import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:ln_jq_app/common/styles/theme.dart';
import 'package:mobile_scanner/mobile_scanner.dart';

import 'controller.dart';

class QrCodePage extends GetView<QrCodeController> {
  const QrCodePage({super.key});

  @override
  Widget build(BuildContext context) {
    Get.put(QrCodeController());
    return Scaffold(
      extendBodyBehindAppBar: true,
      appBar: AppBar(
        title: const Text('扫码', style: TextStyle(color: Colors.white)),
        centerTitle: true,
        backgroundColor: Colors.transparent,
        elevation: 0,
        leading: IconButton(
          icon: const Icon(Icons.arrow_back_ios, color: Colors.white),
          onPressed: () => Get.back(),
        ),
        actions: [
          TextButton(
            onPressed: controller.requestPhotoPermission,
            child: const Text('相册', style: TextStyle(color: Colors.white, fontSize: 16)),
          ),
        ],
      ),
      body: Obx(() { // 1. 使用 Obx 包裹整个 body
        // 根据权限状态来决定显示什么
        if (controller.hasPermission.value) {
          // 如果有权限，显示扫描器
          return _buildScannerView(context);
        } else {
          // 如果没有权限，显示引导界面
          return _buildPermissionDeniedView();
        }
      }),
    );
  }
  Widget _buildScannerView(BuildContext context){
    if (!controller.animationController.isAnimating) {
      controller.animationController.repeat(reverse: false);
    }
    return Stack(
      alignment: Alignment.center,
      children: [
        // 使用 MobileScanner 作为扫描视图
        MobileScanner(
          controller: controller.scannerController,
          onDetect: controller.onDetect,
          // 您可以自定义扫描框的样式
          scanWindow: Rect.fromCenter(
            center: Offset(
              MediaQuery.of(context).size.width / 2,
              MediaQuery.of(context).size.height / 2 - 50,
            ),
            width: 250,
            height: 250,
          ),
        ),
        // 扫描动画和覆盖层
        _buildScannerOverlay(context),
        // 底部的功能按钮
        Positioned(bottom: 80, left: 0, right: 0, child: _buildActionButtons()),
      ],
    );
  }

  Widget _buildPermissionDeniedView() {
    // 确保动画是停止的
    if (controller.animationController.isAnimating) {
      controller.animationController.stop();
    }

    return Container(
      color: Colors.black,
      alignment: Alignment.center,
      padding: const EdgeInsets.all(24.0),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          const Icon(Icons.no_photography, color: Colors.white70, size: 64),
          const SizedBox(height: 16),
          const Text(
            '需要相机权限',
            style: TextStyle(color: Colors.white, fontSize: 18, fontWeight: FontWeight.bold),
          ),
          const SizedBox(height: 8),
          const Text(
            '请授予相机权限以使用扫码功能。',
            style: TextStyle(color: Colors.white70, fontSize: 14),
            textAlign: TextAlign.center,
          ),
          const SizedBox(height: 24),
          ElevatedButton(
            onPressed: controller.requestPermission, // 点击按钮重新请求权限
            child: const Text('授予权限'),
          ),
        ],
      ),
    );
  }

  /// 构建扫描区域的覆盖层和动画
  Widget _buildScannerOverlay(BuildContext context) {
    // 模拟扫描框的位置和大小
    const double scanAreaSize = 250.0;
    return Stack(
      children: [
        // 半透明的覆盖层
        ColorFiltered(
          colorFilter: ColorFilter.mode(Colors.black.withOpacity(0.5), BlendMode.srcOut),
          child: Stack(
            children: [
              Container(decoration: const BoxDecoration(color: Colors.transparent)),
              Align(
                alignment: Alignment.center,
                child: Container(
                  margin: const EdgeInsets.only(bottom: 100), // 微调位置
                  width: scanAreaSize,
                  height: scanAreaSize,
                  decoration: BoxDecoration(
                    color: Colors.black,
                    borderRadius: BorderRadius.circular(12),
                  ),
                ),
              ),
            ],
          ),
        ),
        // 扫描动画
        Align(
          alignment: Alignment.center,
          child: Container(
            margin: const EdgeInsets.only(bottom: 100),
            width: scanAreaSize,
            height: scanAreaSize,
            child: AnimatedBuilder(
              animation: controller.scanAnimation,
              builder: (context, child) {
                return CustomPaint(
                  painter: ScannerAnimationPainter(
                    controller.scanAnimation.value,
                    AppTheme.themeColor,
                  ),
                );
              },
            ),
          ),
        ),
      ],
    );
  }

