import { Inject, Controller, Get } from "@nestjs/common";
import { HealthService } from "./health.service.js";
import { ApiError } from "../../common/errors.js";

@Controller("health")
export class HealthController {
  constructor(@Inject(HealthService) private readonly health: HealthService) {}

  @Get()
  liveness() {
    return this.health.liveness();
  }

  /**
   * Readiness probe: 503 SERVICE_UNAVAILABLE when a dependency is down.
   * Canonical path `GET /api/v1/health/ready` (TASK-0009 + the K8s probe in
   * infrastructure/kubernetes/api.yaml). `GET /api/v1/health/deep` is kept as
   * a deprecated alias so existing references keep resolving.
   */
  @Get("ready")
  async ready() {
    const result = await this.health.deep();
    if (!result.ok) {
      const down = (["postgres", "redis"] as const).filter((k) => !result.checks[k]);
      throw new ApiError("SERVICE_UNAVAILABLE", 503, "Dependency unavailable.", [
        { service: down.join(",") }
      ]);
    }
    return { status: "ready" as const, checks: result.checks };
  }

  /** @deprecated alias of {@link ready} (pre-existing path). */
  @Get("deep")
  async deep() {
    return this.ready();
  }
}