import {
  buildMobileShellUrl,
  type MobileShellBaseWebUrlOptions,
  type MobileShellUrlOptions,
  resolveMobileShellBaseWebUrl,
} from './url';

const supportedHosts = new Set(['open', 'app']);

type MobileShellDeepLinkResolutionStatus = 'default' | 'mapped' | 'rejected';

export type MobileShellDeepLinkResolution = {
  status: MobileShellDeepLinkResolutionStatus;
  url: string;
};

function extractPathFromNativeUrl(url: URL) {
  if (supportedHosts.has(url.hostname)) {
    return `${url.pathname}${url.search}${url.hash}`;
  }

  return `${url.hostname ? `/${url.hostname}` : ''}${url.pathname}${url.search}${url.hash}`;
}

function resolveTargetPath(rawUrl: string, webOrigin: string) {
  try {
    const url = new URL(rawUrl);
    if (url.protocol === 'genarrative:') {
      return extractPathFromNativeUrl(url);
    }

    if (url.protocol !== 'http:' && url.protocol !== 'https:') {
      return null;
    }

    if (url.origin !== webOrigin) {
      return null;
    }

    return `${url.pathname}${url.search}${url.hash}`;
  } catch {
    if (!rawUrl.startsWith('/') && !rawUrl.startsWith('#')) {
      return null;
    }

    try {
      const relativeUrl = new URL(rawUrl, webOrigin);
      if (relativeUrl.origin !== webOrigin) {
        return null;
      }

      return `${relativeUrl.pathname}${relativeUrl.search}${relativeUrl.hash}`;
    } catch {
      return null;
    }
  }
}

export function buildMobileShellUrlFromDeepLink(
  rawUrl: string | null | undefined,
  baseWebUrl: string,
  options: MobileShellUrlOptions,
  baseWebUrlOptions: MobileShellBaseWebUrlOptions = {},
) {
  return resolveMobileShellUrlFromDeepLink(
    rawUrl,
    baseWebUrl,
    options,
    baseWebUrlOptions,
  ).url;
}

export function resolveMobileShellUrlFromDeepLink(
  rawUrl: string | null | undefined,
  baseWebUrl: string,
  options: MobileShellUrlOptions,
  baseWebUrlOptions: MobileShellBaseWebUrlOptions = {},
): MobileShellDeepLinkResolution {
  const normalizedBaseWebUrl = resolveMobileShellBaseWebUrl(
    baseWebUrl,
    baseWebUrlOptions,
  );
  const defaultUrl = buildMobileShellUrl(
    normalizedBaseWebUrl,
    options,
    baseWebUrlOptions,
  );
  if (!rawUrl) {
    return {
      status: 'default',
      url: defaultUrl,
    };
  }

  const webOrigin = new URL(normalizedBaseWebUrl).origin;
  const targetPath = resolveTargetPath(rawUrl, webOrigin);
  if (!targetPath) {
    return {
      status: 'rejected',
      url: defaultUrl,
    };
  }

  return {
    status: 'mapped',
    url: buildMobileShellUrl(
      new URL(targetPath, webOrigin).toString(),
      options,
      baseWebUrlOptions,
    ),
  };
}