import { createApp, App } from "vue";
import { QRScannerService, ScanListener, QRScannerOptions } from "./types";
import QRScannerDialog from "@/components/QRScanner/QRScannerDialog.vue";
import { logger } from "@/utils/logger";

export class WebDialogQRScanner implements QRScannerService {
  private dialogInstance: App | null = null;
  private dialogComponent: InstanceType<typeof QRScannerDialog> | null = null;
  private scanListener: ScanListener | null = null;
  private isScanning = false;
  private container: HTMLElement | null = null;

  constructor(private options?: QRScannerOptions) {}

  async checkPermissions(): Promise<boolean> {
    try {
      const permissions = await navigator.permissions.query({
        name: "camera" as PermissionName,
      });
      return permissions.state === "granted";
    } catch (error) {
      const wrappedError =
        error instanceof Error ? error : new Error(String(error));
      logger.error("Error checking camera permissions:", wrappedError);
      return false;
    }
  }

  async requestPermissions(): Promise<boolean> {
    try {
      // First check if we have any video devices
      const devices = await navigator.mediaDevices.enumerateDevices();
      const videoDevices = devices.filter(device => device.kind === 'videoinput');
      
      if (videoDevices.length === 0) {
        logger.error('No video devices found');
        throw new Error('No camera found on this device');
      }

      // Try to get a stream with specific constraints
      const stream = await navigator.mediaDevices.getUserMedia({
        video: {
          facingMode: 'environment',
          width: { ideal: 1280 },
          height: { ideal: 720 }
        }
      });
      
      // Stop the test stream immediately
      stream.getTracks().forEach(track => track.stop());
      return true;
    } catch (error) {
      const wrappedError = error instanceof Error ? error : new Error(String(error));
      logger.error('Error requesting camera permissions:', {
        error: wrappedError.message,
        stack: wrappedError.stack,
        name: wrappedError.name
      });

      // Provide more specific error messages
      if (wrappedError.name === 'NotFoundError' || wrappedError.name === 'DevicesNotFoundError') {
        throw new Error('No camera found on this device');
      } else if (wrappedError.name === 'NotAllowedError' || wrappedError.name === 'PermissionDeniedError') {
        throw new Error('Camera access denied. Please grant camera permission and try again');
      } else if (wrappedError.name === 'NotReadableError' || wrappedError.name === 'TrackStartError') {
        throw new Error('Camera is in use by another application');
      } else {
        throw new Error(`Camera error: ${wrappedError.message}`);
      }
    }
  }

  async isSupported(): Promise<boolean> {
    try {
    // Check for secure context first
    if (!window.isSecureContext) {
        logger.warn('Camera access requires HTTPS (secure context)');
        return false;
      }

      // Check for camera API support
      if (!navigator.mediaDevices || !navigator.mediaDevices.getUserMedia) {
        logger.warn('Camera API not supported in this browser');
        return false;
      }

      // Check if we have any video devices
      const devices = await navigator.mediaDevices.enumerateDevices();
      const hasVideoDevices = devices.some(device => device.kind === 'videoinput');
      
      if (!hasVideoDevices) {
        logger.warn('No video devices found');
        return false;
      }

      return true;
    } catch (error) {
      logger.error('Error checking camera support:', {
        error: error instanceof Error ? error.message : String(error),
        stack: error instanceof Error ? error.stack : undefined
      });
      return false;
    }
  }

  async startScan(): Promise<void> {
    if (this.isScanning) {
      return;
    }

    try {
      this.isScanning = true;

      // Create and mount dialog component
      this.container = document.createElement("div");
      document.body.appendChild(this.container);

      this.dialogInstance = createApp(QRScannerDialog, {
        onScan: (result: string) => {
          if (this.scanListener) {
            this.scanListener.onScan(result);
          }
        },
        onError: (error: Error) => {
          if (this.scanListener?.onError) {
            this.scanListener.onError(error);
          }
        },
        options: this.options,
      });

      this.dialogComponent = this.dialogInstance.mount(this.container).$refs
        .dialog as InstanceType<typeof QRScannerDialog>;
    } catch (error) {
      this.isScanning = false;
      const wrappedError =
        error instanceof Error ? error : new Error(String(error));
      if (this.scanListener?.onError) {
        this.scanListener.onError(wrappedError);
      }
      logger.error("Error starting scan:", wrappedError);
      this.cleanupContainer();
      throw wrappedError;
    }
  }

  async stopScan(): Promise<void> {
    if (!this.isScanning) {
      return;
    }

    try {
      if (this.dialogComponent) {
        await this.dialogComponent.close();
      }
      if (this.dialogInstance) {
        this.dialogInstance.unmount();
      }
    } catch (error) {
      const wrappedError =
        error instanceof Error ? error : new Error(String(error));
      logger.error("Error stopping scan:", wrappedError);
      throw wrappedError;
    } finally {
      this.isScanning = false;
      this.cleanupContainer();
    }
  }

  addListener(listener: ScanListener): void {
    this.scanListener = listener;
  }

  private cleanupContainer(): void {
    if (this.container && this.container.parentNode) {
      this.container.parentNode.removeChild(this.container);
    }
    this.container = null;
  }

  async cleanup(): Promise<void> {
    try {
      await this.stopScan();
    } catch (error) {
      const wrappedError =
        error instanceof Error ? error : new Error(String(error));
      logger.error("Error during cleanup:", wrappedError);
      throw wrappedError;
    } finally {
      this.dialogComponent = null;
      this.dialogInstance = null;
      this.scanListener = null;
      this.cleanupContainer();
    }
  }
}