// vim: set softtabstop=2 shiftwidth=2 expandtab :
var ADOC_MIMETYPE = "text/asciidoc";

// Open handler to add Menu
function onOpen(e) {
  var ui = DocumentApp.getUi();
  
  if (e && e.authMode == ScriptApp.AuthMode.NONE) {
    ui.createMenu('AsciiDoc')
//    .addItem('Latex Equation', 'ConvertEquation')
      .addToUi();
  } else {
    ui.createMenu('AsciiDoc')
      .addItem('Export File', 'ConvertToAsciiDocFile')
      .addItem('Export Email', 'ConvertToAsciiDocEmail')
//    .addItem('Latex Equation', 'ConvertEquation')
      .addToUi();
  }
}

function onInstall(e) {
  onOpen(e);
}

function ConvertEquation() {
  var element = DocumentApp.getActiveDocument().getCursor().getElement();
  
  // Scan upwards for an equation
  while(element.getType() != DocumentApp.ElementType.EQUATION) {
    if(element.getParent() == null)
      break;
    
    element = element.getParent();  
  }
  
  if(element.getType() != DocumentApp.ElementType.EQUATION) {
    DocumentApp.getUi().alert("Put cursor into an equation element!"); 
    return; 
  }
  
  // Covert equation
  var latexEquation = handleEquationFunction(element); 
  var latexEquationText = "$" + latexEquation.trim() + "$"; 
  
  // Show results
  DocumentApp.getUi().alert(latexEquationText);
}

// Convert current document to asciidoc and email it 
function ConvertToAsciiDocEmail() {
  // Convert to asciidoc
  var convertedDoc = asciidoc(); 
  
  // Add asciidoc document to attachments
  convertedDoc.attachments.push({"fileName":DocumentApp.getActiveDocument().getName()+".adoc", 
                                 "mimeType": ADOC_MIMETYPE, "content": convertedDoc.text});

  // In some cases user email is not accessible  
  var mail = Session.getActiveUser().getEmail(); 
  if(mail === '') {
    DocumentApp.getUi().alert("Could not read your email address"); 
    return;
  }
  
  // Send email with asciidoc document
  MailApp.sendEmail(mail,
		    "[gdoc2adoc] "+DocumentApp.getActiveDocument().getName(),
		    "Your converted AsciiDoc document is attached (converted from "+DocumentApp.getActiveDocument().getUrl()+")",
		    { "attachments": convertedDoc.attachments });
}

function getFolder(parent_folder,folder_name){
  var folders = parent_folder.getFolders();     
  while (folders.hasNext()) {
    var folder = folders.next();
    if(folder_name == folder.getName()) {         
      return folder;
    }
  }
  return false;
}

// Convert current document to file and save it to GDrive
function ConvertToAsciiDocFile() {
  // Convert to asciidoc
    var convertedDoc = asciidoc();
  
  // Create folder
  var id = DocumentApp.getActiveDocument().getId();
  var file = DriveApp.getFileById(id);
  var parents = file.getParents();
  var parent = null;
  
  if(parents.hasNext()) {
    parent = parents.next()
    if(parents.hasNext()) {
      //Logger.log("File has multiple parent directories. Script does not work in this case"); 
      DocumentApp.getUi().alert("Document must not be in multiple directories");
      return; 
    }
  } else {
    DocumentApp.getUi().alert("Document has to be in a directory for the export"); 
    return; 
  }
  
  var targetDirName = DocumentApp.getActiveDocument().getName() + ".adoc"
  var found = getFolder(parent,targetDirName);
  if (found === false){
    //Logger.log("Creating output folder..."); 
    found =  parent.createFolder(targetDirName);
  } else {
    //Logger.log("Reusing existing target");
    var ui = DocumentApp.getUi();
    var result = ui.alert('Existing target folder found!', 'You already have "' + targetDirName + '" in your Drive. Delete folder or Cancel ?', 
                          ui.ButtonSet.OK_CANCEL)
                    
    if(result == ui.Button.OK) {
        //Logger.log("Trashing target folder..."); 
        found.setTrashed(true); 
        //Logger.log("Re-Creating output folder..."); 
        found =  parent.createFolder(targetDirName);
      
