import 'dart:convert';
import 'dart:io';

class Language {
  static final String defalutLocale = "zh_CN";

  static final Map<String, Map<String, String>> _translations = {};

  static void setLanguage(String locale,
      {String? path, Map<String, String>? language}) {
    //载入json文件
    if (path != null) {
      try {
        //暂时只支持本地文件
        var file = File(path);
        file.readAsString().then((data) {
          _translations[locale] = _flattenJson(jsonDecode(data));
        });
      } catch (e) {
        print(e);
      }
      return;
    }

    if (language != null) {
      //构建翻译kv
      _translations[locale] = _flattenJson(language);
    }
  }

  // 扁平化嵌套 JSON 数据
  static Map<String, String> _flattenJson(Map<String, dynamic> json,
      [String prefix = '']) {
    final Map<String, String> flatMap = {};
    json.forEach((key, value) {
      final newKey = prefix.isEmpty ? key : '$prefix.$key';
      if (value is Map<String, dynamic>) {
        flatMap.addAll(_flattenJson(value, newKey));
      } else {
        flatMap[newKey] = value.toString();
      }
    });
    return flatMap;
  }

  static void resetLanguage({String? locale}) {
    if (locale == null) {
      //清空全部语言文件
      _translations.clear();
    } else {
      //清空指定语言文件
      _translations.remove(locale);
    }
  }

  static String getTranslation(String key,
      {String? languageCode, Map<String, String>? params}) {
    var locale = languageCode ?? defalutLocale;
    String text = _translations[locale]?[key] ?? key;

    // 替换动态参数（如 @name）
    params?.forEach((key, value) {
      text = text.replaceAll('@$key', value);
    });

    return text;
  }
}