omegaUndoStack, devilishUndoStack, testUndoStack,
        easyRedoStack, mediumRedoStack, hardRedoStack, expertRedoStack, omegaRedoStack, devilishRedoStack, testRedoStack,
        easyTimer, mediumTimer, hardTimer, expertTimer, omegaTimer, devilishTimer, testTimer,
        easyBestTimer, mediumBestTimer, hardBestTimer, expertBestTimer, omegaBestTimer, devilishBestTimer, testBestTimer];
    var saveState = JSON.stringify(saveArray);

    //log(saveState);

    return saveState;
}

var setInternalState = (state) => {
    // restore all difficulty board states and undo/redo stacks
    log("Restoring...");

    var saveState = JSON.parse(state);

    //log(saveState);

    easyBoard = saveState[0];
    mediumBoard = saveState[1];
    hardBoard = saveState[2];
    expertBoard = saveState[3];
    omegaBoard = saveState[4];
    devilishBoard = saveState[5];
    testBoard = saveState[6];

    easyUndoStack = saveState[7];
    mediumUndoStack = saveState[8];
    hardUndoStack = saveState[9];
    expertUndoStack = saveState[10];
    omegaUndoStack = saveState[11];
    devilishUndoStack = saveState[12];
    testUndoStack = saveState[13];

    easyRedoStack = saveState[14];
    mediumRedoStack = saveState[15];
    hardRedoStack = saveState[16];
    expertRedoStack = saveState[17];
    omegaRedoStack = saveState[18];
    devilishRedoStack = saveState[19];
    testRedoStack = saveState[20];

    easyTimer = saveState[21];
    mediumTimer = saveState[22];
    hardTimer = saveState[23];
    expertTimer = saveState[24];
    omegaTimer = saveState[25];
    devilishTimer = saveState[26];
    testTimer = saveState[27];

    easyBestTimer = saveState[28];
    mediumBestTimer = saveState[29];
    hardBestTimer = saveState[30];
    expertBestTimer = saveState[31];
    omegaBestTimer = saveState[32];
    devilishBestTimer = saveState[33];
    testBestTimer = saveState[34];
}

var getPrimaryEquation = () => {
    return "\\text{Select\\ a\\ difficulty\\ to\\ play\\ a\\ random\\ Sudoku}";
}

var getSecondaryEquation = () => {
    return "\\text{The goal of a Sudoku is to place numbers such that \\\\ each number between 1 and 9 appears exactly once \\\\ in each row, column or 3x3 box.}";
}

var getTau = () => currency.value;

var rewardForDifficulty = (difficulty) => {
    var reward = 0;
    switch(difficulty) {
        case EASY:
            reward = REWARD_EASY;
            break;
        case MEDIUM:
            reward = REWARD_MEDIUM;
            break;
        case HARD:
            reward = REWARD_HARD;
            break;
        case EXPERT:
            reward = REWARD_EXPERT;
            break;
        case OMEGA:
            reward = REWARD_OMEGA;
            break;
        case DEVILISH:
            reward = REWARD_DEVILISH;
            break;
        case TEST:
            reward = REWARD_TEST;
            break;
        default:
            throw new Error("Unrecognized difficulty " + difficulty + "; cannot proceed");
    }

    return reward;
}

var increaseCurrency = (reward) => {
    currency.value += reward;
}

var resetDifficulty = (difficulty) => {
    resetUndoRedoStacks(difficulty);
    resetTimer(difficulty);
    switch(difficulty) {
        case EASY:
            easyBoard = null;
            break;
        case MEDIUM:
            mediumBoard = null;
            break;
        case HARD:
            hardBoard = null;
            break;
        case EXPERT:
            expertBoard = null;
            break;
        case OMEGA:
            omegaBoard = null;
            break;
        case DEVILISH:
            devilishBoard = null;
            break;
        case TEST:
            testBoard = null;
            break;
        default:
            throw new Error("Unrecognized difficulty " + difficulty + "; cannot proceed");
    }
}

var isFinished = (difficulty) => {
    switch(difficulty) {
        case EASY:
            return easyBoard == null;
        case MEDIUM:
            return mediumBoard == null;
        case HARD:
            return hardBoard == null;
        case EXPERT:
            return expertBoard == null;
        case OMEGA:
            return omegaBoard == null;
        case DEVILISH:
            return devilishBoard == null;
        case TEST:
            return testBoard == null;
        default:
            throw new Error("Unrecognized difficulty " + difficulty + "; cannot proceed");
    }
}

init();
//#endregion

//#region UI Utility
var getBackgroundColor = (preset) => {
    switch(game.settings.theme) {
        case Theme.STANDARD:
            if(preset)
                return Color.fromRgb(0.2, 0.2, 0.2);
            return Color.fromRgb(0.4, 0.4, 0.4);
        case Theme.DARK:
            if(preset)
                return Color.fromRgb(0.3, 0.3, 0.3);
            return Color.fromRgb(0, 0, 0);
        case Theme.LIGHT:
            if(preset)
                return Color.fromRgb(0.7, 0.7, 0.7);
            return Color.fromRgb(1, 1, 1);
    }
}

/**
 * Selects a red background color for cells containing invalid numbers.
 * The color is adjusted according to theme and will be different for given and open cells.
 * @param {*} preset If the given square is representing a given number
 * @returns A red color, differing according to the theme and if it is a given or open cell
 */
var getInvalidBackgroundColor = (preset) => {
    switch(game.settings.theme) {
        case Theme.STANDARD:
            if(preset)
                return Color.fromRgb(0.5, 0.2, 0.2);
            return Color.fromRgb(0.7, 0.4, 0.4);
        case Theme.DARK:
            if(preset)
                return Color.fromRgb(0.9, 0.3, 0.3);
            return Color.fromRgb(0.5, 0, 0);
        case Theme.LIGHT:
            if(preset)
                return Color.fromRgb(0.9, 0.3, 0.3);
            return Color.fromRgb(1, 0.7, 0.7);
    }
}

var resetBackgroundColors = () => {
    for (var square of gameGrid.children) {
        var cell = board[getBoardNum(square.row, square.column)];
        square.backgroundColor = getBackgroundColor(cell.isGiven)
    }
}

var getBorderColor = () => {
    switch(game.settings.theme) {
        case Theme.STANDARD:
            return Color.fromRgb(0.7, 0.7, 0.7);
        case Theme.DARK:
            return Color.fromRgb(0.8, 0.8, 0.8);
        case Theme.LIGHT:
            return Color.fromRgb(0.3, 0.3, 0.3);
    }
}

var getSelectedBorderColor = () => {
    switch(game.settings.theme) {
        case Theme.STANDARD:
            return Color.fromRgb(0, 0, 1);
        case Theme.DARK:
            return Color.fromRgb(1, 0, 0);
        case Theme.LIGHT:
            return Color.fromRgb(0, 0, 1);
    }
}

var markInvalidCells = (wrongCells) => {
    for (var wrongCell of wrongCells) {
        var row = wrongCell[0];
        var column = wrongCell[1];
        var wrongSquare = gameGrid.children[row * 9 + column];
        //log("(" + row + "," + column + "): " + wrongSquare.content.children[0].text);
        var isGiven = board[row * 9 + column].isGiven;
        wrongSquare.backgroundColor = getInvalidBackgroundColor(isGiven);
    }
}