    } else {
        //Logger.log("Do not delete target folder, stopping!"); 
        return;
    }
  }
  
  // Write all files to target folder
  for(var file in convertedDoc.files) {
    file = convertedDoc.files[file];
    var blob = file.blob.copyBlob();
    var name = file.name; 
    blob.setName(name); 
    
    
    found.createFile(blob); 
  }
  
  // Write mardown file to target folder
  // using same nameas folder.
  found.createFile(targetDirName, convertedDoc.text, ADOC_MIMETYPE);   

}

function processSection(section) {
  var state = {
    'inSource' : false, // Document read pointer is within a fenced code block
    'images' : [], // Image data found in document
    'imageCounter' : 0, // Image counter 
    'prevDoc' : [], // Pointer to the previous element on aparsing tree level
    'nextDoc' : [], // Pointer to the next element on a parsing tree level
    'size' : [], // Number of elements on a parsing tree level
    'listCounters' : [], // List counter
    'needToc' : false, // saw a toc reference
    'indent' : 0, // indent on current block
    'headingPrefix' : '', // Should headings be prefixed by a `=` to make heading1 `==` (see detectHeadingRules)
  };

  // Detect title, heading1 etc
  detectHeadingRules(section, state);

  // Process element tree outgoing from the root element
  var textElements = processElement(section, state, 0);
  
  return {
    'textElements' : textElements,
    'state' : state,
  }; 
}

function detectHeadingRulesNested(element, state, headingState) {
  Logger.log("detectHeadingRulesNested: " + element.getType()); 

  switch(element.getType()) {
    case DocumentApp.ElementType.DOCUMENT:
    case DocumentApp.ElementType.BODY_SECTION:
      // Iterates over all childs
      for(var i=0; i < element.getNumChildren(); i++)  {
        var child = element.getChild(i); 
        
        detectHeadingRulesNested(child, state, headingState);
      }
      break; 
      
    case DocumentApp.ElementType.PARAGRAPH:
      switch (element.getHeading()) {
        case DocumentApp.ParagraphHeading.HEADING1:
          headingState.nbrOfH1 += 1; break;
        case DocumentApp.ParagraphHeading.TITLE:
          headingState.hasTitle = true;
      }

      // Iterates over all childs
      for(var i=0; i < element.getNumChildren(); i++)  {
        var child = element.getChild(i); 
        
        detectHeadingRulesNested(child, state, headingState);
      }
  }
}

function detectHeadingRules(element, state) {

  var headingState = {
    'nbrOfH1': 0,
    'hasTitle' : false,
  };

  detectHeadingRulesNested(element, state, headingState);

  Logger.log("Heading detection, nbrOfH1: " + headingState.nbrOfH1 + " and title: " + headingState.hasTitle);

  if (headingState.hasTitle == true) {
    Logger.log("Heading prefix `=` because there is a title");
    state.headingPrefix = '=';
  }
  else if (headingState.nbrOfH1 == 1) {
    // we have a single heading1 so we will pretend it's the title and h2 is for subsections
    Logger.log("Heading prefix `` because there is a single h1");
    state.headingPrefix = '';
  }
  else {
    // no title and multiple (or no h1) => treat h1 as a Asciidoc subsection (i.e. `==`)
    Logger.log("No title and multiple (or no h1) => treat h1 as a Asciidoc subsection (i.e. `==`)");
    state.headingPrefix = '=';
  }
}


function asciidoc() {
  // Text elements
  var textElements = []; 
  
  // Process header
  var head = DocumentApp.getActiveDocument().getHeader(); 
  if(head != null) {
    // Do not include empty header sections
    var teHead = processSection(head); 
    if(teHead.textElements.length > 0) {
      textElements = textElements.concat(teHead.textElements); 
      textElements.push('\n\n'); 
      textElements.push('---'); 
      textElements.push('\n\n');
    }
  }
  
  // Process body
  var doc = DocumentApp.getActiveDocument().getBody();
  doc = processSection(doc); 
  textElements = textElements.concat(doc.textElements); 
  
