"use client";

import { useRouter } from "next/navigation";
import { useState } from "react";

import { PasswordInput } from "@/components/password-input";
import { Button, Card, Field, Notice, TextInput } from "@/components/ui";
import { ApiError, apiJson } from "@/lib/api-client";

function useSubmit() {
  const router = useRouter();
  const [pending, setPending] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const submit = async (json: unknown) => {
    setPending(true);
    setError(null);
    try {
      await apiJson("/api/auth", { method: "POST", json });
      // refresh() ist hier entscheidend: Kopfbereich und Startseite werden
      // serverseitig je nach Anmeldung unterschiedlich gerendert, und ohne
      // Verwerfen des Zwischenspeichers käme die Seite von vor der Anmeldung.
      router.replace("/");
      router.refresh();
    } catch (caught) {
      setError(
        caught instanceof ApiError
          ? caught.message
          : "Die Anmeldung ist fehlgeschlagen.",
      );
      setPending(false);
    }
  };

  return { submit, pending, error, router };
}

export function LoginForm() {
  const { submit, pending, error } = useSubmit();
  const [email, setEmail] = useState("");
  const [password, setPassword] = useState("");

  return (
    <Card>
      <form
        className="flex flex-col gap-4"
        onSubmit={(event) => {
          event.preventDefault();
          void submit({ action: "login", email, password });
        }}
      >
        {error ? <Notice tone="error">{error}</Notice> : null}

        <Field label="E-Mail-Adresse" htmlFor="login-email">
          <TextInput
            id="login-email"
            type="email"
            autoComplete="username"
            autoFocus
            required
            value={email}
            disabled={pending}
            onChange={(event) => setEmail(event.target.value)}
          />
        </Field>

        <Field label="Passwort" htmlFor="login-password">
          <PasswordInput
            id="login-password"
            autoComplete="current-password"
            required
            value={password}
            disabled={pending}
            onChange={(event) => setPassword(event.target.value)}
          />
        </Field>

        <Button type="submit" disabled={pending}>
          {pending ? "Wird angemeldet …" : "Anmelden"}
        </Button>
      </form>
    </Card>
  );
}

export function SetupForm({ minLength }: { minLength: number }) {
  const { submit, pending, error } = useSubmit();
  const [email, setEmail] = useState("");
  const [name, setName] = useState("");
  const [password, setPassword] = useState("");
  const [repeat, setRepeat] = useState("");

  const mismatch = repeat.length > 0 && password !== repeat;

  return (
    <Card>
      <form
        className="flex flex-col gap-4"
        onSubmit={(event) => {
          event.preventDefault();
          if (mismatch) return;
          void submit({ action: "setup", email, name, password });
        }}
      >
        {error ? <Notice tone="error">{error}</Notice> : null}

        <Field label="Name (optional)" htmlFor="setup-name">
          <TextInput
            id="setup-name"
            autoComplete="name"
            value={name}
            disabled={pending}
            onChange={(event) => setName(event.target.value)}
          />
        </Field>

        <Field label="E-Mail-Adresse" htmlFor="setup-email">
          <TextInput
            id="setup-email"
            type="email"
            autoComplete="username"
            required
            value={email}
            disabled={pending}
            onChange={(event) => setEmail(event.target.value)}
          />
        </Field>

        <Field
          label="Passwort"
          htmlFor="setup-password"
          hint={`Mindestens ${minLength} Zeichen.`}
        >
          <PasswordInput
            id="setup-password"
            autoComplete="new-password"
            required
            minLength={minLength}
            value={password}
            disabled={pending}
            onChange={(event) => setPassword(event.target.value)}
          />
        </Field>

        <Field
          label="Passwort wiederholen"
          htmlFor="setup-repeat"
          error={mismatch ? "Die beiden Passwörter stimmen nicht überein." : null}
        >
          <PasswordInput
            id="setup-repeat"
            autoComplete="new-password"
            required
            invalid={mismatch}
            value={repeat}
            disabled={pending}
            onChange={(event) => setRepeat(event.target.value)}
          />
        </Field>

        <Button type="submit" disabled={pending || mismatch}>
          {pending ? "Wird angelegt …" : "Administrator anlegen"}
        </Button>
      </form>
    </Card>
  );
}

export function LogoutButton() {
  const router = useRouter();
  const [pending, setPending] = useState(false);

  return (
    <button
      type="button"
      disabled={pending}
      onClick={async () => {
        setPending(true);
        try {
          await apiJson("/api/auth", {
            method: "POST",
            json: { action: "logout" },
          });
        } finally {
          router.replace("/anmelden");
          router.refresh();
        }
      }}
      className="rounded-lg px-3 py-2 text-sm font-medium text-slate-600 transition-colors hover:bg-slate-100 hover:text-slate-900 disabled:opacity-50"
    >
      {pending ? "…" : "Abmelden"}
    </button>
  );
}