import 'package:flutter/material.dart';

import '../models/catalog.dart';

/// 管理页：单元集 / 计划 / 算法三个维度。
class ManagePage extends StatelessWidget {
  const ManagePage({super.key});

  @override
  Widget build(BuildContext context) {
    return DefaultTabController(
      length: 3,
      child: Scaffold(
        appBar: AppBar(
          title: const Text('管理'),
          bottom: const TabBar(
            tabs: <Widget>[
              Tab(text: '单元集'),
              Tab(text: '计划'),
              Tab(text: '算法'),
            ],
          ),
        ),
        body: const TabBarView(
          children: <Widget>[
            _DeckTab(),
            _PlanTab(),
            _AlgorithmTab(),
          ],
        ),
      ),
    );
  }
}

class _DeckTab extends StatelessWidget {
  const _DeckTab();

  @override
  Widget build(BuildContext context) {
    return ListView.separated(
      padding: const EdgeInsets.fromLTRB(16, 16, 16, 32),
      itemCount: DeckInfo.samples.length + 1,
      separatorBuilder: (BuildContext context, int index) =>
          const SizedBox(height: 12),
      itemBuilder: (BuildContext context, int index) {
        if (index == 0) {
          return _CountLabel(text: '共 ${DeckInfo.samples.length} 个单元集');
        }
        return _DeckCard(deck: DeckInfo.samples[index - 1]);
      },
    );
  }
}

class _DeckCard extends StatelessWidget {
  const _DeckCard({required this.deck});

  final DeckInfo deck;

  @override
  Widget build(BuildContext context) {
    final ThemeData theme = Theme.of(context);
    final ColorScheme colors = theme.colorScheme;
    final TextTheme text = theme.textTheme;

    return _ManageCard(
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: <Widget>[
          Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: <Widget>[
              _Badge(icon: Icons.menu_book_rounded, color: colors.primary),
              const SizedBox(width: 12),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: <Widget>[
                    Text(
                      deck.title,
                      style: text.titleMedium,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                    ),
                    const SizedBox(height: 2),
                    Text(
                      deck.description,
                      style: text.bodySmall?.copyWith(
                        color: colors.onSurfaceVariant,
                      ),
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                    ),
                  ],
                ),
              ),
              const SizedBox(width: 8),
              _Chip(label: deck.algorithm),
            ],
          ),
          const SizedBox(height: 14),
          ClipRRect(
            borderRadius: BorderRadius.circular(6),
            child: LinearProgressIndicator(
              value: deck.progress,
              minHeight: 6,
              backgroundColor: colors.surfaceContainerHighest,
            ),
          ),
          const SizedBox(height: 10),
          Row(
            children: <Widget>[
              Expanded(
                child: _MetaText(
                  '${deck.activatedItems} / ${deck.totalItems} · ${deck.progressPercent}',
                ),
              ),
              _MetaText('最近 ${deck.lastStudied}'),
            ],
          ),
          const SizedBox(height: 6),
          _MetaText('标识 ${deck.id}'),
        ],
      ),
    );
  }
}

class _PlanTab extends StatelessWidget {
  const _PlanTab();

  @override
  Widget build(BuildContext context) {
    return ListView.separated(
      padding: const EdgeInsets.fromLTRB(16, 16, 16, 32),
      itemCount: PlanInfo.samples.length + 1,
      separatorBuilder: (BuildContext context, int index) =>
          const SizedBox(height: 12),
      itemBuilder: (BuildContext context, int index) {
        if (index == 0) {
          return _CountLabel(text: '共 ${PlanInfo.samples.length} 个计划');
        }
        return _PlanCard(plan: PlanInfo.samples[index - 1]);
      },
    );
  }
}

class _PlanCard extends StatelessWidget {
  const _PlanCard({required this.plan});

  final PlanInfo plan;

  @override
  Widget build(BuildContext context) {
    final ThemeData theme = Theme.of(context);
    final ColorScheme colors = theme.colorScheme;
    final TextTheme text = theme.textTheme;

    return _ManageCard(
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: <Widget>[
          Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: <Widget>[
              _Badge(icon: Icons.event_note_rounded, color: colors.tertiary),
              const SizedBox(width: 12),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: <Widget>[
                    Text(plan.title, style: text.titleMedium),
                    const SizedBox(height: 2),
                    Text(
                      plan.description,
                      style: text.bodySmall?.copyWith(
                        color: colors.onSurfaceVariant,
                      ),
                    ),
                  ],
                ),
              ),
              const SizedBox(width: 8),
              _Chip(
                label: plan.enabled ? '启用' : '停用',
                emphasized: plan.enabled,
              ),
            ],
          ),
          const SizedBox(height: 14),
          Row(
            children: <Widget>[
              Expanded(
                child: _Metric(
                  label: '新识记',
                  value: '${plan.newPerDay}',
                  suffix: '/ 天',
                ),
              ),
              Expanded(
                child: _Metric(
                  label: '复习上限',
                  value: '${plan.reviewPerDay}',
                  suffix: '/ 天',
                ),
              ),
            ],
          ),
          const SizedBox(height: 10),
          _MetaText('时段 ${plan.window}'),
        ],
      ),
    );
  }
}

class _AlgorithmTab extends StatelessWidget {
  const _AlgorithmTab();