  // Process footer
  var foot = DocumentApp.getActiveDocument().getFooter(); 
  //Logger.log("foot: " + foot);
  if(foot != null) {
    var teFoot = processSection(foot); 
    // Do not include empty footer sections
    if(teFoot.textElements.length > 0) {
      textElements.push('\n\n'); 
      textElements.push('---'); 
      textElements.push('\n\n'); 
      textElements = textElements.concat(teFoot.textElements); 
    }
  }
  
  // Build final output string
  var text = textElements.join('');
  
  // Replace critical chars
  text = text.replace('\u201d', '"').replace('\u201c', '"');
  
  // Debug logging
  //Logger.log("Result: " + text);
  Logger.log("Images: " + doc.state.imageCounter);
  
  // Build attachment and file lists
  var attachments = [];
  var files = [];
  for(var i in doc.state.images) {
    var image = doc.state.images[i];
    attachments.push( {
      "fileName": image.name,
      "mimeType": image.type,
      "content": image.bytes
    } );
    
    files.push( {
      "name" : image.name,
      "blob" : image.blob
    });
  }
  
  // Results
  return {
    'files' : files,
    'attachments' : attachments,
    'text' : text,
  };
}


function escapeHTML(text) {
  return text.replace(/</g, '&lt;').replace(/>/g, '&gt;');
}

// Add repeat function to strings
String.prototype.repeat = function( num ) {
  return new Array( num + 1 ).join( this );
}

function handleTable(element, state, depth) {
  var textElements = [];
  
  textElements.push("\n");
  
  textElements.push("|===\n")
  
  function buildTable(size) {
    var stack = []
    var maxSize = 0; 
    
    for(var ir=0; ir<element.getNumRows(); ir++) {
      var row = element.getRow(ir);
     
      // Add header seperator
      //if(ir == 1) {
      //  for(var ic=0; ic<row.getNumCells(); ic++) {
      //    stack.push("|-" + "-".repeat(size));
      //  }
      //  stack.push("-|\n");
      //}
      
      // Add table data
      for(var ic=0; ic<row.getNumCells(); ic++) {
        var cell = row.getCell(ic);
        
        // Recursively build cell content
        var text = processChilds(cell, state, depth+1).join('');
        
        text = text.replace(/(\r\n|\n|\r)/gm,"");
        maxSize = Math.max(text.length, maxSize); 
        
        if(size > text.length) {
          text += " ".repeat(size - text.length)
        }
        
        stack.push("| " + text);
      }
      
      stack.push(" \n");
    }
  
    stack.push("|===\n")
    stack.push("\n");
    return {
      maxSize : maxSize,
      stack : stack,
    };
  }
  
  var table = buildTable(100); 
  table = buildTable(Math.max(10, table.maxSize + 1)); 
  textElements = textElements.concat(table.stack);
  
  textElements.push('\n');
  return textElements;
}

function formatMd(text, indexLeft, formatLeft, indexRight, formatRight) {
  var leftPad = '' + formatLeft; 
  if(indexLeft > 0) {
    if(text[indexLeft - 1] != ' ')
      leftPad = ' ' + formatLeft; 
  }
  
  var rightPad = formatRight + '';
  if(indexRight < text.length) {
    if(text[indexRight] != ' ') {
      rightPad = formatRight + ' ';
    }
  }
  
  //Note: we do a trim via .replace since asciidoc wont format i.e. * test* with bold.
  var formatted = text.substring(0, indexLeft) + leftPad + text.substring(indexLeft, indexRight).replace(/^\s+|\s+$/g,"") + rightPad + text.substring(indexRight);
  return formatted;
}


function handleText(doc, state) {
  var formatted = doc.getText(); 
  var lastIndex = formatted.length; 
  var attrs = doc.getTextAttributeIndices();
  
  // Iterate backwards through all attributes
  for(var i=attrs.length-1; i >= 0; i--) {
    // Current position in text
    var index = attrs[i];
        
    // Handle links
    if(doc.getLinkUrl(index)) {
      var url = doc.getLinkUrl(index);
      if (i > 0 && attrs[i-1] == index - 1 && doc.getLinkUrl(attrs[i-1]) === url) {
        i -= 1;
        index = attrs[i];
        url = doc.getLinkUrl(index);
      }
      formatted = formatted.substring(0, index) +   url + '[' + formatted.substring(index, lastIndex) + ']' + formatted.substring(lastIndex);
      
