import 'package:flutter/material.dart';
import 'package:miaoji_zhang/shared/api/api_client.dart';
import 'package:miaoji_zhang/shared/services/recognition_import_service.dart';
import 'package:miaoji_zhang/shared/services/screenshot_channel.dart';
import 'package:miaoji_zhang/shared/services/shanghai_time.dart';
import 'package:miaoji_zhang/shared/theme/app_theme.dart';
import 'package:miaoji_zhang/shared/widgets/app_controls.dart';

class RecognitionBatchPage extends StatefulWidget {
  final String? initialBatchId;

  const RecognitionBatchPage({super.key, this.initialBatchId});

  @override
  State<RecognitionBatchPage> createState() => _RecognitionBatchPageState();
}

class _RecognitionBatchPageState extends State<RecognitionBatchPage> {
  List<RecognitionBatch> _batches = const [];
  bool _loading = true;
  String? _error;
  String? _restoringId;
  String? _confirmingId;

  @override
  void initState() {
    super.initState();
    _load();
  }

  Future<void> _load() async {
    try {
      final batches = await ScreenshotChannel.listRecognitionBatches();
      if (!mounted) return;
      setState(() {
        _batches = batches;
        _loading = false;
        _error = null;
      });
    } catch (error) {
      if (!mounted) return;
      setState(() {
        _loading = false;
        _error = apiErrorMessage(error);
      });
    }
  }

  Future<void> _restore(RecognitionBatchItem item) async {
    setState(() => _restoringId = item.candidateId);
    try {
      final restored = await ScreenshotChannel.restoreDroppedRecognition(
        item.candidateId,
      );
      if (!restored) throw StateError('这条候选已恢复或已过期');
      await RecognitionImportService.importAutomatic();
      await _load();
      if (mounted) {
        ScaffoldMessenger.of(
          context,
        ).showSnackBar(const SnackBar(content: Text('候选已恢复并入账')));
      }
    } catch (error) {
      if (mounted) {
        ScaffoldMessenger.of(
          context,
        ).showSnackBar(SnackBar(content: Text(apiErrorMessage(error))));
      }
    } finally {
      if (mounted) setState(() => _restoringId = null);
    }
  }

  Future<void> _confirm(RecognitionBatchItem item) async {
    setState(() => _confirmingId = item.candidateId);
    try {
      await RecognitionImportService.handleAction(context, {
        'action': 'recognition_confirm',
        'candidateId': item.candidateId,
      });
      await _load();
    } finally {
      if (mounted) setState(() => _confirmingId = null);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('最近 AI 对账')),
      body: RefreshIndicator(onRefresh: _load, child: _body()),
    );
  }

  Widget _body() {
    if (_loading) {
      return const Center(child: CircularProgressIndicator());
    }
    if (_error != null) {
      return ListView(
        children: [
          SizedBox(height: MediaQuery.sizeOf(context).height * 0.28),
          Center(
            child: Text(_error!, style: TextStyle(color: context.jz.text2)),
          ),
          const SizedBox(height: 12),
          Center(
            child: JzActionButton(
              label: '重试',
              secondary: true,
              onPressed: _load,
            ),
          ),
        ],
      );
    }
    if (_batches.isEmpty) {
      return ListView(
        children: [
          SizedBox(height: MediaQuery.sizeOf(context).height * 0.3),
          Icon(Icons.fact_check_outlined, size: 42, color: context.jz.text3),
          const SizedBox(height: 12),
          Center(
            child: Text(
              '暂无 AI 对账记录',
              style: TextStyle(color: context.jz.text3),
            ),
          ),
        ],
      );
    }
    return ListView.separated(
      padding: const EdgeInsets.fromLTRB(16, 8, 16, 28),
      itemCount: _batches.length,
      separatorBuilder: (_, _) => const SizedBox(height: 10),
      itemBuilder: (_, index) => _batchCard(_batches[index]),
    );
  }

