/**
 * 云函数共享的 Parse Class 存储工具。
 *
 * 本项目的结构化业务主数据写入带 VideoWorkflow 命名空间的 Parse Class。
 * 这里封装 REST 调用、项目命名空间字段和 owner Pointer，避免业务云函数
 * 继续直接依赖 PSQL。
 */

const PARSE_CLASS_PROJECT_KEY = 'video-workflow';

const VIDEO_WORKFLOW_CLASSES = {
  entity: 'VideoWorkflowEntity',
  audit: 'VideoWorkflowAudit',
  migration: 'VideoWorkflowMigration',
  fileAsset: 'VideoWorkflowFileAsset',
};

function createParseClassStore(options = {}) {
  const parseApiHost = normalizeParseApiHost(options.parseApiHost || parseStoreEnv('PARSE_API_HOST', parseStoreEnv('PARSE_BASE_URL', 'https://server.fmode.cn')));
  const appId = options.appId || parseStoreEnv('PARSE_APP_ID', parseStoreEnv('PARSE_APPLICATION_ID', 'ncloudmaster'));
  const sessionToken = options.sessionToken || '';

  return {
    findFirst: (className, where, opts = {}) => parseFindFirst({ parseApiHost, appId, sessionToken, className, where, opts }),
    list: (className, where, opts = {}) => parseList({ parseApiHost, appId, sessionToken, className, where, opts }),
    create: (className, data) => parseCreate({ parseApiHost, appId, sessionToken, className, data }),
    update: (className, objectId, patch) => parseUpdate({ parseApiHost, appId, sessionToken, className, objectId, patch }),
    deleteRecord: (className, objectId) => parseDelete({ parseApiHost, appId, sessionToken, className, objectId }),
    upsertByQuery: (className, where, data, opts = {}) => parseUpsertByQuery({ parseApiHost, appId, sessionToken, className, where, data, opts }),
    userFields: (userId) => parseUserFields(userId),
    projectKey: PARSE_CLASS_PROJECT_KEY,
  };
}

function parseUserFields(userId) {
  return {
    projectKey: PARSE_CLASS_PROJECT_KEY,
    owner: { __type: 'Pointer', className: '_User', objectId: String(userId || '') },
    ownerId: String(userId || ''),
  };
}

function parseUserWhere(userId, extra = {}) {
  return {
    projectKey: PARSE_CLASS_PROJECT_KEY,
    owner: { __type: 'Pointer', className: '_User', objectId: String(userId || '') },
    ...extra,
  };
}

async function parseFindFirst(ctx) {
  const rows = await parseList({ ...ctx, opts: { ...ctx.opts, limit: 1 } });
  return rows[0] || null;
}

async function parseList({ parseApiHost, appId, sessionToken, className, where, opts = {} }) {
  const query = new URLSearchParams();
  query.set('where', JSON.stringify(where || {}));
  query.set('limit', String(safeParseLimit(opts.limit, 100, 1000)));
  if (opts.skip !== undefined) query.set('skip', String(Math.max(0, parseInt(opts.skip || 0, 10) || 0)));
  if (opts.order) query.set('order', String(opts.order));
  if (opts.include) query.set('include', String(opts.include));
  if (opts.keys) query.set('keys', String(opts.keys));
  const data = await parseRequest({
    parseApiHost,
    appId,
    sessionToken,
    method: 'GET',
    path: `/classes/${encodeURIComponent(className)}?${query.toString()}`,
  });
  return Array.isArray(data.results) ? data.results : [];
}

async function parseCreate({ parseApiHost, appId, sessionToken, className, data }) {
  const created = await parseRequest({
    parseApiHost,
    appId,
    sessionToken,
    method: 'POST',
    path: `/classes/${encodeURIComponent(className)}`,
    body: sanitizeParseWrite(data),
  });
  return { ...sanitizeParseWrite(data), ...created };
}

async function parseUpdate({ parseApiHost, appId, sessionToken, className, objectId, patch }) {
  await parseRequest({
    parseApiHost,
    appId,
    sessionToken,
    method: 'PUT',
    path: `/classes/${encodeURIComponent(className)}/${encodeURIComponent(objectId)}`,
    body: sanitizeParseWrite(patch),
  });
  return parseFindFirst({
    parseApiHost,
    appId,
    sessionToken,
    className,
    where: { objectId },
    opts: { limit: 1 },
  });
}