      // Do not handle additional formattings for links
      continue; 
    } 
    
    // Handle source code
    if(isTextCode(doc, index)) {
      if (!state.inSource) {
        // Scan left until text without source font is found
        while (i > 0 && doc.getFontFamily(attrs[i-1]) && doc.getFontFamily(attrs[i-1]) === sourceFont) {
          i -= 1;
          off = attrs[i];
        }
        
        formatted = formatMd(formatted, index, '`', lastIndex, '`');
        
        // Do not handle additional formattings for code
        continue; 
      }
    }
    
    
    // TODO: does not handle nested formatting well.
    // Handle bold and bold italic
    if(doc.isBold(index)) {
      var dleft, right;
      dleft = dright = "*";
      if (doc.isItalic(index)) 
      {
        // edbacher: changed this to handle bold italic properly.
        dleft = "**__"; 
        dright  = "__**";
      }
      
      formatted = formatMd(formatted, index, dleft, lastIndex, dright); 
    } 
    // Handle italic
    else if(doc.isItalic(index)) {
      formatted = formatMd(formatted, index, '_', lastIndex, '_'); 
    } else if (doc.isUnderline(index)) {
      formatted = formatMd(formatted, index, '[.underline]#', lastIndex, '#'); 
    } else if(doc.isStrikethrough(index)) {
      formatted = formatMd(formatted, index, '[.line-through]#', lastIndex, '#'); 
    } else if(doc.getTextAlignment(index) == DocumentApp.TextAlignment.SUBSCRIPT) {
      formatted = formatMd(formatted, index, '~', lastIndex, '~'); 
    } else if(doc.getTextAlignment(index) == DocumentApp.TextAlignment.SUPERSCRIPT) {
      formatted = formatMd(formatted, index, '^', lastIndex, '^'); 
    }
    
    // replace newlines wit any indent requested from higher up formatting.
    var haslinebreak = /\r/.exec(formatted);
    formatted = formatted.replace(/(?:\r)/g, '\n+\n');
    if (haslinebreak) // add extra newline to let list and others continue
      formatted += "\n";
    // Keep track of last position in text
    lastIndex = index; 
  }
  
  var textElements = [formatted]; 
  return textElements; 
}



function handleListItem(item, state, depth) {
  var textElements = [];
  
  // Prefix
  var prefix = '';
  
  // Add nesting level
  for (var i=0; i<item.getNestingLevel(); i++) {
    prefix += '  ';
  }
  
  var glyphprefix = ''
  // Add marker based on glyph type
  var glyph = item.getGlyphType();
  //Logger.log("Glyph: " + glyph);
  switch(glyph) {
    case DocumentApp.GlyphType.BULLET:
    case DocumentApp.GlyphType.HOLLOW_BULLET:
    case DocumentApp.GlyphType.SQUARE_BULLET: 
      glyphprefix = '*'.repeat(item.getNestingLevel()+1) + ' ';
      break;
    case DocumentApp.GlyphType.NUMBER:
    case DocumentApp.GlyphType.LATIN_LOWER:
    case DocumentApp.GlyphType.LATIN_UPPER:
    case DocumentApp.GlyphType.ROMAN_LOWER:
    case DocumentApp.GlyphType.ROMAN_UPPER:
      var key = item.getListId() + '.' + item.getNestingLevel();
      //Logger.log("key " + key); 
      var counter = state.listCounters[key] || 0;
      counter++;
      state.listCounters[key] = counter;
      glyphprefix += '.'.repeat(item.getNestingLevel()+1) + ' ';
      break;
    default:
      glyphprefix += glyph + '*'.repeat(item.getNestingLevel()+1) + ' ';
      break;
  }
  
  // Add prefix
  textElements.push(prefix + glyphprefix);
  
  oldIndent = state.indent
  state.indent = glyphprefix.length + prefix.length
  children = processChilds(item, state, depth)
  state.indent = oldIndent
  
  
  // Handle all childs
  textElements = textElements.concat(children);
  
  return textElements;
}

function handleImage(image, state) {
  // Determine file extension based on content type
  var contentType = image.getBlob().getContentType();
  var fileExtension = '';
  if (/\/png$/.test(contentType)) {
    fileExtension = ".png";
  } else if (/\/gif$/.test(contentType)) {
    fileExtension = ".gif";
  } else if (/\/jpe?g$/.test(contentType)) {
    fileExtension = ".jpg";
  } else {
    throw "Unsupported image type: " + contentType;
  }

