import 'package:flutter/material.dart';

import '../models/model_manager.dart';

/// 档位展示名（档位码 s/n 仅内部记账，不对用户展示）
String _variantLabel(String v) => v == kVariantN ? '高性能' : '高精度';

/// 设置弹层「模型清单」区块：顶部「识别档位」分段控件（高性能/高精度，默认
/// 高性能，持久化本地）选择**目标档位**——只记录偏好，不直接切换运行中的
/// 模型，决定卡片主按钮面向哪一档（2026-09-11 回归单按钮制：卡内不再同列
/// 两档按钮）。多物种综合识别 App 端下线（2026-09-11）：目录中 combined 条目
/// 直接忽略、不展示，服务端/管理端综合训练功能保持不变。下方 2 列封面网格，
/// 同一数据集合并一张卡（s/n 两档内部记账，各自下载独立进度），卡片只对
/// **目标档**给一个主按钮：
/// - 任一档下载中 → 逐档进度条 + 取消（中止全部进行中的下载）；
/// - 任一档失败 → 错误提示 + 重试（只补下未成功的档）；
/// - 目标档已激活 →「使用中」点击取消使用；
/// - 目标档已下载未激活 →「使用」直接启用（同数据集另一档在运行会自动停用）；
/// - 目标档未下载 →「下载」只取回目标档（双档分别下载，伴档不随下；另一档
///   正在运行而缺目标档时，下载完自动切换过去）。
/// 卡片不展示版本号与档位状态行（2026-09-10 删「高精度/高性能 + 版本」灰字行，
/// 版本仅作内部记账），档位状态看主按钮。新版本由用户在卡片上手动重新
/// 下载（使用中重下会原地生效，2026-09-09 自动更新/待办横幅已退场）。
class ModelCatalogSection extends StatelessWidget {
  final ModelManager manager;

  const ModelCatalogSection({super.key, required this.manager});

  @override
  Widget build(BuildContext context) {
    return ListenableBuilder(
      listenable: manager,
      builder: (context, _) {
        // 目录按数据集分组：同一数据集 s/n 合成一张卡；组内 s（高精度）前 n 后。
        // 综合（combined，datasetId=0）条目 App 端忽略（2026-09-11 多物种下线）
        final byDataset = <int, List<ModelCatalogItem>>{};
        for (final c in manager.catalog) {
          if (c.isCombined) continue;
          byDataset.putIfAbsent(c.datasetId, () => []).add(c);
        }
        final groups = byDataset.values.toList()
          ..sort((a, b) => a.first.datasetId.compareTo(b.first.datasetId));
        const order = {kVariantS: 0, kVariantN: 1};
        for (final g in groups) {
          g.sort((a, b) =>
              (order[a.variant] ?? 9).compareTo(order[b.variant] ?? 9));
        }
        return Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          mainAxisSize: MainAxisSize.min,
          children: [
            Row(
              children: [
                const Text(
                  '识别档位',
                  style: TextStyle(color: Colors.white70, fontSize: 14),
                ),
                const Spacer(),
                _SegmentSwitch(
                  selected: manager.mode,
                  // 高性能在左、高精度在右（档位码仅内部记账）
                  options: const [
                    (value: kVariantN, label: '高性能'),
                    (value: kVariantS, label: '高精度'),
                  ],
                  onSelect: (v) => manager.setMode(v),
                ),
              ],
            ),
            const SizedBox(height: 6),
            const Text(
              '卡片操作面向所选档位；同一数据集一次只运行一档，切换会自动停用另一档',
              style: TextStyle(color: Colors.white38, fontSize: 11),
            ),
            const SizedBox(height: 12),
            Row(
              children: [
                const Text(
                  '模型清单',
                  style: TextStyle(
                    color: Colors.white,
                    fontSize: 14,
                    fontWeight: FontWeight.bold,
                  ),
                ),
                const Spacer(),
                TextButton.icon(
                  onPressed: () => manager.refresh(),
                  icon: const Icon(Icons.refresh, size: 16),
                  label: const Text('刷新'),
                  style: TextButton.styleFrom(
                    foregroundColor: Colors.white70,
                    visualDensity: VisualDensity.compact,
                  ),
                ),
              ],
            ),
            const SizedBox(height: 4),
            if (manager.error != null)
              Padding(
                padding: const EdgeInsets.only(bottom: 8),
                child: Text(
                  manager.error!,
                  style: const TextStyle(color: Colors.orange, fontSize: 12),
                ),
              ),
            if (groups.isEmpty)
              const Text(
                '暂无已发布模型',
                style: TextStyle(color: Colors.white54, fontSize: 13),
              )
            else
              GridView.builder(
                shrinkWrap: true,
                physics: const NeverScrollableScrollPhysics(),
                gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
                  crossAxisCount: 2,
                  mainAxisSpacing: 12,
                  crossAxisSpacing: 12,
                  childAspectRatio: 0.72,
                ),
                itemCount: groups.length,
                itemBuilder: (context, i) =>
                    _SpeciesCard(items: groups[i], manager: manager),
              ),
          ],
        );
      },
    );
  }
}

