"use client";

import { useState, type FormEvent } from "react";

const fieldClass =
  "w-full rounded-2xl border border-anouma-taupe/30 bg-white px-4 py-2.5 text-sm text-anouma-plum placeholder:text-anouma-plum/50 focus:border-anouma-mauve-dark focus:outline-none";

async function callResend(email?: string): Promise<{ ok: boolean; error?: string }> {
  try {
    const res = await fetch("/api/auth/resend-verification", {
      method: "POST",
      credentials: "include",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(email ? { email } : {}),
    });
    const data = await res.json().catch(() => ({}));
    if (!res.ok) return { ok: false, error: data.error || "Die Bestätigungs-E-Mail konnte nicht gesendet werden." };
    return { ok: true };
  } catch {
    return { ok: false, error: "Verbindung fehlgeschlagen." };
  }
}

const GENERIC_SENT_MESSAGE =
  "Falls das Konto noch nicht bestätigt ist, wurde eine neue Bestätigungs-E-Mail gesendet.";

/**
 * variant "session": a single button that resends for the currently logged-in
 * customer (used in /konto and the booking widget, where a session already
 * exists).
 *
 * variant "email-prompt": a toggle link that reveals an email field first
 * (used on /login, where the visitor may not be authenticated yet).
 */
export function ResendVerificationButton({
  variant,
  triggerLabel = "E-Mail noch nicht bestätigt?",
  className,
}: {
  variant: "session" | "email-prompt";
  triggerLabel?: string;
  className?: string;
}) {
  const [open, setOpen] = useState(false);
  const [status, setStatus] = useState<"idle" | "sending" | "sent" | "error">("idle");
  const [error, setError] = useState<string | null>(null);

  async function resendForSession() {
    setStatus("sending");
    const result = await callResend();
    if (result.ok) {
      setStatus("sent");
    } else {
      setStatus("error");
      setError(result.error ?? null);
    }
  }

  async function handleEmailSubmit(e: FormEvent<HTMLFormElement>) {
    e.preventDefault();
    setStatus("sending");
    setError(null);
    const email = String(new FormData(e.currentTarget).get("email") ?? "");
    const result = await callResend(email);
    if (result.ok) {
      setStatus("sent");
    } else {
      setStatus("error");
      setError(result.error ?? null);
    }
  }

  if (variant === "session") {
    return (
      <div className={className}>
        {status === "sent" ? (
          <p className="text-sm text-anouma-olive">{GENERIC_SENT_MESSAGE}</p>
        ) : (
          <button
            type="button"
            onClick={resendForSession}
            disabled={status === "sending"}
            className="text-sm font-medium text-anouma-mauve-dark underline underline-offset-4 disabled:opacity-60"
          >
            {status === "sending" ? "Wird gesendet …" : "Bestätigungs-E-Mail erneut senden"}
          </button>
        )}
        {status === "error" && error && (
          <p role="alert" className="mt-1 text-sm text-red-700">
            {error}
          </p>
        )}
      </div>
    );
  }

  return (
    <div className={className}>
      {!open ? (
        <button
          type="button"
          onClick={() => setOpen(true)}
          className="text-sm font-medium text-anouma-mauve-dark underline underline-offset-4"
        >
          {triggerLabel}
        </button>
      ) : status === "sent" ? (
        <p className="text-sm text-anouma-olive">{GENERIC_SENT_MESSAGE}</p>
      ) : (
        <form onSubmit={handleEmailSubmit} className="mt-2 flex flex-wrap items-start gap-2">
          <input
            type="email"
            name="email"
            required
            placeholder="Deine E-Mail-Adresse"
            className={`${fieldClass} max-w-xs flex-1`}
          />
          <button
            type="submit"
            disabled={status === "sending"}
            className="rounded-full bg-anouma-mauve-dark px-5 py-2.5 text-sm font-medium text-white hover:bg-anouma-plum disabled:opacity-60"
          >
            {status === "sending" ? "Wird gesendet …" : "Bestätigungs-E-Mail erneut senden"}
          </button>
        </form>
      )}
      {status === "error" && error && (
        <p role="alert" className="mt-1 text-sm text-red-700">
          {error}
        </p>
      )}
    </div>
  );
}