/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
import { OAuth2Client, Compute, CodeChallengeMethod, } from 'google-auth-library';
import * as http from 'http';
import url from 'url';
import crypto from 'crypto';
import * as net from 'net';
import open from 'open';
import path from 'node:path';
import { promises as fs } from 'node:fs';
import * as os from 'os';
import { getErrorMessage } from '../utils/errors.js';
import { cacheGoogleAccount, getCachedGoogleAccount, clearCachedGoogleAccount, } from '../utils/user_account.js';
import { AuthType } from '../core/contentGenerator.js';
import readline from 'node:readline';
import { QWEN_DIR } from '../utils/paths.js';
//  OAuth Client ID used to initiate OAuth2Client class.
const OAUTH_CLIENT_ID = '681255809395-oo8ft2oprdrnp9e3aqf6av3hmdib135j.apps.googleusercontent.com';
// OAuth Secret value used to initiate OAuth2Client class.
// Note: It's ok to save this in git because this is an installed application
// as described here: https://developers.google.com/identity/protocols/oauth2#installed
// "The process results in a client ID and, in some cases, a client secret,
// which you embed in the source code of your application. (In this context,
// the client secret is obviously not treated as a secret.)"
const OAUTH_CLIENT_SECRET = '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';
// OAuth Scopes for Cloud Code authorization.
const OAUTH_SCOPE = [
    'https://www.googleapis.com/auth/cloud-platform',
    'https://www.googleapis.com/auth/userinfo.email',
    'https://www.googleapis.com/auth/userinfo.profile',
];
const HTTP_REDIRECT = 301;
const SIGN_IN_SUCCESS_URL = 'https://developers.google.com/gemini-code-assist/auth_success_gemini';
const SIGN_IN_FAILURE_URL = 'https://developers.google.com/gemini-code-assist/auth_failure_gemini';
const CREDENTIAL_FILENAME = 'oauth_creds.json';
const oauthClientPromises = new Map();
async function initOauthClient(authType, config) {
    const client = new OAuth2Client({
        clientId: OAUTH_CLIENT_ID,
        clientSecret: OAUTH_CLIENT_SECRET,
        transporterOptions: {
            proxy: config.getProxy(),
        },
    });
    if (process.env['GOOGLE_GENAI_USE_GCA'] &&
        process.env['GOOGLE_CLOUD_ACCESS_TOKEN']) {
        client.setCredentials({
            access_token: process.env['GOOGLE_CLOUD_ACCESS_TOKEN'],
        });
        await fetchAndCacheUserInfo(client);
        return client;
    }
    client.on('tokens', async (tokens) => {
        await cacheCredentials(tokens);
    });
    // If there are cached creds on disk, they always take precedence
    if (await loadCachedCredentials(client)) {
        // Found valid cached credentials.
        // Check if we need to retrieve Google Account ID or Email
        if (!getCachedGoogleAccount()) {
            try {
                await fetchAndCacheUserInfo(client);
            }
            catch {
                // Non-fatal, continue with existing auth.
            }
        }
        console.log('Loaded cached credentials.');
        return client;
    }
    // In Google Cloud Shell, we can use Application Default Credentials (ADC)
    // provided via its metadata server to authenticate non-interactively using
    // the identity of the user logged into Cloud Shell.
    if (authType === AuthType.CLOUD_SHELL) {
        try {
            console.log("Attempting to authenticate via Cloud Shell VM's ADC.");
            const computeClient = new Compute({
            // We can leave this empty, since the metadata server will provide
            // the service account email.
            });
            await computeClient.getAccessToken();
            console.log('Authentication successful.');
            // Do not cache creds in this case; note that Compute client will handle its own refresh
            return computeClient;
        }
        catch (e) {
            throw new Error(`Could not authenticate using Cloud Shell credentials. Please select a different authentication method or ensure you are in a properly configured environment. Error: ${getErrorMessage(e)}`);
        }
    }
    if (config.isBrowserLaunchSuppressed()) {
        let success = false;
        const maxRetries = 2;
        for (let i = 0; !success && i < maxRetries; i++) {
            success = await authWithUserCode(client);
            if (!success) {
                console.error('\nFailed to authenticate with user code.', i === maxRetries - 1 ? '' : 'Retrying...\n');
            }
        }
        if (!success) {
            process.exit(1);
        }
    }
    else {
        const webLogin = await authWithWeb(client);
        console.log(`\n\nCode Assist login required.\n` +
            `Attempting to open authentication page in your browser.\n` +
            `Otherwise navigate to:\n\n${webLogin.authUrl}\n\n`);
        try {
            // Attempt to open the authentication URL in the default browser.
