// widgets/ds/ds_bar_chart.dart — 原型 finance.html 收支趋势分组柱状图（镜像 .barchart）。
// 度量照原型：图高 180 / 柱宽 26 / pair 内 gap 6 / 列间 gap 18 / 柱顶 mono 数值标签
// （top:-17）/ 顶圆角 r-sm；收入柱=primary、支出柱=brand400；含图例（.chart-legend）。
import 'package:flutter/material.dart';

import '../../core/theme/app_dims.g.dart';
import '../../core/theme/context_tokens.dart';
import '../../core/theme/app_fonts.dart';

class DsBarGroup {
  final String label; // 列底标签（如 1月）
  final double a; // 收入（primary 柱）
  final double b; // 支出（brand400 柱）
  const DsBarGroup(this.label, this.a, this.b);
}

class DsBarChart extends StatelessWidget {
  final List<DsBarGroup> groups;
  final String legendA;
  final String legendB;

  /// 柱顶数值标签格式化（原型显示「万元」整数）。
  final String Function(double v) format;

  const DsBarChart({
    super.key,
    required this.groups,
    this.legendA = '收入',
    this.legendB = '支出',
    required this.format,
  });

  @override
  Widget build(BuildContext context) {
    final t = context.tokens;
    var max = 0.0;
    for (final g in groups) {
      if (g.a > max) max = g.a;
      if (g.b > max) max = g.b;
    }
    if (max <= 0) max = 1;

    return Container(
      // 原型 .chart-card：surface / border / r-lg / padding 18 20 14
      padding: const EdgeInsets.fromLTRB(20, 18, 20, 14),
      decoration: BoxDecoration(
        color: t.surface,
        border: Border.all(color: t.border),
        borderRadius: BorderRadius.circular(AppDims.rLg),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          // .chart-legend
          Row(children: [
            _legend(t, t.primary, legendA),
            const SizedBox(width: 18),
            _legend(t, t.brand400, legendB),
          ]),
          const SizedBox(height: 16),
          // .barchart：高 180 + 顶部标签余量 6
          SizedBox(
            height: 186,
            child: Row(
              crossAxisAlignment: CrossAxisAlignment.end,
              children: [
                for (var i = 0; i < groups.length; i++) ...[
                  if (i > 0) const SizedBox(width: 18),
                  Expanded(child: _col(t, groups[i], max)),
                ],
              ],
            ),
          ),
        ],
      ),
    );
  }

  Widget _legend(dynamic t, Color color, String label) =>
      Row(mainAxisSize: MainAxisSize.min, children: [
        Container(
            width: 11,
            height: 11,
            decoration: BoxDecoration(
                color: color, borderRadius: BorderRadius.circular(3))),
        const SizedBox(width: 7),
        Text(label, style: TextStyle(fontSize: AppDims.fsSm, color: t.muted)),
      ]);

  Widget _col(dynamic t, DsBarGroup g, double max) {
    return LayoutBuilder(builder: (ctx, cons) {
      // 原型柱宽 26；窄屏（列宽不足）按列宽收缩，防横向溢出
      final barW = ((cons.maxWidth - 6) / 2).clamp(8.0, 26.0);
      return Column(
        mainAxisAlignment: MainAxisAlignment.end,
        children: [
          Expanded(
            child: Row(
              mainAxisAlignment: MainAxisAlignment.center,
              crossAxisAlignment: CrossAxisAlignment.end,
              children: [
                _bar(t, g.a, max, t.primary, barW),
                const SizedBox(width: 6),
                _bar(t, g.b, max, t.brand400, barW),
              ],
            ),
          ),
          const SizedBox(height: 8),
          Text(g.label,
              style: TextStyle(fontSize: AppDims.fsSm, color: t.muted)),
        ],
      );
    });
  }

  Widget _bar(dynamic t, double v, double max, Color color, double barW) {
    // 最高柱 140 + 顶标签 ~18 ≈ 原型 .bar-pair 可用高（180 - 月份标签行）
    final h = (v / max * 140).clamp(2.0, 140.0);
    return Column(
      mainAxisSize: MainAxisSize.min,
      children: [
        // .bv 柱顶数值（mono fs-xs muted；原型绝对定位悬浮 → 布局占柱宽、绘制可溢出）
        SizedBox(
          width: barW,
          child: Center(
            child: Text(format(v),
                softWrap: false,
                overflow: TextOverflow.visible,
                style: TextStyle(
                    fontSize: AppDims.fsXs,
                    color: t.muted,
                    fontFamily: AppFonts.mono,
                    fontFamilyFallback: AppFonts.monoFallback)),
          ),
        ),
        const SizedBox(height: 3),
        Container(
          width: barW,
          height: h,
          decoration: BoxDecoration(
            color: color,
            borderRadius:
                const BorderRadius.vertical(top: Radius.circular(AppDims.rSm)),
          ),
        ),
      ],
    );
  }
}