import { Inject, Injectable, type OnModuleDestroy } from "@nestjs/common";
import { createClient, type RedisClientType } from "redis";
import { PrismaService } from "../database/prisma.service.js";
import { DomainException } from "../common/domain.exception.js";
import { ErrorCode } from "@drift/contracts";
import { HttpStatus } from "@nestjs/common";

@Injectable()
export class HealthService implements OnModuleDestroy {
  private readonly redis: RedisClientType;

  get redisClient(): RedisClientType {
    return this.redis;
  }

  constructor(@Inject(PrismaService) private readonly prisma: PrismaService) {
    this.redis = createClient({
      url: process.env.REDIS_URL ?? "redis://127.0.0.1:6379",
      socket: { connectTimeout: 500, reconnectStrategy: false },
    });
    this.redis.on("error", () => undefined);
  }

  async check(): Promise<{ status: "ok"; postgres: "up"; redis: "up" }> {
    try {
      if (!this.redis.isOpen) await this.redis.connect();
      await Promise.all([this.prisma.$queryRaw`SELECT 1`, this.redis.ping()]);
      return { status: "ok", postgres: "up", redis: "up" };
    } catch {
      throw new DomainException(
        ErrorCode.SERVICE_UNAVAILABLE,
        "Dependencies unavailable",
        HttpStatus.SERVICE_UNAVAILABLE,
      );
    }
  }

  async onModuleDestroy(): Promise<void> {
    if (this.redis.isOpen) await this.redis.quit();
  }
}