import { useState } from "react";
import { Form, useLocation, useNavigate, useNavigation } from "react-router";
import { useTranslation } from "react-i18next";
import { FeatherAlertTriangle, FeatherCheck } from "@subframe/core";
import { useRootData } from "~/utils/data/useRootData";
import { AuthShell, AuthStatus } from "~/components/auth/AuthShell";
import { Button } from "~/ui/components/Button";
import { LinkButton } from "~/ui/components/LinkButton";
import { Progress } from "~/ui/components/Progress";
import { TextInput } from "~/ui/components/TextInput";

// Reset-Password-Screen nach Davids Subframe-Design ("Reset Password" + States): Logo + Card
// (Neues Passwort + Staerke-Progress + Bestaetigung + "Passwort speichern"). Token kommt aus der URL (t),
// E-Mail aus dem Loader (e) -> beide als hidden Inputs. action validiert (mismatch/weak/token).
// success -> Davids "Reset Password _ Success"; fehlende/ungueltige Link-Daten -> "Reset Link _ Invalid".

function passwordStrength(pw: string): number {
  if (!pw) return 0;
  const checks = [pw.length >= 8, /[A-Z]/.test(pw), /[a-z]/.test(pw), /\d/.test(pw), /[^A-Za-z0-9]/.test(pw)];
  return Math.round((checks.filter(Boolean).length / checks.length) * 100);
}

export default function ResetPasswordScreen({
  data,
  actionData,
}: {
  data: { email: string };
  actionData: { success?: string; error?: string; fields?: { verifyToken?: string; email?: string } } | null | undefined;
}) {
  const { t } = useTranslation();
  const { csrf } = useRootData();
  const navigation = useNavigation();
  const navigate = useNavigate();
  const location = useLocation();
  const isSubmitting = navigation.state !== "idle";
  const verifyToken = actionData?.fields?.verifyToken || new URLSearchParams(location.search).get("t") || "";
  const [password, setPassword] = useState("");
  const strength = passwordStrength(password);
  const strengthLabel =
    strength < 40 ? t("account.newPassword.strengthWeak") : strength < 80 ? t("account.newPassword.strengthMedium") : t("account.newPassword.strengthStrong");

  if (actionData?.success) {
    return (
      <AuthStatus
        icon={<FeatherCheck />}
        tone="positive"
        title={t("account.newPassword.successTitle")}
        message={t("account.newPassword.successBody")}
        dataUiId="ui.auth.reset.success"
      >
        <LinkButton size="small" hideIcon onClick={() => navigate("/login")} data-ui-id="ui.auth.reset.successBackToLogin">
          {t("account.forgot.backToLogin")}
        </LinkButton>
      </AuthStatus>
    );
  }

  // Kein/ungueltiger Link (keine E-Mail im e-Param) -> Davids "Reset Link _ Invalid".
  if (!data.email) {
    return (
      <AuthStatus
        icon={<FeatherAlertTriangle />}
        tone="negative"
        title={t("account.newPassword.invalidTitle")}
        message={t("account.newPassword.invalidBody")}
        dataUiId="ui.auth.reset.invalid"
      >
        <Button onClick={() => navigate("/forgot-password")} data-ui-id="ui.auth.reset.requestNew">
          {t("account.newPassword.requestNew")}
        </Button>
        <LinkButton size="small" hideIcon onClick={() => navigate("/login")} data-ui-id="ui.auth.reset.invalidBackToLogin">
          {t("account.forgot.backToLogin")}
        </LinkButton>
      </AuthStatus>
    );
  }

  return (
    <AuthShell title={t("account.newPassword.title")} subtitle={t("account.newPassword.subtitle")} dataUiId="ui.auth.reset.page">
      <Form method="post" noValidate className="flex w-full flex-col gap-4" data-ui-id="ui.auth.reset.form">
        <input type="hidden" name="csrf" value={csrf} readOnly />
        <input type="hidden" name="verify-token" value={verifyToken} readOnly />
        <input type="hidden" name="email" value={data.email} readOnly />

        <div className="flex w-full flex-col items-start gap-2">
          <div className="flex w-full items-end gap-2">
            <TextInput className="h-auto grow shrink-0 basis-0" fillContainer showLabel label={t("account.newPassword.passwordLabel")} type="password">
              <TextInput.Input
                name="password"
                type="password"
                required
                autoFocus
                autoComplete="new-password"
                placeholder={t("account.shared.password")}
                value={password}
                onChange={(event) => setPassword(event.target.value)}
                disabled={isSubmitting}
                data-ui-id="ui.auth.reset.password"
              />
            </TextInput>
          </div>
          <Progress className="h-auto w-full flex-none" hideLabel value={strength} state={strength >= 80 ? "success" : undefined} />
          <div className="flex w-full items-center justify-between">
            <span className="text-body-extra-small-regular-0 font-body-extra-small-regular-0 text-text-neutral-tertiary">
              {t("account.register.passwordStrength")}: {strengthLabel}
            </span>
          </div>
          <span className="w-full text-body-extra-small-medium-150 font-body-extra-small-medium-150 text-text-neutral-tertiary">
            {t("account.register.passwordHint")}
          </span>
        </div>

        <div className="flex w-full items-end gap-2">
          <TextInput className="h-auto grow shrink-0 basis-0" fillContainer showLabel label={t("account.register.confirmPassword")} type="password">
            <TextInput.Input
              name="password-confirm"
              type="password"
              required
              autoComplete="new-password"
              placeholder={t("account.register.confirmPassword")}
              disabled={isSubmitting}
              data-ui-id="ui.auth.reset.passwordConfirm"
            />
          </TextInput>
        </div>

        <Button className="h-9 w-full flex-none" type="submit" loading={isSubmitting} disabled={isSubmitting} data-ui-id="ui.auth.reset.submit">
          {t("account.newPassword.button")}
        </Button>

        {actionData?.error && navigation.state === "idle" ? (
          <p className="text-center text-body-small-regular-0 font-body-small-regular-0 text-text-feedback-negative" role="alert">
            {actionData.error}
          </p>
        ) : null}
      </Form>

      <div className="flex w-full items-center justify-center">
        <LinkButton size="small" hideIcon onClick={() => navigate("/login")} data-ui-id="ui.auth.reset.backToLogin">
          {t("account.forgot.backToLogin")}
        </LinkButton>
      </div>
    </AuthShell>
  );
}