smart_grid_iot_app_flutter/lib/shared/widgets/x_common.dart

import 'package:flutter/material.dart';

import '../../core/theme/app_colors.dart';
import '../../core/theme/app_dimens.dart';
import '../../core/theme/app_typography.dart';

/// 页面骨架：固定顶栏 + 内容区。对应源「根容器固定、滚动只发生在内容区」的布局。
class XPageShell extends StatelessWidget {
  const XPageShell({
    super.key,
    required this.topBar,
    required this.child,
    this.backgroundColor = AppColors.bgPage,
  });

  final Widget topBar;
  final Widget child;
  final Color backgroundColor;

  @override
  Widget build(BuildContext context) {
    return Container(
      color: backgroundColor,
      child: Column(
        children: [topBar, Expanded(child: child)],
      ),
    );
  }
}

/// 页面大标题 + 副标题，对应 `.page-header` / `.section-title`（28px/w700）。
class XPageTitle extends StatelessWidget {
  const XPageTitle({super.key, required this.title, this.subtitle});

  final String title;
  final String? subtitle;

  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text(
          title,
          style: AppTypography.navLargeTitle.copyWith(
            color: AppColors.onSurface,
          ),
        ),
        if (subtitle != null) ...[
          const SizedBox(height: 4),
          Text(
            subtitle!,
            style: AppTypography.bodyMd.copyWith(
              color: AppColors.onSurfaceVariant,
            ),
          ),
        ],
      ],
    );
  }
}

/// 空态 / 加载中占位。
class XPlaceholder extends StatelessWidget {
  const XPlaceholder({
    super.key,
    required this.text,
    this.padding = const EdgeInsets.symmetric(vertical: 60),
  });

  final String text;
  final EdgeInsetsGeometry padding;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: padding,
      child: Center(
        child: Text(
          text,
          textAlign: TextAlign.center,
          style: AppTypography.bodyMd.copyWith(color: AppColors.textMuted),
        ),
      ),
    );
  }
}

/// 实心主按钮，对应 `.login-btn` / `.start-btn` 等。
class XPrimaryButton extends StatelessWidget {
  const XPrimaryButton({
    super.key,
    required this.label,
    required this.onPressed,
    this.leading,
    this.loading = false,
    this.height = 48,
    this.radius = AppRadius.lg,
    this.background = AppColors.primary,
    this.foreground = AppColors.onPrimary,
    this.fontSize = 17,
    this.shadows,
  });

  final String label;
  final VoidCallback? onPressed;
  final Widget? leading;
  final bool loading;
  final double height;
  final double radius;
  final Color background;
  final Color foreground;
  final double fontSize;
  final List<BoxShadow>? shadows;

  @override
  Widget build(BuildContext context) {
    final disabled = onPressed == null || loading;

    return Opacity(
      opacity: disabled && !loading ? 0.55 : 1,
      child: SizedBox(
        height: height,
        width: double.infinity,
        child: Material(
          color: background,
          borderRadius: BorderRadius.circular(radius),
          child: InkWell(
            onTap: disabled ? null : onPressed,
            borderRadius: BorderRadius.circular(radius),
            child: Container(
              alignment: Alignment.center,
              decoration: BoxDecoration(
                borderRadius: BorderRadius.circular(radius),
                boxShadow: shadows,
              ),
              child: loading
                  ? SizedBox(
                      width: 20,
                      height: 20,
                      child: CircularProgressIndicator(
                        strokeWidth: 2,
                        valueColor: AlwaysStoppedAnimation(foreground),
                      ),
                    )
                  : Row(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        if (leading != null) ...[
                          leading!,
                          const SizedBox(width: 8),
                        ],
                        Text(
                          label,
                          style: TextStyle(
                            fontSize: fontSize,
                            fontWeight: FontWeight.w600,
                            color: foreground,
                          ),
                        ),
                      ],
                    ),
            ),
          ),
        ),
      ),
    );
  }
}

/// 区块小标题（20/w600），对应 `.chart-title` / `.section-title`。
class XSectionTitle extends StatelessWidget {
  const XSectionTitle(this.text, {super.key, this.trailing});

  final String text;
  final Widget? trailing;

  @override
  Widget build(BuildContext context) {
    final title = Text(
      text,
      style: AppTypography.headlineMd.copyWith(color: AppColors.onSurface),
    );
    if (trailing == null) return title;
    return Row(
      mainAxisAlignment: MainAxisAlignment.spaceBetween,
      children: [title, trailing!],
    );
  }
}