#!/usr/bin/env bash
# Per-project language-bundle freshness check, designed to run at startup.
#
# Detects which language bundle(s) a project has by fingerprint (no marker
# file), then reconciles them against the canonical rulesets source:
#   - AUTO-FIX  (rulesets-owned, safe to overwrite): .claude/rules/*.md,
#               .claude/hooks/*, githooks/*
#   - SURFACE   (project may customize — reported, never written):
#               .claude/settings.json
# CLAUDE.md is intentionally not tracked: it is seed-only in install-lang
# and project-owned afterward (diff-lang skips it for the same reason).
#
# Usage: sync-language-bundle.sh [project-path]    (default: $PWD)
#
# Exit: 0  no bundle, or clean / rules+hooks auto-fixed (resolved)
#       3  manual action recommended (settings.json / CLAUDE.md drift)
#       1  usage / path error
#
# Quiet when there is nothing to report. Resolves the canonical source
# relative to its own location, so it always reads the current checkout.

set -u

PROJECT="${1:-$PWD}"

REPO_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
LANG_ROOT="$REPO_ROOT/languages"
GENERIC_RULES="$REPO_ROOT/claude-rules"

if [ ! -d "$PROJECT" ]; then
  echo "ERROR: project path does not exist: $PROJECT" >&2
  exit 1
fi
PROJECT="$(cd "$PROJECT" && pwd)"

[ -d "$LANG_ROOT" ] || exit 0   # no bundles available — nothing to do

OUT=""           # buffered report, printed once at the end
FIXED=0
MANUAL=0
HEADER_DONE=0
CUR_HEADER=""

ensure_header() {
  if [ "$HEADER_DONE" -eq 0 ]; then
    OUT+="$CUR_HEADER"$'\n'
    HEADER_DONE=1
  fi
}

# fix SRC DST [exec] — overwrite DST from SRC if missing or differing.
fix() {
  local src="$1" dst="$2" want_exec="${3:-}"
  [ -f "$src" ] || return 0
  if [ ! -f "$dst" ] || ! diff -q "$src" "$dst" >/dev/null 2>&1; then
    mkdir -p "$(dirname "$dst")"
    cp "$src" "$dst"
    [ "$want_exec" = exec ] && chmod +x "$dst"
    ensure_header
    OUT+="  fixed   ${dst#"$PROJECT"/}"$'\n'
    FIXED=$((FIXED + 1))
  fi
}

# surface SRC DST — report DST drift without writing.
surface() {
  local src="$1" dst="$2" reason=""
  [ -f "$src" ] || return 0
  if [ ! -f "$dst" ]; then
    reason="missing"
  elif ! diff -q "$src" "$dst" >/dev/null 2>&1; then
    reason="differs"
  else
    return 0
  fi
  ensure_header
  OUT+="  drift   ${dst#"$PROJECT"/} ($reason — not auto-fixed)"$'\n'
  MANUAL=$((MANUAL + 1))
}

for src_lang in "$LANG_ROOT"/*/; do
  [ -d "$src_lang" ] || continue
  src_lang="${src_lang%/}"
  lang="$(basename "$src_lang")"
  lang_rules="$src_lang/claude/rules"
  [ -d "$lang_rules" ] || continue

  # Fingerprint: project has this bundle iff any of the language's own
  # rule files is present in .claude/rules/.
  detected=0
  for rf in "$lang_rules"/*.md; do
    [ -f "$rf" ] || continue
    if [ -f "$PROJECT/.claude/rules/$(basename "$rf")" ]; then
      detected=1
      break
    fi
  done
  [ "$detected" -eq 1 ] || continue

  CUR_HEADER="language bundle '$lang' — $PROJECT:"
  HEADER_DONE=0
  manual_before=$MANUAL

  # AUTO-FIX: generic rules (shared) + language rules
  for f in "$GENERIC_RULES"/*.md; do
    [ -f "$f" ] || continue
    fix "$f" "$PROJECT/.claude/rules/$(basename "$f")"
  done
  for f in "$lang_rules"/*.md; do
    [ -f "$f" ] || continue
    fix "$f" "$PROJECT/.claude/rules/$(basename "$f")"
  done

  # AUTO-FIX: language hooks (executable)
  if [ -d "$src_lang/claude/hooks" ]; then
    while IFS= read -r f; do
      rel="${f#"$src_lang"/claude/}"
      fix "$f" "$PROJECT/.claude/$rel" exec
    done < <(find "$src_lang/claude/hooks" -type f)
  fi

  # AUTO-FIX: githooks (executable)
  if [ -d "$src_lang/githooks" ]; then
    while IFS= read -r f; do
      rel="${f#"$src_lang"/githooks/}"
      fix "$f" "$PROJECT/githooks/$rel" exec
    done < <(find "$src_lang/githooks" -type f)
  fi

  # SURFACE-ONLY: settings.json may carry project customization, so report
  # rather than overwrite. (CLAUDE.md is intentionally untracked here — it's
  # seed-only in install-lang and project-owned after, same as diff-lang skips it.)
  surface "$src_lang/claude/settings.json" "$PROJECT/.claude/settings.json"

  if [ "$MANUAL" -gt "$manual_before" ]; then
    OUT+="  → reconcile: make install-$lang PROJECT=."$'\n'
  fi
done

[ -n "$OUT" ] && printf '%s' "$OUT"
[ "$MANUAL" -gt 0 ] && exit 3
exit 0