import 'package:device_info_plus/device_info_plus.dart';
import 'package:flutter/foundation.dart';
import 'package:package_info_plus/package_info_plus.dart';
import 'package:url_launcher/url_launcher.dart';

import '../../../common/services/device_header_service.dart';
import '../../auth/data/auth_models.dart';

class FeedbackEmailService {
  const FeedbackEmailService._();

  static const recipient = 'business@yqzhice.top';
  static const productName = '金值';

  static Future<void> send(AuthState? authState) async {
    final email = await _buildEmail(authState);
    final uri = composeMailtoUri(
      recipient: email.recipient,
      subject: email.subject,
      body: email.body,
    );
    try {
      final launched = await launchUrl(
        uri,
        mode: LaunchMode.externalApplication,
      );
      if (!launched) throw const FeedbackEmailUnavailableException();
    } catch (_) {
      throw const FeedbackEmailUnavailableException();
    }
  }

  @visibleForTesting
  static Uri composeMailtoUri({
    required String recipient,
    required String subject,
    required String body,
  }) => Uri(
    scheme: 'mailto',
    path: recipient,
    query: _encodeQueryParameters({'subject': subject, 'body': body}),
  );

  static String _encodeQueryParameters(
    Map<String, String> parameters,
  ) => parameters.entries
      .map(
        (entry) =>
            '${Uri.encodeComponent(entry.key)}=${Uri.encodeComponent(entry.value)}',
      )
      .join('&');

  static Future<_FeedbackEmail> _buildEmail(AuthState? authState) async {
    final packageInfo = await PackageInfo.fromPlatform();
    final device = await _loadDeviceInfo();
    try {
      await DeviceHeaderService.to.ensureInitialized();
    } catch (_) {}

    final headers = DeviceHeaderService.to.commonHeaders();
    final loggedIn = authState is LoggedInAuthState ? authState : null;
    final version = '${packageInfo.version}+${packageInfo.buildNumber}';
    final diagnostics = [
      'App version: $version',
      'Channel: ${headers['User-Channel'] ?? ''}',
      'OS version: ${device.osVersion}',
      'Device manufacturer: ${device.manufacturer}',
      'Device model: ${device.model}',
      'Login type: ${loggedIn == null ? 'guest' : 'phone'}',
      'Phone: ${loggedIn?.user.phone ?? ''}',
    ].join('\n');
    return _FeedbackEmail(
      recipient: recipient,
      subject:
          '$productName反馈[$version]-[${device.manufacturer}]-[${device.osVersion}]',
      body: [
        '$productName团队你好，',
        '请描述你的问题，可附上截图或视频：',
        '',
        '',
        '----',
        diagnostics,
      ].join('\n'),
    );
  }

  static Future<_FeedbackDeviceInfo> _loadDeviceInfo() async {
    final plugin = DeviceInfoPlugin();
    try {
      if (kIsWeb) {
        final info = await plugin.webBrowserInfo;
        return _FeedbackDeviceInfo(
          osVersion: info.platform ?? 'web',
          manufacturer: info.browserName.name,
          model: info.userAgent ?? '',
        );
      }
      if (defaultTargetPlatform == TargetPlatform.android) {
        final info = await plugin.androidInfo;
        return _FeedbackDeviceInfo(
          osVersion: info.version.release,
          manufacturer: info.manufacturer,
          model: info.model,
        );
      }
      if (defaultTargetPlatform == TargetPlatform.iOS) {
        final info = await plugin.iosInfo;
        return _FeedbackDeviceInfo(
          osVersion: info.systemVersion,
          manufacturer: 'Apple',
          model: info.utsname.machine,
        );
      }
      return const _FeedbackDeviceInfo(
        osVersion: '',
        manufacturer: '',
        model: '',
      );
    } catch (_) {
      return const _FeedbackDeviceInfo(
        osVersion: '',
        manufacturer: '',
        model: '',
      );
    }
  }
}

class FeedbackEmailUnavailableException implements Exception {
  const FeedbackEmailUnavailableException();
}

class _FeedbackEmail {
  const _FeedbackEmail({
    required this.recipient,
    required this.subject,
    required this.body,
  });

  final String recipient;
  final String subject;
  final String body;
}

class _FeedbackDeviceInfo {
  const _FeedbackDeviceInfo({
    required this.osVersion,
    required this.manufacturer,
    required this.model,
  });

  final String osVersion;
  final String manufacturer;
  final String model;
}