import "dart:io";
import "package:flutter/material.dart";
import "package:flutter_tabler_icons/flutter_tabler_icons.dart";
import "package:inventree/app_colors.dart";
import "package:inventree/preferences.dart";

import "package:qr_code_scanner/qr_code_scanner.dart";

import "package:inventree/l10.dart";

import "package:inventree/barcode/handler.dart";
import "package:inventree/barcode/controller.dart";

/*
 * Barcode controller which uses the device's camera to scan barcodes.
 * Under the hood it uses the qr_code_scanner package.
 */
class CameraBarcodeController extends InvenTreeBarcodeController {
  const CameraBarcodeController(BarcodeHandler handler, {Key? key})
      : super(handler, key: key);

  @override
  State<StatefulWidget> createState() => _CameraBarcodeControllerState();
}

class _CameraBarcodeControllerState extends InvenTreeBarcodeControllerState {
  _CameraBarcodeControllerState() : super();

  QRViewController? _controller;

  bool flash_status = false;

  bool single_scanning = false;
  bool scanning_paused = false;

  Future<void> _loadSettings() async {
    bool _single = await InvenTreeSettingsManager()
        .getBool(INV_BARCODE_SCAN_SINGLE, false);

    if (mounted) {
      setState(() {
        single_scanning = _single;
        scanning_paused = false;
      });
    }
  }

  /* Callback function when the Barcode scanner view is initially created */
  void _onViewCreated(BuildContext context, QRViewController controller) {
    _controller = controller;

    controller.scannedDataStream.listen((barcode) {
      if (!scanning_paused) {
        handleBarcodeData(barcode.code).then((value) => {
              // If in single-scanning mode, pause after successful scan
              if (single_scanning && mounted)
                {
                  setState(() {
                    scanning_paused = true;
                  })
                }
            });
      }
    });

    _loadSettings();
  }

  // In order to get hot reload to work we need to pause the camera if the platform
  // is android, or resume the camera if the platform is iOS.
  @override
  void reassemble() {
    super.reassemble();

    if (mounted) {
      if (Platform.isAndroid) {
        _controller!.pauseCamera();
      }

      _controller!.resumeCamera();
    }
  }

  @override
  void dispose() {
    _controller?.dispose();
    super.dispose();
  }

  @override
  Future<void> pauseScan() async {
    try {
      await _controller?.pauseCamera();
    } on CameraException {
      // do nothing
    }
  }

  @override
  Future<void> resumeScan() async {
    // Do not attempt to resume if the widget is not mounted
    if (!mounted) {
      return;
    }

    try {
      await _controller?.resumeCamera();
    } on CameraException {
      // do nothing
    }
  }

  // Toggle the status of the camera flash
  Future<void> updateFlashStatus() async {
    final bool? status = await _controller?.getFlashStatus();

    if (mounted) {
      setState(() {
        flash_status = status != null && status;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    Widget actionIcon =
        Icon(TablerIcons.player_pause, color: COLOR_WARNING, size: 64);

    if (scanning_paused) {
      actionIcon =
          Icon(TablerIcons.player_play, color: COLOR_ACTION, size: 64);
    }

    String info_text = scanning_paused ? L10().barcodeScanPaused : L10().barcodeScanPause;

    return Scaffold(
        appBar: AppBar(
          title: Text(L10().scanBarcode),
          actions: [
            IconButton(
                icon: Icon(Icons.flip_camera_android),
                onPressed: () {
                  _controller?.flipCamera();
                }),
            IconButton(
              icon: flash_status ? Icon(Icons.flash_off) : Icon(Icons.flash_on),
              onPressed: () {
                _controller?.toggleFlash();
                updateFlashStatus();
              },
            )
          ],
        ),
        body: GestureDetector(
            onTapDown: (details) async {
              setState(() {
                scanning_paused = !scanning_paused;
              });
            },
            onLongPressEnd: (details) async {
              if (mounted) {
                setState(() {
                  scanning_paused = false;
                });
              }
            },
            child: Stack(
              children: <Widget>[
                Column(children: [
                  Expanded(
                      child: QRView(
                    key: barcodeControllerKey,
                    onQRViewCreated: (QRViewController controller) {
                      _onViewCreated(context, controller);
                    },
                    overlay: QrScannerOverlayShape(
                      borderColor:
                          scanning_paused ? COLOR_WARNING : COLOR_ACTION,
                      borderRadius: 10,
                      borderLength: 30,
                      borderWidth: 10,
                      cutOutSize: 300,
                    ),
                  ))
                ]),
                Center(
                    child: Column(children: [
                  Padding(
                      child: Text(
                        widget.handler.getOverlayText(context),
                        style: TextStyle(
                          fontSize: 16,
                            fontWeight: FontWeight.bold, color: Colors.white),
                      ),
                      padding: EdgeInsets.all(25)),
                  Padding(
                    child: CircularProgressIndicator(
                        value: scanning_paused ? 0 : null),
                    padding: EdgeInsets.all(40),
                  ),
                  Spacer(),
                  SizedBox(
                    child: Center(
                      child: actionIcon,
                    ),
                    width: 100,
                    height: 150,
                  ),
                  Padding(
                    child: Text(info_text,
                        textAlign: TextAlign.center,
                        style: TextStyle(
                          color: Colors.white,
                        )),
                    padding: EdgeInsets.all(25),
                  ),
                ]))
              ],
            )));
  }
}