import 'package:flutter/cupertino.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:please_pay_me/theme/tokens.dart';

/// iOS 15+ button styles.
enum AppButtonStyle { filled, tinted, gray, plain, destructive }

/// Apple control sizes: large 50pt, medium 44pt, small 34pt.
enum AppButtonSize { large, medium, small }

class AppButton extends StatelessWidget {
  const AppButton({
    super.key,
    required this.label,
    this.onPressed,
    this.style = AppButtonStyle.filled,
    this.size = AppButtonSize.large,
    this.expanded = true,
    this.icon,
    this.loading = false,
  });

  final String label;
  final VoidCallback? onPressed;
  final AppButtonStyle style;
  final AppButtonSize size;
  final bool expanded;
  final IconData? icon;
  final bool loading;

  double get _height => switch (size) {
        AppButtonSize.large => AppSizes.buttonLarge,
        AppButtonSize.medium => AppSizes.buttonMedium,
        AppButtonSize.small => AppSizes.buttonSmall,
      };

  TextStyle get _textStyle => switch (size) {
        AppButtonSize.large => AppTypography.headline,
        AppButtonSize.medium => AppTypography.body,
        AppButtonSize.small => AppTypography.subhead.copyWith(fontWeight: FontWeight.w600),
      };

  @override
  Widget build(BuildContext context) {
    final accent = AppColors.of(context, AppColors.accent);
    final red = AppColors.of(context, AppColors.systemRed);

    final (Color background, Color foreground) = switch (style) {
      AppButtonStyle.filled => (accent, const Color(0xFFFFFFFF)),
      AppButtonStyle.tinted => (accent.withValues(alpha: 0.15), accent),
      AppButtonStyle.gray => (
          AppColors.of(context, AppColors.systemGray5),
          AppColors.of(context, AppColors.label),
        ),
      AppButtonStyle.plain => (const Color(0x00000000), accent),
      AppButtonStyle.destructive => (red.withValues(alpha: 0.15), red),
    };

    final disabled = onPressed == null || loading;
    final content = loading
        ? CupertinoActivityIndicator(
            radius: size == AppButtonSize.small ? 8 : 10,
            color: foreground,
          )
        : Row(
            mainAxisSize: expanded ? MainAxisSize.max : MainAxisSize.min,
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              if (icon != null) ...[
                Icon(icon, size: size == AppButtonSize.small ? 16 : 19, color: foreground),
                const SizedBox(width: AppSpacing.s2),
              ],
              Flexible(
                child: Text(
                  label,
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                  style: GoogleFonts.inter(textStyle: _textStyle, color: foreground),
                ),
              ),
            ],
          );

    return Opacity(
      opacity: disabled && !loading ? 0.35 : 1,
      child: SizedBox(
        height: _height,
        width: expanded ? double.infinity : null,
        child: CupertinoButton(
          onPressed: disabled ? null : onPressed,
          color: style == AppButtonStyle.plain ? null : background,
          disabledColor: background,
          borderRadius: BorderRadius.circular(
            size == AppButtonSize.small ? AppRadii.md : AppRadii.lg,
          ),
          padding: EdgeInsets.symmetric(
            horizontal: size == AppButtonSize.small ? AppSpacing.s3 : AppSpacing.s4,
          ),
          minimumSize: Size.zero,
          child: content,
        ),
      ),
    );
  }
}