/// 通用分段开关：白底圆角外框，选中段绿色高亮；[options] = (值, 展示名) 列表，
/// 点某段回调 [onSelect]（识别档位行使用）
class _SegmentSwitch extends StatelessWidget {
  final String selected;
  final List<({String value, String label})> options;
  final ValueChanged<String> onSelect;

  const _SegmentSwitch({
    required this.selected,
    required this.options,
    required this.onSelect,
  });

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.all(2),
      decoration: BoxDecoration(
        color: Colors.white12,
        borderRadius: BorderRadius.circular(8),
      ),
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          for (var i = 0; i < options.length; i++) ...[
            if (i > 0) const SizedBox(width: 2),
            _seg(options[i]),
          ],
        ],
      ),
    );
  }

  Widget _seg(({String value, String label}) o) {
    final sel = selected == o.value;
    return InkWell(
      borderRadius: BorderRadius.circular(6),
      onTap: () => onSelect(o.value),
      child: Container(
        padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 4),
        decoration: BoxDecoration(
          color: sel ? Colors.greenAccent : Colors.transparent,
          borderRadius: BorderRadius.circular(6),
        ),
        child: Text(
          o.label,
          style: TextStyle(
            color: sel ? Colors.black : Colors.white70,
            fontSize: 12,
            fontWeight: sel ? FontWeight.bold : FontWeight.normal,
          ),
        ),
      ),
    );
  }
}

/// 单物种卡片：同数据集 s/n 两档合并展示但**只给目标档一个主按钮**；下载/激活
/// 状态按 (数据集, 档位) 独立记账，同物种同时至多一个档位被激活（目标档为准）
class _SpeciesCard extends StatelessWidget {
  final List<ModelCatalogItem> items;
  final ModelManager manager;

  const _SpeciesCard({required this.items, required this.manager});

  @override
  Widget build(BuildContext context) {
    // 目标条目：当前目标档优先；目录缺目标档（存量单档物种）时取 s 档
    final target = items.firstWhere(
      (i) => i.variant == manager.mode,
      orElse: () => items.first,
    );
    final tActive = manager.isActive(target.datasetId, target.variant);
    final tDownloaded = manager.isDownloaded(target.datasetId, target.variant);
    // 同物种另一档正在使用的条目（至多一个——每数据集单档激活约束）
    final activeOther = items
        .where((i) =>
            i.variant != target.variant &&
            manager.isActive(i.datasetId, i.variant))
        .toList();

    // 任一档进行中/失败标志
    final downloading =
        items.any((i) => manager.progressOf(i.datasetId, i.variant) != null);
    final hasError =
        items.any((i) => manager.errorOf(i.datasetId, i.variant) != null);

    final thumb = ClipRRect(
      borderRadius: BorderRadius.circular(8),
      child: AspectRatio(
        aspectRatio: 4 / 3,
        child: Stack(
          fit: StackFit.expand,
          children: [
            Image.network(
              '${manager.baseUrl}${target.coverUrl}',
              fit: BoxFit.cover,
              loadingBuilder: (context, child, chunk) => chunk == null
                  ? child
                  : Container(
                      color: Colors.white12,
                      child: const Center(
                        child: SizedBox(
                          width: 20,
                          height: 20,
                          child: CircularProgressIndicator(strokeWidth: 2),
                        ),
                      ),
                    ),
              errorBuilder: (context, error, stack) => Container(
                color: Colors.white12,
                child: const Icon(
                  Icons.image_not_supported_outlined,
                  color: Colors.white38,
                ),
              ),
            ),
          ],
        ),
      ),
    );

    return Container(
      padding: const EdgeInsets.all(8),
      decoration: BoxDecoration(
        color: Colors.white10,
        borderRadius: BorderRadius.circular(10),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Expanded(child: Center(child: thumb)),
          const SizedBox(height: 6),
          Row(
            children: [
              Expanded(
                child: Text(
                  target.datasetName,
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                  style: const TextStyle(
                    color: Colors.white,
                    fontSize: 13,
                    fontWeight: FontWeight.w600,
                  ),
                ),
              ),
            ],
          ),
          const SizedBox(height: 6),
          _actionArea(
            items: items,
            target: target,
            downloading: downloading,
            hasError: hasError,
            tActive: tActive,
            tDownloaded: tDownloaded,
            activeOther: activeOther,
          ),
        ],
      ),
    );
  }

