import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

import '../../app/app_controller.dart';
import '../../app/app_theme.dart';
import '../../app/app_version.dart' as release;
import '../../services/notification_service.dart';

class ReminderTools extends StatefulWidget {
  const ReminderTools({super.key, required this.controller});

  final AppController controller;

  @override
  State<ReminderTools> createState() => _ReminderToolsState();
}

class _ReminderToolsState extends State<ReminderTools> {
  bool _busy = false;
  Map<String, Object?>? _diagnosis;
  String? _report;

  void _notice(String text) =>
      ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(text)));

  Future<void> _run(Future<void> Function() action) async {
    if (_busy) return;
    setState(() => _busy = true);
    try {
      await action();
    } catch (error) {
      if (mounted) {
        _notice(
          error is ReminderSetupException ? error.message : '操作未完成，请检查系统设置后重试',
        );
      }
    } finally {
      if (mounted) setState(() => _busy = false);
    }
  }

  Future<void> _test(bool scheduled) => _run(() async {
    final message = await widget.controller.notifications.sendTestReminder(
      scheduled: scheduled,
    );
    if (mounted) _notice(message);
  });

  Future<void> _check() => _run(() async {
    await widget.controller.refreshServices();
    final diagnosis = await widget.controller.notifications.diagnose();
    if (!mounted) return;
    final c = widget.controller;
    final s = c.snapshot.settings;
    final rawSystem = diagnosis['system'];
    final system = rawSystem is Map ? rawSystem : const {};
    // Copy an explicit allowlist, never raw platform errors, courses or account.
    final report = <String, Object?>{
      'appVersion': '${release.appVersion}+${release.appBuildNumber}',
      'checkedAt': c.clock().toIso8601String(),
      'remindersEnabled': s.remindersEnabled,
      'semesterStart': s.semester?.startDate.toIso8601String(),
      'semesterWeeks': s.semester?.totalWeeks,
      'reminderOffsets': s.reminderOffsets,
      'courseCount': c.snapshot.courses.length,
      'scheduledCount': c.reminderResult.scheduledCount,
      'reminderStatus': c.reminderResult.status.name,
      for (final key in [
        'notifications',
        'exactAlarm',
        'pendingCount',
        'channelImportance',
        'channelSound',
      ])
        key: _scalar(diagnosis[key]),
      'activeQueryWarning': diagnosis['activeQueryWarning'] != null,
      'errorCode': _errorCode(c.reminderErrorCode),
      'systemError': _errorCode(diagnosis['systemError']),
      'system': {
        for (final key in [
          'manufacturer',
          'model',
          'androidVersion',
          'sdk',
          'backgroundRestricted',
          'batteryOptimizationsIgnored',
          'powerSaveMode',
          'interruptionFilter',
        ])
          key: _scalar(system[key]),
      },
    };
    setState(() {
      _diagnosis = diagnosis;
      _report = const JsonEncoder.withIndent('  ').convert(report);
    });
  });

  Object? _scalar(Object? value) =>
      value is String || value is bool || value is num ? value : null;

  String _errorCode(Object? value) {
    if (value is String && RegExp(r'^[a-zA-Z0-9_]{1,64}$').hasMatch(value)) {
      return value;
    }
    return value == null ? 'none' : 'unknown';
  }

  Future<void> _copy() => _run(() async {
    final report = _report;
    if (report == null) return;
    await Clipboard.setData(ClipboardData(text: report));
    if (mounted) _notice('提醒诊断已复制，可粘贴到意见反馈中');
  });

  String _permission(Object? value) => switch (value) {
    true => '已允许',
    false => '未允许',
    _ => '暂时无法确认',
  };

  List<String> _summary(Map<String, Object?> diagnosis) {
    final rawSystem = diagnosis['system'];
    final system = rawSystem is Map ? rawSystem : const {};
    final pending = diagnosis['pendingCount'];
    return [
      '通知权限：${_permission(diagnosis['notifications'])}',
      '精确提醒：${_permission(diagnosis['exactAlarm'])}',
      if (pending is int) '待发送提醒：$pending 条',
      if (diagnosis['notifications'] == false) '系统通知已关闭，请在通知设置中开启。',
      if (diagnosis['channelImportance'] == 0) '提醒通道已关闭，请在通知设置中开启。',
      if (diagnosis['channelSound'] == false) '提醒通道处于静音，请在通知设置中检查声音。',
      if (diagnosis['exactAlarm'] == false) '精确提醒未获允许，系统发送时间可能延迟。',
      if (system['backgroundRestricted'] == true ||
          system['powerSaveMode'] == true)
        '系统正在限制后台运行，可在后台运行设置中检查。',
      if (system['interruptionFilter'] is int &&
          system['interruptionFilter'] != 0 &&
          system['interruptionFilter'] != 1)
        '勿扰模式可能影响提醒声音。',
      if (pending == 0 && widget.controller.snapshot.settings.remindersEnabled)
        '当前没有待发送提醒，请核对学期、课程日期和提醒提前时间。',
      if (diagnosis['activeQueryWarning'] != null) '部分系统提醒状态暂时无法读取，可稍后再检查。',
      if (diagnosis['systemError'] != null) '设备后台状态暂时无法读取，可在系统设置中检查。',
    ];
  }

  @override
  Widget build(BuildContext context) => SurfaceCard(
    child: Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        const Text(
          '测试与检查',
          style: TextStyle(fontSize: 14, fontWeight: FontWeight.w600),
        ),
        const SizedBox(height: 8),
        Wrap(
          spacing: 8,
          runSpacing: 4,
          children: [
            TextButton(
              onPressed: _busy ? null : () => _test(false),
              child: const Text('立即测试提醒'),
            ),
            TextButton(
              onPressed: _busy ? null : () => _test(true),
              child: const Text('10 秒后台测试'),
            ),
          ],
        ),
        const Text(
          '后台测试：点击后按 Home 键回到桌面，等待约 10 秒；请勿强行停止应用。',
          style: TextStyle(fontSize: 12, height: 1.6, color: river),
        ),
        const SizedBox(height: 8),
        Wrap(
          spacing: 8,
          runSpacing: 4,
          children: [
            TextButton(
              onPressed: _busy ? null : _check,
              child: const Text('检查提醒'),
            ),
            TextButton(
              onPressed: _busy
                  ? null
                  : () => _run(
                      () => widget.controller.notifications.openSettings(
                        background: false,
                      ),
                    ),
              child: const Text('通知设置'),
            ),
            TextButton(
              onPressed: _busy
                  ? null
                  : () => _run(
                      () => widget.controller.notifications.openSettings(
                        background: true,
                      ),
                    ),
              child: const Text('后台运行设置'),
            ),
          ],
        ),
        if (_busy)
          const Padding(
            padding: EdgeInsets.symmetric(vertical: 8),
            child: LinearProgressIndicator(),
          ),
        if (_diagnosis != null) ...[
          const SizedBox(height: 8),
          for (final line in _summary(_diagnosis!))
            Padding(
              padding: const EdgeInsets.only(bottom: 5),
              child: Text(
                line,
                style: const TextStyle(fontSize: 12, height: 1.5),
              ),
            ),
          TextButton(
            onPressed: _busy ? null : _copy,
            child: const Text('复制提醒诊断'),
          ),
        ],
      ],
    ),
  );
}