#!/usr/bin/env sh
set -eu

ROOT_PATH="${GO_GIT_ROOT:-$HOME/git}"
STANDARDS_REPO=""
STANDARDS_REPO_SET=0
EXCLUDE_NAME="project-standards"
CHECK_ONLY=0
WATCH=0
INTERVAL=60

usage() {
  cat <<'EOF'
Usage:
  reconcile-project-standards.sh [options]

Options:
  --root <path>           Root folder containing repositories
  --standards-repo <path> Path to project-standards repository
  --exclude <name>        First-level directory name to skip (default: project-standards)
  --check-only            Check drift only, do not update files
  --watch                 Continuously scan and reconcile
  --interval <seconds>    Watch interval in seconds (default: 60)
  -h, --help              Show this help

Environment:
  GO_GIT_ROOT             Overrides default root path (default: ~/git)
  GO_PROJECT_STANDARDS    Overrides standards repository path

Default resolution:
  ROOT_PATH defaults to GO_GIT_ROOT or ~/git.
  STANDARDS_REPO defaults to GO_PROJECT_STANDARDS or $ROOT_PATH/project-standards.
EOF
}

while [ "$#" -gt 0 ]; do
  case "$1" in
    --root)
      ROOT_PATH=$2
      shift 2
      ;;
    --standards-repo)
      STANDARDS_REPO=$2
      STANDARDS_REPO_SET=1
      shift 2
      ;;
    --exclude)
      EXCLUDE_NAME=$2
      shift 2
      ;;
    --check-only)
      CHECK_ONLY=1
      shift
      ;;
    --watch)
      WATCH=1
      shift
      ;;
    --interval)
      INTERVAL=$2
      shift 2
      ;;
    -h|--help)
      usage
      exit 0
      ;;
    *)
      echo "Unknown option: $1" >&2
      usage >&2
      exit 1
      ;;
  esac
done

if [ "$STANDARDS_REPO_SET" -ne 1 ]; then
  if [ -n "${GO_PROJECT_STANDARDS:-}" ]; then
    STANDARDS_REPO="$GO_PROJECT_STANDARDS"
  else
    STANDARDS_REPO="$ROOT_PATH/project-standards"
  fi
fi

if [ "$INTERVAL" -lt 5 ]; then
  echo "interval must be >= 5" >&2
  exit 1
fi

AGENTS_TEMPLATE="$STANDARDS_REPO/templates/AGENTS.base.md"
DOD_TEMPLATE="$STANDARDS_REPO/templates/DEFINITION_OF_DONE.base.md"
GITIGNORE_TEMPLATE="$STANDARDS_REPO/templates/.gitignore.base"
GITATTRIBUTES_TEMPLATE="$STANDARDS_REPO/templates/.gitattributes.base"
EDITORCONFIG_TEMPLATE="$STANDARDS_REPO/templates/.editorconfig.base"
PRECOMMIT_TEMPLATE="$STANDARDS_REPO/templates/pre-commit.base.sh"
HOOKS_README_TEMPLATE="$STANDARDS_REPO/templates/.githooks.README.base.md"

if [ ! -f "$AGENTS_TEMPLATE" ]; then
  echo "AGENTS template not found: $AGENTS_TEMPLATE" >&2
  exit 1
fi

if [ ! -f "$DOD_TEMPLATE" ]; then
  echo "DoD template not found: $DOD_TEMPLATE" >&2
  exit 1
fi

if [ ! -f "$GITIGNORE_TEMPLATE" ]; then
  echo "gitignore template not found: $GITIGNORE_TEMPLATE" >&2
  exit 1
fi

if [ ! -f "$GITATTRIBUTES_TEMPLATE" ]; then
  echo "gitattributes template not found: $GITATTRIBUTES_TEMPLATE" >&2
  exit 1
fi

if [ ! -f "$EDITORCONFIG_TEMPLATE" ]; then
  echo "editorconfig template not found: $EDITORCONFIG_TEMPLATE" >&2
  exit 1
fi

if [ ! -f "$PRECOMMIT_TEMPLATE" ]; then
  echo "pre-commit hook template not found: $PRECOMMIT_TEMPLATE" >&2
  exit 1
fi

if [ ! -f "$HOOKS_README_TEMPLATE" ]; then
  echo "hooks readme template not found: $HOOKS_README_TEMPLATE" >&2
  exit 1
fi

hash_or_missing() {
  path=$1
  if [ ! -f "$path" ]; then
    printf "%s" "__MISSING__"
    return 0
  fi

