import classNames from "classnames";
import { GetServerSidePropsContext } from "next";
import { getCsrfToken, signIn } from "next-auth/react";
import Link from "next/link";
import { useRouter } from "next/router";
import { useState } from "react";
import { useForm, FormProvider } from "react-hook-form";
import { FaGoogle } from "react-icons/fa";

import { isSAMLLoginEnabled, samlProductID, samlTenantID } from "@calcom/features/ee/sso/lib/saml";
import { getSafeRedirectUrl } from "@calcom/lib/getSafeRedirectUrl";
import { useLocale } from "@calcom/lib/hooks/useLocale";
import { collectPageParameters, telemetryEventTypes, useTelemetry } from "@calcom/lib/telemetry";
import prisma from "@calcom/prisma";
import { Icon } from "@calcom/ui";
import { Alert } from "@calcom/ui/Alert";
import { Button, EmailField, PasswordField } from "@calcom/ui/v2";
import SAMLLogin from "@calcom/ui/v2/modules/auth/SAMLLogin";

import { ErrorCode, getSession } from "@lib/auth";
import { WEBAPP_URL, WEBSITE_URL } from "@lib/config/constants";
import { inferSSRProps } from "@lib/types/inferSSRProps";

import AddToHomescreen from "@components/AddToHomescreen";
import TwoFactor from "@components/auth/TwoFactor";
import AuthContainer from "@components/v2/ui/AuthContainer";

import { IS_GOOGLE_LOGIN_ENABLED } from "@server/lib/constants";
import { ssrInit } from "@server/lib/ssr";

interface LoginValues {
  email: string;
  password: string;
  totpCode: string;
  csrfToken: string;
}

export default function Login({
  csrfToken,
  isGoogleLoginEnabled,
  isSAMLLoginEnabled,
  samlTenantID,
  samlProductID,
}: inferSSRProps<typeof getServerSideProps>) {
  const { t } = useLocale();
  const router = useRouter();
  const methods = useForm<LoginValues>();

  const { register, formState } = methods;

  const [twoFactorRequired, setTwoFactorRequired] = useState(false);
  const [errorMessage, setErrorMessage] = useState<string | null>(null);

  const errorMessages: { [key: string]: string } = {
    // [ErrorCode.SecondFactorRequired]: t("2fa_enabled_instructions"),
    [ErrorCode.IncorrectPassword]: `${t("incorrect_password")} ${t("please_try_again")}`,
    [ErrorCode.UserNotFound]: t("no_account_exists"),
    [ErrorCode.IncorrectTwoFactorCode]: `${t("incorrect_2fa_code")} ${t("please_try_again")}`,
    [ErrorCode.InternalServerError]: `${t("something_went_wrong")} ${t("please_try_again_and_contact_us")}`,
    [ErrorCode.ThirdPartyIdentityProviderEnabled]: t("account_created_with_identity_provider"),
  };

  const telemetry = useTelemetry();

  let callbackUrl = typeof router.query?.callbackUrl === "string" ? router.query.callbackUrl : "";

  if (/"\//.test(callbackUrl)) callbackUrl = callbackUrl.substring(1);

  // If not absolute URL, make it absolute
  if (!/^https?:\/\//.test(callbackUrl)) {
    callbackUrl = `${WEBAPP_URL}/${callbackUrl}`;
  }

  const safeCallbackUrl = getSafeRedirectUrl(callbackUrl);

  callbackUrl = safeCallbackUrl || "";

  const LoginFooter = (
    <a href={`${WEBSITE_URL}/signup`} className="text-brand-500 font-medium">
      {t("dont_have_an_account")}
    </a>
  );

  const TwoFactorFooter = (
    <Button
      onClick={() => {
        setTwoFactorRequired(false);
        methods.setValue("totpCode", "");
      }}
      StartIcon={Icon.FiArrowLeft}
      color="minimal">
      {t("go_back")}
    </Button>
  );

