import { useState } from "react";
import { useTranslation } from "react-i18next";
import { useQuery, useQueryClient } from "@tanstack/react-query";
import { Lock, ShieldCheck } from "lucide-react";
import { api } from "../lib/api";
import * as e2ee from "../lib/e2ee";

// Secure-messaging key gate: first-run setup (choose a passphrase) or unlock on this device.
// Self-contained — on success it updates the shared e2ee unlock state, so any observing view
// (the Messages page, a dock window) swaps out of the gate automatically.
export default function KeyGate({ meId, compact = false }: { meId: number; compact?: boolean }) {
  const { t } = useTranslation();
  const qc = useQueryClient();
  const keyQ = useQuery({ queryKey: ["message-key"], queryFn: api.messageMyKey, staleTime: 60_000 });
  const configured = keyQ.data?.configured ?? false;

  const [pass, setPass] = useState("");
  const [confirm, setConfirm] = useState("");
  const [err, setErr] = useState<string | null>(null);
  const [busy, setBusy] = useState(false);

  async function submit() {
    setErr(null);
    if (pass.length < 6) return setErr(t("messages.passTooShort"));
    if (!configured && pass !== confirm) return setErr(t("messages.passMismatch"));
    setBusy(true);
    try {
      if (configured) {
        await e2ee.unlock(meId, pass, keyQ.data!);
      } else {
        const payload = await e2ee.setup(meId, pass);
        await api.setupMessageKey(payload);
      }
      qc.invalidateQueries({ queryKey: ["message-key"] });
    } catch {
      setErr(configured ? t("messages.wrongPass") : t("messages.setupFailed"));
    } finally {
      setBusy(false);
    }
  }

  if (keyQ.isLoading) return <div className="p-6 text-center text-muted text-sm">{t("common.loading")}</div>;

  return (
    <div className={`glass rounded-2xl space-y-3 ${compact ? "p-3" : "p-4"}`}>
      <div className="flex items-center gap-2">
        <ShieldCheck className="w-5 h-5 text-accent shrink-0" />
        <div className="font-semibold text-sm">{configured ? t("messages.unlockTitle") : t("messages.setupTitle")}</div>
      </div>
      {!compact && <p className="text-sm text-muted">{configured ? t("messages.unlockBody") : t("messages.setupBody")}</p>}
      <input
        type="password"
        value={pass}
        onChange={(e) => setPass(e.target.value)}
        onKeyDown={(e) => e.key === "Enter" && configured && submit()}
        placeholder={t("messages.passphrase")}
        className="w-full bg-card border border-border rounded-xl px-3 py-2 text-sm outline-none focus:border-accent"
      />
      {!configured && (
        <input
          type="password"
          value={confirm}
          onChange={(e) => setConfirm(e.target.value)}
          placeholder={t("messages.passphraseConfirm")}
          className="w-full bg-card border border-border rounded-xl px-3 py-2 text-sm outline-none focus:border-accent"
        />
      )}
      {err && <div className="text-sm text-red-400">{err}</div>}
      <button
        onClick={submit}
        disabled={busy || !pass}
        className="inline-flex items-center gap-2 px-4 py-2 rounded-xl font-semibold bg-accent text-accent-fg hover:opacity-90 transition disabled:opacity-40"
      >
        <Lock className="w-4 h-4" />
        {configured ? t("messages.unlock") : t("messages.setUp")}
      </button>
      {!configured && !compact && <p className="text-xs text-muted">{t("messages.setupWarn")}</p>}
    </div>
  );
}
