import { FormEvent, useState } from "react";
import { apiPost } from "../lib/api";
import { useSession } from "../lib/session";
import type { UserOption } from "../lib/types";

type FeedbackState =
  | { type: "error"; text: string }
  | { type: "success"; text: string }
  | null;

export default function LoginPage() {
  const [showRegistration, setShowRegistration] = useState(false);
  const [identifier, setIdentifier] = useState("");
  const [password, setPassword] = useState("");
  const [showLoginValidation, setShowLoginValidation] = useState(false);
  const [showRegisterValidation, setShowRegisterValidation] = useState(false);
  const [registration, setRegistration] = useState({
    companyName: "",
    street: "",
    houseNumber: "",
    postalCode: "",
    city: "",
    email: "",
    phoneNumber: "",
    password: "",
    passwordConfirmation: "",
  });
  const [feedback, setFeedback] = useState<FeedbackState>(null);
  const { setUser } = useSession();

  async function handlePasswordLogin(event: FormEvent<HTMLFormElement>) {
    event.preventDefault();
    setShowLoginValidation(true);
    if (!identifier.trim() || !password.trim()) {
      setFeedback({
        type: "error",
        text: "Bitte E-Mail oder Benutzername und Passwort eingeben.",
      });
      return;
    }
    try {
      setFeedback(null);
      const response = await apiPost<UserOption>("/session/password-login", {
        identifier: identifier.trim(),
        password,
      });
      setUser(response);
    } catch (loginError) {
      setFeedback({ type: "error", text: (loginError as Error).message });
    }
  }

  async function handleRegister(event: FormEvent<HTMLFormElement>) {
    event.preventDefault();
    setShowRegisterValidation(true);
    if (
      !registration.companyName.trim()
      || !registration.street.trim()
      || !registration.houseNumber.trim()
      || !registration.postalCode.trim()
      || !registration.city.trim()
      || !registration.email.trim()
      || !registration.phoneNumber.trim()
      || !registration.password.trim()
    ) {
      setFeedback({
        type: "error",
        text: "Bitte alle Pflichtfelder inklusive Telefonnummer fuer die Registrierung ausfuellen.",
      });
      return;
    }
    if (registration.password !== registration.passwordConfirmation) {
      setFeedback({ type: "error", text: "Die beiden Passwoerter stimmen nicht ueberein." });
      return;
    }
    try {
      setFeedback(null);
      const { passwordConfirmation, ...registrationPayload } = registration;
      void passwordConfirmation;
      const response = await apiPost<UserOption>("/session/register", registrationPayload);
      setFeedback({
        type: "success",
        text: `Registrierung erfolgreich. Willkommen ${response.companyName ?? response.displayName}.`,
      });
      setUser(response);
    } catch (registrationError) {
      setFeedback({ type: "error", text: (registrationError as Error).message });
    }
  }

  return (
    <div className="login-page">
      <section className="login-hero">
        <div className="login-hero__copy">
          <p className="eyebrow">MUH-App</p>
          <h1>Moderne Steuerung fuer Milchproben und Therapien.</h1>
          <p className="hero-text">
            Fokus auf klare Arbeitsablaeufe, schnelle Probenbearbeitung und ein Portal
            fuer Verwaltung, Berichtsdruck und Versandstatus.
          </p>
        </div>

        <div className="login-hero__panel">
          <div className="panel-glow" />
          <p className="eyebrow">Zugang</p>
          <h2>Anmelden oder registrieren</h2>
          <p className="muted-text">
            Anmeldung per E-Mail oder Benutzername mit Passwort sowie direkte
            Kundenregistrierung.
          </p>

          {feedback ? (
            <div className={`alert ${feedback.type === "success" ? "alert--success" : "alert--error"}`}>
              {feedback.text}
            </div>
          ) : null}

