"use client";

/**
 * AuthModal — login + signup tabs in a portal-rendered dialog.
 *
 * The two forms share the existing LoginForm / SignUpForm widgets, so the
 * behaviour is identical to the standalone /login and /signup pages.
 *
 * The forms call `onSuccess` after they finish, but the modal does NOT close
 * from that callback — AuthGate's effect on `user` change handles the close
 * + promise resolution. This lets a single source of truth (AuthProvider's
 * user state) drive the whole flow.
 *
 * No router pushes here — the user's URL stays exactly where it was.
 */

import { useState, useEffect } from "react";
import { createPortal } from "react-dom";
import Link from "next/link";
import { X } from "lucide-react";
import { cn } from "@/lib/utils";
import { LoginForm } from "./login-form";
import { SignUpForm } from "./signup-form";

type Mode = "login" | "signup";

export function AuthModal({ onDismiss }: { onDismiss: () => void }) {
  const [mode, setMode] = useState<Mode>("login");

  // Esc-to-close — matches the pattern used elsewhere (reading settings,
  // search overlay) so the keyboard behavior feels consistent.
  useEffect(() => {
    function onKey(e: KeyboardEvent) {
      if (e.key === "Escape") onDismiss();
    }
    document.addEventListener("keydown", onKey);
    return () => document.removeEventListener("keydown", onKey);
  }, [onDismiss]);

  // Lock scroll on the body while the modal is open.
  useEffect(() => {
    const prev = document.body.style.overflow;
    document.body.style.overflow = "hidden";
    return () => {
      document.body.style.overflow = prev;
    };
  }, []);

  if (typeof document === "undefined") return null;

  return createPortal(
    <>
      <div
        className="fixed inset-0 z-100 bg-foreground/40 backdrop-blur-sm animate-in fade-in-0"
        onClick={onDismiss}
        aria-hidden
      />
      <div
        role="dialog"
        aria-modal="true"
        aria-labelledby="auth-modal-title"
        className="fixed left-1/2 top-1/2 z-101 w-full max-w-md -translate-x-1/2 -translate-y-1/2 px-4"
      >
        <div className="rounded-2xl border border-border bg-card shadow-xl overflow-hidden">
          <header className="flex items-center justify-between px-5 py-4 border-b border-border">
            <h2
              id="auth-modal-title"
              className="font-[family-name:var(--font-title)] font-semibold text-xl text-foreground"
            >
              {mode === "login" ? "Welcome back" : "Create your account"}
            </h2>
            <button
              type="button"
              onClick={onDismiss}
              className="size-8 rounded-lg text-muted-foreground hover:text-foreground hover:bg-muted inline-flex items-center justify-center"
              aria-label="Close"
            >
              <X className="size-4" />
            </button>
          </header>

          {/* Tab toggle */}
          <div className="px-5 pt-4 grid grid-cols-2 gap-1 rounded-lg">
            <ModeTab active={mode === "login"} onClick={() => setMode("login")}>
              Log in
            </ModeTab>
            <ModeTab
              active={mode === "signup"}
              onClick={() => setMode("signup")}
            >
              Sign up
            </ModeTab>
          </div>

          <div className="px-5 py-5">
            {mode === "login" ? (
              <LoginForm
                /* onSuccess is a no-op here — AuthGate watches `user` directly
                   and closes the modal + resolves the pending promise itself. */
                onSuccess={() => {}}
                forgotPasswordHref="/forgot-password"
              />
            ) : (
              <SignUpForm onSuccess={() => {}} />
            )}
          </div>

          <footer className="px-5 pb-5 -mt-1 text-xs text-muted-foreground">
            {mode === "login" ? (
              <>
                Need to reset your password?{" "}
                <Link
                  href="/forgot-password"
                  className="text-primary hover:underline"
                  onClick={onDismiss}
                >
                  Click here
                </Link>
                .
              </>
            ) : (
              <>
                By signing up you agree to our acceptable-use policy. Posts on
                your feed are public.
              </>
            )}
          </footer>
        </div>
      </div>
    </>,
    document.body,
  );
}

function ModeTab({
  active,
  onClick,
  children,
}: {
  active: boolean;
  onClick: () => void;
  children: React.ReactNode;
}) {
  return (
    <button
      type="button"
      onClick={onClick}
      className={cn(
        "h-10 rounded-md text-sm font-medium transition-colors",
        active
          ? "bg-primary text-primary-foreground"
          : "text-muted-foreground hover:text-foreground hover:bg-muted",
      )}
    >
      {children}
    </button>
  );
}