import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart';
import 'package:mobile_scanner/mobile_scanner.dart';
import '../l10n/app_localizations.dart';
import '../models/tasks/barcode_task.dart';
import '../widgets/offline_banner.dart';

class BarcodeCaptureScreen extends StatefulWidget {
  final BarcodeTask task;
  final Function(List<String>) onBarcodesCompleted;

  const BarcodeCaptureScreen({
    super.key,
    required this.task,
    required this.onBarcodesCompleted,
  });

  @override
  State<BarcodeCaptureScreen> createState() => _BarcodeCaptureScreenState();
}

class _BarcodeCaptureScreenState extends State<BarcodeCaptureScreen> {
  final List<String> _scannedBarcodes = [];
  final List<TextEditingController> _textControllers = [];
  MobileScannerController? _scannerController;
  bool _isMobilePlatform = false;
  bool _isScannerInitialized = false;

  @override
  void initState() {
    super.initState();
    _detectPlatformAndInit();
  }

  @override
  void dispose() {
    _scannerController?.dispose();
    for (final controller in _textControllers) {
      controller.dispose();
    }
    super.dispose();
  }

  void _detectPlatformAndInit() {
    // Determine if we're on a mobile platform
    if (kIsWeb) {
      _isMobilePlatform = false;
      _initializeDesktopMode();
    } else {
      switch (defaultTargetPlatform) {
        case TargetPlatform.android:
        case TargetPlatform.iOS:
          _isMobilePlatform = true;
          _initializeMobileScanner();
          break;
        case TargetPlatform.macOS:
        case TargetPlatform.windows:
        case TargetPlatform.linux:
          _isMobilePlatform = false;
          _initializeDesktopMode();
          break;
        default:
          _isMobilePlatform = false;
          _initializeDesktopMode();
      }
    }
  }

  void _initializeMobileScanner() {
    try {
      _scannerController = MobileScannerController();
      setState(() {
        _isScannerInitialized = true;
      });
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('${AppLocalizations.of(context).cameraError}: $e'),
          ),
        );
      }
    }
  }

  void _initializeDesktopMode() {
    // Create text controllers for desktop input fields
    for (int i = 0; i < widget.task.maxBarcodeCount; i++) {
      _textControllers.add(TextEditingController());
    }
    setState(() {
      _isScannerInitialized = true;
    });
  }

  void _onBarcodeDetected(BarcodeCapture capture) {
    final List<Barcode> barcodes = capture.barcodes;
    for (final barcode in barcodes) {
      final String? code = barcode.rawValue;
      if (code != null && code.isNotEmpty && !_scannedBarcodes.contains(code)) {
        if (_scannedBarcodes.length < widget.task.maxBarcodeCount) {
          setState(() {
            _scannedBarcodes.add(code);
          });
        }
      }
    }
  }

  void _removeBarcode(int index) {
    setState(() {
      _scannedBarcodes.removeAt(index);
    });
  }

  void _finishTask() {
    final List<String> barcodes;
    if (_isMobilePlatform) {
      barcodes = _scannedBarcodes;
    } else {
      // Collect barcodes from text fields
      barcodes = [];
      for (final controller in _textControllers) {
        if (controller.text.trim().isNotEmpty) {
          barcodes.add(controller.text.trim());
        }
      }
    }

    // Navigate back to task view first
    Navigator.of(context).pop();

    // Then call the completion callback
    widget.onBarcodesCompleted(barcodes);
  }

  bool _canFinish() {
    if (_isMobilePlatform) {
      return _scannedBarcodes.length >= widget.task.minBarcodeCount;
    } else {
      int filledFields = 0;
      for (final controller in _textControllers) {
        if (controller.text.trim().isNotEmpty) {
          filledFields++;
        }
      }
      return filledFields >= widget.task.minBarcodeCount;
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(AppLocalizations.of(context).barcodeScan),
        leading: IconButton(
          icon: const Icon(Icons.arrow_back),
          onPressed: () => Navigator.of(context).pop(),
        ),
      ),
      body: Column(
        children: [
          const OfflineBanner(),
          Expanded(
            child:
                _isScannerInitialized
                    ? (_isMobilePlatform
                        ? _buildMobileView()
                        : _buildDesktopView())
                    : const Center(child: CircularProgressIndicator()),
          ),
        ],
      ),
    );
  }