/**
 * Gets the currently used time for the open puzzle (if existing) and updates the timer.
 * It will also reset the current start time to now.
 * @returns 
 */
var updateTimerInSave = () => {
    // No puzzle open or not started
    if(difficulty == undefined || difficulty == null || currentStartTime == null)
        return;

    var timer = getTimerForDifficulty(difficulty);

    log(timer.time);

    var elapsedTime = getElapsedTime(timer);

    timer.time = elapsedTime;

    log(timer.time);
    
    // TODO: save hints when implemented

    currentStartTime = Date.now();
}

var UpdateBoardAndSquare = (cell, cellIndex) => {
    board[cellIndex] = cell;

    var square = GetSquare(cellIndex);
    updateSquareFromCell(square, cell);
}

var GetSquare = (index) => {
    return gameGrid.children[index];
}

let markFontSize = 12;

var createSquare = (i, j, cell) => {
    let number = ui.createLabel({
        fontSize: 30,
        horizontalOptions: LayoutOptions.CENTER,
        verticalOptions: LayoutOptions.CENTER,
        text: cell.number < 1 ? "" : `${cell.number}`,
    });

    let pencilMarks = [];
    let layoutOptions = [LayoutOptions.START, LayoutOptions.CENTER, LayoutOptions.END]
    for (let v = 0; v < layoutOptions.length; v++) {
        for (let h = 0; h < layoutOptions.length; h++) {
            if(h == 1 && v != 1 || h != 1 && v == 1)
                continue;

            let markLabel = ui.createLabel({
                fontSize: markFontSize,
                horizontalOptions: layoutOptions[h],
                verticalOptions: layoutOptions[v]
            });

            pencilMarks.push(markLabel);
        }
    }

    let markGrid = ui.createGrid({
        children: pencilMarks
    });

    var square = ui.createFrame({
        row: i,
        column: j,
        margin: new Thickness(1, 1, j % 3 == 2 ? 4 : 1, i % 3 == 2 ? 4 : 1),
        backgroundColor: getBackgroundColor(cell.isGiven),
        borderColor: getBorderColor(),
        content: ui.createGrid({
            children: [number, markGrid]
        }),
    });

    if(isEmpty(cell)) {
        if(cell.cornerMarks.length > 0)
            setCornerNumbers(cell, square.content);
        
        if(cell.centerMarks.length > 0)
            setCenterNumbers(cell, square.content);
    }

    square.onTouched = (e) => {
        if (e.type == TouchType.PRESSED) {
            if(isFinished(difficulty))
                return;

            if(selectedGivenSquare != null) {
                selectedGivenSquare.borderColor = getBorderColor();
            }

            if(selectedSquare != null) {
                selectedSquare.borderColor = getBorderColor();
            }

            if(cell.isGiven) {
                selectedGivenSquare = square;
                selectedSquare = null;
            } 
            else{
                selectedSquare = square;
                selectedGivenSquare = null;
            }
            
            square.borderColor = getSelectedBorderColor();
        }
    }

    return square;
}

var createGameGrid = (board) => {
    gameGrid = ui.createGrid({
        columnSpacing: 1,
        rowSpacing: 1,
    });
    let c = [];
    for (let x = 0; x < 9; x++) {
        for (let y = 0; y < 9; y++) {
            var cell = board[getBoardNum(x, y)];
            var square = createSquare(x, y, cell);
            c.push(square);
        }
    }
    gameGrid.children = c;

    return gameGrid;
}

var createNumberButtonsGrid = (difficulty, board, stateLabel) => {
    let numberButtons = [];
    for(let i = 1; i <= 9; i++) {
        var numberButton = ui.createButton({
            row: 0,
            column: i - 1,
            text: `${i}`,
            onClicked: () => {
                if(selectedSquare === null || isFinished(difficulty))
                    return;

                log("clicked " + i + " for mode " + textForMode(mode) + " and square (" + selectedSquare.row + "," + selectedSquare.column + ")");

                if(currentStartTime == null) {
                    currentStartTime = Date.now();
                }

                var cellIndex = getBoardNum(selectedSquare.row, selectedSquare.column);
                var cell = board[cellIndex];
                
                addToUndoStack(difficulty, cell, cellIndex);
                resetRedoStack(difficulty);

                setNumber(i, board, selectedSquare.row, selectedSquare.column);
                if(mode != NORMAL_MODE)
                    return;

                resetBackgroundColors();

                var checkResult = checkBoard(board);
                var fullBoard = hasAllNumbers(board);
                if(checkResult[0] && fullBoard) {
                    var timer = getTimerForDifficulty(difficulty);
                    var elapsedTime = getElapsedTime(timer);

                    timer.time = elapsedTime;

                    var timerString = TimerAsString(timer);

                    UpdateTimerIfBetter(difficulty);

                    log("Won " + difficulty + " in " + timerString);
                    var stars = rewardForDifficulty(difficulty);
                    increaseCurrency(stars);
                    stateLabel.text = "Congratulations! You won " + stars + " stars as a reward.";
                    resetDifficulty(difficulty);
                    undoButton.isEnabled = false;

                    gameGrid.FadeTo(0.5, 10);
                } 
                else {
                    if(fullBoard)
                        stateLabel.text = "Solution is incorrect!";

                    markInvalidCells(checkResult[1]);
                }
            }
        });
        numberButtons.push(numberButton);
    }

    let numberButtonGrid = ui.createGrid({
        children: numberButtons
    });

    return numberButtonGrid;
}

var createButtonsGrid = (difficulty) => {
    let buttons = [null, null, null, null, null, null];
    
    buttons[0] = ui.createButton({
        row: 0,
        column: 0,
        text: "Clear",
        onClicked: () => {
            if(selectedSquare === null || isFinished(difficulty))
                return;

            var cellIndex = getBoardNum(selectedSquare.row, selectedSquare.column);
            var cell = board[cellIndex];
            
            addToUndoStack(difficulty, cell, cellIndex);
            resetRedoStack(difficulty);

