observer/flutter_app/lib/annotate/annotate_tasks_screen.dart

import 'package:flutter/material.dart';

import 'annotate_api.dart';
import 'annotator_screen.dart';

String _fmt(DateTime t) {
  String p(int n) => n.toString().padLeft(2, '0');
  return '${t.month}/${t.day} ${p(t.hour)}:${p(t.minute)}';
}

/// 标注赚时长首页：我的统计（进度/今日已得/冻结态）+ 可领任务列表。
/// 领取后进入标注器逐张画框提交，提交满 [AnnotateStats.rewardPerImages] 张自动到账时长。
class AnnotateTasksScreen extends StatefulWidget {
  final AnnotateApi api;

  const AnnotateTasksScreen({super.key, required this.api});

  @override
  State<AnnotateTasksScreen> createState() => _AnnotateTasksScreenState();
}

class _AnnotateTasksScreenState extends State<AnnotateTasksScreen> {
  late Future<(List<AnnotateTaskInfo>, AnnotateStats)> _future;
  bool _claiming = false;

  @override
  void initState() {
    super.initState();
    _future = widget.api.tasks();
  }

  void _reload() {
    setState(() => _future = widget.api.tasks());
  }

  Future<void> _claim(AnnotateTaskInfo task) async {
    if (_claiming) return;
    setState(() => _claiming = true);
    try {
      final images = await widget.api.claim(task.id);
      if (!mounted) return;
      if (images.isEmpty) {
        ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(content: Text('任务池暂时没有可领取的图片，稍后再来')));
        _reload();
        return;
      }
      final earned = await Navigator.of(context).push<bool>(MaterialPageRoute(
        builder: (_) => AnnotatorScreen(api: widget.api, task: task, images: images),
      ));
      if (earned == true) _reload(); // 本批有提交：回列表刷新进度/奖励
    } on SessionExpiredException {
      if (mounted) _sessionExpired();
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context)
            .showSnackBar(SnackBar(content: Text('$e'.replaceFirst('Exception: ', ''))));
      }
    } finally {
      if (mounted) setState(() => _claiming = false);
    }
  }

  void _sessionExpired() {
    ScaffoldMessenger.of(context)
        .showSnackBar(const SnackBar(content: Text('登录已失效，请重新登录')));
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('标注赚时长')),
      body: FutureBuilder<(List<AnnotateTaskInfo>, AnnotateStats)>(
        future: _future,
        builder: (context, snap) {
          if (snap.connectionState != ConnectionState.done) {
            return const Center(child: CircularProgressIndicator());
          }
          if (snap.hasError) {
            return Center(
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  Text('加载失败：${snap.error}'.replaceFirst('Exception: ', '')),
                  const SizedBox(height: 12),
                  FilledButton(onPressed: _reload, child: const Text('重试')),
                ],
              ),
            );
          }
          final (tasks, stats) = snap.data!;
          return RefreshIndicator(
            onRefresh: () async => _reload(),
            child: ListView(
              physics: const AlwaysScrollableScrollPhysics(),
              padding: const EdgeInsets.all(16),
              children: [
                _StatsCard(stats: stats),
                const SizedBox(height: 16),
                Text('可领任务', style: Theme.of(context).textTheme.titleMedium),
                const SizedBox(height: 8),
                if (tasks.isEmpty)
                  const Padding(
                    padding: EdgeInsets.symmetric(vertical: 32),
                    child: Center(child: Text('暂无可领任务，敬请期待')),
                  )
                else
                  ...tasks.map((t) => Card(
                        margin: const EdgeInsets.only(bottom: 10),
                        child: ListTile(
                          title: Text(t.name,
                              style: const TextStyle(fontWeight: FontWeight.w600)),
                          subtitle: Text(
                              '物种：${t.species.isEmpty ? t.datasetName : t.species} · 池余量 ${t.poolRemain} 张'),
                          trailing: FilledButton(
                            onPressed: _claiming || stats.frozen || t.poolRemain <= 0
                                ? null
                                : () => _claim(t),
                            child: const Text('领取'),
                          ),
                        ),
                      )),
              ],
            ),
          );
        },
      ),
    );
  }
}

class _StatsCard extends StatelessWidget {
  final AnnotateStats stats;

  const _StatsCard({required this.stats});

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                Icon(Icons.emoji_events,
                    color: Colors.amber.shade700, size: 28),
                const SizedBox(width: 8),
                Text('标 ${stats.rewardPerImages} 张得 ${stats.rewardMinutes} 分钟',
                    style: theme.textTheme.titleMedium
                        ?.copyWith(fontWeight: FontWeight.w600)),
              ],
            ),
            const SizedBox(height: 12),
            LinearProgressIndicator(
              value: stats.rewardPerImages <= 0
                  ? 0
                  : (stats.progressDone % stats.rewardPerImages) /
                      stats.rewardPerImages,
            ),
            const SizedBox(height: 6),
            Text(
              '本档进度 ${stats.progressDone}/${stats.rewardPerImages} · 今日已得 ${stats.todayEarnedMinutes}/${stats.dailyCapMinutes} 分钟 · 累计 ${stats.totalEarnedMinutes} 分钟',
              style: theme.textTheme.bodySmall?.copyWith(color: Colors.grey.shade600),
            ),
            Text(
              '通过 ${stats.approved} / 拒绝 ${stats.rejected}（通过率 ${(stats.approveRatio * 100).toStringAsFixed(0)}%）',
              style: theme.textTheme.bodySmall?.copyWith(color: Colors.grey.shade600),
            ),
            if (stats.frozen) ...[
              const SizedBox(height: 8),
              Container(
                padding: const EdgeInsets.all(10),
                decoration: BoxDecoration(
                  color: Colors.red.shade50,
                  borderRadius: BorderRadius.circular(8),
                ),
                child: Row(children: [
                  const Icon(Icons.block, color: Colors.red, size: 20),
                  const SizedBox(width: 8),
                  Expanded(
                    child: Text(
                      '标注质量未达标，资格冻结中（${_fmt(stats.frozenUntil!)} 解冻）',
                      style: const TextStyle(color: Colors.red, fontSize: 13),
                    ),
                  ),
                ]),
              ),
            ],
          ],
        ),
      ),
    );
  }
}