// 多语言支持配置
export type Language = 'zh' | 'en';

export interface Translations {
  // 通用
  loading: string;
  error: string;
  expand: string;
  collapse: string;
  
  // 页面标题和描述
  appTitle: string;
  appDescription: string;
  welcomeMessage: string;
  
  // 工具相关
  toolSearching: string;
  toolProcessing: string;
  toolCompleted: string;
  toolFailed: string;
  toolStandardSearch: string;
  toolDocumentSearch: string;
  toolQuery: string;
  toolFound: string;
  toolRetrieved: string;
  toolResults: string;
  toolChunks: string;
  toolMoreResults: string;
  toolMoreChunks: string;
  toolDocumentChunk: string;
  
  // 状态消息
  statusSearching: string;
  statusProcessing: string;
  statusCompleted: string;
  statusError: string;
  
  // 新增：工具汇总相关
  toolExecutionSummary: string;
  resultsText: string;
  tooltip: string;
}

export const translations: Record<Language, Translations> = {
  zh: {
    // 通用
    loading: '加载中...',
    error: '错误',
    expand: '展开',
    collapse: '收起',
    
    // 页面标题和描述
    appTitle: '代理式RAG',
    appDescription: '先进的AI代理，支持RAG检索和工具调用',
    welcomeMessage: '你好！我是你的 AI 助手。我可以解答有关标准和法规的问题，基于从知识库智能检索到的信息。',
    
    // 工具相关
    toolSearching: '搜索中...',
    toolProcessing: '处理中...',
    toolCompleted: '已完成',
    toolFailed: '失败',
    toolStandardSearch: '标准/法规语义检索',
    toolDocumentSearch: '文档块语义检索',
    toolQuery: '查询',
    toolFound: '找到',
    toolRetrieved: '获取',
    toolResults: '条结果',
    toolChunks: '片段',
    toolMoreResults: '还有',
    toolMoreChunks: '还有',
    toolDocumentChunk: '文档块',
    
    // 状态消息
    statusSearching: '搜索中...',
    statusProcessing: '处理中...',
    statusCompleted: '已完成',
    statusError: '发生错误',
    
    // 工具汇总相关
    toolExecutionSummary: '工具执行汇总',
    resultsText: '个结果',
    tooltip: 'AI 可能会出错，请核对重要信息。'
  },
  
  en: {
    // 通用
    loading: 'Loading...',
    error: 'Error',
    expand: 'Expand',
    collapse: 'Collapse',
    
    // 页面标题和描述
    appTitle: 'Agentic RAG',
    appDescription: 'Advanced AI Agent with RAG and Tool Support',
    welcomeMessage: 'Hello! I\'m AI agent that answer your questions about standards and regulations, grounded on information intelligently retrieved from the knowledge base.',
    
    // 工具相关
    toolSearching: 'Searching...',
    toolProcessing: 'Processing...',
    toolCompleted: 'Completed',
    toolFailed: 'Failed',
    toolStandardSearch: 'Standard/Regulation Semantic Retrieval',
    toolDocumentSearch: 'Document Chunk Semantic Retrieval',
    toolQuery: 'Query',
    toolFound: 'Found',
    toolRetrieved: 'Retrieved',
    toolResults: 'results',
    toolChunks: 'Fragment',
    toolMoreResults: 'more results',
    toolMoreChunks: 'more chunks',
    toolDocumentChunk: 'Document Chunk',
    
    // 状态消息
    statusSearching: 'Searching...',
    statusProcessing: 'Processing...',
    statusCompleted: 'Completed',
    statusError: 'Error occurred',
    
    // 工具汇总相关
    toolExecutionSummary: 'Tool Execution Summary',
    resultsText: 'results',
    tooltip: 'AI can make mistakes. Please check important info'
  },
};

// 获取浏览器首选语言
export function getBrowserLanguage(): Language {
  if (typeof window === 'undefined') return 'zh'; // SSR fallback
  
  const browserLang = navigator.language.toLowerCase();
  
  // 检查是否为中文
  if (browserLang.startsWith('zh')) {
    return 'zh';
  }
  
  // 默认返回英文
  return 'en';
}

// 从URL参数获取语言设置
export function getLanguageFromURL(): Language | null {
  if (typeof window === 'undefined') return null; // SSR fallback
  
  const urlParams = new URLSearchParams(window.location.search);
  const langParam = urlParams.get('lang')?.toLowerCase();
  
  if (langParam === 'zh' || langParam === 'en') {
    return langParam as Language;
  }
  
  return null;
}

// 获取当前应该使用的语言
export function getCurrentLanguage(): Language {
  // 优先使用URL参数
  const urlLang = getLanguageFromURL();
  if (urlLang) {
    return urlLang;
  }
  
  // 其次使用localStorage保存的语言
  if (typeof window !== 'undefined') {
    const savedLang = localStorage.getItem('preferred-language') as Language;
    if (savedLang && (savedLang === 'zh' || savedLang === 'en')) {
      return savedLang;
    }
  }
  
  // 最后使用浏览器语言
  return getBrowserLanguage();
}

// 保存语言设置到localStorage
export function saveLanguagePreference(language: Language) {
  if (typeof window !== 'undefined') {
    localStorage.setItem('preferred-language', language);
  }
}

// 切换语言并更新URL
export function switchLanguage(language: Language) {
  saveLanguagePreference(language);
  
  if (typeof window !== 'undefined') {
    const url = new URL(window.location.href);
    url.searchParams.set('lang', language);
    window.history.replaceState({}, '', url.toString());
    
    // 触发重新渲染
    window.dispatchEvent(new Event('languagechange'));
  }
}