import { isString } from '@sindresorhus/is';
import { GoogleAuth } from 'google-auth-library';
import { logger } from '../../logger/index.ts';
import type { HostRule } from '../../types/index.ts';
import { getEnv } from '../../util/env.ts';
import type { HttpResponse } from '../../util/http/types.ts';
import { addSecretForSanitizing } from '../../util/sanitize.ts';
import { parseUrl, resolveSameOriginUrl } from '../../util/url.ts';

const JFROG_ARTIFACTORY_RES_HEADER = 'x-jfrog-version';

/**
 * Experimental, per-datasource env var that opts a datasource into following
 * server-provided pagination links across origins. Each datasource has its own
 * flag so relaxing the restriction for one registry cannot weaken the others.
 */
const crossOriginPaginationEnv: Record<string, string> = {
  docker: 'RENOVATE_X_DOCKER_PAGINATION_ALLOW_CROSS_ORIGIN',
  nuget: 'RENOVATE_X_NUGET_PAGINATION_ALLOW_CROSS_ORIGIN',
};

/**
 * Whether a datasource is opted in to following server-provided pagination
 * links across origins, via its experimental `RENOVATE_X_<DATASOURCE>_PAGINATION_ALLOW_CROSS_ORIGIN`
 * env var.
 *
 * By default such links are restricted to the same origin as the request so a
 * malicious or compromised registry cannot attempt to redirect our requests in an attempt for Server Side Request Forgery.
 */
export function isCrossOriginPaginationAllowed(datasource: string): boolean {
  const envVar = crossOriginPaginationEnv[datasource];
  return envVar ? !!getEnv()[envVar] : false;
}

/**
 * Resolves a server-provided pagination `next` URL against `baseUrl`, returning
 * the URL to follow or `null` if it must not be followed.
 *
 * When `allowCrossOrigin` is false (the default; see
 * {@link isCrossOriginPaginationAllowed}) the link is dropped unless it stays on
 * the same origin. When true, the link is followed regardless of origin.
 */
export function resolvePaginationUrl(
  baseUrl: string,
  nextUrl: string,
  allowCrossOrigin: boolean,
): string | null {
  if (!allowCrossOrigin) {
    return resolveSameOriginUrl(baseUrl, nextUrl);
  }
  try {
    const resolved = new URL(nextUrl, baseUrl).href;
    if (parseUrl(baseUrl)?.origin !== parseUrl(resolved)?.origin) {
      logger.once.warn(
        { baseUrl, nextUrl },
        'Following cross-origin pagination link',
      );
    }
    return resolved;
  } catch {
    return null;
  }
}

export function isArtifactoryServer<T = unknown>(
  res: HttpResponse<T> | undefined,
): boolean {
  return isString(res?.headers[JFROG_ARTIFACTORY_RES_HEADER]);
}

/**
 * Whether the host is a Google Artifact Registry endpoint, which authenticates with a short-lived Google access token instead of static credentials.
 */
export function isGoogleArtifactRegistry(hostname: string): boolean {
  return hostname.endsWith('.pkg.dev');
}

export async function getGoogleAuthHostRule(): Promise<HostRule | null> {
  try {
    const googleAuth: GoogleAuth = new GoogleAuth({
      scopes: 'https://www.googleapis.com/auth/cloud-platform',
    });
    const accessToken = await googleAuth.getAccessToken();
    if (accessToken) {
      // sanitize token
      addSecretForSanitizing(accessToken);
      return {
        username: 'oauth2accesstoken',
        password: accessToken,
      };
    }
    logger.warn(
      'Could not retrieve access token using google-auth-library getAccessToken',
    );
  } catch (err) {
    if (err.message?.includes('Could not load the default credentials')) {
      return null;
    }
    throw err;
  }
  return null;
}

export async function getGoogleAuthToken(): Promise<string | null> {
  const rule = await getGoogleAuthHostRule();
  if (rule) {
    const token = Buffer.from(`${rule.username}:${rule.password}`).toString(
      'base64',
    );
    addSecretForSanitizing(token);
    return token;
  }
  return null;
}