import 'dart:ui' as ui;

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

class SCMobileLoginContext {
  static const MethodChannel _channel = MethodChannel(
    'com.org.yumiparty/mobile_context',
  );

  static Future<Map<String, dynamic>> loginBodyFields() async {
    return <String, dynamic>{
      'mobileLang': mobileLang,
      'mobileZone': await mobileZone(),
    };
  }

  static String get mobileLang {
    final locales = ui.PlatformDispatcher.instance.locales;
    final locale =
        locales.isNotEmpty
            ? locales.first
            : ui.PlatformDispatcher.instance.locale;
    final languageTag = locale.toLanguageTag().trim();
    if (languageTag.isNotEmpty) {
      return languageTag;
    }
    return locale.languageCode.trim();
  }

  static Future<String> mobileZone() async {
    try {
      final zone = await _channel.invokeMethod<String>('getTimeZoneIdentifier');
      final value = zone?.trim() ?? '';
      if (value.isNotEmpty) {
        return value;
      }
    } on PlatformException catch (e) {
      debugPrint('get mobile timezone failed: ${e.code} ${e.message}');
    } catch (e) {
      debugPrint('get mobile timezone failed: $e');
    }

    return _fallbackZone();
  }

  static String _fallbackZone() {
    final now = DateTime.now();
    final zoneName = now.timeZoneName.trim();
    if (zoneName.contains('/')) {
      return zoneName;
    }

    final offset = now.timeZoneOffset;
    final sign = offset.isNegative ? '-' : '+';
    final absoluteOffset = offset.abs();
    final hours = absoluteOffset.inHours.toString().padLeft(2, '0');
    final minutes = (absoluteOffset.inMinutes % 60).toString().padLeft(2, '0');
    return 'UTC$sign$hours:$minutes';
  }
}