import Surreal from 'surrealdb';

const SURREALDB_URL = process.env.SURREALDB_URL;
const SURREALDB_NAMESPACE = process.env.SURREALDB_NS;
const SURREALDB_DATABASE = process.env.SURREALDB_DB;
const SURREALDB_USER = process.env.SURREALDB_USER;
const SURREALDB_PASS = process.env.SURREALDB_PASS;

if (!SURREALDB_URL || !SURREALDB_NAMESPACE || !SURREALDB_DATABASE || !SURREALDB_USER || !SURREALDB_PASS) {
  throw new Error('SurrealDB configuration is missing. Please set SURREALDB_URL, SURREALDB_NS, SURREALDB_DB, SURREALDB_USER, and SURREALDB_PASS in .env');
}

interface OAuthState {
  state: string;
  code_verifier: string;
  pds_url: string;
  created_at: string;
}

/**
 * Gets a SurrealDB connection for OAuth state management.
 * This uses a separate, unauthenticated connection since OAuth happens before user auth.
 */
async function getDb() {
  const db = new Surreal();
  await db.connect(SURREALDB_URL);

  // Sign in with root credentials for OAuth state management
  await db.signin({
    username: SURREALDB_USER,
    password: SURREALDB_PASS,
  });

  await db.use({ namespace: SURREALDB_NAMESPACE, database: SURREALDB_DATABASE });
  return db;
}

/**
 * Stores OAuth state parameters in SurrealDB for the duration of the OAuth flow.
 * The state is used as the record ID for easy lookup.
 *
 * @param state - The OAuth state parameter (CSRF token)
 * @param codeVerifier - The PKCE code verifier
 * @param pdsUrl - The user's PDS URL
 */
export async function storeOAuthState(
  state: string,
  codeVerifier: string,
  pdsUrl: string
): Promise<void> {
  const db = await getDb();

  try {
    // Store with a 10 minute TTL (OAuth flows should complete quickly)
    const created_at = new Date().toISOString();
    console.log('[OAuth State] Storing state:', state);

    // Use CREATE with CONTENT to store all fields
    const result = await db.create(`oauth_state:⟨${state}⟩`, {
      state,
      code_verifier: codeVerifier,
      pds_url: pdsUrl,
      created_at,
    });
    console.log('[OAuth State] Stored successfully:', JSON.stringify(result, null, 2));
  } finally {
    await db.close();
  }
}

/**
 * Retrieves and deletes OAuth state from SurrealDB.
 * This ensures one-time use of the state parameter (security best practice).
 *
 * @param state - The OAuth state parameter to look up
 * @returns The OAuth state data, or null if not found or expired
 */
export async function consumeOAuthState(
  state: string
): Promise<{ codeVerifier: string; pdsUrl: string } | null> {
  const db = await getDb();

  try {
    console.log('[OAuth State] Retrieving state:', state);
    // Retrieve the state by record ID
    const selectResult = await db.select<OAuthState>(`oauth_state:⟨${state}⟩`);
    console.log('[OAuth State] Select result:', JSON.stringify(selectResult, null, 2));

    // db.select() returns an array when selecting a specific record ID
    const result = Array.isArray(selectResult) ? selectResult[0] : selectResult;
    console.log('[OAuth State] Retrieved record:', JSON.stringify(result, null, 2));

    if (!result) {
      console.log('[OAuth State] No result found for state:', state);
      return null;
    }

    // Check if expired (older than 10 minutes)
    const createdAt = new Date(result.created_at);
    const now = new Date();
    const ageMinutes = (now.getTime() - createdAt.getTime()) / 1000 / 60;
    console.log('[OAuth State] State age:', ageMinutes, 'minutes');

    if (ageMinutes > 10) {
      console.log('[OAuth State] State expired, deleting');
      // Delete expired state
      await db.delete(`oauth_state:⟨${state}⟩`);
      return null;
    }

    // Delete the state (one-time use)
    console.log('[OAuth State] Deleting state (one-time use)');
    await db.delete(`oauth_state:⟨${state}⟩`);

    return {
      codeVerifier: result.code_verifier,
      pdsUrl: result.pds_url,
    };
  } finally {
    await db.close();
  }
}

/**
 * Cleans up expired OAuth states (should be called periodically).
 * In production, this would be a cron job or scheduled task.
 */
export async function cleanupExpiredOAuthStates(): Promise<number> {
  const db = await getDb();

  try {
    const tenMinutesAgo = new Date(Date.now() - 10 * 60 * 1000).toISOString();

    const result = await db.query<[OAuthState[]]>(
      'DELETE FROM oauth_state WHERE created_at < $cutoff RETURN BEFORE',
      { cutoff: tenMinutesAgo }
    );

    return result[0]?.length || 0;
  } finally {
    await db.close();
  }
}