  Widget _batchCard(RecognitionBatch batch) {
    final count = batch.kept + batch.updated + batch.created + batch.dropped;
    return Card(
      clipBehavior: Clip.antiAlias,
      child: ExpansionTile(
        initiallyExpanded: batch.id == widget.initialBatchId,
        leading: Icon(
          batch.fallback
              ? Icons.offline_bolt_outlined
              : Icons.auto_fix_high_rounded,
          color: batch.fallback ? AppTheme.orange : AppTheme.primary,
        ),
        title: Text(
          '${ShanghaiTime.formatDateTime(batch.completedAt)} · $count 条候选',
          style: const TextStyle(fontSize: 14, fontWeight: FontWeight.w700),
        ),
        subtitle: Padding(
          padding: const EdgeInsets.only(top: 4),
          child: Text(
            batch.fallback
                ? 'AI 不可用，已按本地识别结果处理'
                : '保留 ${batch.kept} · 修正 ${batch.updated} · 补全 ${batch.created} · 剔除 ${batch.dropped}',
            style: TextStyle(fontSize: 11.5, color: context.jz.text2),
          ),
        ),
        children: [
          Divider(height: 1, color: context.jz.line),
          for (var index = 0; index < batch.items.length; index++) ...[
            _batchItem(batch.items[index]),
            if (index != batch.items.length - 1)
              Divider(height: 1, indent: 54, color: context.jz.line),
          ],
          if (batch.items.isEmpty)
            Padding(
              padding: const EdgeInsets.all(16),
              child: Text(
                '本批次没有候选明细',
                style: TextStyle(color: context.jz.text3),
              ),
            ),
        ],
      ),
    );
  }

  Widget _batchItem(RecognitionBatchItem item) {
    final action = _actionDisplay(item.action);
    final restoring = _restoringId == item.candidateId;
    final confirming = _confirmingId == item.candidateId;
    return Padding(
      padding: const EdgeInsets.fromLTRB(16, 13, 12, 13),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          SizedBox(
            width: 30,
            height: 30,
            child: Icon(action.icon, size: 19, color: action.color),
          ),
          const SizedBox(width: 8),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Row(
                  children: [
                    Expanded(
                      child: Text(
                        item.merchant?.trim().isNotEmpty == true
                            ? item.merchant!.trim()
                            : '智能识别账单',
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                        style: const TextStyle(
                          fontSize: 13,
                          fontWeight: FontWeight.w700,
                        ),
                      ),
                    ),
                    const SizedBox(width: 8),
                    Text(
                      '${item.type == 'income' ? '+' : '-'}¥${item.amount.toStringAsFixed(2)}',
                      style: TextStyle(
                        fontSize: 13,
                        fontWeight: FontWeight.w700,
                        color: item.type == 'income'
                            ? AppTheme.primary
                            : AppTheme.red,
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 4),
                Text(
                  '${action.label}${item.reason.isEmpty ? '' : ' · ${item.reason}'}',
                  style: TextStyle(
                    fontSize: 11.5,
                    height: 1.45,
                    color: context.jz.text2,
                  ),
                ),
              ],
            ),
          ),
          if (item.canRestore) ...[
            const SizedBox(width: 8),
            IconButton(
              tooltip: '恢复并入账',
              onPressed: restoring ? null : () => _restore(item),
              icon: restoring
                  ? const SizedBox(
                      width: 18,
                      height: 18,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : const Icon(Icons.restore_rounded),
            ),
          ] else if (item.state == 'pending_confirm') ...[
            const SizedBox(width: 8),
            IconButton(
              tooltip: '确认入账',
              onPressed: confirming ? null : () => _confirm(item),
              icon: confirming
                  ? const SizedBox(
                      width: 18,
                      height: 18,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : const Icon(Icons.check_rounded),
            ),
          ],
        ],
      ),
    );
  }

  _ActionDisplay _actionDisplay(String action) => switch (action) {
    'update' => const _ActionDisplay(
      'AI 已修正',
      Icons.edit_note_rounded,
      AppTheme.orange,
    ),
    'create' => const _ActionDisplay(
      'AI 已补全',
      Icons.add_circle_outline_rounded,
      AppTheme.primary,
    ),
    'drop' => const _ActionDisplay(
      'AI 已剔除',
      Icons.remove_circle_outline_rounded,
      AppTheme.red,
    ),
    'restored' => const _ActionDisplay(
      '已手动恢复',
      Icons.restore_rounded,
      AppTheme.primary,
    ),
    'fallback' => const _ActionDisplay(
      '本地结果',
      Icons.offline_bolt_outlined,
      AppTheme.orange,
    ),
    _ => const _ActionDisplay(
      'AI 已保留',
      Icons.check_circle_outline_rounded,
      AppTheme.primary,
    ),
  };
}

class _ActionDisplay {
  final String label;
  final IconData icon;
  final Color color;

  const _ActionDisplay(this.label, this.icon, this.color);
}