import { Injectable } from '@nestjs/common'
import { RpcException } from '@nestjs/microservices'
import { RpcStatus } from '@teacinema/common'
import { createHash } from 'node:crypto'

import { RedisService } from '@/infra/redis/redis.service'

@Injectable()
export class OtpService {
  public constructor(private readonly redisService: RedisService) {}

  public async send(indentifier: string, type: 'email' | 'phone') {
    const { code, hash } = this.generateCode()

    await this.redisService.set(
      `otp:${type}:${indentifier}`,
      hash,
      'EX',
      60 * 5
    )

    return code
  }

  public async verify(
    indentifier: string,
    code: string,
    type: 'email' | 'phone'
  ) {
    const stroredHash = await this.redisService.get(
      `otp:${type}:${indentifier}`
    )

    if (!stroredHash) {
      throw new RpcException({
        code: RpcStatus.NOT_FOUND,
        details: 'Invalid or expired code'
      })
    }

    const hash = createHash('sha256').update(code).digest('hex')
    if (stroredHash !== hash) {
      throw new RpcException({
        code: RpcStatus.NOT_FOUND,
        details: 'Invalid or expired code'
      })
    }

    await this.redisService.del(`otp:${type}:${indentifier}`)
  }

  private generateCode() {
    // todo посмотреть готовые бибилотеки для генерации friendly otp
    const code = Math.floor(100_000 + Math.random() * 900_000)
    const hash = createHash('sha256').update(String(code)).digest('hex')

    return { code, hash }
  }
}