/**
 * NAC知识引擎 - 多语言AI翻译服务
 *
 * 支持七种语言：zh（中文）、en（英文）、ar（阿拉伯文）、ja（日文）、ko（韩文）、fr（法文）、ru（俄文）
 *
 * 使用OpenAI兼容接口（无Manus依赖，中国大陆可正常访问）
 * 通过环境变量配置：
 *   NAC_AI_API_URL  - AI接口地址（如 https://api.openai.com 或国内兼容端点）
 *   NAC_AI_API_KEY  - AI接口密钥
 *   NAC_AI_MODEL    - 模型名称（默认 gpt-3.5-turbo）
 *
 * 阿拉伯语（ar）特殊处理：
 *   - 文本方向：RTL（从右到左）
 *   - 字符集：Unicode阿拉伯字符块（U+0600-U+06FF）
 *   - 前端需设置 dir="rtl" 属性
 */

export const SUPPORTED_LANGUAGES = ["zh", "en", "ar", "ja", "ko", "fr", "ru"] as const;
export type SupportedLanguage = typeof SUPPORTED_LANGUAGES[number];

export const LANGUAGE_NAMES: Record<SupportedLanguage, string> = {
  zh: "中文（简体）",
  en: "English",
  ar: "العربية",
  ja: "日本語",
  ko: "한국어",
  fr: "Français",
  ru: "Русский",
};

/**
 * RTL语言列表（从右到左书写）
 * 前端渲染时需要为这些语言设置 dir="rtl"
 */
export const RTL_LANGUAGES: SupportedLanguage[] = ["ar"];

/**
 * 判断语言是否为RTL
 */
export function isRTL(lang: SupportedLanguage): boolean {
  return RTL_LANGUAGES.includes(lang);
}

/**
 * 多语言内容结构
 */
export interface MultiLangContent {
  zh?: string;
  en?: string;
  ar?: string;
  ja?: string;
  ko?: string;
  fr?: string;
  ru?: string;
}

// ─── AI翻译接口（OpenAI兼容，无Manus依赖）────────────────────────

/**
 * 检查AI翻译服务是否已配置
 */
export function isAiTranslationConfigured(): boolean {
  return !!(process.env.NAC_AI_API_URL && process.env.NAC_AI_API_KEY);
}

/**
 * 调用AI接口进行翻译（OpenAI兼容格式）
 */
async function callAiTranslation(
  systemPrompt: string,
  userPrompt: string
): Promise<string> {
  const apiUrl = process.env.NAC_AI_API_URL;
  const apiKey = process.env.NAC_AI_API_KEY;
  const model = process.env.NAC_AI_MODEL || "gpt-3.5-turbo";

  if (!apiUrl || !apiKey) {
    throw new Error(
      "[AI翻译] 未配置AI接口。请在 .env 文件中设置 NAC_AI_API_URL 和 NAC_AI_API_KEY。\n" +
      "支持任何OpenAI兼容接口（如 OpenAI、Azure OpenAI、国内大模型等）。"
    );
  }

  const endpoint = `${apiUrl.replace(/\/$/, "")}/v1/chat/completions`;

  const response = await fetch(endpoint, {
    method: "POST",
    headers: {
      "content-type": "application/json",
      authorization: `Bearer ${apiKey}`,
    },
    body: JSON.stringify({
      model,
      messages: [
        { role: "system", content: systemPrompt },
        { role: "user", content: userPrompt },
      ],
      max_tokens: 2048,
      temperature: 0.3, // 低温度保证翻译一致性
    }),
  });

  if (!response.ok) {
    const errorText = await response.text();
    throw new Error(`AI接口调用失败: ${response.status} ${response.statusText} – ${errorText}`);
  }

  const result = await response.json() as {
    choices: Array<{ message: { content: string } }>;
  };

  const content = result.choices?.[0]?.message?.content;
  return (typeof content === "string" ? content : "").trim();
}

