# alias: LeadDirectingDbl
# button-text: Lead Dir Dbl
# gib-works: false
# bba-works: true
# auction-filter: (1N +Pass +2[CDH]|1N +Pass +3[CDHS])
# convention-card-ns: 21GF-GIB
# convention-card-ew: 21GF-GIB

/*@chat
--- Lead Directing Double
When opponents bid an artificial suit (e.g., Stayman 2C or transfer 2D/2H), 
double shows length and strength in that suit, requesting that lead.  The X shows
    5-card suit: 3+ of top 5 honors (e.g., KJTxx, AKJxx).
    6-card suit: 2+ of top 4 honors (e.g., KQxxxx, AJxxxx).
NOTE: BBA does not make lead-directing doubles.
https://www.bridgebum.com/lead_directing_double.php
@chat*/

# Lead Directing Double
# West opens 1NT, East responds with artificial bid
# South has a strong suit matching the artificial bid

dealer west

# West opens 1NT (15-17 HCP balanced)
westNT = hcp(west)>14 and hcp(west)<18 and shape(west,any 4333+any 4432+any 5332)

# South can have a wider range since West opens first
southRange = hcp(south)<15

# East has enough to respond to 1NT
eastResponds = hcp(east)>7

# LDD suit quality for South
# 5-card suit: 3+ of top 5 honors
# 6+ card suit: 2+ of top 4 honors
lddC5 = clubs(south)==5    and top5(south,clubs)>2
lddC6 = clubs(south)>5     and top4(south,clubs)>1
lddC = lddC5 or lddC6

lddD5 = diamonds(south)==5 and top5(south,diamonds)>2
lddD6 = diamonds(south)>5  and top4(south,diamonds)>1
lddD = lddD5 or lddD6

lddH5 = hearts(south)==5   and top5(south,hearts)>2
lddH6 = hearts(south)>5    and top4(south,hearts)>1
lddH = lddH5 or lddH6

lddS5 = spades(south)==5   and top5(south,spades)>2
lddS6 = spades(south)>5    and top4(south,spades)>1
lddS = lddS5 or lddS6

# Match South's strong suit with East's likely artificial bid
# Clubs: East uses Stayman (4-card major, no 5-card major)
matchC = lddC and (hearts(east)==4 or spades(east)==4) and hearts(east)<5 and spades(east)<5

# Diamonds: East transfers to hearts (5+ hearts)
matchD = lddD and hearts(east)>4

# Hearts: East transfers to spades (5+ spades)
matchH = lddH and spades(east)>4

# Splinter: East has shortness in South's strong suit with 4+ card major support
matchSplC = lddC and clubs(east)<2    and (hearts(east)>3 or spades(east)>3)
matchSplD = lddD and diamonds(east)<2 and (hearts(east)>3 or spades(east)>3)
matchSplH = lddH and hearts(east)<2   and spades(east)>3
matchSplS = lddS and spades(east)<2   and hearts(east)>3

hasMatch = matchC or matchD or matchH or matchSplC or matchSplD or matchSplH or matchSplS

westNT and southRange and eastResponds and hasMatch

action
average "South HCP  " hcp(south),
average "West HCP   " hcp(west),
average "East HCP   " hcp(east),
average "Club LDD   " 100 * matchC,
average "Diamond LDD" 100 * matchD,
average "Heart LDD  " 100 * matchH,