import {
  BarcodeScanner,
  BarcodeFormat,
  LensFacing
} from '@capacitor-mlkit/barcode-scanning'
import type { PluginListenerHandle } from '@capacitor/core'
import { QRScannerService, ScanListener } from './types'

export class NativeQRScanner implements QRScannerService {
  private scanListener: ScanListener | null = null
  private isScanning = false
  private listenerHandle: PluginListenerHandle | null = null

  async checkPermissions(): Promise<boolean> {
    const { camera } = await BarcodeScanner.checkPermissions()
    return camera === 'granted'
  }

  async requestPermissions(): Promise<boolean> {
    const { camera } = await BarcodeScanner.requestPermissions()
    return camera === 'granted'
  }

  async isSupported(): Promise<boolean> {
    const { supported } = await BarcodeScanner.isSupported()
    return supported
  }

  async startScan(): Promise<void> {
    if (this.isScanning) {
      throw new Error('Scanner is already running')
    }

    try {
      this.isScanning = true
      await BarcodeScanner.startScan({
        formats: [BarcodeFormat.QrCode],
        lensFacing: LensFacing.Back
      })

      this.listenerHandle = await BarcodeScanner.addListener(
        'barcodesScanned',
        async (result) => {
          if (result.barcodes.length > 0 && this.scanListener) {
            const barcode = result.barcodes[0]
            this.scanListener.onScan(barcode.rawValue)
            await this.stopScan()
          }
        }
      )
    } catch (error) {
      this.isScanning = false
      if (this.scanListener?.onError) {
        this.scanListener.onError(new Error(String(error)))
      }
      throw error
    }
  }

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

    try {
      await BarcodeScanner.stopScan()
      this.isScanning = false
    } catch (error) {
      if (this.scanListener?.onError) {
        this.scanListener.onError(new Error(String(error)))
      }
      throw error
    }
  }

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

  async cleanup(): Promise<void> {
    await this.stopScan()
    if (this.listenerHandle) {
      await this.listenerHandle.remove()
      this.listenerHandle = null
    }
    this.scanListener = null
  }
}