import fs from "fs";
import path from "path";

export interface DBConfig {
  host: string;
  port: number;
  user: string;
  password: string;
  database: string;
}

export interface AIConfig {
  apiKey: string;
  baseUrl: string;
  model: string;
}

export interface ExportConfig {
  // 未翻译文本的颜色 (hex)
  untranslatedColor: string;
  // 第二页是否显示表头
  secondPageHeader: boolean;
  // 页面方向: portrait | landscape
  orientation: "portrait" | "landscape";
}

export interface AppConfig {
  db: DBConfig;
  ai: AIConfig;
  export: ExportConfig;
}

// 配置文件路径（单一文件）
const configPath = path.join(process.cwd(), "config.json");

/**
 * 读取完整配置
 */
function readConfigFile(): Partial<AppConfig> {
  try {
    if (fs.existsSync(configPath)) {
      const content = fs.readFileSync(configPath, "utf-8");
      return JSON.parse(content);
    }
  } catch (e) {
    console.error("Config read error:", e);
  }
  return {};
}

/**
 * 写入完整配置
 */
function writeConfigFile(config: AppConfig): void {
  fs.writeFileSync(configPath, JSON.stringify(config, null, 2), "utf-8");
}

/**
 * 获取数据库配置
 * 优先级：环境变量 > config.json
 */
export function getDBConfig(): DBConfig {
  let host = "127.0.0.1";
  let port = 3306;
  let user = "root";
  let password = "";
  let database = "recipe_tools";

  // 环境变量优先级最高
  if (process.env.DB_HOST) host = process.env.DB_HOST;
  if (process.env.DB_PORT) port = parseInt(process.env.DB_PORT);
  if (process.env.DB_USER) user = process.env.DB_USER;
  if (process.env.DB_PASSWORD) password = process.env.DB_PASSWORD;
  if (process.env.DB_NAME) database = process.env.DB_NAME;

  // config.json 次之（仅当环境变量未设置时）
  const fileConfig = readConfigFile();
  if (fileConfig.db) {
    if (fileConfig.db.host && !process.env.DB_HOST) host = fileConfig.db.host;
    if (fileConfig.db.port && !process.env.DB_PORT) port = fileConfig.db.port;
    if (fileConfig.db.user && !process.env.DB_USER) user = fileConfig.db.user;
    if (fileConfig.db.password && !process.env.DB_PASSWORD) password = fileConfig.db.password;
    if (fileConfig.db.database && !process.env.DB_NAME) database = fileConfig.db.database;
  }

  return { host, port, user, password, database };
}

/**
 * 获取AI翻译配置
 * 优先级：环境变量 > config.json
 */
export function getAIConfig(): AIConfig {
  let apiKey = "";
  let baseUrl = "https://api.openai.com/v1";
  let model = "gpt-3.5-turbo";

  // 环境变量优先级最高
  if (process.env.AI_API_KEY) apiKey = process.env.AI_API_KEY;
  if (process.env.AI_BASE_URL) baseUrl = process.env.AI_BASE_URL;
  if (process.env.AI_MODEL) model = process.env.AI_MODEL;

  // config.json 次之（仅当环境变量未设置时）
  const fileConfig = readConfigFile();
  if (fileConfig.ai) {
    if (fileConfig.ai.apiKey && !process.env.AI_API_KEY) apiKey = fileConfig.ai.apiKey;
    if (fileConfig.ai.baseUrl && !process.env.AI_BASE_URL) baseUrl = fileConfig.ai.baseUrl;
    if (fileConfig.ai.model && !process.env.AI_MODEL) model = fileConfig.ai.model;
  }

  return { apiKey, baseUrl, model };
}

/**
 * 获取导出配置
 * 优先级：config.json（没有环境变量）
 */
export function getExportConfig(): ExportConfig {
  const defaultConfig: ExportConfig = {
    untranslatedColor: "CC0000",
    secondPageHeader: false,
    orientation: "landscape",
  };

  const fileConfig = readConfigFile();
  if (fileConfig.export) {
    return {
      untranslatedColor: fileConfig.export.untranslatedColor || defaultConfig.untranslatedColor,
      secondPageHeader: fileConfig.export.secondPageHeader ?? defaultConfig.secondPageHeader,
      orientation: fileConfig.export.orientation || defaultConfig.orientation,
    };
  }

  return defaultConfig;
}

/**
 * 获取完整配置（兼容旧接口）
 */
export function getConfig(): AppConfig {
  return {
    db: getDBConfig(),
    ai: getAIConfig(),
    export: getExportConfig(),
  };
}

/**
 * 保存数据库配置
 */
export function saveDBConfig(config: Partial<DBConfig>): DBConfig {
  const current = getDBConfig();

  const newConfig: DBConfig = {
    host: config.host ?? current.host,
    port: config.port ?? current.port,
    user: config.user ?? current.user,
    password: config.password ?? current.password,
    database: config.database ?? current.database,
  };

  // 读取现有配置，更新 db 部分
  const fileConfig = readConfigFile();
  const updatedConfig: AppConfig = {
    ai: fileConfig.ai ?? { apiKey: "", baseUrl: "https://api.openai.com/v1", model: "gpt-3.5-turbo" },
    export: fileConfig.export ?? { untranslatedColor: "CC0000", secondPageHeader: false, orientation: "landscape" },
    db: newConfig,
  };
  writeConfigFile(updatedConfig);

  return newConfig;
}

/**
 * 保存AI翻译配置
 */
export function saveAIConfig(config: Partial<AIConfig>): AIConfig {
  const current = getAIConfig();

  const newConfig: AIConfig = {
    apiKey: config.apiKey ?? current.apiKey,
    baseUrl: config.baseUrl ?? current.baseUrl,
    model: config.model ?? current.model,
  };

  // 读取现有配置，更新 ai 部分
  const fileConfig = readConfigFile();
  const updatedConfig: AppConfig = {
    db: fileConfig.db ?? { host: "127.0.0.1", port: 3306, user: "root", password: "", database: "recipe_tools" },
    export: fileConfig.export ?? { untranslatedColor: "CC0000", secondPageHeader: false, orientation: "landscape" },
    ai: newConfig,
  };
  writeConfigFile(updatedConfig);

  return newConfig;
}

/**
 * 保存导出配置
 */
export function saveExportConfig(config: Partial<ExportConfig>): ExportConfig {
  const current = getExportConfig();

  const newConfig: ExportConfig = {
    untranslatedColor: config.untranslatedColor ?? current.untranslatedColor,
    secondPageHeader: config.secondPageHeader ?? current.secondPageHeader,
    orientation: config.orientation ?? current.orientation,
  };

  // 读取现有配置，更新 export 部分
  const fileConfig = readConfigFile();
  const updatedConfig: AppConfig = {
    db: fileConfig.db ?? { host: "127.0.0.1", port: 3306, user: "root", password: "", database: "recipe_tools" },
    ai: fileConfig.ai ?? { apiKey: "", baseUrl: "https://api.openai.com/v1", model: "gpt-3.5-turbo" },
    export: newConfig,
  };
  writeConfigFile(updatedConfig);

  return newConfig;
}

/**
 * 保存完整配置（兼容旧接口）
 */
export function saveConfig(config: Partial<AppConfig>): AppConfig {
  const current = getConfig();
  const fileConfig = readConfigFile();

  return {
    db: config.db ? saveDBConfig(config.db) : current.db,
    ai: config.ai ? saveAIConfig(config.ai) : current.ai,
    export: config.export ? saveExportConfig(config.export) : current.export,
  };
}