import { AcInfinityApiClient, AcInfinityApiError } from "../http/AcInfinityApiClient";
import { TyphonMetrics } from "../metrics/TyphonMetrics";
import { Logger } from "../observability/Logger";

export class ClimatePollingService {
  private timer: NodeJS.Timeout | null = null;
  private inFlight = false;

  public constructor(
    private readonly client: AcInfinityApiClient,
    private readonly metrics: TyphonMetrics,
    private readonly logger: Logger,
    private readonly pollIntervalSeconds: number
  ) {}

  public start(): void {
    void this.pollOnce();
    this.timer = setInterval(() => {
      void this.pollOnce();
    }, this.pollIntervalSeconds * 1000);
  }

  public stop(): void {
    if (this.timer) {
      clearInterval(this.timer);
      this.timer = null;
    }
  }

  private async pollOnce(): Promise<void> {
    if (this.inFlight) {
      this.logger.warn("skipping poll because previous poll is still running");
      return;
    }

    this.inFlight = true;
    try {
      const snapshot = await this.client.fetchSnapshot();
      this.metrics.updateFromSnapshot(snapshot);
      this.logger.info("poll succeeded", {
        controller_count: snapshot.controllers.length
      });
    } catch (error) {
      const { reason, code } = this.classifyError(error);
      this.metrics.markPollFailure(reason, code);
      this.logger.error("poll failed", {
        reason,
        code,
        error_message: error instanceof Error ? error.message : String(error)
      });
    } finally {
      this.metrics.refreshDataAgeGauge();
      this.inFlight = false;
    }
  }

  private classifyError(error: unknown): { reason: string; code: string } {
    if (error instanceof AcInfinityApiError) {
      if (error.apiCode === "10001" || error.apiCode === "invalid_auth") {
        return { reason: "auth", code: error.apiCode };
      }
      return { reason: "api", code: error.apiCode };
    }

    if (error instanceof Error && error.name === "AbortError") {
      return { reason: "timeout", code: "timeout" };
    }

    return { reason: "unknown", code: "unknown" };
  }
}