  // Create filename
  var filename = 'img_' + state.imageCounter + fileExtension;
  state.imageCounter++;
  
  // Add image
  var textElements = []
  textElements.push('image:' + filename + '[]'); // TODO: this is inline only
  state.images.push( {
    "bytes": image.getBlob().getBytes(), 
    "blob": image.getBlob(), 
    "type": contentType, 
    "name": filename,
  });
  
  return textElements;
}


// Escape chars with a special meaning in Latex
function latexSanitize(text) {
  text = text.replace("\\", "\\\\"); 
  text = text.replace("%", "\\%");
  return text; 
}


// Converte an Equation or Function element to a Latex expression
function handleEquationFunction(func, state) {
  //Logger.log("Equation converter handling: " + func.getType());
  var equation =  ""; 
  
  for(var i=0; i<func.getNumChildren(); i++) {
    var child = func.getChild(i); 
    
    if(child.getType() == DocumentApp.ElementType.EQUATION_FUNCTION) {
      equation += child.getCode() + "{" + handleEquationFunction(child, state); 
    }
    else if(child.getType() == DocumentApp.ElementType.EQUATION_FUNCTION_ARGUMENT_SEPARATOR) {
      equation = equation.trim() + "}{"; 
    }
    else if(child.getType() == DocumentApp.ElementType.EQUATION_SYMBOL) {
      equation += child.getCode() + " "; 
    }
    else if(child.getType() == DocumentApp.ElementType.TEXT) {
      equation += latexSanitize(child.getText()) + " "; 
    }
  }
  
  if(func.getType() == DocumentApp.ElementType.EQUATION_FUNCTION)
    equation = equation.trim() + "}";
  
  //Logger.log("Equation converter result: " + equation);
  return equation;
}


function processChilds(doc, state, depth) {
  // Text element buffer
  var textElements = []
  
  // Keep track of child count on this depth
  state.size[depth] = doc.getNumChildren(); 
  
  // Iterates over all childs
  for(var i=0; i < doc.getNumChildren(); i++)  {
    var child = doc.getChild(i); 
    
    // Update pointer on next document
    var nextDoc = (i+1 < doc.getNumChildren())?doc.getChild(i+1) : child;
    state.nextDoc[depth] = nextDoc; 
    
    // Update pointer on prev element 
    var prevDoc = (i-1 >= 0)?doc.getChild(i-1) : child;
    state.prevDoc[depth] = prevDoc; 
    
    textElements = textElements.concat(processElement(child, state, depth+1)); 
    
  }
  
  
  return textElements;
}


function processElement(element, state, depth) {
  // Result
  var textElements = [];
    
  switch(element.getType()) {
    case DocumentApp.ElementType.DOCUMENT:
      Logger.log("this is a document"); 
      break; 
      
    case DocumentApp.ElementType.BODY_SECTION: 
      textElements = textElements.concat(processChilds(element, state, depth));
      break; 
      
    case DocumentApp.ElementType.PARAGRAPH:
      // Determine header prefix
      var prefix = ''; 
      switch (element.getHeading()) {
        case DocumentApp.ParagraphHeading.HEADING6: prefix = state.headingPrefix + '======'; break;
        case DocumentApp.ParagraphHeading.HEADING5: prefix = state.headingPrefix + '====='; break;
        case DocumentApp.ParagraphHeading.HEADING4: prefix = state.headingPrefix + '===='; break;
        case DocumentApp.ParagraphHeading.HEADING3: prefix = state.headingPrefix + '==='; break;
        case DocumentApp.ParagraphHeading.HEADING2: prefix = state.headingPrefix + '=='; break;
        case DocumentApp.ParagraphHeading.HEADING1: prefix = state.headingPrefix + '='; break;
        case DocumentApp.ParagraphHeading.TITLE:
          prefix = '='; state.needToc = true; break;
        //default:prefix = element.getHeading(); break;
       }

      // Add space
      if(prefix.length > 0)
        prefix += ' ';
      