            clearCell(board, selectedSquare.row, selectedSquare.column, selectedSquare.content);
            
            resetBackgroundColors();

            var checkResult = checkBoard(board);
            if(checkResult[1].size > 0)
                markInvalidCells(checkResult[1]);
        }
    });
    
    buttons[1] = ui.createButton({
        row: 0,
        column: 1,
        text: textForMode(mode),
        onClicked: () => {
            log("Pressed Mode");
            mode = (mode + 1) % 3;
            buttons[1].text = textForMode(mode);
        }
    });

    buttons[2] = ui.createButton({
        row: 0,
        column: 2,
        text: "Replay",
        onClicked: () => {
            //reset timer etc.
            log("Pressed Replay");

            clearAndSetBoard(difficulty);
        }
    });

    undoButton = ui.createButton({
        row: 1,
        column: 0,
        text: "Undo",
        onClicked: () => {
            log("Pressed Undo");

            undo(difficulty);
        }
    });
    undoButton.isEnabled = getStackForModeAndDifficulty(difficulty, UNDO_MODE).length > 0;
    buttons[3] = undoButton;

    redoButton = ui.createButton({
        row: 1,
        column: 1,
        text: "Redo",
        onClicked: () => {
            log("Pressed Redo");

            redo(difficulty);
        }
    });
    redoButton.isEnabled = getStackForModeAndDifficulty(difficulty, REDO_MODE).length > 0;
    buttons[4] = redoButton;

    buttons[5] = ui.createButton({
        row: 1,
        column: 2,
        text: "Hint (+10s)",
        onClicked: () => {
            log("Pressed Hint");
            hintLabel.text = "Hint: not implemented";
        }
    });
    buttons[5].isEnabled = false;

    let buttonGrid = ui.createGrid({
        columnDefinitions: ["1*", "1*", "1*"],
        rowDefinitions: ["1*", "1*"],
        children: buttons
    });

    return buttonGrid;
}

var createPopupUI = (difficulty, board) => {
    var gameGrid = createGameGrid(board);

    var currentTimer = getTimerForDifficulty(difficulty);
    var currentTimerString = TimerAsString(currentTimer);

    var timerString = "Time: " + currentTimerString;

    var bestTimer = getBestTimerForDifficulty(difficulty);
    var bestTimerReadable = TimerAsString(bestTimer);

    var bestTimerString = "Best Time: " + bestTimerReadable;

    timerLabel = ui.createLatexLabel({text: timerString, horizontalTextAlignment: TextAlignment.CENTER, margin: new Thickness(0, 5, 0, 5)});
    bestTimeLabel = ui.createLatexLabel({text: bestTimerString, horizontalTextAlignment: TextAlignment.CENTER, margin: new Thickness(0, 3, 0, 5)});
    hintLabel = ui.createLatexLabel({text: "Hint: not included in Alpha", horizontalTextAlignment: TextAlignment.CENTER, margin: new Thickness(0, 3, 0, 5)});
    var stateLabel = ui.createLatexLabel({text: "Solve for " + rewardForDifficulty(difficulty) + " stars", horizontalTextAlignment: TextAlignment.CENTER, margin: new Thickness(0, 3, 0, 5)});

    var numberButtonGrid = createNumberButtonsGrid(difficulty, board, stateLabel);
    var buttonGrid = createButtonsGrid(difficulty);

    popup = ui.createPopup({
        title: `Sudoku - ${difficulty}`,
        closeOnBackgroundClicked: false,
        content: ui.createStackLayout({
            children: [
                timerLabel,
                bestTimeLabel,
                hintLabel,
                stateLabel,
                gameGrid,
                numberButtonGrid,
                buttonGrid
            ]
        }),
        onDisappearing: () => {
            log("Popup closed");

            // When closed by us after pressing "Replay" timer is already taken care of
            if(currentStartTime != null){
                var timer = getTimerForDifficulty(difficulty);
                var elapsedTime = getElapsedTime(timer);

                timer.time = elapsedTime;

                currentStartTime = null;
            }
            else {
                difficulty == undefined;
            }
        }
    });

    var checkResult = checkBoard(board);
    if(checkResult[1].size > 0)
        markInvalidCells(checkResult[1]);

    return popup;
}

var popup = null;
var selectedGivenSquare = null;
var selectedSquare = null;
var mode = NORMAL_MODE;

var textForMode = (mode) => {
    switch(mode) {
        case NORMAL_MODE:
            return "Normal";
        case CORNER_MODE:
            return "Corners";
        case CENTER_MODE:
            return "Center";
        default:
            throw new Error("Unknown mode! Cannot continue execution.");
    }
}
//#endregion

//#region UI Sudoku Popup
var showSudokuPopup = (difficulty) => {
    selectedSquare = null;
    mode = NORMAL_MODE;
    board = getBoard(difficulty)

    var popup = createPopupUI(difficulty, board);

    popup.show();
}
//#endregion

//#region Sudoku Minigame Utility
var getBoard = (difficulty) => {
    var randomBoard = null;
    switch(difficulty) {
        case EASY:
            if(easyBoard == null || easyBoard.length == 0) {       
                randomBoard = getRandomBoard(difficulty);
                easyBoard = generate(randomBoard);
            }
            return easyBoard;
        case MEDIUM:
            if(mediumBoard == null || mediumBoard.length == 0) {       
                randomBoard = getRandomBoard(difficulty);
                mediumBoard = generate(randomBoard);
            }
            return mediumBoard;
        case HARD:
            if(hardBoard == null || hardBoard.length == 0) {       
                randomBoard = getRandomBoard(difficulty);
                hardBoard = generate(randomBoard);
            }
            return hardBoard;
        case EXPERT:
            if(expertBoard == null || expertBoard.length == 0) {       
                randomBoard = getRandomBoard(difficulty);
                expertBoard = generate(randomBoard);
            }
            return expertBoard;
        case OMEGA:
            if(omegaBoard == null || omegaBoard.length == 0) {       
                randomBoard = getRandomBoard(difficulty);
                omegaBoard = generate(randomBoard);
            }
            return omegaBoard;
        case DEVILISH:
            if(devilishBoard == null || devilishBoard.length == 0) {       
                randomBoard = getRandomBoard(difficulty);
                devilishBoard = generate(randomBoard);
            }
            return devilishBoard;
        case TEST:
            if(testBoard == null || testBoard.length == 0) {       
                randomBoard = getRandomBoard(difficulty);
                testBoard = generate(randomBoard);
            }
            return testBoard;
        default:
            throw new Error("Unrecognized difficulty " + difficulty + "; cannot proceed");
    }
}

var clearAndSetBoard = (difficulty) => {
    board = null;
    selectedSquare = null;
    mode = NORMAL_MODE;

    resetDifficulty(difficulty);

    board = getBoard(difficulty);