  if command -v sha256sum >/dev/null 2>&1; then
    sha256sum "$path" | awk '{print $1}'
  else
    shasum -a 256 "$path" | awk '{print $1}'
  fi
}

ensure_file() {
  template=$1
  target=$2

  template_hash=$(hash_or_missing "$template")
  target_hash=$(hash_or_missing "$target")

  if [ "$template_hash" = "$target_hash" ]; then
    printf "%s" "ok"
    return 0
  fi

  if [ "$CHECK_ONLY" -eq 1 ]; then
    printf "%s" "drift"
    return 0
  fi

  mkdir -p "$(dirname "$target")"
  cp "$template" "$target"
  printf "%s" "updated"
}

ensure_gitignore_entries_from_template() {
  template_path=$1
  gitignore_path=$2

  missing=0

  if [ ! -f "$gitignore_path" ]; then
    if [ "$CHECK_ONLY" -eq 1 ]; then
      printf "%s" "drift"
      return 0
    fi

    : > "$gitignore_path"
  fi

  while IFS= read -r entry; do
    entry=$(printf '%s' "$entry" | tr -d '\r')
    [ -n "$entry" ] || continue
    case "$entry" in
      \#*)
        continue
        ;;
    esac

    if tr -d '\r' < "$gitignore_path" | grep -Fqx "$entry"; then
      continue
    fi

    missing=1
    if [ "$CHECK_ONLY" -ne 1 ]; then
      printf '%s\n' "$entry" >> "$gitignore_path"
    fi
  done < "$template_path"

  if [ "$missing" -eq 0 ]; then
    printf "%s" "ok"
    return 0
  fi

  if [ "$CHECK_ONLY" -eq 1 ]; then
    printf "%s" "drift"
  else
    printf "%s" "updated"
  fi
}

run_once() {
  scanned=0
  updated=0
  drift=0

  for repo in "$ROOT_PATH"/*; do
    [ -d "$repo" ] || continue

    name=$(basename "$repo")
    [ "$name" = "$EXCLUDE_NAME" ] && continue

    scanned=$((scanned + 1))

    agents_target="$repo/AGENTS.md"
    dod_target="$repo/docs/DEFINITION_OF_DONE.md"
    gitattributes_target="$repo/.gitattributes"
    editorconfig_target="$repo/.editorconfig"
    precommit_target="$repo/.githooks/pre-commit"
    hooks_readme_target="$repo/.githooks/README.md"
    gitignore_target="$repo/.gitignore"

    agents_state=$(ensure_file "$AGENTS_TEMPLATE" "$agents_target")
    dod_state=$(ensure_file "$DOD_TEMPLATE" "$dod_target")
    gitattributes_state=$(ensure_file "$GITATTRIBUTES_TEMPLATE" "$gitattributes_target")
    editorconfig_state=$(ensure_file "$EDITORCONFIG_TEMPLATE" "$editorconfig_target")
    precommit_state=$(ensure_file "$PRECOMMIT_TEMPLATE" "$precommit_target")
    hooks_readme_state=$(ensure_file "$HOOKS_README_TEMPLATE" "$hooks_readme_target")
    gitignore_state=$(ensure_gitignore_entries_from_template "$GITIGNORE_TEMPLATE" "$gitignore_target")

    if [ "$agents_state" = "updated" ] || [ "$dod_state" = "updated" ] || [ "$gitattributes_state" = "updated" ] || [ "$editorconfig_state" = "updated" ] || [ "$precommit_state" = "updated" ] || [ "$hooks_readme_state" = "updated" ] || [ "$gitignore_state" = "updated" ]; then
      updated=$((updated + 1))
      echo "UPDATED: $repo"
      continue
    fi

    if [ "$agents_state" = "drift" ] || [ "$dod_state" = "drift" ] || [ "$gitattributes_state" = "drift" ] || [ "$editorconfig_state" = "drift" ] || [ "$precommit_state" = "drift" ] || [ "$hooks_readme_state" = "drift" ] || [ "$gitignore_state" = "drift" ]; then
      drift=$((drift + 1))
      echo "DRIFT:   $repo"
      continue
    fi

    echo "OK:      $repo"
  done

  echo "Summary -> scanned=$scanned, updated=$updated, drift=$drift"

  if [ "$CHECK_ONLY" -eq 1 ] && [ "$drift" -gt 0 ]; then
    return 1
  fi

  return 0
}

if [ "$WATCH" -eq 1 ]; then
  while :; do
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] Reconciling project standards..."
    run_once || true
    sleep "$INTERVAL"
  done
else
  run_once
fi