# alias: BasicOpenersRebid
# button-text: Opener's Rebid
# gib-works: true
# bba-works: true
# auction-filter: Auction.....\n1[CDHS] +Pass +[1-5][CDHSN] .* Pass\n(P|[1-5])
# curate: kind=bidding
# convention-card-ns: Basic-Bridge
# convention-card-ew: Basic-Bridge

/*@chat
--- Basic: Opener's Rebid (beginner)
You opened one of a suit and partner responded. Your REBID finishes the picture in
one more call -- how strong you are (a minimum, or a little extra) and what shape.
• Balanced 12-14 with no fit: rebid 1NT. One call shows the whole hand.
• Four-card support for partner's suit: raise. Two of the suit shows a minimum; a jump
  to three shows about 16-18 and invites game.
• A six-card suit and no fit: rebid your suit. Cheaply (the two level) shows a minimum;
  a jump (the three level) shows extra and invites.
• A second four-card suit you can show at the ONE level: bid it. A new suit up the line
  needs no extra strength.
The level of the rebid is the message: the cheapest call shows a minimum, a jump shows
about 16-18 and asks partner to think about game.
@chat*/

dealer south

#include "script/Leveling"
#include "script/Calm-Opponents"
# provides calmOpps (both opponents too weak or flat to interfere)

sHcp = hcp(south)
s = spades(south)
h = hearts(south)
d = diamonds(south)
c = clubs(south)

# Strength bands. A minimum opener rebids cheaply; 16-18 jumps to invite. Cap below 19
# so we never stray into strong / 2C / reversing territory (not on the basic card).
minOpener = sHcp > 11 and sHcp < 16      // 12-15: the cheapest rebid
invOpener = sHcp > 15 and sHcp < 18      // 16-17: the invitational jump (cap below game-force)
opener    = minOpener or invOpener

# Responder: 6-9, a minimal one-level response so OPENER'S rebid carries the message
# (a stronger responder would jump or force, stealing the rebid decision from South).
northHand = hcp(north) > 5 and hcp(north) < 10

# The major North will introduce (BBA bids 4-card suits up the line; 4-4 -> 1H).
nRespH = hearts(north) > 3 and (hearts(north) > spades(north) or (hearts(north) == 4 and spades(north) == 4))
nRespS = spades(north) > 3 and not nRespH

# ===== Family 1 -- rebid 1NT: balanced 12-14, no 4-card major, opens a minor =====
f1 = shape(south, any 4432 + any 4333 + any 5332) and s < 4 and h < 4 and sHcp > 11 and sHcp < 15

# ===== Family 2 -- raise partner's major: minor opener with 4-card support =====
# South opens a minor (no 5-card major) and holds exactly 4 of the major North bids.
f2support = s < 5 and h < 5 and ((nRespH and h == 4) or (nRespS and s == 4))
f2min = f2support and minOpener
f2inv = f2support and invOpener

# ===== Family 3 -- rebid own six-card suit: no fit for partner =====
# Six-card minor opener North answers in a major, or a six-card heart opener North
# answers 1S. North is short in opener's suit, so North introduces a new suit instead
# of raising, and opener repeats the long suit.
sixMinor  = (d > 5 or c > 5) and s < 5 and h < 5
noSupport = not ((nRespH and h > 3) or (nRespS and s > 3))
sixHeart  = h > 5 and s < 5 and nRespS and hearts(north) < 3
f3base = (sixMinor and noSupport) or sixHeart
f3min = f3base and minOpener
f3inv = f3base and invOpener

# ===== Family 4 -- new suit at the one level: open 1D, rebid 1S over partner's 1H =====
# South opens 1D holding four spades; North responds 1H; South shows spades cheaply, 1S.
f4 = d > 3 and d >= s and s == 4 and h < 4 and c < 4 and nRespH and minOpener

southHand = f1 or f2min or f2inv or f3min or f3inv or f4

# ===== Level toward mostly-minimum spread; invitational jumps are the minority tier =====
levF1    = f1     and keep75
levF2min = f2min  and keep
levF2inv = f2inv  and keep47
levF3min = f3min  and keep
levF3inv = f3inv  and keep47
levF4    = f4     and keep
levelTheDeal = levF1 or levF2min or levF2inv or levF3min or levF3inv or levF4

southHand and northHand and calmOpps and levelTheDeal

produce 30

action
average "South HCP avg            " hcp(south),
average "F1 rebid 1NT           % " 100 * f1,
average "F2 raise partner (min) % " 100 * f2min,
average "F2 raise partner (inv) % " 100 * f2inv,
average "F3 rebid suit (min)    % " 100 * f3min,
average "F3 rebid suit (inv)    % " 100 * f3inv,
average "F4 new suit 1-level    % " 100 * f4,