    // TODO: maybe invest the effort to use the existing popup
    popup.hide();
    popup = createPopupUI(difficulty, board);
    popup.show();
}

var checkBoard = (board) => {
    return checkForDuplicates(board, hasAllNumbers(board));
}

var setNormalNumber = (number, cell, gridCellContent) => {
    if(cell.number == number) {
        cell.number = 0;
        cell.cornerMarks = []
        cell.centerMarks = []
        gridCellContent.children[0].text = "";
        return;
    }

    var marksGrid = gridCellContent.children[1];
    for(var j = 0; j < marksGrid.children.length; j++) {
        marksGrid.children[j].text = ""
    }
    cell.number = number;
    gridCellContent.children[0].text = `${number}`
}

var setNormalNumberFromCell = (cell, gridCellContent) => {
    if(cell.number < 1) {
        gridCellContent.children[0].text = "";
        return;
    }

    var marksGrid = gridCellContent.children[1];
    for(var j = 0; j < marksGrid.children.length; j++) {
        marksGrid.children[j].text = ""
    }

    gridCellContent.children[0].text = `${cell.number}`
}

var clearCornerNumbers = (gridCellContent) => {
    for (let i of [0, 1, 3, 4]) {
        gridCellContent.children[1].children[i].text = "";
    }    
}

var setCornerNumbers = (cell, gridCellContent) => {
    let markIndices = [0, 1, 3, 4, 0, 1, 3, 4, 4]
    for(let i = 0; i < cell.cornerMarks.length; i++) {                  
        var markIndex = markIndices[i];

        if(i <= 3) {
            gridCellContent.children[1].children[markIndex].text = [0, 3].includes(markIndex)
                ? ` ${cell.cornerMarks[i]}` 
                : `${cell.cornerMarks[i]} `;
        }
        else {
            gridCellContent.children[1].children[markIndex].text += [0, 3].includes(markIndex)
                ? ` ${cell.cornerMarks[i]}` 
                : `${cell.cornerMarks[i]} `;
        }
    }
}

var setCornerNumber = (number, cell, gridCellContent) => {
    if(!isEmpty(cell))
        return;

    if(cell.cornerMarks.length == 0) {
        cell.cornerMarks.push(number);
        gridCellContent.children[1].children[0].text = ` ${number}`;
        return;
    }

    if(cell.cornerMarks.includes(number)) {
        log(cell.cornerMarks.join(', '));
        cell.cornerMarks.splice(cell.cornerMarks.indexOf(number), 1);
        log(cell.cornerMarks.join(', '));
    } else {
        cell.cornerMarks.push(number);
        cell.cornerMarks.sort();
    }
    
    clearCornerNumbers(selectedSquare.content);
    setCornerNumbers(cell, selectedSquare.content);
}

var setCornerNumbersFromCell = (cell, square, clearBeforeSet) => {
    if(!isEmpty(cell))
        return;

    if(cell.cornerMarks.length == 0)
        return;
  
    if(clearBeforeSet)
        clearCornerNumbers(square.content);

    setCornerNumbers(cell, square.content);
}

var clearCenterNumbers = (gridCellContent) => {
    gridCellContent.children[1].children[2].text = "";
}

var setCenterNumbers = (cell, gridCellContent) => {
    gridCellContent.children[1].children[2].text = cell.centerMarks.join('');
}

var setCenterNumber = (number, cell, gridCellContent) => {
    if(!isEmpty(cell))
        return;

    if(cell.centerMarks.length == 0) {
        cell.centerMarks.push(number);
        gridCellContent.children[1].children[2].text = `${number}`;
        return;
    }

    if(cell.centerMarks.includes(number)) {
        cell.centerMarks.splice(cell.centerMarks.indexOf(number), 1);
    } else {
        cell.centerMarks.push(number);
        cell.centerMarks.sort();
    }

    setCenterNumbers(cell, gridCellContent);
}

var setCenterNumbersFromCell = (cell, square) => {
    if(!isEmpty(cell))
        return;

    if(cell.centerMarks.length == 0)
        return;

    setCenterNumbers(cell, square.content);
}

var setNumber = (number, board, r, c) => {
    if(selectedSquare != null) {
        var cell = board[getBoardNum(r, c)];
        switch (mode) {
            case NORMAL_MODE:
                setNormalNumber(number, cell, selectedSquare.content);
                break;
            case CORNER_MODE:
                setCornerNumber(number, cell, selectedSquare.content);
                break;
            case CENTER_MODE:
                setCenterNumber(number, cell, selectedSquare.content);
                break;
            default:
                break;
        } 
    }
}

/**
 * Updates the UI of a square according to the values of a given cell
 * @param {*} square 
 * @param {*} cell 
 */
var updateSquareFromCell = (square, cell) => { 
    clearSquare(square.content);

    setNormalNumberFromCell(cell, square.content);

    if(cell.number >= 1)
        return;

    setCornerNumbersFromCell(cell, square, false);
    setCenterNumbersFromCell(cell, square);
}

/**
 * Resets the UI for a square (removing any number, corner- and center marks)
 * @param {*} gridCellContent 
 */
var clearSquare = (gridCellContent) => {
    gridCellContent.children[0].text = "";
    clearCornerNumbers(gridCellContent);
    clearCenterNumbers(gridCellContent);
}

/**
 * Resets a cell and updates the UI accordingly
 * @param {*} board 
 * @param {*} r 
 * @param {*} c 
 * @param {*} gridCellContent 
 */
var clearCell = (board, r, c, gridCellContent) => {
    var cell = board[getBoardNum(r, c)];
    cell.number = 0;
    cell.cornerMarks = [];
    cell.centerMarks = [];
    clearSquare(gridCellContent);
}

var increaseCurrency = (reward) => {
    currency.value += reward;
}

var getStackForModeAndDifficulty = (difficulty, operationMode) => {
    var difficultyStack;
    switch(difficulty) {
        case EASY:
            if(operationMode == UNDO_MODE){
                if(easyUndoStack == null)
                    easyUndoStack = [];
                
                difficultyStack = easyUndoStack;
            } 
            else if (operationMode == REDO_MODE) {
                if(easyRedoStack == null)
                    easyRedoStack = [];
                
                difficultyStack = easyRedoStack;
            }
            else{
                throw new Error("Unrecognized operationMode " + operationMode + "; cannot proceed");
            }
            break;
        case MEDIUM:
            if(operationMode == UNDO_MODE){
                if(mediumUndoStack == null)
                    mediumUndoStack = [];
                
