import { Controller, Get, HttpException, HttpStatus } from "@nestjs/common";
import { sql } from "drizzle-orm";
import { db } from "../../config/database.js";
import { isRedisHealthy } from "../../config/redis.js";
import { isKafkaConnected } from "../../config/kafka.js";

const SERVICE_NAME = "core-edu";

interface HealthResponse {
  status: string;
  service: string;
  timestamp: string;
  checks?: Record<string, string>;
}

@Controller()
export class HealthController {
  @Get("healthz")
  liveness(): HealthResponse {
    return {
      status: "ok",
      service: SERVICE_NAME,
      timestamp: new Date().toISOString(),
    };
  }

  @Get("readyz")
  async readiness(): Promise<HealthResponse> {
    const checks: Record<string, string> = {};
    let allHealthy = true;

    // DB check
    try {
      await db.execute(sql`SELECT 1`);
      checks.db = "ok";
    } catch (error) {
      checks.db = error instanceof Error ? error.message : "unreachable";
      allHealthy = false;
    }

    // Redis check (optional - degrade gracefully)
    try {
      const redisOk = await isRedisHealthy();
      checks.redis = redisOk ? "ok" : "disabled";
    } catch {
      checks.redis = "disabled";
    }

    // Kafka check (optional - degrade gracefully)
    try {
      checks.kafka = isKafkaConnected() ? "ok" : "disconnected";
    } catch {
      checks.kafka = "unknown";
    }

    if (!allHealthy) {
      throw new HttpException(
        {
          status: "error",
          service: SERVICE_NAME,
          timestamp: new Date().toISOString(),
          checks,
        },
        HttpStatus.SERVICE_UNAVAILABLE,
      );
    }

    return {
      status: "ok",
      service: SERVICE_NAME,
      timestamp: new Date().toISOString(),
      checks,
    };
  }
}