  const onSubmit = async (values: LoginValues) => {
    setErrorMessage(null);
    telemetry.event(telemetryEventTypes.login, collectPageParameters());
    const res = await signIn<"credentials">("credentials", {
      ...values,
      callbackUrl,
      redirect: false,
    });
    if (!res) setErrorMessage(errorMessages[ErrorCode.InternalServerError]);
    // we're logged in! let's do a hard refresh to the desired url
    else if (!res.error) router.push(callbackUrl);
    // reveal two factor input if required
    else if (res.error === ErrorCode.SecondFactorRequired) setTwoFactorRequired(true);
    // fallback if error not found
    else setErrorMessage(errorMessages[res.error] || t("something_went_wrong"));
  };

  return (
    <>
      <AuthContainer
        title={t("login")}
        description={t("login")}
        showLogo
        heading={twoFactorRequired ? t("2fa_code") : t("welcome_back")}
        footerText={twoFactorRequired ? TwoFactorFooter : LoginFooter}>
        <FormProvider {...methods}>
          <form onSubmit={methods.handleSubmit(onSubmit)} data-testid="login-form">
            <div>
              <input defaultValue={csrfToken || undefined} type="hidden" hidden {...register("csrfToken")} />
            </div>
            <div className="space-y-6">
              <div className={classNames("space-y-6", { hidden: twoFactorRequired })}>
                <EmailField
                  id="email"
                  label={t("email_address")}
                  defaultValue={router.query.email as string}
                  placeholder="john.doe@example.com"
                  required
                  {...register("email")}
                />
                <div className="relative">
                  <div className="absolute right-0 -top-[6px] z-10">
                    <Link href="/auth/forgot-password">
                      <a tabIndex={-1} className="text-sm font-medium text-gray-600">
                        {t("forgot")}
                      </a>
                    </Link>
                  </div>
                  <PasswordField
                    id="password"
                    autoComplete="current-password"
                    required
                    className="mb-0"
                    {...register("password")}
                  />
                </div>
              </div>

              {twoFactorRequired && <TwoFactor center />}

              {errorMessage && <Alert severity="error" title={errorMessage} />}
              <Button
                type="submit"
                color="primary"
                disabled={formState.isSubmitting}
                className="w-full justify-center">
                {twoFactorRequired ? t("submit") : t("sign_in")}
              </Button>
            </div>
          </form>
          {!twoFactorRequired && (
            <>
              {(isGoogleLoginEnabled || isSAMLLoginEnabled) && <hr className="my-8" />}
              <div className="space-y-3">
                {isGoogleLoginEnabled && (
                  <Button
                    color="secondary"
                    className="w-full justify-center"
                    data-testid="google"
                    StartIcon={FaGoogle}
                    onClick={async (e) => {
                      e.preventDefault();
                      // track Google logins. Without personal data/payload
                      telemetry.event(telemetryEventTypes.googleLogin, collectPageParameters());
                      await signIn("google");
                    }}>
                    {t("signin_with_google")}
                  </Button>
                )}
                {isSAMLLoginEnabled && (
                  <SAMLLogin
                    samlTenantID={samlTenantID}
                    samlProductID={samlProductID}
                    setErrorMessage={setErrorMessage}
                  />
                )}
              </div>
            </>
          )}
        </FormProvider>
      </AuthContainer>
      <AddToHomescreen />
    </>
  );
}

export async function getServerSideProps(context: GetServerSidePropsContext) {
  const { req } = context;
  const session = await getSession({ req });
  const ssr = await ssrInit(context);

  if (session) {
    return {
      redirect: {
        destination: "/",
        permanent: false,
      },
    };
  }

  const userCount = await prisma.user.count();
  if (userCount === 0) {
    // Proceed to new onboarding to create first admin user
    return {
      redirect: {
        destination: "/auth/setup",
        permanent: false,
      },
    };
  }

  return {
    props: {
      csrfToken: await getCsrfToken(context),
      trpcState: ssr.dehydrate(),
      isGoogleLoginEnabled: IS_GOOGLE_LOGIN_ENABLED,
      isSAMLLoginEnabled,
      samlTenantID,
      samlProductID,
    },
  };
}