#!/usr/bin/env bash
# verify-colour-channels.sh — Block G of preflight.
#
# EnsureContrast works in ABGR. ThemeColors fields are RGBA. Feeding one into
# the other swaps red and blue on both arguments, measures a contrast between
# two colours that are never on screen, and returns a value in the wrong order
# on top — and because RgbaToAbgr is an involution, a stray extra conversion
# around the call makes it LOOK plausible while being wrong.
#
# This happened four times on 2026-08-19 alone (channel header, ghost buttons,
# pill text, popup rows), each found only by a human staring at an unreadable
# window. The compiler cannot catch it — both layouts are uint. This script
# catches the one shape every occurrence shared: a raw ThemeColors member as a
# direct argument to EnsureContrast.
#
# Legitimate calls convert first (RgbaToAbgr(...)) or pass values that are
# already ABGR (fields/locals named *Abgr, palette.Abgr(...)).

set -euo pipefail
ROOT="$(cd "$(dirname "$0")/.." && pwd)"

fail() { echo "verify-colour-channels: FAIL — $1" >&2; exit 1; }
ok()   { echo "verify-colour-channels: OK — $1"; }

HITS="$(python3 - "$ROOT/HellionChat" <<'PY'
import re
import sys
from pathlib import Path

root = Path(sys.argv[1])
# A ThemeColors member (via any local alias) fed straight into EnsureContrast,
# in either argument position, spanning line breaks. Members already in ABGR
# end in "Abgr" and are exempt.
pattern = re.compile(
    r"EnsureContrast\(\s*"
    r"(?:[A-Za-z_][\w.]*\.)?(?:Colors|c|colors)\.(?!\w*Abgr\b)\w+\s*,"
    r"|EnsureContrast\([^;]{0,200}?,\s*"
    r"(?:[A-Za-z_][\w.]*\.)?(?:Colors|c|colors)\.(?!\w*Abgr\b)\w+\s*[,)]",
    re.S,
)

hits = []
for f in root.rglob("*.cs"):
    if "obj" in f.parts or "bin" in f.parts:
        continue
    text = f.read_text(encoding="utf-8")
    for m in pattern.finditer(text):
        line = text.count("\n", 0, m.start()) + 1
        hits.append(f"{f.relative_to(root.parent)}:{line}")

print("\n".join(hits))
PY
)"

if [ -n "$HITS" ]; then
  fail "raw ThemeColors member fed into EnsureContrast (expects ABGR — wrap in RgbaToAbgr):
$HITS"
fi

ok "no raw RGBA theme members reach EnsureContrast"