/*
 * ============================================================
 * CONFIGURAÇÕES PRINCIPAIS
 * ============================================================
 */

const CHECKOUT_PAGE =
  "https://myangelcenter.com/checkout/";

const SALES_PAGE_NORMAL =
  "https://angelsaintapp.lovable.app/";


/*
 * COOKIE
 *
 * Criado ao acessar:
 *
 * https://healthnewsfr.com/salespage?_dst=true
 */

const COOKIE_NAME = "r_code";
const COOKIE_VALUE = "rasputin";

/*
 * 6 horas
 */
const COOKIE_DURATION_SECONDS =
  6 * 60 * 60;


/*
 * ============================================================
 * UPSELLS
 * ============================================================
 */

const UPSELLS = {
  "/up1": {
    normal:
      "https://myangelcenter.com/up1xmllllllllll",

    special:
      "https://myangelcenter.com/up1xmlllllllll-copia",
  },

  "/up2": {
    normal:
      "https://myangelcenter.com/up2xmllllllllll",

    special:
      "https://myangelcenter.com/up2xmlllllllll-copia",
  },

  "/up3": {
    normal:
      "https://myangelcenter.com/up3xmllllllllll",

    special:
      "https://myangelcenter.com/up3xmlllllllll-copia",
  },
};


/*
 * ============================================================
 * FUNÇÕES AUXILIARES
 * ============================================================
 */


/*
 * Faz:
 *
 * /up1
 * /up1/
 *
 * serem tratados da mesma forma.
 */

function normalizePath(pathname) {
  if (
    pathname.length > 1 &&
    pathname.endsWith("/")
  ) {
    return pathname.slice(0, -1);
  }

  return pathname;
}


/*
 * ============================================================
 * LER COOKIE
 * ============================================================
 */

function getCookie(
  request,
  cookieName
) {
  const cookieHeader =
    request.headers.get("cookie") || "";

  const cookies =
    cookieHeader.split(";");

  for (const cookie of cookies) {
    const separatorIndex =
      cookie.indexOf("=");

    if (separatorIndex === -1) {
      continue;
    }

    const name = cookie
      .slice(0, separatorIndex)
      .trim();

    const value = cookie
      .slice(separatorIndex + 1)
      .trim();

    if (name === cookieName) {
      try {
        return decodeURIComponent(value);
      } catch {
        return value;
      }
    }
  }

  return null;
}


/*
 * ============================================================
 * CRIAR COOKIE
 * ============================================================
 *
 * r_code=rasputin
 *
 * válido por 6 horas em healthnewsfr.com
 */

function createAuthorizedCookie() {
  return [
    `${COOKIE_NAME}=${encodeURIComponent(
      COOKIE_VALUE
    )}`,
    "Path=/",
    `Max-Age=${COOKIE_DURATION_SECONDS}`,
    "HttpOnly",
    "Secure",
    "SameSite=Lax",
  ].join("; ");
}


/*
 * ============================================================
 * APAGAR COOKIE
 * ============================================================
 */

function createExpiredCookie() {
  return [
    `${COOKIE_NAME}=`,
    "Path=/",
    "Max-Age=0",
    "HttpOnly",
    "Secure",
    "SameSite=Lax",
  ].join("; ");
}


/*
 * ============================================================
 * CRIAR URL EXTERNA
 * ============================================================
 *
 * Copia TODOS os parâmetros recebidos.
 *
 * Se removeDst = true:
 * não envia _dst para a página externa.
 */

function createTargetUrl(
  incomingUrl,
  targetAddress,
  removeDst = false
) {
  const targetUrl =
    new URL(targetAddress);

  for (
    const [name, value]
    of incomingUrl.searchParams.entries()
  ) {
    /*
     * _dst só serve para nossa lógica interna.
     */
    if (
      removeDst &&
      name === "_dst"
    ) {
      continue;
    }

    targetUrl.searchParams.append(
      name,
      value
    );
  }

  return targetUrl;
}


/*
 * ============================================================
 * PROXY
 * ============================================================
 *
 * Busca a página externa e devolve seu conteúdo
 * mantendo healthnewsfr.com na barra.
 *
 * Também pode adicionar cabeçalhos extras,
 * como Set-Cookie.
 */

async function proxyPage(
  request,
  targetAddress,
  options = {}
) {
  const {
    removeDst = false,
    extraHeaders = {},
  } = options;

  const incomingUrl =
    new URL(request.url);

  const targetUrl =
    createTargetUrl(
      incomingUrl,
      targetAddress,
      removeDst
    );


  /*
   * Busca a página externa.
   */

  const originResponse =
    await fetch(
      targetUrl.toString(),
      {
        method: "GET",

        redirect: "follow",

        headers: {
          Accept:
            request.headers.get("accept") ||
            "text/html,application/xhtml+xml",

          "Accept-Language":
            request.headers.get(
              "accept-language"
            ) ||
            "en-US,en;q=0.9",

          "User-Agent":
            request.headers.get(
              "user-agent"
            ) ||
            "Mozilla/5.0",
        },
      }
    );


  /*
   * Trata erro da origem.
   */

  if (!originResponse.ok) {
    throw new Error(
      `Página externa respondeu com status ${originResponse.status}`
    );
  }


  /*
   * Obtém o HTML.
   */

  let html =
    await originResponse.text();


