import type { Env } from './env';
import { withPrivateNoStoreHeaders } from './lib/responses';
import { handleAuthApi } from './routes/api.auth';
import { handleDevAuth } from './routes/api.dev-auth';
import { handleLinksApi } from './routes/api.links';
import { handleNotificationsApi } from './routes/api.notifications';
import { handleOAuthApi } from './routes/api.oauth';
import { handleLinkGoRoute } from './routes/link-go';
import { handlePromotionsApi } from './routes/api.promotions';
import { handlePrivateShortlink, isHeygoPrivateHost } from './routes/private-redirect';
import { handlePublicShortlink, isHeygoPublicHost, isReservedPublicPath } from './routes/redirect';

export type { Env } from './env';

const jsonHeaders = {
  'content-type': 'application/json; charset=utf-8',
};

function json(body: unknown, init: ResponseInit = {}) {
  return Response.json(body, {
    ...init,
    headers: {
      ...jsonHeaders,
      ...init.headers,
    },
  });
}

function withPrivateHostNoStoreHeaders(url: URL, response: Response, privateHost: string): Response {
  return isHeygoPrivateHost(url.hostname, privateHost) ? withPrivateNoStoreHeaders(response) : response;
}

function isHtmlNavigationRequest(request: Request): boolean {
  const accept = request.headers.get('accept') ?? '';
  const secFetchDest = request.headers.get('sec-fetch-dest') ?? '';
  return accept.includes('text/html') || secFetchDest === 'document';
}

function spaHashUrl(appBaseUrl: string, route: string): string {
  return `${appBaseUrl}/#${route}`;
}

function spaRedirectForAppPath(url: URL, appBaseUrl: string): Response | null {
  const pathname = url.pathname.replace(/\/+$/, '') || '/';
  if (pathname === '/app') {
    return Response.redirect(spaHashUrl(appBaseUrl, '/'), 302);
  }
  if (pathname === '/app/private') {
    return Response.redirect(spaHashUrl(appBaseUrl, '/my-links'), 302);
  }
  if (pathname === '/app/login') {
    return Response.redirect(spaHashUrl(appBaseUrl, '/login'), 302);
  }
  if (pathname === '/app/dev-login') {
    return Response.redirect(spaHashUrl(appBaseUrl, '/dev-login'), 302);
  }
  if (pathname === '/app/admin') {
    return Response.redirect(spaHashUrl(appBaseUrl, '/admin'), 302);
  }
  if (pathname === '/app/profile') {
    return Response.redirect(spaHashUrl(appBaseUrl, '/profile'), 302);
  }
  if (pathname === '/app/settings') {
    return Response.redirect(spaHashUrl(appBaseUrl, '/settings'), 302);
  }
  return null;
}

async function serveSpaShell(request: Request, env: Env): Promise<Response | null> {
  if (!env.ASSETS) {
    return null;
  }

  const url = new URL(request.url);
  if (url.pathname.startsWith('/assets/')) {
    return env.ASSETS.fetch(request);
  }

  if (url.pathname !== '/' || !isHtmlNavigationRequest(request)) {
    return null;
  }

  const assetUrl = new URL('/index.html', url);
  return env.ASSETS.fetch(new Request(assetUrl, request));
}

export default {
  async fetch(request, env, ctx): Promise<Response> {
    const url = new URL(request.url);

    const appPathRedirect = spaRedirectForAppPath(url, env.APP_BASE_URL);
    if (appPathRedirect) {
      return withPrivateHostNoStoreHeaders(url, appPathRedirect, env.PRIVATE_HOST);
    }

    const spaShellResponse = await serveSpaShell(request, env);
    if (spaShellResponse && isHeygoPublicHost(url.hostname, env.PUBLIC_HOST)) {
      return withPrivateHostNoStoreHeaders(url, spaShellResponse, env.PRIVATE_HOST);
    }

    if (url.pathname === '/api/health') {
      return withPrivateHostNoStoreHeaders(url, json({ ok: true, service: 'heygo-worker' }), env.PRIVATE_HOST);
    }

    if (url.pathname.startsWith('/api/')) {
      const oauthResponse = await handleOAuthApi(request, env);
      if (oauthResponse) {
        return withPrivateHostNoStoreHeaders(url, oauthResponse, env.PRIVATE_HOST);
      }
      const authResponse = await handleAuthApi(request, env);
      if (authResponse) {
        return withPrivateHostNoStoreHeaders(url, authResponse, env.PRIVATE_HOST);
      }
      const devAuthResponse = await handleDevAuth(request, env);
      if (devAuthResponse) {
        return withPrivateHostNoStoreHeaders(url, devAuthResponse, env.PRIVATE_HOST);
      }
      const apiResponse = await handleLinksApi(request, env);
      if (apiResponse) {
        return withPrivateHostNoStoreHeaders(url, apiResponse, env.PRIVATE_HOST);
      }
      const promotionsResponse = await handlePromotionsApi(request, env);
      if (promotionsResponse) {
        return withPrivateHostNoStoreHeaders(url, promotionsResponse, env.PRIVATE_HOST);
      }
      const notificationsResponse = await handleNotificationsApi(request, env);
      if (notificationsResponse) {
        return withPrivateHostNoStoreHeaders(url, notificationsResponse, env.PRIVATE_HOST);
      }
      return withPrivateHostNoStoreHeaders(url, json({ error: 'Not found' }, { status: 404 }), env.PRIVATE_HOST);
    }

    const linkGoResponse = await handleLinkGoRoute(request, env, ctx);
    if (linkGoResponse) {
      return withPrivateHostNoStoreHeaders(url, linkGoResponse, env.PRIVATE_HOST);
    }

    // In local dev (PUBLIC_HOST=*), public and private share the same host.
    // Try public first; if it returns 404 (alias not found), fall through to
    // private so authenticated users can resolve their personal shortlinks.
    // If private also returns 404, keep the original public 404 response.
    if (isHeygoPublicHost(url.hostname, env.PUBLIC_HOST) && !isReservedPublicPath(url.pathname)) {
      const publicResponse = await handlePublicShortlink(request, env, ctx);
      if (publicResponse.status !== 404) {
        return withPrivateHostNoStoreHeaders(url, publicResponse, env.PRIVATE_HOST);
      }
      // Public alias not found — try private route (for local dev with shared host)
      if (isHeygoPrivateHost(url.hostname, env.PRIVATE_HOST)) {
        const privateResponse = await handlePrivateShortlink(request, env, ctx);
        if (privateResponse.status !== 404) {
          return withPrivateHostNoStoreHeaders(url, privateResponse, env.PRIVATE_HOST);
        }
      }
      return withPrivateHostNoStoreHeaders(url, publicResponse, env.PRIVATE_HOST);
    }

    if (isHeygoPrivateHost(url.hostname, env.PRIVATE_HOST) && !isReservedPublicPath(url.pathname)) {
      return withPrivateHostNoStoreHeaders(url, await handlePrivateShortlink(request, env, ctx), env.PRIVATE_HOST);
    }

    return withPrivateHostNoStoreHeaders(url, json({ error: 'Not found' }, { status: 404 }), env.PRIVATE_HOST);
  },
} satisfies ExportedHandler<Env>;