  /// 构建底部的功能按钮（闪光灯、相册）
  Widget _buildActionButtons() {
      return Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          const Text(
            '将二维码/条形码放入框内，即可自动扫描',
            style: TextStyle(color: Colors.white, fontSize: 14),
          ),
          const SizedBox(height: 20),
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            crossAxisAlignment: CrossAxisAlignment.center,
            children: <Widget>[
              // 闪光灯按钮
              _buildIconButton(
                onPressed: controller.toggleFlash,
                //闪光灯状态的变化
                child: Obx(
                      () => IconButton(
                    icon: Icon(
                      controller.isFlashOn.value ? Icons.flash_on : Icons.flash_off,
                      color: Colors.white,
                      size: 28,
                    ),
                    onPressed: controller.toggleFlash,
                  ),
                ),
              ),
              // 翻转相机按钮
              _buildIconButton(
                onPressed: controller.flipCamera,
                child: const Icon(
                  Icons.flip_camera_ios,
                  color: Colors.white,
                  size: 28,
                ),
              ),
            ],
          ),
        ],
      );
    }


  Widget _buildIconButton({required VoidCallback onPressed, required Widget child}) {
    return Container(
      decoration: BoxDecoration(
        color: Colors.black.withOpacity(0.3),
        shape: BoxShape.circle,
      ),
      child: IconButton(
        onPressed: onPressed,
        icon: child,
        iconSize: 32, // 增大点击区域
      ),
    );
  }
}

/// 扫描动画的绘制器
class ScannerAnimationPainter extends CustomPainter {
  final double value;
  final Color borderColor;

  ScannerAnimationPainter(this.value, this.borderColor);

  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()
      ..color = borderColor
      ..strokeWidth = 3
      ..style = PaintingStyle.stroke;

    final cornerLength = 20.0;
    // 绘制四个角的边框
    // Top-left
    canvas.drawPath(
      Path()
        ..moveTo(0, cornerLength)
        ..lineTo(0, 0)
        ..lineTo(cornerLength, 0),
      paint,
    );
    // Top-right
    canvas.drawPath(
      Path()
        ..moveTo(size.width - cornerLength, 0)
        ..lineTo(size.width, 0)
        ..lineTo(size.width, cornerLength),
      paint,
    );
    // Bottom-left
    canvas.drawPath(
      Path()
        ..moveTo(0, size.height - cornerLength)
        ..lineTo(0, size.height)
        ..lineTo(cornerLength, size.height),
      paint,
    );
    // Bottom-right
    canvas.drawPath(
      Path()
        ..moveTo(size.width - cornerLength, size.height)
        ..lineTo(size.width, size.height)
        ..lineTo(size.width, size.height - cornerLength),
      paint,
    );

    // 绘制扫描线
    final linePaint = Paint()
      ..color = borderColor.withOpacity(0.8)
      ..strokeWidth = 2
      ..shader = LinearGradient(
        colors: [borderColor.withOpacity(0), borderColor, borderColor.withOpacity(0)],
        stops: const [0.0, 0.5, 1.0],
      ).createShader(Rect.fromLTWH(0, 0, size.width, size.height));

    final y = size.height * value;
    canvas.drawLine(Offset(0, y), Offset(size.width, y), linePaint);
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) {
    return true;
  }
}