          <div className="auth-grid">
            {!showRegistration ? (
              <form className={`login-panel__section ${showLoginValidation ? "show-validation" : ""}`} onSubmit={handlePasswordLogin}>
                <label className="field field--required">
                  <span>E-Mail / Benutzername</span>
                  <input
                    value={identifier}
                    onChange={(event) => setIdentifier(event.target.value)}
                    placeholder="z. B. admin oder name@hof.de"
                    required
                  />
                </label>
                <label className="field field--required">
                  <span>Passwort</span>
                  <input
                    type="password"
                    value={password}
                    onChange={(event) => setPassword(event.target.value)}
                    required
                  />
                </label>
                <div className="page-actions">
                  <button type="submit" className="accent-button">
                    Mit Passwort anmelden
                  </button>
                  <button
                    type="button"
                    className="secondary-button"
                    onClick={() => {
                      setFeedback(null);
                      setShowRegisterValidation(false);
                      setShowRegistration(true);
                    }}
                  >
                    Registrieren
                  </button>
                </div>
              </form>
            ) : (
              <form className={`login-panel__section ${showRegisterValidation ? "show-validation" : ""}`} onSubmit={handleRegister}>
                <div className="field-grid">
                  <label className="field field--wide field--required">
                    <span>Firmenname</span>
                    <input
                      value={registration.companyName}
                      onChange={(event) =>
                        setRegistration((current) => ({ ...current, companyName: event.target.value }))
                      }
                      placeholder="z. B. Muster Agrar GmbH"
                      required
                    />
                  </label>
                  <label className="field field--required">
                    <span>Strasse</span>
                    <input
                      value={registration.street}
                      onChange={(event) =>
                        setRegistration((current) => ({ ...current, street: event.target.value }))
                      }
                      placeholder="z. B. Dorfstrasse"
                      required
                    />
                  </label>
                  <label className="field field--required">
                    <span>Hausnummer</span>
                    <input
                      value={registration.houseNumber}
                      onChange={(event) =>
                        setRegistration((current) => ({ ...current, houseNumber: event.target.value }))
                      }
                      placeholder="z. B. 12a"
                      required
                    />
                  </label>
                  <label className="field field--required">
                    <span>PLZ</span>
                    <input
                      value={registration.postalCode}
                      onChange={(event) =>
                        setRegistration((current) => ({ ...current, postalCode: event.target.value }))
                      }
                      placeholder="z. B. 12345"
                      required
                    />
                  </label>
                  <label className="field field--required">
                    <span>Ort</span>
                    <input
                      value={registration.city}
                      onChange={(event) =>
                        setRegistration((current) => ({ ...current, city: event.target.value }))
                      }
                      placeholder="z. B. Musterstadt"
                      required
                    />
                  </label>
                  <label className="field field--required">
                    <span>E-Mail</span>
                    <input
                      type="email"
                      value={registration.email}
                      onChange={(event) =>
                        setRegistration((current) => ({ ...current, email: event.target.value }))
                      }
                      required
                    />
                  </label>
                  <label className="field field--required">
                    <span>Telefonnummer</span>
                    <input
                      type="tel"
                      value={registration.phoneNumber}
                      onChange={(event) =>
                        setRegistration((current) => ({ ...current, phoneNumber: event.target.value }))
                      }
                      placeholder="z. B. 04531 181424"
                      required
                    />
                  </label>
                  <label className="field field--wide field--required">
                    <span>Passwort</span>
                    <input
                      type="password"
                      value={registration.password}
                      onChange={(event) =>
                        setRegistration((current) => ({ ...current, password: event.target.value }))
                      }
                      required
                    />
                  </label>
                  <label className="field field--wide field--required">
                    <span>Passwort wiederholen</span>
                    <input
                      type="password"
                      value={registration.passwordConfirmation}
                      className={
                        showRegisterValidation
                        && registration.password !== registration.passwordConfirmation
                          ? "is-invalid"
                          : ""
                      }
                      aria-invalid={
                        showRegisterValidation && registration.password !== registration.passwordConfirmation
                      }
                      onChange={(event) =>
                        setRegistration((current) => ({
                          ...current,
                          passwordConfirmation: event.target.value,
                        }))
                      }
                      required
                    />
                  </label>
                </div>
                <div className="page-actions">
                  <button type="submit" className="accent-button">
                    Registrieren
                  </button>
                  <button
                    type="button"
                    className="secondary-button"
                    onClick={() => {
                      setFeedback(null);
                      setShowLoginValidation(false);
                      setShowRegistration(false);
                    }}
                  >
                    Zurück
                  </button>
                </div>
              </form>
            )}
          </div>
        </div>
      </section>
    </div>
  );
}