import { Config, Provide } from '@midwayjs/core';
import { InjectDataSource, InjectEntityModel } from '@midwayjs/typeorm';
import { DataSource, Repository, getCustomRepository, getManager } from 'typeorm';
import { get, head, upperFirst } from 'lodash';
import * as fs from 'fs';
import * as path from 'path';
@Provide()
export class DbBackupService {
  @InjectDataSource('default')
  defaultDataSource: DataSource;

  @Config('PathConfig.path')
  filePath;

  dbBackupDir = 'dbBackUp';

  async getTables() {
    console.log('to dump');
    const entitys = this.defaultDataSource.entityMetadatas;
    const dbBackUpPath = path.resolve(this.filePath, this.dbBackupDir);
    const res = fs.existsSync(dbBackUpPath);
    if (!res) {
      fs.mkdirSync(dbBackUpPath);
    }
    for (const e of entitys) {
      const tableNames = e.givenTableName;
      const dataSql = `SELECT * from "public"."${tableNames}" ORDER BY "id" ;`;
      const dataRes = await this.defaultDataSource.query(dataSql);
      const fileFullPath = path.resolve(dbBackUpPath, `${tableNames}.json`);
      fs.writeFileSync(fileFullPath, JSON.stringify(dataRes), 'utf-8');
    }
    console.log('dump finish');
  }
  /**
   * 根据表名,找entity
   * 有entity,通过数据源创建createQueryBuilder.对数据进行批量添加
   * @param {string} dirPath 文件夹路径,没有就默认使用备份路径
   */
  async restore(dirPath?: string) {
    console.log('to restore');
    if (!dirPath) dirPath = path.resolve(this.filePath, this.dbBackupDir);
    const dbBackUpPathDir = dirPath;
    let dir = fs.readdirSync(dbBackUpPathDir);
    dir = dir.map(i => {
      const arr = i.split('.');
      return head(arr);
    });
    for (const tableName of dir) {
      // 清空表, 重置id;
      console.log(tableName);
      const filePath = path.resolve(dbBackUpPathDir, `${tableName}.json`);
      let datas = fs.readFileSync(filePath, 'utf-8');
      if (datas) datas = JSON.parse(datas);
      console.log(`${tableName} start`);
      await this.defaultDataSource.query(`TRUNCATE TABLE "public"."${tableName}" RESTART IDENTITY RESTRICT;`);
      await this.defaultDataSource.query(`SELECT setval('"${tableName}_id_seq"', (SELECT max(id) FROM "${tableName}"));`);
      const entities: any = this.defaultDataSource.options.entities;
      const entity = entities.find(f => get(f, 'name') === `${upperFirst(tableName)}`);
      for (const i of datas) {
        try {
          // 需要处理id的问题
          const data_id = get(i, 'id', 1);
          // 获取当前表id的序列
          const lastIdResult = await this.defaultDataSource.query(`SELECT max(id) FROM "${tableName}"`);
          let last_id = get(head(lastIdResult), 'max', 0);
          // 判断same_id: 表中最后一个id和当前数据id是否一致
          let same_id = last_id === data_id;
          if (!same_id && data_id > 1) {
            // 不一致:只有一种情况----当前数据的id比表中的数据id要大.那就直接执行id补上

            await this.defaultDataSource.query(`SELECT setval('"${tableName}_id_seq"', ${data_id - 1});`);
          }
          const builder = await this.defaultDataSource.manager.createQueryBuilder().insert().into(entity);
          await builder.values(i).execute();
        } catch (error) {
          console.log(`${tableName} - ${get(i, 'id')} -  发生错误`);
          console.log(error);
        }
      }
    }
    console.log('restore finish');
  }
}