#!/usr/bin/env bash
# check-agent-docs-drift.sh — Fast drift check for per-repo agent docs.
# Exits 1 if any repo has drifted from the canonical pattern.
#
# Modelled on check-npmrc-drift.sh. Marker-based (no generator runs),
# so this is fast and side-effect-free.
#
# Usage:
#   bash scripts/check-agent-docs-drift.sh
#
# What is checked per repo:
#   1. Legacy files MUST NOT exist (they used to duplicate AGENTS.md):
#        .cursorrules, .windsurfrules, .clinerules, CLAUDE.md
#   2. AGENTS.md MUST contain the canonical-behavior-pointer marker.
#   3. .github/copilot-instructions.md MUST contain the AUTO-GENERATED marker
#      AND a reference to the canonical guidelines file.
#   4. .aider.conf.yml MUST exist and reference AGENTS.md.
#   5. .editorconfig MUST exist with the canonical first line "root = true".
#
# Repair: bash scripts/update-agent-docs.sh

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPOS_TXT="${SCRIPT_DIR}/../.windsurf/workflows/repos.txt"
BASE_DIR="$(cd "${SCRIPT_DIR}/../.." && pwd)"

RED='\033[0;31m'; GREEN='\033[0;32m'; YELLOW='\033[1;33m'; NC='\033[0m'

if [[ ! -f "$REPOS_TXT" ]]; then
  echo -e "${RED}❌ repos.txt not found: $REPOS_TXT${NC}" >&2
  exit 1
fi

LEGACY_FILES=(.cursorrules .windsurfrules .clinerules CLAUDE.md)
AGENTS_POINTER_MARKER="<!-- BEGIN: canonical-behavior-pointer (auto-managed) -->"
COPILOT_GENERATED_MARKER="<!-- AUTO-GENERATED by learning_ai_common_plat/scripts/update-agent-docs.sh -->"
COPILOT_CANONICAL_REF="agent-behavior-guidelines.md"

drifted=0
clean=0
missing=0

REPOS=()
while IFS= read -r line; do
  [[ "$line" =~ ^[[:space:]]*# ]] && continue
  [[ -z "${line// }" ]] && continue
  REPOS+=("$line")
done < "$REPOS_TXT"

for repo in "${REPOS[@]}"; do
  repo_dir="${BASE_DIR}/${repo}"

  if [[ ! -d "$repo_dir" ]]; then
    continue
  fi
  if [[ ! -f "${repo_dir}/AGENTS.md" ]]; then
    echo -e "${YELLOW}⚠️  $repo — AGENTS.md missing${NC}"
    ((missing++)) || true
    continue
  fi

  issues=()

  # 1 — Legacy files must be gone.
  for f in "${LEGACY_FILES[@]}"; do
    if [[ -e "${repo_dir}/${f}" ]]; then
      issues+=("legacy file still present: $f")
    fi
  done

  # 2 — AGENTS.md must have the canonical pointer block.
  if ! grep -qF "$AGENTS_POINTER_MARKER" "${repo_dir}/AGENTS.md"; then
    issues+=("AGENTS.md missing canonical-behavior-pointer block")
  fi

  # 3 — Copilot file: must exist, must be AUTO-GENERATED, must reference canonical.
  copilot="${repo_dir}/.github/copilot-instructions.md"
  if [[ ! -f "$copilot" ]]; then
    issues+=(".github/copilot-instructions.md missing")
  else
    if ! grep -qF "$COPILOT_GENERATED_MARKER" "$copilot"; then
      issues+=(".github/copilot-instructions.md missing AUTO-GENERATED marker (hand-edited?)")
    fi
    if ! grep -qF "$COPILOT_CANONICAL_REF" "$copilot"; then
      issues+=(".github/copilot-instructions.md missing reference to $COPILOT_CANONICAL_REF")
    fi
  fi

  # 4 — Aider config: must exist and reference AGENTS.md.
  aider="${repo_dir}/.aider.conf.yml"
  if [[ ! -f "$aider" ]]; then
    issues+=(".aider.conf.yml missing")
  elif ! grep -qF "AGENTS.md" "$aider"; then
    issues+=(".aider.conf.yml does not reference AGENTS.md")
  fi

  # 5 — Editorconfig: must exist with canonical first line.
  editorconfig="${repo_dir}/.editorconfig"
  if [[ ! -f "$editorconfig" ]]; then
    issues+=(".editorconfig missing")
  elif ! head -1 "$editorconfig" | grep -qE '^root = true$'; then
    issues+=(".editorconfig first line not 'root = true' (hand-edited?)")
  fi

  if [[ ${#issues[@]} -gt 0 ]]; then
    echo -e "${RED}❌ $repo${NC}"
    for i in "${issues[@]}"; do
      echo "    - $i"
    done
    ((drifted++)) || true
  else
    ((clean++)) || true
  fi
done

echo "────────────────────────────────"
echo -e "${GREEN}✅ $clean repos in sync${NC}"
[[ "$missing" -gt 0 ]] && echo -e "${YELLOW}⚠️  $missing repos missing AGENTS.md${NC}"
[[ "$drifted" -gt 0 ]] && echo -e "${RED}❌ $drifted repos drifted${NC}"
echo ""

if [[ "$drifted" -gt 0 ]] || [[ "$missing" -gt 0 ]]; then
  echo "Fix: bash scripts/update-agent-docs.sh"
  exit 1
fi

echo "All repos in sync ✅"