reclaim/app/lib/pages/heatmap_page.dart

import 'package:flutter/material.dart';

import '../data/models.dart';
import '../data/repository.dart';
import '../theme/reclaim_tokens.dart';
import '../widgets/demo_banner.dart';
import '../widgets/heatmap_grid.dart';
import '../widgets/reclaim_card.dart';
import '../widgets/tier_badge.dart';
import 'norm_detail_page.dart';

class HeatmapPage extends StatefulWidget {
  const HeatmapPage({super.key, required this.repository});

  final EvaluationRepository repository;

  @override
  State<HeatmapPage> createState() => _HeatmapPageState();
}

class _HeatmapPageState extends State<HeatmapPage> {
  late Future<List<Evaluation>> _future;

  @override
  void initState() {
    super.initState();
    _future = widget.repository.list();
  }

  @override
  Widget build(BuildContext context) {
    final t = Theme.of(context).textTheme;
    return Column(
      children: [
        const DemoBanner(),
        Expanded(
          child: Padding(
            padding: const EdgeInsets.all(ReclaimSpace.xl),
            child: FutureBuilder<List<Evaluation>>(
              future: _future,
              builder: (context, snap) {
                if (!snap.hasData) {
                  return const Center(
                      child: CircularProgressIndicator());
                }
                final items = snap.data!;
                return Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text('Heatmap', style: t.displaySmall),
                    const SizedBox(height: ReclaimSpace.xs),
                    Text(
                      'Schaden × Nutzen × Betroffenheit pro Norm. '
                      'Klick auf einen Punkt öffnet das Detail mit '
                      'Pflichten, Quellen und Gesetzestext.',
                      style: t.bodyLarge?.copyWith(
                        color: ReclaimColors.mute,
                      ),
                    ),
                    const SizedBox(height: ReclaimSpace.lg),
                    Expanded(
                      child: ReclaimCard(
                        accent: true,
                        expand: true,
                        child: HeatmapGrid(
                          evaluations: items,
                          onTap: (e) {
                            Navigator.of(context).push(
                              MaterialPageRoute(
                                builder: (_) => NormDetailPage(
                                  repository: widget.repository,
                                  evaluation: e,
                                ),
                              ),
                            );
                          },
                        ),
                      ),
                    ),
                    const SizedBox(height: ReclaimSpace.md),
                    const _LegendCard(),
                    const SizedBox(height: ReclaimSpace.lg),
                    Wrap(
                      spacing: ReclaimSpace.md,
                      runSpacing: ReclaimSpace.sm,
                      children: [
                        for (final e in items)
                          InkWell(
                            onTap: () {
                              Navigator.of(context).push(
                                MaterialPageRoute(
                                  builder: (_) => NormDetailPage(
                                    repository: widget.repository,
                                    evaluation: e,
                                  ),
                                ),
                              );
                            },
                            child: ReclaimCard(
                              padding: const EdgeInsets.symmetric(
                                horizontal: ReclaimSpace.md,
                                vertical: ReclaimSpace.sm,
                              ),
                              child: Row(
                                mainAxisSize: MainAxisSize.min,
                                children: [
                                  TierBadge(
                                      tier: e.tierLowest, compact: true),
                                  const SizedBox(
                                      width: ReclaimSpace.sm),
                                  Text(
                                    '${e.norm.jurabk} ${e.norm.paragraph}',
                                    style: t.labelLarge,
                                  ),
                                ],
                              ),
                            ),
                          ),
                      ],
                    ),
                  ],
                );
              },
            ),
          ),
        ),
      ],
    );
  }
}

/// Axis + circle legend below the heatmap. Spells out what is
/// plotted and how — the four-line top description deliberately
/// stays short and high-level, this card carries the precise
/// reading instructions a reviewer needs to defend the plot
/// against "what does that even mean?"
class _LegendCard extends StatelessWidget {
  const _LegendCard();

  @override
  Widget build(BuildContext context) {
    final t = Theme.of(context).textTheme;
    return ReclaimCard(
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text('Legende', style: t.headlineSmall),
          const SizedBox(height: ReclaimSpace.md),
          const _LegendRow(
            symbol: '↔',
            axis: 'Abszisse (X)',
            label: 'Schaden',
            description:
                'Bürokratiekosten pro Jahr in Euro, logarithmisch '
                'skaliert (10⁴ = 10 k, 10⁶ = 1 Mio, 10⁹ = 1 Mrd). '
                'Berechnet nach Standardkostenmodell '
                'P × F × T × h (Studie §3.1).',
          ),
          const SizedBox(height: ReclaimSpace.sm),
          const _LegendRow(
            symbol: '↕',
            axis: 'Ordinate (Y)',
            label: 'Nutzen',
            description:
                'Komposit-Score von 0–5, Mittelwert aus den sieben '
                'Dimensionen Schutz · Markt · Rechtssicherheit · '
                'EU-Binnenmarkt · Sicherheit · Umwelt · Einnahmen '
                '(Studie §3.2). Jede Dimension einzeln '
                'quellen-begründet.',
          ),
          const SizedBox(height: ReclaimSpace.sm),
          const _LegendRow(
            symbol: '●',
            axis: 'Punktgröße',
            label: 'Betroffenheit',
            description:
                'Anzahl der Adressaten (KMU, Bürger, Behörden), '
                'wurzel-skaliert. Mehr Adressaten → größerer Kreis. '
                'Quellen: DESTATIS Unternehmensregister, '
                'IHK-/Handwerkskammer-Mitgliederzahlen.',
          ),
          const SizedBox(height: ReclaimSpace.sm),
          const _LegendRow(
            symbol: '◐',
            axis: 'Farb-Kante',
            label: 'Evidenz-Stufe',
            description:
                'Jeder Wert trägt eine von vier Stufen — '
                'T1 amtlich (NKR, DESTATIS, ifo, ZEW), '
                'T2 Verband (DIHK, IHK, ZDH, BDI), '
                'T3 eigene Erhebung, '
                'T4 qualitatives Signal. '
                'Eine Zahl bekommt die Stufe ihrer schwächsten '
                'Eingangs-Variable — wenn h nur geschätzt ist (T4), '
                'ist die ganze SKM-Zahl T4. Petrol → warm = stark → '
                'schwach.',
          ),
        ],
      ),
    );
  }
}

class _LegendRow extends StatelessWidget {
  const _LegendRow({
    required this.symbol,
    required this.axis,
    required this.label,
    required this.description,
  });

  final String symbol;
  final String axis;
  final String label;
  final String description;

  @override
  Widget build(BuildContext context) {
    final t = Theme.of(context).textTheme;
    return Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        SizedBox(
          width: 28,
          child: Text(
            symbol,
            style: t.titleMedium?.copyWith(
              color: ReclaimColors.signal,
              fontSize: 18,
            ),
          ),
        ),
        SizedBox(
          width: 140,
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                axis,
                style: t.labelSmall?.copyWith(
                  color: ReclaimColors.mute,
                  letterSpacing: 0.4,
                ),
              ),
              Text(
                label,
                style: t.titleMedium,
              ),
            ],
          ),
        ),
        const SizedBox(width: ReclaimSpace.md),
        Expanded(
          child: Padding(
            padding: const EdgeInsets.only(top: 2),
            child: Text(
              description,
              style: t.bodyLarge?.copyWith(
                color: ReclaimColors.mute,
                height: 1.5,
              ),
            ),
          ),
        ),
      ],
    );
  }
}