/**
 * Manifest — 清单文件读写
 *
 * 存储在 control-ui/clawlink-manifest.json，
 * 记录当前已加载的扩展点及其版本，用于 reconciliation。
 */

import { readFileSync, writeFileSync, unlinkSync, existsSync } from 'node:fs';
import { join } from 'node:path';
import { logger } from '../../util/logger.js';

const MANIFEST_FILENAME = 'clawlink-manifest.json';

export interface ManifestData {
  bundleHash: string;
  /** 当前使用的注入策略。 */
  strategy?: 'regex';
  extensions: Record<string, { version: number }>;
}

/**
 * 读取清单文件。不存在或解析失败返回 null。
 */
export function readManifest(controlUiDir: string): ManifestData | null {
  const filepath = join(controlUiDir, MANIFEST_FILENAME);
  if (!existsSync(filepath)) {
    return null;
  }

  try {
    const raw = readFileSync(filepath, 'utf-8');
    return JSON.parse(raw) as ManifestData;
  } catch (err) {
    logger.warn(`[ui-ext] Failed to parse manifest: ${(err as Error).message}`);
    return null;
  }
}

/**
 * 写入清单文件。
 */
export function writeManifest(controlUiDir: string, data: ManifestData): void {
  const filepath = join(controlUiDir, MANIFEST_FILENAME);
  writeFileSync(filepath, JSON.stringify(data, null, 2), 'utf-8');
  logger.debug('[ui-ext] Manifest written');
}

/**
 * 删除清单文件。
 */
export function removeManifest(controlUiDir: string): void {
  const filepath = join(controlUiDir, MANIFEST_FILENAME);
  if (existsSync(filepath)) {
    unlinkSync(filepath);
    logger.debug('[ui-ext] Manifest removed');
  }
}