                difficultyStack = mediumUndoStack;
            } 
            else if (operationMode == REDO_MODE) {
                if(mediumRedoStack == null)
                    mediumRedoStack = [];
                
                difficultyStack = mediumRedoStack;
            }
            else{
                throw new Error("Unrecognized operationMode " + operationMode + "; cannot proceed");
            }
            break;
        case HARD:
            if(operationMode == UNDO_MODE){
                if(hardUndoStack == null)
                    hardUndoStack = [];
                
                difficultyStack = hardUndoStack;
            } 
            else if (operationMode == REDO_MODE) {
                if(hardRedoStack == null)
                    hardRedoStack = [];
                
                difficultyStack = hardRedoStack;
            }
            else{
                throw new Error("Unrecognized operationMode " + operationMode + "; cannot proceed");
            }
            break;
        case EXPERT:
            if(operationMode == UNDO_MODE){
                if(expertUndoStack == null)
                    expertUndoStack = [];
                
                difficultyStack = expertUndoStack;
            } 
            else if (operationMode == REDO_MODE) {
                if(expertRedoStack == null)
                    expertRedoStack = [];
                
                difficultyStack = expertRedoStack;
            }
            else{
                throw new Error("Unrecognized operationMode " + operationMode + "; cannot proceed");
            }
            break;
        case OMEGA:
            if(operationMode == UNDO_MODE){
                if(omegaUndoStack == null)
                    omegaUndoStack = [];
                
                difficultyStack = omegaUndoStack;
            } 
            else if (operationMode == REDO_MODE) {
                if(omegaRedoStack == null)
                    omegaRedoStack = [];
                
                difficultyStack = omegaRedoStack;
            }
            else{
                throw new Error("Unrecognized operationMode " + operationMode + "; cannot proceed");
            }
            break;
        case DEVILISH:
            if(operationMode == UNDO_MODE){
                if(devilishUndoStack == null)
                    devilishUndoStack = [];
                
                difficultyStack = devilishUndoStack;
            } 
            else if (operationMode == REDO_MODE) {
                if(devilishRedoStack == null)
                    devilishRedoStack = [];
                
                difficultyStack = devilishRedoStack;
            }
            else{
                throw new Error("Unrecognized operationMode " + operationMode + "; cannot proceed");
            }
            break;
        case TEST:
            if(operationMode == UNDO_MODE){
                if(testUndoStack == null)
                    testUndoStack = [];
                
                difficultyStack = testUndoStack;
            } 
            else if (operationMode == REDO_MODE) {
                if(testRedoStack == null)
                    testRedoStack = [];
                
                difficultyStack = testRedoStack;
            }
            else{
                throw new Error("Unrecognized operationMode " + operationMode + "; cannot proceed");
            }
            break;
        default:
            throw new Error("Unrecognized difficulty " + difficulty + "; cannot proceed");
    }

    return difficultyStack;
}

var resetUndoRedoStacks = (difficulty) => {
    switch(difficulty) {
        case EASY:
            easyUndoStack = [];
            easyRedoStack = [];
            break;
        case MEDIUM:
            mediumUndoStack = [];
            mediumRedoStack = [];
            break;
        case HARD:
            hardUndoStack = [];
            hardRedoStack = [];
            break;
        case EXPERT:
            expertUndoStack = [];
            expertRedoStack = [];
            break;
        case OMEGA:
            omegaUndoStack = [];
            omegaRedoStack = [];
            break;
        case DEVILISH:
            devilishUndoStack = [];
            devilishRedoStack = [];
            break;
        case TEST:
            testUndoStack = [];
            testRedoStack = [];
            break;
        default:
            throw new Error("Unrecognized difficulty " + difficulty + "; cannot proceed");
    }
}

var resetRedoStack = (difficulty) => {
    var difficultyRedoStack = getStackForModeAndDifficulty(difficulty, REDO_MODE);
    difficultyRedoStack = [];
    redoButton.isEnabled = false;
}

/**
 * For a given difficulty adds a cell to the stack containing all the previous states.
 * @param {*} difficulty The difficulty of the puzzle to select the correct stack
 * @param {*} cell The cell before an action took place, to save it for future restoration
 * @param {number} cellIndex The index of the saved cell in the board
 */
var addToUndoStack = (difficulty, cell, cellIndex) => {
    var undoState = {
        cellIndex: cellIndex,
        cell: deepcopyCell(cell)
    };

    var difficultyUndoStack = getStackForModeAndDifficulty(difficulty, UNDO_MODE);
    difficultyUndoStack.push(undoState);

    undoButton.isEnabled = true;
}

/**
 * For a given difficulty adds a cell to the stack containing all the states reverted by undo operations.
 * @param {*} difficulty The difficulty of the puzzle to select the correct stack
 * @param {*} cell The cell before an action took place, to save it for future restoration
 * @param {number} cellIndex The index of the saved cell in the board
 */
var addToRedoStack = (difficulty, cell, cellIndex) => {
    var redoState = {
        cellIndex: cellIndex,
        cell: deepcopyCell(cell)
    };

    var difficultyRedoStack = getStackForModeAndDifficulty(difficulty, REDO_MODE);
    difficultyRedoStack.push(redoState);

    redoButton.isEnabled = true;
}

/**
 * Undo the last taken action. This will pop the latest entry from the undo stack, update the board, update the UI and add the cell to the redo stack.
 * @param {*} difficulty The difficulty stack to get the previous state from
 */
var undo = (difficulty) => {
    restoreState(difficulty, UNDO_MODE);
}

/**
 * Redo the last undone action. This will pop the latest entry from the redo stack, update the board, update the UI and add the cell to the undo stack.
 * @param {*} difficulty The difficulty stack to get the previous state from
 */
var redo = (difficulty) => {
    restoreState(difficulty, REDO_MODE);
}

var restoreState = (difficulty, operationMode) => {
    if(operationMode != UNDO_MODE && operationMode != REDO_MODE)
        throw new Error("Unrecognized operation mode " + operationMode + "; cannot proceed");
    
    var difficultyStack = getStackForModeAndDifficulty(difficulty, operationMode);
    var previousState = difficultyStack.pop();
    var currentState = board[previousState.cellIndex];

    var operation = operationMode == UNDO_MODE ? "Undo" : "Redo";
    logObject(previousState, operation + " to following cell state: ");
    logObject(previousState.cell, "Cell: ");

    UpdateBoardAndSquare(previousState.cell, previousState.cellIndex);

    if(operationMode == UNDO_MODE) {
        addToRedoStack(difficulty, currentState, previousState.cellIndex);
    }
    else
    {
        addToUndoStack(difficulty, currentState, previousState.cellIndex);
    }

    log(difficultyStack.length);
    if(difficultyStack.length == 0) {
        var operationButton = operationMode == UNDO_MODE ? undoButton : redoButton;
        operationButton.isEnabled = false;
    }
        
