import 'package:flutter/material.dart';
import '../../theme/app_colors.dart';
import '../../utils/constants.dart';

/// 按钮类型
enum ButtonType { primary, secondary, danger, text }

/// 按钮尺寸
enum ButtonSize { small, medium, large }

/// 应用按钮组件
class AppButton extends StatelessWidget {
  final String? text;
  final Widget? child;
  final VoidCallback? onPressed;
  final ButtonType type;
  final ButtonSize size;
  final bool loading;
  final IconData? icon;
  final bool fullWidth;

  const AppButton({
    Key? key,
    this.text,
    this.child,
    this.onPressed,
    this.type = ButtonType.primary,
    this.size = ButtonSize.medium,
    this.loading = false,
    this.icon,
    this.fullWidth = false,
  }) : assert(text != null || child != null, 'text or child must be provided'),
       super(key: key);

  @override
  Widget build(BuildContext context) {
    final content = child ?? Text(text!);
    final buttonContent = loading
        ? SizedBox(
            width: _getIconSize(),
            height: _getIconSize(),
            child: CircularProgressIndicator(
              strokeWidth: 2,
              valueColor: AlwaysStoppedAnimation<Color>(_getTextColor()),
            ),
          )
        : Row(
            mainAxisSize: fullWidth ? MainAxisSize.max : MainAxisSize.min,
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              if (icon != null) ...[
                Icon(icon, size: _getIconSize(), color: _getTextColor()),
                SizedBox(width: AppSpacing.sm),
              ],
              content,
            ],
          );

    final button = _buildButton(context, buttonContent);

    if (fullWidth) {
      return SizedBox(width: double.infinity, child: button);
    }

    return button;
  }

  Widget _buildButton(BuildContext context, Widget content) {
    switch (type) {
      case ButtonType.primary:
        return ElevatedButton(
          onPressed: loading ? null : onPressed,
          style: ElevatedButton.styleFrom(
            backgroundColor: AppColors.primary,
            foregroundColor: Colors.white,
            padding: _getPadding(),
            minimumSize: Size(0, _getHeight()),
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(6),
            ),
          ),
          child: content,
        );
      case ButtonType.secondary:
        return OutlinedButton(
          onPressed: loading ? null : onPressed,
          style: OutlinedButton.styleFrom(
            foregroundColor: AppColors.primary,
            padding: _getPadding(),
            minimumSize: Size(0, _getHeight()),
            side: const BorderSide(color: AppColors.primary),
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(6),
            ),
          ),
          child: content,
        );
      case ButtonType.danger:
        return ElevatedButton(
          onPressed: loading ? null : onPressed,
          style: ElevatedButton.styleFrom(
            backgroundColor: AppColors.error,
            foregroundColor: Colors.white,
            padding: _getPadding(),
            minimumSize: Size(0, _getHeight()),
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(6),
            ),
          ),
          child: content,
        );
      case ButtonType.text:
        return TextButton(
          onPressed: loading ? null : onPressed,
          style: TextButton.styleFrom(
            foregroundColor: AppColors.primary,
            padding: _getPadding(),
            minimumSize: Size(0, _getHeight()),
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(6),
            ),
          ),
          child: content,
        );
    }
  }

  EdgeInsets _getPadding() {
    switch (size) {
      case ButtonSize.small:
        return const EdgeInsets.symmetric(horizontal: 12, vertical: 6);
      case ButtonSize.medium:
        return const EdgeInsets.symmetric(horizontal: 24, vertical: 12);
      case ButtonSize.large:
        return const EdgeInsets.symmetric(horizontal: 32, vertical: 16);
    }
  }

  double _getHeight() {
    switch (size) {
      case ButtonSize.small:
        return 28;
      case ButtonSize.medium:
        return 40;
      case ButtonSize.large:
        return 48;
    }
  }

  double _getIconSize() {
    switch (size) {
      case ButtonSize.small:
        return 14;
      case ButtonSize.medium:
        return 18;
      case ButtonSize.large:
        return 20;
    }
  }

  Color _getTextColor() {
    switch (type) {
      case ButtonType.primary:
      case ButtonType.danger:
        return Colors.white;
      case ButtonType.secondary:
      case ButtonType.text:
        return AppColors.primary;
    }
  }
}