  Widget _buildMobileView() {
    return Column(
      children: [
        // Scanner view
        Expanded(
          flex: 3,
          child: Stack(
            children: [
              MobileScanner(
                controller: _scannerController,
                onDetect: _onBarcodeDetected,
              ),
              // Overlay with scanning frame
              Container(
                decoration: BoxDecoration(
                  color: Colors.black.withValues(alpha: 0.5),
                ),
                child: Center(
                  child: Container(
                    width: 250,
                    height: 250,
                    decoration: BoxDecoration(
                      border: Border.all(color: Colors.white, width: 2),
                      borderRadius: BorderRadius.circular(12),
                    ),
                    child: Container(
                      margin: const EdgeInsets.all(20),
                      decoration: BoxDecoration(
                        border: Border.all(color: Colors.green, width: 2),
                        borderRadius: BorderRadius.circular(8),
                      ),
                    ),
                  ),
                ),
              ),
            ],
          ),
        ),
        // Scanned barcodes list
        Expanded(
          flex: 2,
          child: Container(
            padding: const EdgeInsets.all(16),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  '${AppLocalizations.of(context).scannedBarcodes} (${_scannedBarcodes.length}/${widget.task.maxBarcodeCount})',
                  style: const TextStyle(
                    fontSize: 16,
                    fontWeight: FontWeight.bold,
                  ),
                ),
                const SizedBox(height: 8),
                Text(
                  '${AppLocalizations.of(context).minBarcodes} ${widget.task.minBarcodeCount} ${AppLocalizations.of(context).barcodesRequired}',
                  style: TextStyle(fontSize: 14, color: Colors.grey[600]),
                ),
                const SizedBox(height: 16),
                Expanded(
                  child: ListView.builder(
                    itemCount: _scannedBarcodes.length,
                    itemBuilder: (context, index) {
                      return Card(
                        child: ListTile(
                          leading: const Icon(Icons.qr_code),
                          title: Text(_scannedBarcodes[index]),
                          trailing: IconButton(
                            icon: const Icon(Icons.delete, color: Colors.red),
                            onPressed: () => _removeBarcode(index),
                          ),
                        ),
                      );
                    },
                  ),
                ),
                const SizedBox(height: 16),
                SizedBox(
                  width: double.infinity,
                  child: ElevatedButton(
                    onPressed: _canFinish() ? _finishTask : null,
                    style: ElevatedButton.styleFrom(
                      padding: const EdgeInsets.symmetric(vertical: 16),
                    ),
                    child: Text(AppLocalizations.of(context).finish),
                  ),
                ),
              ],
            ),
          ),
        ),
      ],
    );
  }

  Widget _buildDesktopView() {
    return Padding(
      padding: const EdgeInsets.all(16),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(
            AppLocalizations.of(context).enterBarcode,
            style: const TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
          ),
          const SizedBox(height: 8),
          Text(
            '${AppLocalizations.of(context).barcodeEnterDescription} (${widget.task.minBarcodeCount}-${widget.task.maxBarcodeCount})',
            style: TextStyle(fontSize: 16, color: Colors.grey[600]),
          ),
          const SizedBox(height: 24),
          Expanded(
            child: ListView.builder(
              itemCount: widget.task.maxBarcodeCount,
              itemBuilder: (context, index) {
                return Padding(
                  padding: const EdgeInsets.only(bottom: 12),
                  child: TextField(
                    controller: _textControllers[index],
                    decoration: InputDecoration(
                      labelText:
                          index < widget.task.minBarcodeCount
                              ? AppLocalizations.of(
                                context,
                              ).barcodeNumberRequired(index + 1)
                              : AppLocalizations.of(
                                context,
                              ).barcodeNumberOptional(index + 1),
                      border: const OutlineInputBorder(),
                      prefixIcon: const Icon(Icons.qr_code),
                    ),
                    onChanged: (value) {
                      setState(() {
                        // Trigger rebuild to update button state
                      });
                    },
                  ),
                );
              },
            ),
          ),
          const SizedBox(height: 16),
          SizedBox(
            width: double.infinity,
            child: ElevatedButton(
              onPressed: _canFinish() ? _finishTask : null,
              style: ElevatedButton.styleFrom(
                padding: const EdgeInsets.symmetric(vertical: 16),
              ),
              child: Text(AppLocalizations.of(context).finish),
            ),
          ),
        ],
      ),
    );
  }
}