  @override
  Widget build(BuildContext context) {
    return ListView.separated(
      padding: const EdgeInsets.fromLTRB(16, 16, 16, 32),
      itemCount: AlgorithmInfo.samples.length + 1,
      separatorBuilder: (BuildContext context, int index) =>
          const SizedBox(height: 12),
      itemBuilder: (BuildContext context, int index) {
        if (index == 0) {
          return _CountLabel(
            text: '共 ${AlgorithmInfo.samples.length} 个调度算法',
          );
        }
        return _AlgorithmCard(algorithm: AlgorithmInfo.samples[index - 1]);
      },
    );
  }
}

class _AlgorithmCard extends StatelessWidget {
  const _AlgorithmCard({required this.algorithm});

  final AlgorithmInfo algorithm;

  @override
  Widget build(BuildContext context) {
    final ThemeData theme = Theme.of(context);
    final ColorScheme colors = theme.colorScheme;
    final TextTheme text = theme.textTheme;

    return _ManageCard(
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: <Widget>[
          Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: <Widget>[
              _Badge(icon: Icons.functions_rounded, color: colors.secondary),
              const SizedBox(width: 12),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: <Widget>[
                    Row(
                      children: <Widget>[
                        Text(algorithm.name, style: text.titleMedium),
                        const SizedBox(width: 6),
                        _MetaText('v${algorithm.version}'),
                      ],
                    ),
                    const SizedBox(height: 2),
                    Text(
                      algorithm.description,
                      style: text.bodySmall?.copyWith(
                        color: colors.onSurfaceVariant,
                      ),
                    ),
                  ],
                ),
              ),
              if (algorithm.isDefault) ...<Widget>[
                const SizedBox(width: 8),
                const _Chip(label: '默认', emphasized: true),
              ],
            ],
          ),
          const SizedBox(height: 12),
          _MetaText(algorithm.parameters),
        ],
      ),
    );
  }
}

/// 卡片统一外观。
class _ManageCard extends StatelessWidget {
  const _ManageCard({required this.child});

  final Widget child;

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: Theme.of(context).colorScheme.surfaceContainerLow,
        borderRadius: BorderRadius.circular(20),
      ),
      child: child,
    );
  }
}

class _Badge extends StatelessWidget {
  const _Badge({required this.icon, required this.color});

  final IconData icon;
  final Color color;

  @override
  Widget build(BuildContext context) {
    return Container(
      width: 40,
      height: 40,
      decoration: BoxDecoration(
        color: color.withValues(alpha: 0.16),
        borderRadius: BorderRadius.circular(12),
      ),
      child: Icon(icon, size: 20, color: color),
    );
  }
}

class _Chip extends StatelessWidget {
  const _Chip({required this.label, this.emphasized = false});

  final String label;
  final bool emphasized;

  @override
  Widget build(BuildContext context) {
    final ColorScheme colors = Theme.of(context).colorScheme;
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 4),
      decoration: ShapeDecoration(
        color: emphasized
            ? colors.primaryContainer
            : colors.surfaceContainerHighest,
        shape: const StadiumBorder(),
      ),
      child: Text(
        label,
        style: Theme.of(context).textTheme.labelSmall?.copyWith(
          color: emphasized
              ? colors.onPrimaryContainer
              : colors.onSurfaceVariant,
          fontWeight: FontWeight.w600,
        ),
      ),
    );
  }
}

class _Metric extends StatelessWidget {
  const _Metric({required this.label, required this.value, this.suffix});

  final String label;
  final String value;
  final String? suffix;

  @override
  Widget build(BuildContext context) {
    final ThemeData theme = Theme.of(context);
    final ColorScheme colors = theme.colorScheme;
    final String? suffix = this.suffix;

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: <Widget>[
        Text(
          label,
          style: theme.textTheme.bodySmall?.copyWith(
            color: colors.onSurfaceVariant,
          ),
        ),
        const SizedBox(height: 2),
        Row(
          crossAxisAlignment: CrossAxisAlignment.baseline,
          textBaseline: TextBaseline.alphabetic,
          children: <Widget>[
            Text(
              value,
              style: theme.textTheme.titleLarge?.copyWith(
                fontWeight: FontWeight.w700,
              ),
            ),
            if (suffix != null) ...<Widget>[
              const SizedBox(width: 4),
              Text(
                suffix,
                style: theme.textTheme.bodySmall?.copyWith(
                  color: colors.onSurfaceVariant,
                ),
              ),
            ],
          ],
        ),
      ],
    );
  }
}

class _MetaText extends StatelessWidget {
  const _MetaText(this.value);

  final String value;

  @override
  Widget build(BuildContext context) {
    return Text(
      value,
      style: Theme.of(context).textTheme.bodySmall?.copyWith(
        color: Theme.of(context).colorScheme.onSurfaceVariant,
      ),
      maxLines: 1,
      overflow: TextOverflow.ellipsis,
    );
  }
}

class _CountLabel extends StatelessWidget {
  const _CountLabel({required this.text});

  final String text;

  @override
  Widget build(BuildContext context) {
    return Text(
      text,
      style: Theme.of(context).textTheme.labelMedium?.copyWith(
        color: Theme.of(context).colorScheme.onSurfaceVariant,
      ),
    );
  }
}