import fs from 'fs';
import os from 'os';
import path from 'path';

export const CONFIG_DIR = path.join(os.homedir(), '.config', 'deepseek');
export const CONFIG_FILE = path.join(CONFIG_DIR, 'config.json');
export const DEFAULT_PROMPT = '你是Deepseek人工智能助手';

function createDefaultConfig() {
  return { api_key: '', system_prompt: DEFAULT_PROMPT };
}

export function ensureConfigFile() {
  if (!fs.existsSync(CONFIG_DIR)) {
    fs.mkdirSync(CONFIG_DIR, { recursive: true });
  }
  if (!fs.existsSync(CONFIG_FILE)) {
    fs.writeFileSync(CONFIG_FILE, JSON.stringify(createDefaultConfig(), null, 2), 'utf8');
    fs.chmodSync(CONFIG_FILE, 0o600);
  }
}

export function readConfig() {
  ensureConfigFile();
  try {
    const raw = fs.readFileSync(CONFIG_FILE, 'utf8');
    const data = JSON.parse(raw);
    return {
      apiKey: data.api_key || '',
      prompt: data.system_prompt || DEFAULT_PROMPT,
    };
  } catch {
    return { apiKey: '', prompt: DEFAULT_PROMPT };
  }
}

export function saveConfig({ apiKey, prompt }) {
  ensureConfigFile();
  const data = { api_key: apiKey ?? '', system_prompt: prompt ?? DEFAULT_PROMPT };
  fs.writeFileSync(CONFIG_FILE, JSON.stringify(data, null, 2), 'utf8');
  fs.chmodSync(CONFIG_FILE, 0o600);
}

export function resolveApiKey(config) {
  const envKey = process.env.DEEPSEEK_API_KEY;
  if (envKey && envKey.trim()) {
    return { apiKey: envKey.trim(), source: 'env' };
  }
  if (config.apiKey && config.apiKey.trim()) {
    return { apiKey: config.apiKey.trim(), source: 'file' };
  }
  return { apiKey: '', source: 'none' };
}