import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:camera/camera.dart';
import '../bloc/scanner/scanner_bloc.dart';
import '../bloc/scanner/scanner_event.dart';
import '../bloc/scanner/scanner_state.dart';
import '../services/camera_service.dart';

class ScannerScreen extends StatelessWidget {
  final String? geminiApiKey;
  final String? openaiApiKey;
  final String openaiBaseUrl;

  const ScannerScreen({
    super.key,
    this.geminiApiKey,
    this.openaiApiKey,
    this.openaiBaseUrl = 'http://localhost:8317',
  });

  @override
  Widget build(BuildContext context) {
    return BlocProvider(
      create: (context) =>
          ScannerBloc(cameraService: CameraService())..add(InitializeCamera()),
      child: _ScannerScreenContent(
        geminiApiKey: geminiApiKey,
        openaiApiKey: openaiApiKey,
        openaiBaseUrl: openaiBaseUrl,
      ),
    );
  }
}

class _ScannerScreenContent extends StatelessWidget {
  final String? geminiApiKey;
  final String? openaiApiKey;
  final String openaiBaseUrl;

  const _ScannerScreenContent({
    this.geminiApiKey,
    this.openaiApiKey,
    this.openaiBaseUrl = 'http://localhost:8317',
  });

  void _showErrorDialog(BuildContext context, String errorMessage) {
    showDialog(
      context: context,
      builder: (dialogContext) => AlertDialog(
        title: const Text('Ошибка'),
        content: Text(errorMessage),
        actions: [
          TextButton(
            onPressed: () {
              Navigator.of(dialogContext).pop();
              context.read<ScannerBloc>().add(DismissError());
            },
            child: const Text('OK'),
          ),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return BlocListener<ScannerBloc, ScannerState>(
      listener: (context, state) {
        // Show error dialog when error message is present
        if (state.errorMessage != null) {
          _showErrorDialog(context, state.errorMessage!);
        }

        // Navigate back with analyzed book
        if (state.analyzedBook != null) {
          Navigator.pop(context, state.analyzedBook);
        }
      },
      child: BlocBuilder<ScannerBloc, ScannerState>(
        builder: (context, state) {
          final cameraService = context.read<ScannerBloc>().cameraService;

          return Scaffold(
            backgroundColor: Colors.black,
            body: Stack(
              children: [
                // Camera preview
                if (state.isInitialized && cameraService.controller != null)
                  Center(child: CameraPreview(cameraService.controller!))
                else if (state.hasPermissionError)
                  _buildPermissionError(context)
                else
                  _buildLoading(),

                // Scan frame overlay
                if (state.isInitialized && !state.isAnalyzing)
                  _buildScanFrame(),

                // Header
                _buildHeader(context),

                // Processing overlay
                if (state.isAnalyzing) _buildProcessingOverlay(),

                // Controls
                if (state.isInitialized && !state.isAnalyzing)
                  _buildControls(context, state.isCapturing),

                // Instructions
                if (state.isInitialized && !state.isAnalyzing)
                  _buildInstructions(),
              ],
            ),
          );
        },
      ),
    );
  }

  Widget _buildLoading() {
    return const Center(
      child: CircularProgressIndicator(
        valueColor: AlwaysStoppedAnimation<Color>(Colors.white),
      ),
    );
  }

  Widget _buildPermissionError(BuildContext context) {
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(24.0),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Icon(
              Icons.camera_alt_outlined,
              size: 64,
              color: Colors.white38,
            ),
            const SizedBox(height: 16),
            const Text(
              'Нет доступа к камере',
              style: TextStyle(
                color: Colors.white,
                fontSize: 20,
                fontWeight: FontWeight.bold,
              ),
            ),
            const SizedBox(height: 8),
            const Text(
              'Разрешите доступ к камере для сканирования обложек книг',
              style: TextStyle(color: Colors.white70, fontSize: 14),
              textAlign: TextAlign.center,
            ),
            const SizedBox(height: 24),
            ElevatedButton(
              onPressed: () {
                context.read<ScannerBloc>().add(InitializeCamera());
              },
              style: ElevatedButton.styleFrom(
                backgroundColor: const Color(0xFF17CF54),
              ),
              child: const Text('Повторить'),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildScanFrame() {
    return Center(
      child: FractionallySizedBox(
        widthFactor: 0.75,
        child: AspectRatio(
          aspectRatio: 2 / 3,
          child: Container(
            decoration: BoxDecoration(
              border: Border.all(color: Colors.white30, width: 2),
              borderRadius: BorderRadius.circular(12),
            ),
            // Corner accents
            child: Stack(
              children: [
                // Top left corner
                Positioned(
                  top: -2,
                  left: -2,
                  child: Container(
                    width: 20,
                    height: 20,
                    decoration: const BoxDecoration(
                      border: Border(
                        left: BorderSide(color: Color(0xFF17CF54), width: 4),
                        top: BorderSide(color: Color(0xFF17CF54), width: 4),
                      ),
                    ),
                  ),
                ),
                // Top right corner
                Positioned(
                  top: -2,
                  right: -2,
                  child: Container(
                    width: 20,
                    height: 20,
                    decoration: const BoxDecoration(
                      border: Border(
                        right: BorderSide(color: Color(0xFF17CF54), width: 4),
                        top: BorderSide(color: Color(0xFF17CF54), width: 4),
                      ),
                    ),
                  ),
                ),
                // Bottom left corner
                Positioned(
                  bottom: -2,
                  left: -2,
                  child: Container(
                    width: 20,
                    height: 20,
                    decoration: const BoxDecoration(
                      border: Border(
                        left: BorderSide(color: Color(0xFF17CF54), width: 4),
                        bottom: BorderSide(color: Color(0xFF17CF54), width: 4),
                      ),
                    ),
                  ),
                ),
                // Bottom right corner
                Positioned(
                  bottom: -2,
                  right: -2,
                  child: Container(
                    width: 20,
                    height: 20,
                    decoration: const BoxDecoration(
                      border: Border(
                        right: BorderSide(color: Color(0xFF17CF54), width: 4),
                        bottom: BorderSide(color: Color(0xFF17CF54), width: 4),
                      ),
                    ),
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }

  Widget _buildHeader(BuildContext context) {
    return SafeArea(
      child: Padding(
        padding: const EdgeInsets.all(8),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            IconButton(
              icon: const Icon(Icons.close, color: Colors.white),
              onPressed: () => Navigator.pop(context),
            ),
            Container(
              padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
              decoration: BoxDecoration(
                color: const Color(0xFF17CF54),
                borderRadius: BorderRadius.circular(8),
              ),
              child: const Text(
                'СКАНЕР',
                style: TextStyle(
                  fontWeight: FontWeight.bold,
                  fontSize: 12,
                  color: Colors.white,
                ),
              ),
            ),
            const SizedBox(width: 48),
          ],
        ),
      ),
    );
  }

  Widget _buildProcessingOverlay() {
    return Container(
      color: Colors.black87,
      child: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const CircularProgressIndicator(
              valueColor: AlwaysStoppedAnimation<Color>(Color(0xFF17CF54)),
            ),
            const SizedBox(height: 24),
            const Text(
              'Анализ обложки...',
              style: TextStyle(
                color: Colors.white,
                fontSize: 18,
                fontWeight: FontWeight.bold,
              ),
            ),
            const SizedBox(height: 8),
            Text(
              'Это может занять несколько секунд',
              style: TextStyle(color: Colors.grey.shade400, fontSize: 14),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildControls(BuildContext context, bool isCapturing) {
    return Positioned(
      bottom: 50,
      left: 0,
      right: 0,
      child: Row(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          // Flash button (placeholder)
          Container(
            width: 50,
            height: 50,
            margin: const EdgeInsets.only(right: 20),
            child: IconButton(
              icon: const Icon(Icons.flash_off, color: Colors.white),
              onPressed: () {
                // Flash functionality can be added later
              },
            ),
          ),
          // Capture button
          GestureDetector(
            onTap: isCapturing
                ? null
                : () {
                    context.read<ScannerBloc>().add(
                      CaptureAndAnalyze(
                        openaiApiKey: openaiApiKey,
                        openaiBaseUrl: openaiBaseUrl,
                        geminiApiKey: geminiApiKey,
                      ),
                    );
                  },
            child: Container(
              width: 80,
              height: 80,
              decoration: BoxDecoration(
                shape: BoxShape.circle,
                border: Border.all(color: Colors.white, width: 4),
              ),
              child: Center(
                child: Container(
                  width: 64,
                  height: 64,
                  decoration: BoxDecoration(
                    shape: BoxShape.circle,
                    color: isCapturing ? Colors.white38 : Colors.white,
                  ),
                ),
              ),
            ),
          ),
          // Camera switch button
          Container(
            width: 50,
            height: 50,
            margin: const EdgeInsets.only(left: 20),
            child: IconButton(
              icon: const Icon(Icons.flip_camera_ios, color: Colors.white),
              onPressed: () {
                context.read<ScannerBloc>().add(SwitchCamera());
              },
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildInstructions() {
    return Positioned(
      bottom: 140,
      left: 0,
      right: 0,
      child: Column(
        children: [
          Text(
            'Поместите обложку в рамку',
            textAlign: TextAlign.center,
            style: TextStyle(
              color: Colors.grey.shade400,
              fontSize: 16,
              fontWeight: FontWeight.w500,
            ),
          ),
          const SizedBox(height: 8),
          Text(
            'Убедитесь, что текст читается четко',
            textAlign: TextAlign.center,
            style: TextStyle(color: Colors.grey.shade500, fontSize: 12),
          ),
        ],
      ),
    );
  }
}