  /*
   * ==========================================================
   * BASE URL
   * ==========================================================
   *
   * Isso ajuda CSS, JS, imagens, fontes,
   * formulários e links relativos a usarem
   * o domínio original.
   */

  if (/<head[\s>]/i.test(html)) {
    if (/<base[\s>]/i.test(html)) {
      html = html.replace(
        /<base[^>]*>/i,
        `<base href="${targetAddress}">`
      );
    } else {
      html = html.replace(
        /<head([^>]*)>/i,
        `<head$1><base href="${targetAddress}">`
      );
    }
  }


  /*
   * ==========================================================
   * RESPOSTA
   * ==========================================================
   */

  return new Response(
    html,
    {
      status: 200,

      headers: {
        "Content-Type":
          "text/html; charset=UTF-8",

        /*
         * Não deixa uma versão ficar armazenada
         * e ser reutilizada para outra pessoa.
         */

        "Cache-Control":
          "private, no-store, no-cache, must-revalidate",

        Pragma:
          "no-cache",

        Expires:
          "0",

        "X-Robots-Tag":
          "noindex, nofollow",

        /*
         * Cabeçalhos adicionais.
         *
         * Aqui entra Set-Cookie quando necessário.
         */

        ...extraHeaders,
      },
    }
  );
}


/*
 * ============================================================
 * FUNÇÃO PRINCIPAL
 * ============================================================
 */

export default async function handler(
  request
) {
  try {
    const url =
      new URL(request.url);

    const pathname =
      normalizePath(
        url.pathname
      );


    /*
     * ========================================================
     * SALES PAGE
     * ========================================================
     */

    if (
      pathname ===
      "/salespage"
    ) {

      /*
       * Verifica:
       *
       * ?_dst=true
       */

      const hasDst =
        url.searchParams.get(
          "_dst"
        ) === "true";


      /*
       * ======================================================
       * SALES PAGE COM _dst=true
       * ======================================================
       *
       * Exemplo:
       *
       * healthnewsfr.com/salespage?_dst=true
       *
       *
       * Faz:
       *
       * 1. cria r_code=rasputin;
       *
       * 2. exibe:
       *    myangelcenter.com/checkout/
       *
       * 3. mantém:
       *    healthnewsfr.com/salespage?_dst=true
       *
       * 4. preserva TODOS os outros parâmetros;
       *
       * 5. não envia _dst para myangelcenter.
       */

      if (hasDst) {
        return await proxyPage(
          request,
          CHECKOUT_PAGE,
          {
            removeDst: true,

            extraHeaders: {
              "Set-Cookie":
                createAuthorizedCookie(),
            },
          }
        );
      }


      /*
       * ======================================================
       * SALES PAGE SEM _dst=true
       * ======================================================
       *
       * Exemplo:
       *
       * healthnewsfr.com/salespage
       *
       *
       * Faz:
       *
       * 1. apaga eventual r_code antigo;
       *
       * 2. exibe:
       *    angelsaintapp.lovable.app
       *
       * 3. mantém:
       *    healthnewsfr.com/salespage
       */

      return await proxyPage(
        request,
        SALES_PAGE_NORMAL,
        {
          removeDst: true,

          extraHeaders: {
            "Set-Cookie":
              createExpiredCookie(),
          },
        }
      );
    }


    /*
     * ========================================================
     * VERIFICA COOKIE
     * ========================================================
     */

    const rCode =
      getCookie(
        request,
        COOKIE_NAME
      );

    const isAuthorized =
      rCode === COOKIE_VALUE;


    /*
     * ========================================================
     * IDENTIFICA UPSELL
     * ========================================================
     */

    const upsell =
      UPSELLS[pathname];


    /*
     * Rota que não pertence ao funil.
     */

    if (!upsell) {
      return new Response(
        "Rota não encontrada.",
        {
          status: 404,

          headers: {
            "Content-Type":
              "text/plain; charset=UTF-8",

            "Cache-Control":
              "no-store",
          },
        }
      );
    }


    /*
     * ========================================================
     * ESCOLHE A VERSÃO DO UPSELL
     * ========================================================
     *
     * r_code=rasputin
     * → especial
     *
     * sem cookie
     * → normal
     */

    const targetPage =
      isAuthorized
        ? upsell.special
        : upsell.normal;


    /*
     * ========================================================
     * EXIBE O UPSELL
     * ========================================================
     *
     * Mantém:
     *
     * healthnewsfr.com/up1
     * healthnewsfr.com/up2
     * healthnewsfr.com/up3
     *
     * na barra do navegador.
     *
     * Todos os parâmetros recebidos no upsell
     * também são enviados para a página externa.
     */

    return await proxyPage(
      request,
      targetPage
    );

  } catch (error) {

    /*
     * ========================================================
     * ERRO
     * ========================================================
     */

    console.error(
      "Erro no funnel-router:",
      error
    );

    return new Response(
      "Não foi possível carregar esta página.",
      {
        status: 502,

        headers: {
          "Content-Type":
            "text/plain; charset=UTF-8",

          "Cache-Control":
            "no-store",
        },
      }
    );
  }
}


/*
 * ============================================================
 * ROTAS CONTROLADAS
 * ============================================================
 */

export const config = {
  path: [
    "/salespage",
    "/salespage/",

    "/up1",
    "/up1/",

    "/up2",
    "/up2/",

    "/up3",
    "/up3/",
  ],
};