            // We do not use the `wait` option here because the main script's execution
            // is already paused by `loginCompletePromise`, which awaits the server callback.
            const childProcess = await open(webLogin.authUrl);
            // IMPORTANT: Attach an error handler to the returned child process.
            // Without this, if `open` fails to spawn a process (e.g., `xdg-open` is not found
            // in a minimal Docker container), it will emit an unhandled 'error' event,
            // causing the entire Node.js process to crash.
            childProcess.on('error', (_) => {
                console.error('Failed to open browser automatically. Please try running again with NO_BROWSER=true set.');
                process.exit(1);
            });
        }
        catch (err) {
            console.error('An unexpected error occurred while trying to open the browser:', err, '\nPlease try running again with NO_BROWSER=true set.');
            process.exit(1);
        }
        console.log('Waiting for authentication...');
        await webLogin.loginCompletePromise;
    }
    return client;
}
export async function getOauthClient(authType, config) {
    if (!oauthClientPromises.has(authType)) {
        oauthClientPromises.set(authType, initOauthClient(authType, config));
    }
    return oauthClientPromises.get(authType);
}
async function authWithUserCode(client) {
    const redirectUri = 'https://codeassist.google.com/authcode';
    const codeVerifier = await client.generateCodeVerifierAsync();
    const state = crypto.randomBytes(32).toString('hex');
    const authUrl = client.generateAuthUrl({
        redirect_uri: redirectUri,
        access_type: 'offline',
        scope: OAUTH_SCOPE,
        code_challenge_method: CodeChallengeMethod.S256,
        code_challenge: codeVerifier.codeChallenge,
        state,
    });
    console.log('Please visit the following URL to authorize the application:');
    console.log('');
    console.log(authUrl);
    console.log('');
    const code = await new Promise((resolve) => {
        const rl = readline.createInterface({
            input: process.stdin,
            output: process.stdout,
        });
        rl.question('Enter the authorization code: ', (code) => {
            rl.close();
            resolve(code.trim());
        });
    });
    if (!code) {
        console.error('Authorization code is required.');
        return false;
    }
    try {
        const { tokens } = await client.getToken({
            code,
            codeVerifier: codeVerifier.codeVerifier,
            redirect_uri: redirectUri,
        });
        client.setCredentials(tokens);
    }
    catch (_error) {
        return false;
    }
    return true;
}
async function authWithWeb(client) {
    const port = await getAvailablePort();
    // The hostname used for the HTTP server binding (e.g., '0.0.0.0' in Docker).
    const host = process.env['OAUTH_CALLBACK_HOST'] || 'localhost';
    // The `redirectUri` sent to Google's authorization server MUST use a loopback IP literal
    // (i.e., 'localhost' or '127.0.0.1'). This is a strict security policy for credentials of
    // type 'Desktop app' or 'Web application' (when using loopback flow) to mitigate
    // authorization code interception attacks.
    const redirectUri = `http://localhost:${port}/oauth2callback`;
    const state = crypto.randomBytes(32).toString('hex');
    const authUrl = client.generateAuthUrl({
        redirect_uri: redirectUri,
        access_type: 'offline',
        scope: OAUTH_SCOPE,
        state,
    });
    const loginCompletePromise = new Promise((resolve, reject) => {
        const server = http.createServer(async (req, res) => {
            try {
                if (req.url.indexOf('/oauth2callback') === -1) {
                    res.writeHead(HTTP_REDIRECT, { Location: SIGN_IN_FAILURE_URL });
                    res.end();
                    reject(new Error('Unexpected request: ' + req.url));
                }
                // acquire the code from the querystring, and close the web server.
