const { get, run } = require('./postgres');

const TIKTOK_ACCOUNT_KEY = 'hermes-agent';

const saveTiktokTokens = async (db, tokens) => {
  const now = Date.now();
  const accessExpiresAt = new Date(now + Number(tokens.expires_in || 0) * 1000);
  const refreshExpiresAt = tokens.refresh_expires_in
    ? new Date(now + Number(tokens.refresh_expires_in) * 1000)
    : null;

  await run(
    db,
    `INSERT INTO tiktok_tokens (account_key, open_id, access_token, refresh_token, scope, access_token_expires_at, refresh_token_expires_at, updated_at)
     VALUES (?, ?, ?, ?, ?, ?, ?, CURRENT_TIMESTAMP)
     ON CONFLICT (account_key) DO UPDATE SET
       open_id = EXCLUDED.open_id,
       access_token = EXCLUDED.access_token,
       refresh_token = EXCLUDED.refresh_token,
       scope = EXCLUDED.scope,
       access_token_expires_at = EXCLUDED.access_token_expires_at,
       refresh_token_expires_at = EXCLUDED.refresh_token_expires_at,
       updated_at = CURRENT_TIMESTAMP`,
    [
      TIKTOK_ACCOUNT_KEY,
      tokens.open_id,
      tokens.access_token,
      tokens.refresh_token,
      tokens.scope || null,
      accessExpiresAt,
      refreshExpiresAt,
    ],
  );
};

const getTiktokTokens = async (db) =>
  get(db, `SELECT * FROM tiktok_tokens WHERE account_key = ?`, [TIKTOK_ACCOUNT_KEY]);

const exchangeCodeForTokens = async ({ code, clientKey, clientSecret, redirectUri }) => {
  const response = await fetch('https://open.tiktokapis.com/v2/oauth/token/', {
    method: 'POST',
    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    body: new URLSearchParams({
      client_key: clientKey,
      client_secret: clientSecret,
      code,
      grant_type: 'authorization_code',
      redirect_uri: redirectUri,
    }),
  });

  const data = await response.json();
  if (!response.ok || data.error) {
    const message = data.error_description || data.error || 'TikTok token exchange failed.';
    const error = new Error(message);
    error.status = 502;
    throw error;
  }
  return data;
};

const refreshTiktokTokens = async (db, { clientKey, clientSecret }) => {
  const existing = await getTiktokTokens(db);
  if (!existing) {
    const error = new Error('No TikTok account connected.');
    error.status = 404;
    throw error;
  }

  const response = await fetch('https://open.tiktokapis.com/v2/oauth/token/', {
    method: 'POST',
    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    body: new URLSearchParams({
      client_key: clientKey,
      client_secret: clientSecret,
      grant_type: 'refresh_token',
      refresh_token: existing.refresh_token,
    }),
  });

  const data = await response.json();
  if (!response.ok || data.error) {
    const message = data.error_description || data.error || 'TikTok token refresh failed.';
    const error = new Error(message);
    error.status = 502;
    throw error;
  }

  await saveTiktokTokens(db, data);
  return getTiktokTokens(db);
};

module.exports = {
  exchangeCodeForTokens,
  getTiktokTokens,
  refreshTiktokTokens,
  saveTiktokTokens,
};