async function parseDelete({ parseApiHost, appId, sessionToken, className, objectId }) {
  return parseRequest({
    parseApiHost,
    appId,
    sessionToken,
    method: 'DELETE',
    path: `/classes/${encodeURIComponent(className)}/${encodeURIComponent(objectId)}`,
  });
}

async function parseUpsertByQuery({ parseApiHost, appId, sessionToken, className, where, data, opts = {} }) {
  const findExisting = () => parseFindFirst({
    parseApiHost,
    appId,
    sessionToken,
    className,
    where,
    opts: { order: opts.order || '-updatedAt', limit: 1 },
  });
  const existing = await findExisting();
  if (existing && existing.objectId) {
    return parseUpdate({
      parseApiHost,
      appId,
      sessionToken,
      className,
      objectId: existing.objectId,
      patch: data,
    });
  }
  try {
    return await parseCreate({ parseApiHost, appId, sessionToken, className, data: { ...where, ...data } });
  } catch (error) {
    if (!isRetryableParseError(error)) throw error;
    await parseStoreSleep(500);
    const created = await findExisting();
    if (created && created.objectId) {
      return parseUpdate({
        parseApiHost,
        appId,
        sessionToken,
        className,
        objectId: created.objectId,
        patch: data,
      });
    }
    return parseCreate({ parseApiHost, appId, sessionToken, className, data: { ...where, ...data } });
  }
}

async function parseRequest({ parseApiHost, appId, sessionToken, method, path, body }) {
  const headers = {
    'Accept': 'application/json',
    'X-Parse-Application-Id': appId,
  };
  if (sessionToken) headers['X-Parse-Session-Token'] = sessionToken;
  if (body !== undefined) headers['Content-Type'] = 'application/json';

  const maxAttempts = isSafeParseRetryMethod(method) ? 3 : 1;
  let lastError = null;
  for (let attempt = 1; attempt <= maxAttempts; attempt += 1) {
    try {
      const resp = await fetch(`${parseApiHost}/parse${path}`, {
        method,
        headers,
        body: body !== undefined ? JSON.stringify(body) : undefined,
      });
      const data = await resp.json().catch(() => ({}));
      if (!resp.ok || data.error) {
        const error = new Error(data.error || data.message || `Parse ${method} ${path} failed`);
        error.status = resp.status || 500;
        error.detail = data;
        if (attempt < maxAttempts && isRetryableParseError(error)) {
          await parseStoreSleep(350 * attempt);
          continue;
        }
        throw error;
      }
      return data;
    } catch (error) {
      lastError = error;
      if (attempt < maxAttempts && isRetryableParseError(error)) {
        await parseStoreSleep(350 * attempt);
        continue;
      }
      throw error;
    }
  }
  throw lastError || new Error(`Parse ${method} ${path} failed`);
}

function sanitizeParseWrite(value) {
  const source = normalizeParseObject(value);
  const next = {};
  for (const [key, item] of Object.entries(source)) {
    if (['objectId', 'createdAt', 'updatedAt'].includes(key)) continue;
    if (item === undefined) continue;
    next[key] = item;
  }
  return next;
}

function normalizeParseObject(value) {
  if (!value || typeof value !== 'object' || Array.isArray(value)) return {};
  return value;
}

function normalizeParseApiHost(value) {
  return String(value || 'https://server.fmode.cn').replace(/\/+$/, '').replace(/\/parse$/i, '');
}

function safeParseLimit(value, fallback, max) {
  const parsed = parseInt(value || fallback, 10);
  return Number.isFinite(parsed) ? Math.min(Math.max(parsed, 1), max) : fallback;
}

function parseStoreEnv(name, fallback = '') {
  if (typeof process !== 'undefined' && process.env && process.env[name] !== undefined) {
    return process.env[name];
  }
  return fallback;
}

function isSafeParseRetryMethod(method) {
  return ['GET', 'PUT', 'DELETE'].includes(String(method || '').toUpperCase());
}

function isRetryableParseError(error) {
  const status = Number(error?.status || 0);
  const message = `${error?.message || ''} ${error?.detail?.error || ''} ${error?.detail?.message || ''}`;
  return status >= 500 || /fetch failed|Failed to fetch|NetworkError|Load failed|ECONNRESET|ETIMEDOUT|EAI_AGAIN/i.test(message);
}

function parseStoreSleep(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

module.exports = {
  PARSE_CLASS_PROJECT_KEY,
  VIDEO_WORKFLOW_CLASSES,
  createParseClassStore,
  parseUserFields,
  parseUserWhere,
};