/**
 * 使用AI翻译单个文本到指定语言
 *
 * 阿拉伯语特殊说明：
 * - 翻译结果为标准现代阿拉伯语（MSA）
 * - 返回的文本为Unicode阿拉伯字符，前端需设置 dir="rtl"
 * - 专有名词（NAC、RWA等）保持英文不翻译
 */
export async function translateText(
  sourceText: string,
  sourceLang: SupportedLanguage,
  targetLang: SupportedLanguage,
  context?: string
): Promise<string> {
  if (sourceLang === targetLang) return sourceText;
  if (!sourceText.trim()) return sourceText;

  const contextHint = context
    ? `\n\n背景信息（仅供参考，不要翻译）：${context}`
    : "";

  // 阿拉伯语特殊提示
  const arabicHint = targetLang === "ar"
    ? "\n特别说明：翻译成标准现代阿拉伯语（MSA），使用Unicode阿拉伯字符，文本方向为从右到左（RTL）。"
    : "";

  const systemPrompt = `你是NAC（NewAssetChain）公链的专业法律合规翻译专家。
NAC是一条专注于RWA（真实世界资产）的原生公链，使用Charter智能合约语言、NVM虚拟机、CBPP共识协议。
你的任务是将合规规则文本从${LANGUAGE_NAMES[sourceLang]}翻译成${LANGUAGE_NAMES[targetLang]}。
要求：
1. 保持法律术语的准确性和专业性
2. 保留专有名词（如：NAC、RWA、Charter、NVM、CBPP、CSNP、CNNL、ACC-20、GNACS、XTZH）不翻译
3. 保留机构名称（如：SEC、SFC、MAS、ESMA、DFSA、DLD）不翻译
4. 只返回翻译结果，不要添加任何解释或注释${arabicHint}`;

  const userPrompt = `请将以下文本翻译成${LANGUAGE_NAMES[targetLang]}：\n\n${sourceText}${contextHint}`;

  try {
    const translated = await callAiTranslation(systemPrompt, userPrompt);
    return translated || sourceText;
  } catch (error) {
    console.error(`[Translation] 翻译到 ${targetLang} 失败:`, (error as Error).message);
    return sourceText; // 降级返回原文
  }
}

/**
 * 为合规规则生成完整的七语言翻译
 * @param ruleName 规则名称（源语言）
 * @param description 规则描述（源语言）
 * @param sourceLang 源语言
 * @param existingTranslations 已有的翻译（跳过已有的）
 */
export async function generateRuleTranslations(
  ruleName: string,
  description: string,
  sourceLang: SupportedLanguage = "zh",
  existingTranslations?: { ruleNameI18n?: MultiLangContent; descriptionI18n?: MultiLangContent }
): Promise<{ ruleNameI18n: MultiLangContent; descriptionI18n: MultiLangContent }> {
  const ruleNameI18n: MultiLangContent = { ...(existingTranslations?.ruleNameI18n || {}) };
  const descriptionI18n: MultiLangContent = { ...(existingTranslations?.descriptionI18n || {}) };

  // 设置源语言内容
  ruleNameI18n[sourceLang] = ruleName;
  descriptionI18n[sourceLang] = description;

  // 并行翻译所有缺失的语言
  const targetLangs = SUPPORTED_LANGUAGES.filter(
    (lang) => lang !== sourceLang && !ruleNameI18n[lang]
  );

  await Promise.all(
    targetLangs.map(async (targetLang) => {
      const [translatedName, translatedDesc] = await Promise.all([
        translateText(ruleName, sourceLang, targetLang, `这是一条${description.slice(0, 50)}...的合规规则`),
        translateText(description, sourceLang, targetLang),
      ]);
      ruleNameI18n[targetLang] = translatedName;
      descriptionI18n[targetLang] = translatedDesc;
    })
  );

  return { ruleNameI18n, descriptionI18n };
}

/**
 * 批量迁移现有规则，为其生成多语言翻译
 */
export async function migrateRuleToMultiLang(rule: {
  ruleName: string;
  description: string;
  ruleNameI18n?: MultiLangContent;
  descriptionI18n?: MultiLangContent;
}): Promise<{ ruleNameI18n: MultiLangContent; descriptionI18n: MultiLangContent }> {
  const sourceLang: SupportedLanguage = "zh";

  return generateRuleTranslations(
    rule.ruleName,
    rule.description,
    sourceLang,
    { ruleNameI18n: rule.ruleNameI18n, descriptionI18n: rule.descriptionI18n }
  );
}

