import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import '../theme/app_colors.dart';
import '../theme/product_theme.dart';

class GradientButton extends StatelessWidget {
  final String text;
  final VoidCallback? onPressed;
  final double width;
  final double height;
  final bool isLoading;
  final Gradient? gradient;
  final List<BoxShadow>? shadows;

  const GradientButton({
    super.key,
    required this.text,
    this.onPressed,
    this.width = double.infinity,
    this.height = 48.0, // 统一规范高度
    this.isLoading = false,
    this.gradient,
    this.shadows,
  });

  /// 从 ProductThemeData 创建，自动匹配渐变和阴影
  factory GradientButton.fromTheme({
    Key? key,
    required String text,
    required ProductThemeData theme,
    VoidCallback? onPressed,
    double width = double.infinity,
    double height = 48.0,
    bool isLoading = false,
  }) {
    return GradientButton(
      key: key,
      text: text,
      onPressed: onPressed,
      width: width,
      height: height,
      isLoading: isLoading,
      gradient: theme.buttonGradient,
      shadows: theme.buttonShadows,
    );
  }

  List<BoxShadow> get _boxShadows {
    if (shadows != null) return shadows!;
    // 根据渐变颜色自动推断阴影
    if (gradient is LinearGradient) {
      final lg = gradient as LinearGradient;
      if (lg.colors.length >= 2) {
        final shadowColor = lg.colors[lg.colors.length ~/ 2];
        return [
          BoxShadow(
            color: shadowColor.withOpacity(0.4),
            offset: const Offset(0, 4),
            blurRadius: 20,
          ),
          BoxShadow(
            color: lg.colors.last.withOpacity(0.2),
            offset: Offset.zero,
            blurRadius: 40,
          ),
        ];
      }
    }
    return AppColors.shadowPrimaryButton;
  }

  @override
  Widget build(BuildContext context) {
    final bool isDisabled = onPressed == null || isLoading;

    return Opacity(
      opacity: isDisabled ? 0.7 : 1.0,
      child: Container(
        width: width,
        height: height,
        decoration: BoxDecoration(
          borderRadius: BorderRadius.circular(height / 2),
          gradient: gradient ?? AppColors.btnPrimaryGradient,
          boxShadow: _boxShadows,
        ),
        child: Stack(
          children: [
            // Shine overlay (top half gradient)
            Positioned.fill(
              child: ClipRRect(
                borderRadius: BorderRadius.circular(height / 2),
                child: DecoratedBox(
                  decoration: BoxDecoration(
                    gradient: LinearGradient(
                      begin: Alignment.topCenter,
                      end: Alignment.bottomCenter,
                      colors: [
                        Colors.white.withOpacity(0.15),
                        Colors.transparent,
                      ],
                      stops: const [0.0, 0.5],
                    ),
                  ),
                ),
              ),
            ),
            // Button content
            Material(
              color: Colors.transparent,
              elevation: 0,
              child: InkWell(
                onTap: isDisabled ? null : onPressed,
                borderRadius: BorderRadius.circular(height / 2),
                splashColor: Colors.white.withOpacity(0.2),
                highlightColor: Colors.white.withOpacity(0.1),
                child: Center(
                  child: isLoading
                      ? const SizedBox(
                          width: 24,
                          height: 24,
                          child: CircularProgressIndicator(
                            color: Colors.white,
                            strokeWidth: 2.5,
                          ),
                        )
                      : Text(
                          text,
                          style: GoogleFonts.dmSans(
                            fontSize: 17,
                            fontWeight: FontWeight.w600,
                            color: Colors.white,
                          ),
                        ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}