import { NextFunction, Request, Response } from 'express';
import { existsSync } from 'fs';
import { join } from 'path';

import { CacheConf, configService, Database } from '../../config/env.config';
import { INSTANCE_DIR } from '../../config/path.config';
import {
  BadRequestException,
  ForbiddenException,
  InternalServerErrorException,
  NotFoundException,
} from '../../exceptions';
import { dbserver } from '../../libs/db.connect';
import { InstanceDto } from '../dto/instance.dto';
import { cache, waMonitor } from '../server.module';

async function getInstance(instanceName: string) {
  try {
    const db = configService.get<Database>('DATABASE');
    const cacheConf = configService.get<CacheConf>('CACHE');

    const exists = !!waMonitor.waInstances[instanceName];

    if (cacheConf.REDIS.ENABLED && cacheConf.REDIS.SAVE_INSTANCES) {
      const keyExists = await cache.has(instanceName);

      return exists || keyExists;
    }

    if (db.ENABLED) {
      const collection = dbserver
        .getClient()
        .db(db.CONNECTION.DB_PREFIX_NAME + '-instances')
        .collection(instanceName);
      return exists || (await collection.find({}).toArray()).length > 0;
    }

    return exists || existsSync(join(INSTANCE_DIR, instanceName));
  } catch (error) {
    throw new InternalServerErrorException(error?.toString());
  }
}

export async function instanceExistsGuard(req: Request, _: Response, next: NextFunction) {
  if (req.originalUrl.includes('/instance/create') || req.originalUrl.includes('/instance/fetchInstances')) {
    return next();
  }

  const param = req.params as unknown as InstanceDto;
  if (!param?.instanceName) {
    throw new BadRequestException('"instanceName" not provided.');
  }

  if (!(await getInstance(param.instanceName))) {
    throw new NotFoundException(`The "${param.instanceName}" instance does not exist`);
  }

  next();
}

export async function instanceLoggedGuard(req: Request, _: Response, next: NextFunction) {
  if (req.originalUrl.includes('/instance/create')) {
    const instance = req.body as InstanceDto;
    if (await getInstance(instance.instanceName)) {
      throw new ForbiddenException(`This name "${instance.instanceName}" is already in use.`);
    }

    if (waMonitor.waInstances[instance.instanceName]) {
      waMonitor.waInstances[instance.instanceName]?.removeRabbitmqQueues();
      delete waMonitor.waInstances[instance.instanceName];
    }
  }

  next();
}