// widgets/ds/ds_kpi.dart — 原型 .kpi 卡（镜像 atoms.css）。
import 'package:flutter/material.dart';
import '../../core/theme/context_tokens.dart';
import '../../core/theme/app_dims.g.dart';
import '../../core/theme/app_fonts.dart';

/// 图标块 .ic 变体（软底 + 前景色）。
enum DsKpiTone { info, ok, blue, alert, warn }

/// 环比方向 .d.up/.down（绿/红），neutral=纯文案(muted)。
enum DsKpiDelta { up, down, neutral }

/// 原型 .kpi：surface/border/r-lg/pad 15 16；右上 .ic(30×30 r-md)；
/// .t(fs-sm muted) / .v(24 fw700 heading mono，alert→accent) / .d(fs-xs，up绿/down红)。
class DsKpi extends StatelessWidget {
  final String title;
  final String value;
  // 原型 users.html 的 KPI 无右上图标块 → icon 可空时不渲染 .ic
  final IconData? icon;
  final DsKpiTone tone;
  final String? delta;
  final DsKpiDelta deltaTone;
  final VoidCallback? onTap;

  const DsKpi({
    super.key,
    required this.title,
    required this.value,
    this.icon,
    this.tone = DsKpiTone.info,
    this.delta,
    this.deltaTone = DsKpiDelta.neutral,
    this.onTap,
  });

  @override
  Widget build(BuildContext context) {
    final t = context.tokens;
    final (icBg, icFg) = switch (tone) {
      DsKpiTone.info => (t.infoSoft, t.primary),
      DsKpiTone.ok => (t.okSoft, t.success),
      DsKpiTone.blue => (t.infoSoft, t.brand400),
      DsKpiTone.alert => (t.accentSoft, t.accent),
      // 暗黄（草稿卡）：icon 与数字走 warn token
      DsKpiTone.warn => (t.warnBg, t.warn),
    };
    final deltaColor = switch (deltaTone) {
      DsKpiDelta.up => t.success,
      DsKpiDelta.down => t.danger,
      DsKpiDelta.neutral => t.muted,
    };
    final card = Container(
      padding: const EdgeInsets.fromLTRB(16, 15, 16, 15),
      decoration: BoxDecoration(
        color: t.surface,
        border: Border.all(color: t.border),
        borderRadius: BorderRadius.circular(AppDims.rLg),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        mainAxisSize: MainAxisSize.min,
        children: [
          Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Expanded(
                child: Padding(
                  padding: const EdgeInsets.only(top: 2),
                  child: Text(title,
                      style: TextStyle(fontSize: AppDims.fsSm, color: t.muted)),
                ),
              ),
              if (icon != null)
                Container(
                  width: 30,
                  height: 30,
                  decoration: BoxDecoration(
                      color: icBg,
                      borderRadius: BorderRadius.circular(AppDims.rMd)),
                  alignment: Alignment.center,
                  child: Icon(icon, size: 17, color: icFg),
                ),
            ],
          ),
          const SizedBox(height: 7),
          Text(value,
              style: TextStyle(
                  fontSize: 24,
                  fontWeight: FontWeight.w700,
                  letterSpacing: 0.3,
                  fontFamily: AppFonts.mono,
                  fontFamilyFallback: AppFonts.monoFallback,
                  color: switch (tone) {
                    DsKpiTone.alert => t.accent,
                    DsKpiTone.warn => t.warn,
                    _ => t.heading,
                  })),
          if (delta != null) ...[
            const SizedBox(height: 5),
            // 原型 .d 的箭头是文本字符 ▲/▼（非图标），gap4。
            Text(
              switch (deltaTone) {
                DsKpiDelta.up => '▲ ${delta!}',
                DsKpiDelta.down => '▼ ${delta!}',
                DsKpiDelta.neutral => delta!,
              },
              style: TextStyle(fontSize: AppDims.fsXs, color: deltaColor),
            ),
          ],
        ],
      ),
    );
    if (onTap == null) return card;
    return MouseRegion(
      cursor: SystemMouseCursors.click,
      child: GestureDetector(onTap: onTap, child: card),
    );
  }
}