'use strict';

/**
 * ops 存储门面
 * ----------------------------------------------------------------------------
 * 读 config.storage 决定驱动（默认 SQLite），把驱动实例藏起来，对外只暴露业务接口。
 * 关键约束：初始化失败不能拖垮主服务 —— 所有失败都收敛成 health() 的 ok:false，
 * 只有「店铺运营」相关接口会返回 503。
 */

const path = require('path');

const ROOT_DIR = __dirname;

function pickDriver(storage) {
  const raw = String((storage && storage.driver) || 'sqlite').toLowerCase();
  return raw === 'postgres' || raw === 'postgresql' || raw === 'pg' ? 'postgres' : 'sqlite';
}

function createOpsStore(config) {
  const storage = (config && config.storage) || {};
  const driver = pickDriver(storage);

  let impl = null;
  let initPromise = null;
  let lastFailure = null;

  function build() {
    if (driver === 'postgres') {
      const pgCfg = storage.postgres || {};
      let connectionString = process.env.OPS_DATABASE_URL || pgCfg.connectionString || '';
      // 也支持「主机/库/用户/密码」分开填（设置页用这种）
      if (!String(connectionString).trim() && pgCfg.host && pgCfg.database) {
        const user = encodeURIComponent(pgCfg.user || 'postgres');
        const pass = pgCfg.password ? ':' + encodeURIComponent(pgCfg.password) : '';
        const port = pgCfg.port || 5432;
        connectionString = `postgres://${user}${pass}@${pgCfg.host}:${port}/${pgCfg.database}`;
        if (pgCfg.ssl) connectionString += (connectionString.includes('?') ? '&' : '?') + 'sslmode=require';
      }
      if (!String(connectionString).trim()) {
        const err = new Error('未配置 PostgreSQL 连接信息');
        err.reason = 'storage-not-configured';
        throw err;
      }
      const { createPgStore } = require('./server/stores/ops-pg.js');
      return createPgStore({ ...pgCfg, connectionString });
    }
    const sqliteCfg = storage.sqlite || {};
    const file = sqliteCfg.file
      ? path.resolve(ROOT_DIR, String(sqliteCfg.file))
      : path.join(ROOT_DIR, 'data', 'ops.db');
    const { createSqliteStore } = require('./server/stores/ops-sqlite.js');
    return createSqliteStore({ file });
  }

  function get() {
    if (impl) return impl;
    try {
      impl = build();
      lastFailure = null;
      return impl;
    } catch (e) {
      lastFailure = e;
      throw e;
    }
  }

  function reset() {
    impl = null;
    initPromise = null;
  }

  async function init() {
    if (!initPromise) {
      initPromise = Promise.resolve()
        .then(() => get())
        .then((store) => store.init())
        .then(() => get())
        .catch((e) => {
          lastFailure = e;
          initPromise = null;
          throw e;
        });
    }
    return initPromise;
  }

  /** never throws：{ ok, kind, reason?, detail? } */
  async function health() {
    try {
      await init();
      const result = await get().health();
      return { ...result, kind: driver };
    } catch (e) {
      return {
        ok: false,
        kind: driver,
        reason: e.reason || (e.code === 'MODULE_NOT_FOUND' ? 'driver-missing' : 'storage-unreachable'),
        detail: e.message || String(e),
        stack: undefined,
      };
    }
  }

  /** 包装：统一先 ensure init，再调用驱动方法 */
  function call(name) {
    return async (...args) => {
      await init();
      return get()[name](...args);
    };
  }

  return {
    kind: driver,
    init,
    health,
    reset,
    close: async () => {
      if (impl && typeof impl.close === 'function') {
        try { await impl.close(); } catch { /* ignore */ }
      }
      reset();
    },
    withTransaction: async (fn) => {
      await init();
      return get().withTransaction(fn);
    },
    findUploadBySha: call('findUploadBySha'),
    listUploads: call('listUploads'),
    getUpload: call('getUpload'),
    getContent: call('getContent'),
    queryRows: call('queryRows'),
    queryPlatformRows: call('queryPlatformRows'),
    insertReport: call('insertReport'),
    getReportCache: call('getReportCache'),
    saveReportCache: call('saveReportCache'),
    listReports: call('listReports'),
    getReport: call('getReport'),
    deleteReport: call('deleteReport'),
    summary: call('summary'),
    get failure() {
      return lastFailure;
    },
  };
}

module.exports = { createOpsStore, pickDriver };