    // Update invalid markers
    resetBackgroundColors();
    var checkResult = checkBoard(board);
    if(checkResult[1].size > 0)
        markInvalidCells(checkResult[1]);
}

var getBestTimerForDifficulty = (difficulty) => {
    switch(difficulty) {
        case EASY:
            if(easyBestTimer == null){
                easyBestTimer = {
                    time: -1,
                    hints: -1
                };
            }
            return easyBestTimer;
        case MEDIUM:
            if(mediumBestTimer == null){
                mediumBestTimer = {
                    time: -1,
                    hints: -1
                };
            }
            return mediumBestTimer;
        case HARD:
            if(hardBestTimer == null){
                hardBestTimer = {
                    time: -1,
                    hints: -1
                };
            }
            return hardBestTimer;
        case EXPERT:
            if(expertBestTimer == null){
                expertBestTimer = {
                    time: -1,
                    hints: -1
                };
            }
            return expertBestTimer;
        case OMEGA:
            if(omegaBestTimer == null){
                omegaBestTimer = {
                    time: -1,
                    hints: -1
                };
            }
            return omegaBestTimer;
        case DEVILISH:
            if(devilishBestTimer == null){
                devilishBestTimer = {
                    time: -1,
                    hints: -1
                };
            }
            return devilishBestTimer;
        case TEST:
            if(testBestTimer == null){
                testBestTimer = {
                    time: -1,
                    hints: -1
                };
            }
            return testBestTimer;
        default:
            throw new Error("Unrecognized difficulty " + difficulty + "; cannot proceed");
    }
}

var getTimerForDifficulty = (difficulty) => {
    //log("Getting timer for difficulty " + difficulty);
    switch(difficulty) {
        case EASY:
            if(easyTimer == null){
                easyTimer = {
                    time: 0,
                    hints: 0
                };
            }
            return easyTimer;
        case MEDIUM:
            if(mediumTimer == null){
                mediumTimer = {
                    time: 0,
                    hints: 0
                };
            }
            return mediumTimer;
        case HARD:
            if(hardTimer == null){
                hardTimer = {
                    time: 0,
                    hints: 0
                };
            }
            return hardTimer;
        case EXPERT:
            if(expertTimer == null){
                expertTimer = {
                    time: 0,
                    hints: 0
                };
            }
            return expertTimer;
        case OMEGA:
            if(omegaTimer == null){
                omegaTimer = {
                    time: 0,
                    hints: 0
                };
            }
            return omegaTimer;
        case DEVILISH:
            if(devilishTimer == null){
                devilishTimer = {
                    time: 0,
                    hints: 0
                };
            }
            return devilishTimer;
        case TEST:
            if(testTimer == null){
                testTimer = {
                    time: 0,
                    hints: 0
                };
            }
            return testTimer;
        default:
            throw new Error("Unrecognized difficulty " + difficulty + "; cannot proceed");
    }
}

var resetTimer = (difficulty) => {
    currentStartTime = null;

    log("Resetting timer for difficulty " + difficulty);
    switch(difficulty) {
        case EASY:
            easyTimer.time = 0;
            easyTimer.hints = 0;
            break;
        case MEDIUM:
            mediumTimer.time = 0;
            mediumTimer.hints = 0;
            break;
        case HARD:
            hardTimer.time = 0;
            hardTimer.hints = 0;
            break;
        case EXPERT:
            expertTimer.time = 0;
            expertTimer.hints = 0;
            break;
        case OMEGA:
            omegaTimer.time = 0;
            omegaTimer.hints = 0;
            break;
        case DEVILISH:
            devilishTimer.time = 0;
            devilishTimer.hints = 0;
            break;
        case TEST:
            testTimer.time = 0;
            testTimer.hints = 0;
            break;
        default:
            throw new Error("Unrecognized difficulty " + difficulty + "; cannot proceed");
    }
}

var UpdateTimerIfBetter = (difficulty) => {
    var timer = getTimerForDifficulty(difficulty);
    var bestTimer = getBestTimerForDifficulty(difficulty);

    if(bestTimer.time < 0 || timer.time < bestTimer.time || 
        timer.time == bestTimer.time && timer.hints < bestTimer.hints) {
        bestTimer.time = timer.time;
        bestTimer.hints = timer.hints;
    }
}

var getElapsedTime  = (timer) => {
    var currentTime = Date.now();
    var difference = currentTime - currentStartTime + timer.time;

    return difference;
}

var updateTimerLabel = () => {
    var timer = getTimerForDifficulty(difficulty);

    var elapsedTime = getElapsedTime(timer);

    var tempTimer = {
        time: elapsedTime,
        hints: timer.hints
    };

    //logObject(tempTimer);
    var timerString = TimerAsString(tempTimer);
    timerLabel.text = "Time: " + timerString;
}

/**
 * Converts the number of milliseconds saved in a timer into a human readable format.
 * The format is analogous to the one used for minigames, except including hours (maybe useful for really difficult puzzles):
 * hh:mm:ss:fff
 * @param {*} timer The timer to use
 * @param {bool} includeHints If true, the string will include the amount of hints used for this timer in brackets
 * @returns The time converted to a string formatted hh:mm:ss:fff or - when no time was set so far; optionally includes (X hints)
 */
var TimerAsString = (timer, includeHints) => {
    if(timer.time < 0)
        return "-";

    //log("Creating human readable form of " + timer.time);

    //Get hours from milliseconds
    var hours = timer.time / (1000 * 60 * 60);
    var absoluteHours = Math.floor(hours);
    var h = absoluteHours > 9 ? absoluteHours : '0' + absoluteHours;

    //Get remainder from hours and convert to minutes
    var minutes = (hours - absoluteHours) * 60;
    var absoluteMinutes = Math.floor(minutes);
    var m = absoluteMinutes > 9 ? absoluteMinutes : '0' +  absoluteMinutes;

    //Get remainder from minutes and convert to seconds
    var seconds = (minutes - absoluteMinutes) * 60;
    var absoluteSeconds = Math.floor(seconds);
    var s = absoluteSeconds > 9 ? absoluteSeconds : '0' + absoluteSeconds;

