#!/usr/bin/env node
/**
 * PreToolUse hook: auto-backup config files before Edit/Write.
 * Reads $TOOL_INPUT to check if the target file is a config file.
 * If yes, backs it up via scanners/lib/backup.mjs.
 * Fast path — no scanner execution.
 */

import { existsSync } from 'node:fs';
import { basename, dirname, sep } from 'node:path';

// Config file patterns to protect
const CONFIG_PATTERNS = [
  /CLAUDE\.md$/i,
  /CLAUDE\.local\.md$/i,
  /settings\.json$/,
  /settings\.local\.json$/,
  /hooks\.json$/,
  /\.mcp\.json$/,
  /keybindings\.json$/,
];

const CONFIG_DIRS = ['rules'];

function isConfigFile(filePath) {
  if (!filePath) return false;
  const name = basename(filePath);
  const dir = dirname(filePath);

  // Check filename patterns
  for (const pattern of CONFIG_PATTERNS) {
    if (pattern.test(name)) return true;
  }

  // Check if inside a rules/ directory
  for (const d of CONFIG_DIRS) {
    if (dir.includes(`${sep}${d}${sep}`) || dir.endsWith(`${sep}${d}`)) {
      if (name.endsWith('.md')) return true;
    }
  }

  return false;
}

/**
 * Read all data from stdin asynchronously.
 * @returns {Promise<string>}
 */
function readStdin() {
  return new Promise((resolve, reject) => {
    const chunks = [];
    process.stdin.setEncoding('utf-8');
    process.stdin.on('data', chunk => chunks.push(chunk));
    process.stdin.on('end', () => resolve(chunks.join('')));
    process.stdin.on('error', reject);
  });
}

async function main() {
  let input;
  try {
    input = await readStdin();
  } catch {
    process.exit(0);
  }

  let toolInput;
  try {
    toolInput = JSON.parse(input);
  } catch {
    process.exit(0);
  }

  const filePath = toolInput.file_path || toolInput.path;
  if (!filePath || !isConfigFile(filePath) || !existsSync(filePath)) {
    process.exit(0);
  }

  const { createBackup } = await import('../../scanners/lib/backup.mjs');
  const { backupPath } = createBackup([filePath]);
  process.stderr.write(`[config-audit] Auto-backup: ${basename(filePath)} → ${backupPath}\n`);
}

main().catch(() => process.exit(0));