                const qs = new url.URL(req.url, 'http://localhost:3000').searchParams;
                if (qs.get('error')) {
                    res.writeHead(HTTP_REDIRECT, { Location: SIGN_IN_FAILURE_URL });
                    res.end();
                    reject(new Error(`Error during authentication: ${qs.get('error')}`));
                }
                else if (qs.get('state') !== state) {
                    res.end('State mismatch. Possible CSRF attack');
                    reject(new Error('State mismatch. Possible CSRF attack'));
                }
                else if (qs.get('code')) {
                    const { tokens } = await client.getToken({
                        code: qs.get('code'),
                        redirect_uri: redirectUri,
                    });
                    client.setCredentials(tokens);
                    // Retrieve and cache Google Account ID during authentication
                    try {
                        await fetchAndCacheUserInfo(client);
                    }
                    catch (error) {
                        console.error('Failed to retrieve Google Account ID during authentication:', error);
                        // Don't fail the auth flow if Google Account ID retrieval fails
                    }
                    res.writeHead(HTTP_REDIRECT, { Location: SIGN_IN_SUCCESS_URL });
                    res.end();
                    resolve();
                }
                else {
                    reject(new Error('No code found in request'));
                }
            }
            catch (e) {
                reject(e);
            }
            finally {
                server.close();
            }
        });
        server.listen(port, host);
    });
    return {
        authUrl,
        loginCompletePromise,
    };
}
export function getAvailablePort() {
    return new Promise((resolve, reject) => {
        let port = 0;
        try {
            const portStr = process.env['OAUTH_CALLBACK_PORT'];
            if (portStr) {
                port = parseInt(portStr, 10);
                if (isNaN(port) || port <= 0 || port > 65535) {
                    return reject(new Error(`Invalid value for OAUTH_CALLBACK_PORT: "${portStr}"`));
                }
                return resolve(port);
            }
            const server = net.createServer();
            server.listen(0, () => {
                const address = server.address();
                port = address.port;
            });
            server.on('listening', () => {
                server.close();
                server.unref();
            });
            server.on('error', (e) => reject(e));
            server.on('close', () => resolve(port));
        }
        catch (e) {
            reject(e);
        }
    });
}
async function loadCachedCredentials(client) {
    const pathsToTry = [
        getCachedCredentialPath(),
        process.env['GOOGLE_APPLICATION_CREDENTIALS'],
    ].filter((p) => !!p);
    for (const keyFile of pathsToTry) {
        try {
            const creds = await fs.readFile(keyFile, 'utf-8');
            client.setCredentials(JSON.parse(creds));
            // This will verify locally that the credentials look good.
            const { token } = await client.getAccessToken();
            if (!token) {
                continue;
            }
            // This will check with the server to see if it hasn't been revoked.
            await client.getTokenInfo(token);
            return true;
        }
        catch (_) {
            // Ignore and try next path.
        }
    }
    return false;
}
async function cacheCredentials(credentials) {
    const filePath = getCachedCredentialPath();
    await fs.mkdir(path.dirname(filePath), { recursive: true });
    const credString = JSON.stringify(credentials, null, 2);
    await fs.writeFile(filePath, credString, { mode: 0o600 });
}
function getCachedCredentialPath() {
    return path.join(os.homedir(), QWEN_DIR, CREDENTIAL_FILENAME);
}
export function clearOauthClientCache() {
    oauthClientPromises.clear();
}
export async function clearCachedCredentialFile() {
    try {
        await fs.rm(getCachedCredentialPath(), { force: true });
        // Clear the Google Account ID cache when credentials are cleared
        await clearCachedGoogleAccount();
        // Clear the in-memory OAuth client cache to force re-authentication
        clearOauthClientCache();
    }
    catch (e) {
        console.error('Failed to clear cached credentials:', e);
    }
}
async function fetchAndCacheUserInfo(client) {
    try {
        const { token } = await client.getAccessToken();
        if (!token) {
            return;
        }
        const response = await fetch('https://www.googleapis.com/oauth2/v2/userinfo', {
            headers: {
                Authorization: `Bearer ${token}`,
            },
        });
        if (!response.ok) {
            console.error('Failed to fetch user info:', response.status, response.statusText);
            return;
        }
        const userInfo = await response.json();
        if (userInfo.email) {
            await cacheGoogleAccount(userInfo.email);
        }
    }
    catch (error) {
        console.error('Error retrieving user info:', error);
    }
}
// Helper to ensure test isolation
export function resetOauthClientForTesting() {
    oauthClientPromises.clear();
}
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