      
      // Process childs
      var child = processChilds(element, state, depth)
      
      // Only Push prefix if it has kids otherwise it will just be treated as lone =='s
      if (child.length > 0) {
        textElements.push(prefix);
        textElements = textElements.concat(child);
        if(state.needToc) {
          textElements.push("\n:toc: macro\n")
          state.needToc = false;
        }

        // look for positioned images
        var positionedImages = element.getPositionedImages()
        for(var image in positionedImages) {
          image = positionedImages[image];
          textElements.push("\n" + handleImage(image, state) + "\n")
        }
      
      }
      
      // Add paragraph break only if its not the last element on this layer
        if(state.nextDoc[depth-1] == element)
          break; 
      
        if(state.inSource)
          textElements.push('\n');
        else
          textElements.push('\n\n');
      
      break; 
      
    case DocumentApp.ElementType.LIST_ITEM:
      textElements = textElements.concat(handleListItem(element, state, depth)); 
      textElements.push('\n');
      
      if(state.nextDoc[depth-1].getType() != element.getType()) {
        textElements.push('\n');
      }
      
      break;
     
    case DocumentApp.ElementType.HEADER_SECTION:
      textElements = textElements.concat(processChilds(element, state, depth));
      break; 
      
    case DocumentApp.ElementType.FOOTER_SECTION:
      textElements = textElements.concat(processChilds(element, state, depth));
      break;
      
    case DocumentApp.ElementType.FOOTNOTE:
      //adoced
      textElements.push('.footnote:[');
      textElements = textElements.concat(processChilds(element.getFootnoteContents(), state, depth));
      textElements.push(']');
      break; 
      
    case DocumentApp.ElementType.HORIZONTAL_RULE:
      textElements.push('---\n');
      break; 
     
    case DocumentApp.ElementType.INLINE_DRAWING:
      // Cannot handle this type - there is no export function for rasterized or SVG images...
      break; 
      
    case DocumentApp.ElementType.TABLE:
      textElements = textElements.concat(handleTable(element, state, depth));
      break;
      
    case DocumentApp.ElementType.TABLE_OF_CONTENTS:
      textElements.push('toc::[]');
      state.needToc = true
      break;
      
    case DocumentApp.ElementType.TEXT:
      var text = handleText(element, state);
      
      // Check for source code delimiter
      if(/^```.+$/.test(text.join(''))) {
        state.inSource = true; 
      }
      
      if(text.join('') === '```') {
        state.inSource = false; 
      }
      
      textElements = textElements.concat(text);
      break;

    case DocumentApp.ElementType.INLINE_IMAGE: 
      textElements = textElements.concat(handleImage(element, state));
      break; 
      
    case DocumentApp.ElementType.PAGE_BREAK:
      // Ignore page breaks
      break; 
      
    case DocumentApp.ElementType.EQUATION: 
      var latexEquation = handleEquationFunction(element, state); 

      // If equation is the only one in a paragraph - center it 
      var wrap = '$'
      if(state.size[depth-1] == 1) {
        wrap = '$$'
      }
      
      latexEquation = wrap + latexEquation.trim() + wrap; 
      textElements.push(latexEquation);
      break; 
    default:
      throw("Unknown element type: " + element.getType());
  }
  
  return textElements; 
}

// from https://github.com/Mogztter/asciidoc-googledocs-addon/blob/master/app/Code.gs
/** Guess if the text is code by looking at the font family. */
function isTextCode(doc, index) {
  // Things will be better if Google Fonts can tell us about a font
  var i, fontFamily = doc.getFontFamily(index), /* Now it returns a string! */
  monospaceFonts = ['Consolas', 'Courier New', 'Source Code Pro'];
  if (fontFamily === null) {
    return false; // Handle null early.. It means multiple values.
  }
  // See ES7 Array.prototype.includes(elem, pos)
  for (i = 0; i < monospaceFonts.length; i++) {
    if (fontFamily === monospaceFonts[i]) {
      return true;
    }
  }
  // Last Try: Assume it's mono if it ends with ' Mono'.
  // This works for all Google Fonts as of 2016-10-21.
  // See ES6 String.prototype.endsWith(str, pos).
  return fontFamily.indexOf(' Mono') === fontFamily.length - 5;
}