  /// 动作区：进度/错误优先级最高；其次按目标档的下载/激活状态给唯一主按钮
  Widget _actionArea({
    required List<ModelCatalogItem> items,
    required ModelCatalogItem target,
    required bool downloading,
    required bool hasError,
    required bool tActive,
    required bool tDownloaded,
    required List<ModelCatalogItem> activeOther,
  }) {
    if (downloading) {
      return Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          for (final i in items)
            if (manager.progressOf(i.datasetId, i.variant) != null)
              _progressRow(item: i),
          Align(
            alignment: Alignment.centerRight,
            child: TextButton(
              onPressed: () {
                for (final i in items) {
                  if (manager.progressOf(i.datasetId, i.variant) != null) {
                    manager.cancelDownload(i.datasetId, i.variant);
                  }
                }
              },
              style: TextButton.styleFrom(
                foregroundColor: Colors.white54,
                visualDensity: VisualDensity.compact,
                padding: const EdgeInsets.symmetric(horizontal: 8),
                minimumSize: const Size(0, 24),
                tapTargetSize: MaterialTapTargetSize.shrinkWrap,
              ),
              child: const Text('取消', style: TextStyle(fontSize: 11)),
            ),
          ),
        ],
      );
    }
    if (hasError) {
      return Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          for (final i in items)
            if (manager.errorOf(i.datasetId, i.variant) != null)
              Text(
                '${_variantLabel(i.variant)}下载失败',
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
                style: const TextStyle(
                    color: Colors.redAccent, fontSize: 10),
              ),
          Align(
            alignment: Alignment.centerRight,
            child: TextButton(
              onPressed: () {
                for (final i in items) {
                  if (manager.errorOf(i.datasetId, i.variant) != null) {
                    manager.downloadModel(i);
                  }
                }
              },
              style: TextButton.styleFrom(
                foregroundColor: Colors.redAccent,
                visualDensity: VisualDensity.compact,
                padding: const EdgeInsets.symmetric(horizontal: 8),
                minimumSize: const Size(0, 24),
                tapTargetSize: MaterialTapTargetSize.shrinkWrap,
              ),
              child: const Text('重试', style: TextStyle(fontSize: 11)),
            ),
          ),
        ],
      );
    }

    final Widget mainBtn;
    if (tActive) {
      // 目标档使用中：点击取消使用
      mainBtn = SizedBox(
        height: 30,
        child: OutlinedButton(
          onPressed: () =>
              manager.setActive(target.datasetId, target.variant, false),
          style: OutlinedButton.styleFrom(
            foregroundColor: Colors.greenAccent,
            side: const BorderSide(color: Colors.greenAccent),
          ),
          child: const Text('使用中', style: TextStyle(fontSize: 12)),
        ),
      );
    } else if (tDownloaded) {
      // 已下载未激活（目标档）：点「使用」直接启用——同物种另一档在使用会
      // 自动停用（每数据集至多一档运行）
      mainBtn = SizedBox(
        height: 30,
        child: FilledButton(
          onPressed: () =>
              manager.setActive(target.datasetId, target.variant, true),
          style: FilledButton.styleFrom(
            backgroundColor: Colors.greenAccent,
            foregroundColor: Colors.black,
            visualDensity: VisualDensity.compact,
          ),
          child: const Text('使用', style: TextStyle(fontSize: 12)),
        ),
      );
    } else {
      // 目标档未下载：只下载目标档（双档分别下载——伴档不随下，缺失档由
      // 切档后按钮补下）；另一档在使用时补下目标档后自动切换过去
      final use = activeOther.isNotEmpty;
      mainBtn = SizedBox(
        height: 30,
        child: FilledButton(
          onPressed: () async {
            if (!manager.isDownloaded(target.datasetId, target.variant)) {
              if (use) {
                final ok = await manager.downloadModel(target);
                if (!ok) return; // 下载失败/取消：错误分支展示，保持现状
              } else {
                manager.downloadModel(target);
                return;
              }
            }
            await manager.setActive(target.datasetId, target.variant, true);
          },
          style: FilledButton.styleFrom(
            backgroundColor: Colors.greenAccent,
            foregroundColor: Colors.black,
            visualDensity: VisualDensity.compact,
          ),
          child: const Text('下载', style: TextStyle(fontSize: 12)),
        ),
      );
    }

    return Column(
      mainAxisSize: MainAxisSize.min,
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [mainBtn],
    );
  }

  Widget _progressRow({required ModelCatalogItem item}) {
    final p = manager.progressOf(item.datasetId, item.variant) ?? 0.0;
    final label = _variantLabel(item.variant);
    return Column(
      mainAxisSize: MainAxisSize.min,
      children: [
        Row(
          children: [
            Text(
              '$label ${(p * 100).toStringAsFixed(0)}%',
              style: const TextStyle(color: Colors.white70, fontSize: 10),
            ),
          ],
        ),
        LinearProgressIndicator(
          value: p,
          backgroundColor: Colors.white12,
          color: Colors.greenAccent,
        ),
      ],
    );
  }
}