import 'package:aioa_mobile/features/tasks/application/approval_task_controller.dart';
import 'package:aioa_mobile/features/tasks/application/notification_controller.dart';
import 'package:aioa_mobile/features/tasks/data/approval_task_repository.dart';
import 'package:aioa_mobile/features/tasks/data/notification_repository.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:intl/intl.dart';

class TasksPage extends ConsumerWidget {
  const TasksPage({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final notifications = ref.watch(notificationProvider);
    final tasks = ref.watch(approvalTaskProvider);
    final unread =
        notifications.value?.where((item) => !item.isRead).length ?? 0;
    final taskCount = tasks.value?.length ?? 0;
    return DefaultTabController(
      length: 2,
      child: Scaffold(
        appBar: AppBar(
          title: const Text('待办与通知'),
          bottom: TabBar(
            tabs: [
              Tab(text: taskCount == 0 ? '待办' : '待办 ($taskCount)'),
              Tab(text: unread == 0 ? '通知' : '通知 ($unread)'),
            ],
          ),
        ),
        body: TabBarView(
          children: [
            _ApprovalTaskList(tasks: tasks),
            _NotificationList(notifications: notifications),
          ],
        ),
      ),
    );
  }
}

class _ApprovalTaskList extends ConsumerWidget {
  const _ApprovalTaskList({required this.tasks});

  final AsyncValue<List<ApprovalTaskItem>> tasks;

  @override
  Widget build(BuildContext context, WidgetRef ref) => tasks.when(
    loading: () => const Center(child: CircularProgressIndicator()),
    error: (error, _) => Center(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          Text('待办加载失败：$error'),
          const SizedBox(height: 8),
          FilledButton(
            onPressed: ref.read(approvalTaskProvider.notifier).refresh,
            child: const Text('重试'),
          ),
        ],
      ),
    ),
    data: (items) {
      if (items.isEmpty) return const Center(child: Text('暂无待办'));
      return RefreshIndicator(
        onRefresh: ref.read(approvalTaskProvider.notifier).refresh,
        child: ListView.separated(
          padding: const EdgeInsets.all(12),
          itemCount: items.length,
          separatorBuilder: (_, _) => const SizedBox(height: 8),
          itemBuilder: (context, index) =>
              _ApprovalTaskCard(task: items[index]),
        ),
      );
    },
  );
}

class _ApprovalTaskCard extends ConsumerWidget {
  const _ApprovalTaskCard({required this.task});

  final ApprovalTaskItem task;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final request = task.leaveRequest;
    final formatter = DateFormat('MM-dd HH:mm');
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            Row(
              children: [
                const CircleAvatar(child: Icon(Icons.assignment_ind_outlined)),
                const SizedBox(width: 12),
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(
                        task.name,
                        style: const TextStyle(fontWeight: FontWeight.w700),
                      ),
                      Text(_typeLabel(request.type)),
                    ],
                  ),
                ),
              ],
            ),
            const SizedBox(height: 12),
            Text(
              '${formatter.format(request.startsAt.toLocal())} — ${formatter.format(request.endsAt.toLocal())}',
            ),
            const SizedBox(height: 6),
            Text(request.reason),
            const SizedBox(height: 14),
            Row(
              children: [
                Expanded(
                  child: OutlinedButton(
                    onPressed: () => _decide(context, ref, approved: false),
                    child: const Text('驳回'),
                  ),
                ),
                const SizedBox(width: 10),
                Expanded(
                  child: FilledButton(
                    onPressed: () => _decide(context, ref, approved: true),
                    child: const Text('批准'),
                  ),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }

  Future<void> _decide(
    BuildContext context,
    WidgetRef ref, {
    required bool approved,
  }) async {
    final comment = await showDialog<String>(
      context: context,
      builder: (context) => _DecisionDialog(approved: approved),
    );
    if (comment == null || !context.mounted) return;
    final error = await ref
        .read(approvalTaskProvider.notifier)
        .decide(task: task, approved: approved, comment: comment);
    if (!context.mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text(error ?? (approved ? '已批准' : '已驳回'))),
    );
  }

  String _typeLabel(String type) => switch (type) {
    'PERSONAL' => '事假',
    'SICK' => '病假',
    'ANNUAL' => '年假',
    _ => type,
  };
}

class _DecisionDialog extends StatefulWidget {
  const _DecisionDialog({required this.approved});

  final bool approved;

  @override
  State<_DecisionDialog> createState() => _DecisionDialogState();
}

class _DecisionDialogState extends State<_DecisionDialog> {
  final controller = TextEditingController();

  @override
  void dispose() {
    controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) => AlertDialog(
    title: Text(widget.approved ? '批准申请' : '驳回申请'),
    content: TextField(
      controller: controller,
      maxLength: 1000,
      maxLines: 3,
      decoration: InputDecoration(
        labelText: widget.approved ? '审批意见（选填）' : '驳回原因',
      ),
    ),
    actions: [
      TextButton(
        onPressed: () => Navigator.pop(context),
        child: const Text('取消'),
      ),
      FilledButton(
        onPressed: () => Navigator.pop(context, controller.text),
        child: Text(widget.approved ? '确认批准' : '确认驳回'),
      ),
    ],
  );
}

class _NotificationList extends ConsumerWidget {
  const _NotificationList({required this.notifications});

  final AsyncValue<List<AppNotification>> notifications;

  @override
  Widget build(BuildContext context, WidgetRef ref) => notifications.when(
    loading: () => const Center(child: CircularProgressIndicator()),
    error: (error, _) => Center(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          Text('通知加载失败：$error'),
          const SizedBox(height: 8),
          FilledButton(
            onPressed: ref.read(notificationProvider.notifier).refresh,
            child: const Text('重试'),
          ),
        ],
      ),
    ),
    data: (items) {
      if (items.isEmpty) return const Center(child: Text('暂无通知'));
      return RefreshIndicator(
        onRefresh: ref.read(notificationProvider.notifier).refresh,
        child: ListView.separated(
          padding: const EdgeInsets.all(12),
          itemCount: items.length,
          separatorBuilder: (_, _) => const SizedBox(height: 8),
          itemBuilder: (context, index) {
            final item = items[index];
            return Card(
              color: item.isRead
                  ? null
                  : Theme.of(
                      context,
                    ).colorScheme.primaryContainer.withValues(alpha: 0.35),
              child: ListTile(
                leading: Icon(_icon(item.type)),
                title: Text(
                  item.title,
                  style: TextStyle(
                    fontWeight: item.isRead ? FontWeight.w500 : FontWeight.w700,
                  ),
                ),
                subtitle: Text(
                  '${item.body}\n${DateFormat('MM-dd HH:mm').format(item.createdAt.toLocal())}',
                ),
                isThreeLine: true,
                trailing: item.isRead ? null : const Badge(),
                onTap: item.isRead
                    ? null
                    : () => ref
                          .read(notificationProvider.notifier)
                          .markRead(item.id),
              ),
            );
          },
        ),
      );
    },
  );

  IconData _icon(String type) => switch (type) {
    'APPROVAL_TASK_ASSIGNED' => Icons.assignment_outlined,
    'LEAVE_APPROVED' => Icons.check_circle_outline,
    'LEAVE_REJECTED' => Icons.cancel_outlined,
    _ => Icons.notifications_none,
  };
}