import Services from "./service";
import Database from "./database.service";

/**
 * Service Worker Controller - Manages SW registration and communication
 */
export class SWController {
  private static instance: SWController;
  private serviceWorkerRegistration: ServiceWorkerRegistration | null = null;
  private serviceWorkerCheckIntervalId: number | null = null;

  private constructor() {
    // Singleton
  }

  public static async getInstance(): Promise<SWController> {
    if (!SWController.instance) {
      SWController.instance = new SWController();
    }
    return SWController.instance;
  }

  public async init(): Promise<void> {
    await this.registerServiceWorker("/data.worker.js");
  }

  private async registerServiceWorker(path: string): Promise<void> {
    if (!("serviceWorker" in navigator)) return;
    console.log("[SWController] Initializing Service Worker:", path);

    try {
      // Nettoyage des anciens workers si nécessaire (logique conservée)
      const registrations = await navigator.serviceWorker.getRegistrations();
      for (const registration of registrations) {
        const scriptURL =
          registration.active?.scriptURL ||
          registration.installing?.scriptURL ||
          registration.waiting?.scriptURL;
        const scope = registration.scope;

        if (
          scope.includes("/src/service-workers/") ||
          (scriptURL && scriptURL.includes("/src/service-workers/"))
        ) {
          console.warn(`[SWController] Removing old Service Worker (${scope})`);
          await registration.unregister();
        }
      }

      const existingValidWorker = registrations.find((r) => {
        const url =
          r.active?.scriptURL ||
          r.installing?.scriptURL ||
          r.waiting?.scriptURL;
        return url && url.endsWith(path.replace(/^\//, ""));
      });

      if (!existingValidWorker) {
        console.log("[SWController] Registering new Service Worker");
        this.serviceWorkerRegistration = await navigator.serviceWorker.register(
          path,
          { type: "module", scope: "/" }
        );
      } else {
        console.log("[SWController] Service Worker already active");
        this.serviceWorkerRegistration = existingValidWorker;
        await this.serviceWorkerRegistration.update();
      }

      navigator.serviceWorker.addEventListener("message", async (event) => {
        await this.handleServiceWorkerMessage(event.data);
      });

      // Boucle de scan périodique
      if (this.serviceWorkerCheckIntervalId)
        clearInterval(this.serviceWorkerCheckIntervalId);

      this.serviceWorkerCheckIntervalId = window.setInterval(async () => {
        const activeWorker =
          this.serviceWorkerRegistration?.active ||
          (await this.waitForServiceWorkerActivation(
            this.serviceWorkerRegistration!
          ));

        // On récupère les processus via le proxy Services
        const service = await Services.getInstance();
        const payload = await service.getMyProcesses();

        if (payload && Object.keys(payload).length !== 0) {
          activeWorker?.postMessage({ type: "SCAN", payload });
        }
      }, 5000);
    } catch (error) {
      console.error("[SWController] Service Worker error:", error);
    }
  }

  private async waitForServiceWorkerActivation(
    registration: ServiceWorkerRegistration
  ): Promise<ServiceWorker | null> {
    return new Promise((resolve) => {
      if (registration.active) {
        resolve(registration.active);
      } else {
        const listener = () => {
          if (registration.active) {
            navigator.serviceWorker.removeEventListener(
              "controllerchange",
              listener
            );
            resolve(registration.active);
          }
        };
        navigator.serviceWorker.addEventListener("controllerchange", listener);
      }
    });
  }

  // ============================================
  // MESSAGE HANDLERS
  // ============================================

  private async handleServiceWorkerMessage(message: any) {
    switch (message.type) {
      case "TO_DOWNLOAD":
        await this.handleDownloadList(message.data);
        break;
      case "DIFFS_TO_CREATE":
        await this.handleDiffsToCreate(message.data);
        break;
      default:
        console.warn("[SWController] Unknown message type received:", message);
    }
  }

  private async handleDiffsToCreate(diffs: any[]): Promise<void> {
    console.log(
      `[SWController] Creating ${diffs.length} diffs from Service Worker scan`
    );
    try {
      const db = await Database.getInstance();
      await db.saveDiffs(diffs);
      console.log("[SWController] Diffs created successfully");
    } catch (error) {
      console.error("[SWController] Error creating diffs:", error);
    }
  }

  private async handleDownloadList(downloadList: string[]): Promise<void> {
    let requestedStateId: string[] = [];

    // On a besoin de Services pour la logique métier (fetch, network)
    const service = await Services.getInstance();

    for (const hash of downloadList) {
      const diff = await service.getDiffByValue(hash);
      if (!diff) {
        console.warn(`[SWController] Missing a diff for hash ${hash}`);
        continue;
      }

      const processId = diff.process_id;
      const stateId = diff.state_id;
      const roles = diff.roles;

      try {
        const valueBytes = await service.fetchValueFromStorage(hash);
        if (valueBytes) {
          const blob = new Blob([valueBytes], {
            type: "application/octet-stream",
          });

          await service.saveBlobToDb(hash, blob);

          document.dispatchEvent(
            new CustomEvent("newDataReceived", {
              detail: { processId, stateId, hash },
            })
          );
        } else {
          console.log(
            "[SWController] Request data from managers of the process"
          );
          if (!requestedStateId.includes(stateId)) {
            await service.requestDataFromPeers(processId, [stateId], [roles]);
            requestedStateId.push(stateId);
          }
        }
      } catch (e) {
        console.error(e);
      }
    }
  }
}