import 'package:aioa_mobile/features/requests/application/leave_request_controller.dart';
import 'package:aioa_mobile/features/requests/data/leave_request_repository.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:intl/intl.dart';

class LeaveRequestDetailPage extends ConsumerWidget {
  const LeaveRequestDetailPage({required this.id, super.key});
  final String id;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final detail = ref.watch(leaveRequestDetailProvider(id));
    return Scaffold(
      appBar: AppBar(title: const Text('申请详情')),
      body: detail.when(
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (error, _) => Center(child: Text('详情加载失败：$error')),
        data: (value) => _DetailBody(id: id, detail: value),
      ),
    );
  }
}

class _DetailBody extends ConsumerWidget {
  const _DetailBody({required this.id, required this.detail});
  final String id;
  final LeaveRequestDetail detail;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final request = detail.request;
    final formatter = DateFormat('yyyy-MM-dd HH:mm');
    return ListView(
      padding: const EdgeInsets.all(16),
      children: [
        Card(
          child: Padding(
            padding: const EdgeInsets.all(16),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  _statusLabel(request.status),
                  style: Theme.of(
                    context,
                  ).textTheme.titleLarge?.copyWith(fontWeight: FontWeight.w800),
                ),
                const SizedBox(height: 14),
                _row('请假类型', _typeLabel(request.type)),
                _row('开始时间', formatter.format(request.startsAt.toLocal())),
                _row('结束时间', formatter.format(request.endsAt.toLocal())),
                _row('请假原因', request.reason),
              ],
            ),
          ),
        ),
        const SizedBox(height: 14),
        Text(
          '流程时间线',
          style: Theme.of(
            context,
          ).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.w700),
        ),
        const SizedBox(height: 8),
        if (detail.timeline.isEmpty)
          const Card(
            child: ListTile(
              leading: Icon(Icons.edit_note),
              title: Text('草稿已创建'),
            ),
          )
        else
          for (final event in detail.timeline) _TimelineTile(event: event),
        const SizedBox(height: 16),
        if (request.status == 'DRAFT')
          FilledButton.icon(
            onPressed: () => _transition(context, ref, 'submit'),
            icon: const Icon(Icons.send_outlined),
            label: const Padding(
              padding: EdgeInsets.symmetric(vertical: 12),
              child: Text('提交审批'),
            ),
          ),
        if (request.status == 'PENDING')
          OutlinedButton.icon(
            onPressed: () => _transition(context, ref, 'withdraw'),
            icon: const Icon(Icons.undo),
            label: const Padding(
              padding: EdgeInsets.symmetric(vertical: 12),
              child: Text('撤回申请'),
            ),
          ),
      ],
    );
  }

  Future<void> _transition(
    BuildContext context,
    WidgetRef ref,
    String action,
  ) async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: Text(action == 'submit' ? '提交审批' : '撤回申请'),
        content: Text(action == 'submit' ? '提交后将进入审批流程，确认继续？' : '确认撤回当前申请？'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text('取消'),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(context, true),
            child: const Text('确认'),
          ),
        ],
      ),
    );
    if (confirmed != true || !context.mounted) return;
    final error = await ref
        .read(leaveRequestDetailProvider(id).notifier)
        .transition(action);
    if (!context.mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text(error ?? (action == 'submit' ? '已提交审批' : '已撤回'))),
    );
  }

  Widget _row(String label, String value) => Padding(
    padding: const EdgeInsets.only(bottom: 10),
    child: Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        SizedBox(width: 78, child: Text(label)),
        Expanded(
          child: Text(
            value,
            style: const TextStyle(fontWeight: FontWeight.w600),
          ),
        ),
      ],
    ),
  );

  String _typeLabel(String value) => switch (value) {
    'PERSONAL' => '事假',
    'SICK' => '病假',
    'ANNUAL' => '年假',
    _ => value,
  };
  String _statusLabel(String value) => switch (value) {
    'DRAFT' => '草稿',
    'PENDING' => '审批中',
    'APPROVED' => '已通过',
    'REJECTED' => '已驳回',
    'WITHDRAWN' => '已撤回',
    _ => value,
  };
}

class _TimelineTile extends StatelessWidget {
  const _TimelineTile({required this.event});
  final LeaveTimelineEvent event;

  @override
  Widget build(BuildContext context) => Card(
    child: ListTile(
      leading: const Icon(Icons.radio_button_checked),
      title: Text(_eventLabel(event.eventType)),
      subtitle: Text(
        '${event.fromStatus} → ${event.toStatus}\n${DateFormat('MM-dd HH:mm').format(event.occurredAt.toLocal())}',
      ),
      isThreeLine: true,
    ),
  );

  String _eventLabel(String value) => switch (value) {
    'LEAVE_REQUEST_SUBMITTED' => '申请已提交',
    'LEAVE_REQUEST_WITHDRAWN' => '申请已撤回',
    'LEAVE_REQUEST_APPROVED' => '申请已通过',
    'LEAVE_REQUEST_REJECTED' => '申请已驳回',
    'LEAVE_APPROVAL_TASK_APPROVED' => '审批节点已通过',
    'LEAVE_APPROVAL_TASK_REJECTED' => '审批节点已驳回',
    _ => value,
  };
}