    //Get remainder from seconds and convert to milliseconds
    var milliseconds = (seconds - absoluteSeconds) * 1000;
    var absoluteMilliSeconds = Math.floor(milliseconds);
    var ms = absoluteMilliSeconds > 99 ? absoluteMilliSeconds : '0' + absoluteMilliSeconds > 9 ? absoluteMilliSeconds : '0' + absoluteMilliSeconds;

    var humanReadableString = h + ':' + m + ':' + s + ':' + ms;

    if(includeHints){
        humanReadableString = humanReadableString + " (" + timer.hints + " hints)";
    }

    return humanReadableString;
}

//#endregion


////////////////////////////////////////////////////////
//
//              SUDOKU Code
//

//#region Sudoku Game Utility
var getBoardNum = (row, col) => row * ROWS + col;

/**
 * Checks if the cell has no valid Sudoku number (pencilmarks do not count!)
 * @param {*} cell 
 * @returns True if no number is in the cell
 */
var isEmpty = (cell) => {
    return cell.number < 1;
}

var hasAllNumbers = (board) => {
    for(let i = 0; i < BOARD_SIZE; i++) {
        if(board[i].number < 1) {
            return false;
        }
    }

    return true;
}

/**
 * Checks a given board for numbers violating the Sudoku rules, so appearing more than once in a row, column or box.
 * Can be used to check if a board is solved, if all cells have a number.
 * It will check for every rule violation and not abort early.
 * @param {*} board The board to be checked
 * @param {*} fullBoard If the board has numbers in every cell
 * @returns An array where the first entry indicates if the board is in a correctly solved state (impossible if fullBoard is false) 
 * and the second entry is an array holding [row, column] pairs of all numbers violating the rules (empty if solved)
 */
var checkForDuplicates = (board, fullBoard) => {
    var correct = fullBoard;
    var wrongCells = new Set();

    // Check rows
    for(let r = 0; r < ROWS; r++) {
        for (let rc = 0; rc < COLS; rc++) {
            var currentNumber = board[getBoardNum(r, rc)].number;
            if(currentNumber < 1)
                continue;
            for(let rcc = rc + 1; rcc < COLS; rcc++) {
                var rowCompareNumber = board[getBoardNum(r, rcc)].number;
                if(currentNumber == rowCompareNumber) {
                    correct = false;
                    wrongCells.add([r, rc]);
                    wrongCells.add([r, rcc]);
                }
            }
        }
    }

    // Check columns
    for(let c = 0; c < COLS; c++) {
        for (let cr = 0; cr < ROWS; cr++) {
            var currentNumber = board[getBoardNum(cr, c)].number;
            if(currentNumber < 1)
                continue;
            for(let crc = cr + 1; crc < ROWS; crc++) {
                var columnCompareNumber = board[getBoardNum(crc, c)].number;
                if(currentNumber == columnCompareNumber) {
                    correct = false;
                    wrongCells.add([cr, c]);
                    wrongCells.add([crc, c]);
                }
            }
        }
    }

    // Check boxes
    for(let bri = 0; bri < ROWS; bri += 3) {
        for(let bci = 0; bci < COLS; bci += 3) {
            for(let br = 0; br < BOX_SIZE; br++) {
                for(let bc = 0; bc < BOX_SIZE; bc++) {
                    var currentNumber = board[getBoardNum(bri + br, bci + bc)].number;
                    if(currentNumber < 1)
                        continue;
                    for(let brc = 0; brc < BOX_SIZE; brc++) {
                        for(let bcc = 0; bcc < BOX_SIZE; bcc++) {
                            if(brc == br && bcc == bc)
                                continue;

                            var boxCompareNumber = board[getBoardNum(bri + brc, bci + bcc)].number;
                            if(currentNumber == boxCompareNumber) {
                                correct = false;
                                wrongCells.add([bri + br, bci + bc]);
                                wrongCells.add([bri + brc, bci + bcc]);
                            }
                        }
                    }
                }
            }
        }
    }

    return [correct, wrongCells];
}

var boardFromString = (boardString) => {
    var board = []
    for(let i = 0; i < boardString.length; i++) {
        var curChar = boardString.charAt(i);
        var number = parseInt(curChar, 10);

        board[i] = {
            number: number,
            isGiven: number > 0,
            cornerMarks: [],
            centerMarks: []
        }
    }

    return board
}

var getRandomBoard = (difficulty) => {
    var boardString = ''
    switch(difficulty) {
        case EASY:
            var index = Math.min(easyPuzzles.length -1 , Math.round(Math.random() * easyPuzzles.length));
            boardString = easyPuzzles[index];
            break;
        case MEDIUM:
            var index = Math.min(mediumPuzzles.length -1 , Math.round(Math.random() * mediumPuzzles.length));
            boardString = mediumPuzzles[index];
            break;
        case HARD:
            var index = Math.min(hardPuzzles.length -1 , Math.round(Math.random() * hardPuzzles.length));
            boardString = hardPuzzles[index];
            break;
        case EXPERT:
            var index = Math.min(expertPuzzles.length -1 , Math.round(Math.random() * expertPuzzles.length));
            boardString = expertPuzzles[index];
            break;
        case OMEGA:
            var index = Math.min(omegaPuzzles.length -1 , Math.round(Math.random() * omegaPuzzles.length));
            boardString = omegaPuzzles[index];
            break;
        case DEVILISH:
            var index = Math.min(devilishPuzzles.length -1 , Math.round(Math.random() * devilishPuzzles.length));
            boardString = devilishPuzzles[index];
            break;
        case TEST:
            var index = Math.min(testPuzzles.length -1 , Math.round(Math.random() * testPuzzles.length));
            boardString = testPuzzles[index];
            break;
        default:
            throw new Error("Unrecognized difficulty " + difficulty + "; cannot proceed");
    }

    return boardFromString(boardString);
}

var deepcopyCell = (cell) => {
    var cellcopy = JSON.parse(JSON.stringify(cell));
    return cellcopy;
}

var deepcopy = (board) => {
    var copy = []
    for(let i = 0; i < board.length; i++) {
        // Apparently that is the way to go?
        var cellcopy = JSON.parse(JSON.stringify(board[i]));
        copy[i] = cellcopy;
    }
    return copy;
}

var rotateBoard = (board, numRotations) => {
    for(let i = 0; i < numRotations; i++) {
        var copy = deepcopy(board);
        for(let r = 0; r < ROWS; r++) {
            for(let c = 0; c < COLS; c++) {
                // index magic was adapted from here: https://math.stackexchange.com/a/1676457/528931 (and here https://github.com/MitchelPaulin/sudoku-rs/blob/main/src/puzzle_transformer.rs)
                board[c * 9 + 9 - r - 1] = copy[getBoardNum(r, c)]
            }
        }
    }    
}

var mirrorBoardHorizontally = (board) => {
    var copy = deepcopy(board);

    for(let r = 0; r < ROWS; r++) {
        for(let c = 0; c < COLS; c++) {
            board[getBoardNum(r, c)] = copy[getBoardNum(r, COLS - 1 - c)];
        }
    }
}

