import fs from 'fs';
import path from 'path';
import { fileURLToPath } from 'url';
import { logInfo } from './logger.js';
import { getCurrentUserAgent } from './user-agent-updater.js';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

let config = null;

export function loadConfig() {
  try {
    const configPath = path.join(__dirname, 'config.json');
    const configData = fs.readFileSync(configPath, 'utf-8');
    config = JSON.parse(configData);
    return config;
  } catch (error) {
    throw new Error(`Failed to load config.json: ${error.message}`);
  }
}

export function getConfig() {
  if (!config) {
    loadConfig();
  }
  return config;
}

export function getModelById(modelId) {
  const cfg = getConfig();
  return cfg.models.find(m => m.id === modelId);
}

export function getEndpointByType(type) {
  const cfg = getConfig();
  return cfg.endpoint.find(e => e.name === type);
}

export function isDevMode() {
  const cfg = getConfig();
  return cfg.dev_mode === true;
}

export function getPort() {
  const cfg = getConfig();
  return cfg.port || 3000;
}

export function getSystemPrompt() {
  const cfg = getConfig();
  return cfg.system_prompt || '';
}

export function getModelReasoning(modelId) {
  const model = getModelById(modelId);
  if (!model || !model.reasoning) {
    return null;
  }
  const reasoningLevel = model.reasoning.toLowerCase();
  if (['low', 'medium', 'high', 'xhigh', 'auto'].includes(reasoningLevel)) {
    return reasoningLevel;
  }
  return null;
}

export function getModelProvider(modelId) {
  const model = getModelById(modelId);
  return model?.provider || null;
}

export function getUserAgent() {
  return getCurrentUserAgent();
}

export function getProxyConfigs() {
  const cfg = getConfig();
  if (!Array.isArray(cfg.proxies)) {
    return [];
  }
  return cfg.proxies.filter(proxy => proxy && typeof proxy === 'object');
}

export function getRedirectedModelId(modelId) {
  const cfg = getConfig();
  if (cfg.model_redirects && cfg.model_redirects[modelId]) {
    const redirectedId = cfg.model_redirects[modelId];
    console.log(`[REDIRECT] Model redirected: ${modelId} -> ${redirectedId}`);
    logInfo(`Model redirected: ${modelId} -> ${redirectedId}`);
    return redirectedId;
  }
  return modelId;
}

/**
 * 获取 CORS 配置
 * 优先级: 环境变量 > config.json > 默认值
 * @returns {Object} CORS 配置对象
 */
export function getCorsConfig() {
  const cfg = getConfig();
  const configCors = cfg.cors || {};

  // 环境变量覆盖
  const envAllowAll = process.env.CORS_ALLOW_ALL;
  const envOrigins = process.env.CORS_ORIGINS;

  // 解析 allow_all
  let allowAll = configCors.allow_all ?? false;
  if (envAllowAll !== undefined) {
    allowAll = ['true', '1', 'yes'].includes(envAllowAll.toLowerCase());
  }

  // 解析 origins
  let origins = configCors.origins || [];
  if (envOrigins) {
    origins = envOrigins.split(',').map(o => o.trim()).filter(o => o);
  }

  // 解析 enabled
  let enabled = configCors.enabled ?? true;
  if (process.env.CORS_ENABLED !== undefined) {
    enabled = ['true', '1', 'yes'].includes(process.env.CORS_ENABLED.toLowerCase());
  }

  return {
    enabled,
    allowAll,
    origins,
    methods: configCors.methods || ['GET', 'POST', 'PUT', 'DELETE', 'OPTIONS'],
    headers: configCors.headers || ['Content-Type', 'Authorization', 'X-API-Key', 'anthropic-version']
  };
}