import 'package:camera/camera.dart';
import 'package:flutter/material.dart';
import 'package:flutter_lucide/flutter_lucide.dart';
import 'package:permission_handler/permission_handler.dart';

import '../../core/log/app_logger.dart';
import '../../core/theme/app_colors.dart';
import '../../core/theme/app_spacing.dart';

/// 应用内拍照：不跳出系统相机 Activity，避免与 Flutter Surface / 截屏防护等叠加导致黑屏卡死。
class InAppCameraPage extends StatefulWidget {
  const InAppCameraPage({super.key});

  static final _log = AppLogger('InAppCamera');

  @override
  State<InAppCameraPage> createState() => _InAppCameraPageState();
}

class _InAppCameraPageState extends State<InAppCameraPage> {
  CameraController? _controller;
  bool _initializing = true;
  bool _capturing = false;
  String? _error;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) => _prepareCamera());
  }

  Future<void> _prepareCamera() async {
    final status = await Permission.camera.request();
    if (!status.isGranted) {
      if (mounted) {
        setState(() {
          _initializing = false;
          _error = 'Camera permission is required';
        });
      }
      return;
    }

    try {
      final cameras = await availableCameras();
      if (cameras.isEmpty) {
        if (mounted) {
          setState(() {
            _initializing = false;
            _error = 'No camera available';
          });
        }
        return;
      }
      final back = cameras.where((c) => c.lensDirection == CameraLensDirection.back);
      final selected = back.isEmpty ? cameras.first : back.first;

      final c = CameraController(
        selected,
        ResolutionPreset.medium,
        enableAudio: false,
      );
      await c.initialize();
      if (!mounted) {
        await c.dispose();
        return;
      }
      setState(() {
        _controller = c;
        _initializing = false;
      });
    } catch (e, st) {
      InAppCameraPage._log.e('Camera init failed', e, st);
      if (mounted) {
        setState(() {
          _initializing = false;
          _error = 'Could not open camera';
        });
      }
    }
  }

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

  Future<void> _onShutter() async {
    final c = _controller;
    if (c == null || !c.value.isInitialized || _capturing) return;
    setState(() => _capturing = true);
    try {
      final shot = await c.takePicture();
      if (!mounted) return;
      Navigator.of(context, rootNavigator: true).pop<String>(shot.path);
    } catch (e, st) {
      InAppCameraPage._log.e('takePicture failed', e, st);
      if (mounted) setState(() => _capturing = false);
    }
  }

  void _onClose() {
    Navigator.of(context, rootNavigator: true).pop<String>(null);
  }

  @override
  Widget build(BuildContext context) {
    final c = _controller;
    final showPreview =
        !_initializing && _error == null && c != null && c.value.isInitialized;

    return Scaffold(
      backgroundColor: Colors.black,
      body: Stack(
        fit: StackFit.expand,
        children: [
          if (showPreview)
            Positioned.fill(
              child: ColoredBox(
                color: Colors.black,
                // 勿再包一层自定义 aspect 的 SizedBox/FittedBox：[CameraPreview] 已在竖屏下使用
                // 1/value.aspectRatio + Android [RotatedBox]，外层乱算比例会把它压扁。
                child: Center(
                  child: CameraPreview(c),
                ),
              ),
            ),
          SafeArea(
            child: Stack(
              fit: StackFit.expand,
              children: [
                if (_initializing)
                  const Center(
                    child:
                        CircularProgressIndicator(color: AppColors.primary),
                  )
                else if (_error != null)
                  Center(
                    child: Padding(
                      padding: const EdgeInsets.all(AppSpacing.lg),
                      child: Column(
                        mainAxisSize: MainAxisSize.min,
                        children: [
                          Icon(
                            LucideIcons.camera_off,
                            size: 48,
                            color: AppColors.surface.withValues(alpha: 0.6),
                          ),
                          const SizedBox(height: AppSpacing.md),
                          Text(
                            _error!,
                            textAlign: TextAlign.center,
                            style: TextStyle(
                              color: AppColors.surface.withValues(alpha: 0.85),
                              fontSize: 15,
                            ),
                          ),
                          const SizedBox(height: AppSpacing.lg),
                          TextButton(
                            onPressed: _onClose,
                            child: const Text('Close'),
                          ),
                        ],
                      ),
                    ),
                  ),
                if (showPreview)
                  Positioned(
                    left: 0,
                    right: 0,
                    bottom: 24,
                    child: Row(
                      mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                      children: [
                        IconButton(
                          onPressed: _capturing ? null : _onClose,
                          icon: Icon(
                            LucideIcons.x,
                            color: AppColors.surface.withValues(alpha: 0.9),
                            size: 28,
                          ),
                        ),
                        GestureDetector(
                          onTap: _capturing ? null : _onShutter,
                          child: Container(
                            width: 72,
                            height: 72,
                            decoration: BoxDecoration(
                              shape: BoxShape.circle,
                              border: Border.all(
                                color: AppColors.surface,
                                width: 4,
                              ),
                              color: AppColors.surface.withValues(alpha: 0.2),
                            ),
                            child: _capturing
                                ? const Padding(
                                    padding: EdgeInsets.all(20),
                                    child: CircularProgressIndicator(
                                      strokeWidth: 2,
                                      color: AppColors.surface,
                                    ),
                                  )
                                : null,
                          ),
                        ),
                        const SizedBox(width: 48),
                      ],
                    ),
                  ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}