var mirrorBoardVertically = (board) => {
    var copy = deepcopy(board);
		
    for(let r = 0; r < ROWS; r++) {
        for(let c = 0; c < COLS; c++) {
            board[getBoardNum(r, c)] = copy[getBoardNum(ROWS -1 - r, c)];
        }
    }
}

var permutateRowsGlobally = (board) => {
    var permutation = getPermutationMapping(3, false);

    var copy = deepcopy(board);
    
    for(let rb = 0; rb < 3; rb++) {
        var correspondentRowBlock = permutation[rb];
        for(let r = 0; r < 3; r++) {
            for(let c = 0; c < COLS; c++) {
                board[getBoardNum(rb * 3 + r, c)] = copy[getBoardNum(correspondentRowBlock * 3 + r, c)];
            }
        }
    }
}

var permutateRowsBlockwise = (board) => {
    var permutationBlock1 = getPermutationMapping(3, false);
    var permutationBlock2 = getPermutationMapping(3, false);
    var permutationBlock3 = getPermutationMapping(3, false);

    var copy = deepcopy(board);
    
    for(let r = 0; r < 3; r++) {
        for(let c = 0; c < COLS; c++) {
            board[getBoardNum(permutationBlock1[r], c)] = copy[getBoardNum(r, c)];
            board[getBoardNum(permutationBlock2[r] + 3, c)] = copy[getBoardNum(r + 3, c)];
            board[getBoardNum(permutationBlock3[r] + 6, c)] = copy[getBoardNum(r + 6, c)];
        }
    }
}

var permutateColumnsGlobally = (board) => {
    var permutation = getPermutationMapping(3, false);

    var copy = deepcopy(board);
    
    for(let cb = 0; cb < 3; cb++) {
        var correspondentColumnBlock = permutation[cb];
        for(let r = 0; r < ROWS; r++) {
            for(let c = 0; c < 3; c++) {
                board[getBoardNum(r, cb * 3 + c)] = copy[getBoardNum(r, correspondentColumnBlock * 3 + c)];
            }
        }
    }
}

var permutateColumnsBlockwise = (board) => {
    var permutationBlock1 = getPermutationMapping(3, false);
    var permutationBlock2 = getPermutationMapping(3, false);
    var permutationBlock3 = getPermutationMapping(3, false);

    var copy = deepcopy(board);
    
    for(let c = 0; c < 3; c++) {
        for(let r = 0; r < ROWS; r++) {
            board[getBoardNum(r, permutationBlock1[c])] = copy[getBoardNum(r, c)];
            board[getBoardNum(r, permutationBlock2[c] + 3)] = copy[getBoardNum(r, c + 3)];
            board[getBoardNum(r, permutationBlock3[c] + 6)] = copy[getBoardNum(r, c + 6)];
        }
    }
}

var permutateNumbers = (board) => {
    var permutation = getPermutationMapping(ROWS + 1, true);
    
    var copy = deepcopy(board);
    
    for(let r = 0; r < ROWS; r++) {
        for(let c = 0; c < COLS; c++) {
            board[getBoardNum(r, c)].number = permutation[copy[getBoardNum(r, c)].number];
        }
    }
}

var getPermutationMapping = (size, includeFixedZero) => {
    var mapping = [];
    var index = includeFixedZero ? 1 : 0;
    
    var numbers = []
    for(let n = index; n < size; n++) {
        numbers[n - index] = n;
    }

    for(let i = 0; i < size; i++) {
        var mappedNumber = Math.round((Math.random() * (numbers.length - 1)));
        var chosen = numbers.splice(mappedNumber, 1)[0];
        mapping[i] = chosen;
    }

    if(includeFixedZero) {
        mapping.unshift(0);
    }

    return mapping;
}

/**
 * This is currently just doing some symmetry rotation and number permutation.
 * In the future it should actually generate a puzzle whose difficulty is dependent on the strategies needed to solve it.
 * If that can be done in a reasonable enough time...
 * @param {*} board 
 * @returns 
 */
 var generate = (board) => {
    // This has the potential for a lot (> 1e10 if somebody else's math is correct) of combinations, so you shouldn't really see any repeat or anything looking that familiar :)
    var percentage = 0.5;

    //logBoard(board);
    
    var rotate = Math.random() > percentage;
    if(rotate) {
        var numRotations = Math.round( Math.random() * 3);
        if(numRotations > 0) {
            rotateBoard(board, numRotations);
            //log("rotated board " + numRotations + " times");
            //logBoard(board);
        }      
    }
    
    var mirrorHorizontally = Math.random() > percentage;
    if(mirrorHorizontally) {
        mirrorBoardHorizontally(board);
        //log("mirrored horizontally");
        //logBoard(board);
    }
        
    var mirrorVertically = Math.random() > percentage;
    if(mirrorVertically) {
        mirrorBoardVertically(board);
        //log("mirrored vertically");
        //logBoard(board);
    }

    var permutateRowsGlobal = Math.random() > percentage;
    if(permutateRowsGlobal) {
        permutateRowsGlobally(board);
        //log("permutated rows globally");
        //logBoard(board);
    }

    var permutateRowsBlock = Math.random() > percentage;
    if(permutateRowsBlock) {
        permutateRowsBlockwise(board);
        //log("permutated rows blockwise");
        //logBoard(board);
    }

    var permutateColumnsGlobal = Math.random() > percentage;
    if(permutateColumnsGlobal) {
        permutateColumnsGlobally(board);
        //log("permutated columns globally");
        //logBoard(board);
    }

    var permutateColumnsBlock = Math.random() > percentage;
    if(permutateColumnsBlock) {
        permutateColumnsBlockwise(board);
        //log("permutated columns blockwise");
        //logBoard(board);
    }

    
    var permutateNums = Math.random() > percentage;
    if(permutateNums) {
        permutateNumbers(board);
        //log("permutated numbers");
        //logBoard(board);
    }

    return board;
}

//#endregion

//#region DEBUG
var logObject = (object, prefix = "") => {
    var output = '';
    for (var property in object) {
        output += property + ': ' + object[property]+'; ';
    }
    log(prefix + "object: " + output);
}

var logBoard = (board) => {
    for(var r = 0; r < ROWS; r++){
        log("-------------------------------------");

        currentRowCells = []
        for(var c = 0; c < COLS; c++){
            var cell = board[r * 9 + c];
            currentRowCells.push(cell.number < 1 ? ' ' : cell.number);
            currentRowCells.push('|');
        }

        log('| ' + currentRowCells.join(' '));
    }

    log("-------------------------------------");
}
//#endregion