"use client";

import { useEffect, useRef, useState } from "react";
import { useRouter } from "next/navigation";
import { useAuth, useAppShell } from "@abe-kap/appshell-sdk/react";
import { PortalAside, PanelBrand } from "@/components/portal/parts";
import { CookieBanner, Spinner } from "@/components/portal/bits";
import { isShellConfigured } from "@/lib/appshell";

interface InviteInfo { ok: boolean; status?: string; email?: string; roleNames?: string[]; hasAccount?: boolean }

/**
 * Team invitation landing page (/portal/invite?token=…). It looks the token up
 * (public, pre-auth) to learn the invited email and whether an account exists, then:
 * - signed in + registered → accept now (creates the membership with the invited role);
 * - signed in, no CRM profile → onboarding, which redeems the token on finish;
 * - not signed in + email already has an account → sign in (email prefilled);
 * - not signed in + first-time invitee → register (email prefilled + locked).
 * The register/login/onboarding flows redeem the stashed token on completion.
 */
export default function InvitePage() {
  const router = useRouter();
  const { status, getUserEmail } = useAuth();
  const { ready, sdk } = useAppShell();
  const [error, setError] = useState("");
  const started = useRef(false);

  useEffect(() => {
    let token = "";
    try { token = new URLSearchParams(window.location.search).get("token") ?? ""; } catch { /* ignore */ }
    if (!token) { setError("This invitation link is invalid or incomplete."); return; }
    if (!isShellConfigured()) { try { sessionStorage.setItem("invite_token", token); } catch { /* ignore */ } router.replace("/portal/register"); return; }
    if (!ready || started.current) return;
    started.current = true;

    (async () => {
      try { sessionStorage.setItem("invite_token", token); } catch { /* ignore */ }

      // Look the invitation up (pre-auth) to get the email + account state.
      let info: InviteInfo = { ok: false };
      try {
        const res = await fetch(`/api/invite/lookup?token=${encodeURIComponent(token)}`, { cache: "no-store" });
        info = await res.json();
      } catch { /* treat as unavailable below */ }

      if (!info.ok) {
        const msg = info.status === "expired" ? "This invitation has expired. Ask for a new one."
          : info.status === "accepted" ? "This invitation has already been used."
          : info.status === "revoked" ? "This invitation was revoked."
          : "This invitation link is invalid.";
        setError(msg);
        try { sessionStorage.removeItem("invite_token"); } catch { /* ignore */ }
        return;
      }
      if (info.email) { try { sessionStorage.setItem("invite_email", info.email); } catch { /* ignore */ } }

      // Signed in already: accept if registered, else finish onboarding first.
      if (status === "authenticated") {
        try {
          const st = await sdk.query<{ registered: boolean }>("crm.account.registrationStatus");
          if (!st?.registered) {
            try { const em = await getUserEmail(); if (em) sessionStorage.setItem("onboard_email", em); } catch { /* ignore */ }
            router.replace("/portal/onboarding");
            return;
          }
        } catch { /* fall through to accept */ }
        try {
          await sdk.command("crm.team.invitation.accept", { token });
          try { sessionStorage.removeItem("invite_token"); sessionStorage.removeItem("invite_email"); } catch { /* ignore */ }
          router.replace("/dashboard");
        } catch {
          setError("We couldn't accept this invitation — it may have expired or already been used.");
        }
        return;
      }

      // Not signed in: existing account → sign in; first-time invitee → register.
      router.replace(info.hasAccount ? "/portal/login" : "/portal/register");
    })();
  }, [ready, status, router, sdk, getUserEmail]);

  return (
    <main className="portal-main">
      <span className="portal-grid" />
      <div className="portal-split anim-in">
        <PortalAside />
        <section className="portal-panel">
          <div style={{ width: "100%", maxWidth: 420 }}>
            <PanelBrand />
            <div className="card anim-fade-up" style={{ textAlign: "center" }}>
              {error ? (
                <>
                  <h1>Invitation problem</h1>
                  <p className="sub">{error}</p>
                  <button className="btn btn-primary" style={{ marginTop: 16 }} onClick={() => router.replace("/portal/login")}>
                    Go to sign in
                  </button>
                </>
              ) : (
                <div className="interstitial">
                  <Spinner lg />
                  <h1 style={{ fontSize: 20, marginTop: 8 }}>Checking your invitation…</h1>
                  <p className="sub">One moment while we set things up.</p>
                </div>
              )}
            </div>
          </div>
        </section>
      </div>
      <CookieBanner />
    </main>
  );
}