/**
 * Provider Configuration Persistence
 *
 * 提供商配置持久化
 */

import { existsSync } from 'node:fs';
import { readFile, writeFile, mkdir } from 'node:fs/promises';
import { join } from 'node:path';
import type { ProvidersConfigFile, CustomProviderDefinition, ProviderConfig, ServiceConfig, ServiceType } from './types.js';
import { getConfigDir as getGlobalConfigDir } from '../constants/paths.js';

/** 配置文件名 */
const CONFIG_FILE = 'providers.json';

/**
 * 获取配置文件路径
 * 始终使用全局配置目录 ~/.ai-terminal-assistant/
 */
export function getConfigPath(): string {
  return join(getGlobalConfigDir(), CONFIG_FILE);
}

/**
 * 加载提供商配置
 */
export async function loadProvidersConfig(): Promise<ProvidersConfigFile> {
  const configPath = getConfigPath();

  if (!existsSync(configPath)) {
    return { providers: {}, configs: {}, services: {} };
  }

  try {
    const content = await readFile(configPath, 'utf-8');
    const config = JSON.parse(content) as ProvidersConfigFile;
    return {
      providers: config.providers ?? {},
      configs: config.configs ?? {},
      services: config.services ?? {},
    };
  } catch {
    // 解析失败返回空配置
    return { providers: {}, configs: {}, services: {} };
  }
}

/**
 * 保存提供商配置
 */
export async function saveProvidersConfig(config: ProvidersConfigFile): Promise<void> {
  const configDir = getGlobalConfigDir();
  const configPath = getConfigPath();

  // 确保目录存在
  if (!existsSync(configDir)) {
    await mkdir(configDir, { recursive: true });
  }

  await writeFile(configPath, JSON.stringify(config, null, 2), 'utf-8');
}

/**
 * 获取提供商的 API Key
 * 从配置文件获取
 */
export function resolveApiKey(config?: ProviderConfig): string | undefined {
  return config?.apiKey;
}

/**
 * 合并自定义提供商定义和配置
 */
export function mergeProviderConfig(
  definition: CustomProviderDefinition,
  config?: ProviderConfig
): CustomProviderDefinition & { enabled: boolean } {
  return {
    ...definition,
    // 配置可以覆盖 baseUrl
    baseUrl: config?.baseUrl ?? definition.baseUrl,
    // 合并模型列表
    models: [...(definition.models ?? []), ...(config?.customModels ?? [])],
    enabled: config?.enabled ?? true,
  };
}

/**
 * 获取服务配置
 */
export async function getServiceConfig(serviceId: ServiceType): Promise<ServiceConfig | undefined> {
  const config = await loadProvidersConfig();
  return config.services?.[serviceId];
}

/**
 * 获取服务 API Key
 */
export async function getServiceApiKey(serviceId: ServiceType): Promise<string | undefined> {
  const serviceConfig = await getServiceConfig(serviceId);
  if (serviceConfig?.enabled === false) {
    return undefined;
  }
  return serviceConfig?.apiKey;
}

/**
 * 保存服务配置
 */
export async function saveServiceConfig(serviceId: ServiceType, serviceConfig: Omit<ServiceConfig, 'id'>): Promise<void> {
  const config = await loadProvidersConfig();
  config.services = config.services ?? {};
  config.services[serviceId] = { ...serviceConfig, id: serviceId };
  await saveProvidersConfig(config);
}

/**
 * 删除服务配置
 */
export async function deleteServiceConfig(serviceId: ServiceType): Promise<void> {
  const config = await loadProvidersConfig();
  if (config.services) {
    delete config.services[serviceId];
    await saveProvidersConfig(config);
  }
}