/**
 * 阿拉伯语RTL测试用例
 * 用于验证阿拉伯语翻译质量和RTL布局
 */
export const ARABIC_RTL_TEST_CASES = [
  {
    id: "ar-rtl-001",
    sourceLang: "zh" as SupportedLanguage,
    targetLang: "ar" as SupportedLanguage,
    sourceText: "不动产登记证要求",
    expectedContains: ["عقار", "تسجيل", "شهادة"], // 应包含房产/登记/证书相关词汇
    isRTL: true,
    description: "房产登记证要求（阿拉伯语RTL测试）",
  },
  {
    id: "ar-rtl-002",
    sourceLang: "en" as SupportedLanguage,
    targetLang: "ar" as SupportedLanguage,
    sourceText: "RWA asset compliance verification",
    expectedContains: ["امتثال", "أصول", "التحقق"], // 应包含合规/资产/验证相关词汇
    isRTL: true,
    description: "RWA资产合规验证（阿拉伯语RTL测试）",
  },
  {
    id: "ar-rtl-003",
    sourceLang: "zh" as SupportedLanguage,
    targetLang: "ar" as SupportedLanguage,
    sourceText: "NAC公链智能合约审批流程",
    expectedContains: ["NAC", "عقد", "موافقة"], // NAC不翻译，包含合约/审批相关词汇
    isRTL: true,
    description: "NAC专有名词保留测试（阿拉伯语RTL）",
  },
];

/**
 * 执行阿拉伯语RTL专项测试
 * 返回测试结果报告
 */
export async function runArabicRTLTests(): Promise<{
  passed: number;
  failed: number;
  results: Array<{
    id: string;
    description: string;
    passed: boolean;
    translated: string;
    isRTL: boolean;
    issues: string[];
  }>;
}> {
  if (!isAiTranslationConfigured()) {
    return {
      passed: 0,
      failed: ARABIC_RTL_TEST_CASES.length,
      results: ARABIC_RTL_TEST_CASES.map(tc => ({
        id: tc.id,
        description: tc.description,
        passed: false,
        translated: "",
        isRTL: true,
        issues: ["AI翻译服务未配置，请设置 NAC_AI_API_URL 和 NAC_AI_API_KEY"],
      })),
    };
  }

  const results = await Promise.all(
    ARABIC_RTL_TEST_CASES.map(async (tc) => {
      const issues: string[] = [];
      let translated = "";

      try {
        translated = await translateText(tc.sourceText, tc.sourceLang, tc.targetLang);

        // 检查是否包含阿拉伯字符（Unicode范围 U+0600-U+06FF）
        const hasArabicChars = /[\u0600-\u06FF]/.test(translated);
        if (!hasArabicChars) {
          issues.push("翻译结果不包含阿拉伯字符");
        }

        // 检查专有名词是否保留（NAC不应被翻译）
        if (tc.sourceText.includes("NAC") && !translated.includes("NAC")) {
          issues.push("专有名词NAC被错误翻译，应保留英文");
        }

        // 检查是否为空
        if (!translated.trim()) {
          issues.push("翻译结果为空");
        }

      } catch (error) {
        issues.push(`翻译失败: ${(error as Error).message}`);
      }

      return {
        id: tc.id,
        description: tc.description,
        passed: issues.length === 0,
        translated,
        isRTL: tc.isRTL,
        issues,
      };
    })
  );

  const passed = results.filter(r => r.passed).length;
  const failed = results.filter(r => !r.passed).length;

  return { passed, failed, results };
}