"use client";

import { useEffect } from "react";
import { parseWebcal } from "@/lib/protocol-handlers/webcal";
import { savePendingWebcal } from "@/lib/protocol-handlers/session";
import { useSettingsStore } from "@/stores/settings-store";

type StandaloneNavigator = Navigator & { standalone?: boolean };

function getProtocolPathPrefix(): string {
  const marker = "/protocol/webcal";
  const index = window.location.pathname.indexOf(marker);
  return index > 0 ? window.location.pathname.slice(0, index) : "";
}

function returnToSourcePage() {
  window.close();

  window.setTimeout(() => {
    if (window.history.length > 1) {
      window.history.back();
    }
  }, 150);
}

function openFallbackAppTab(raw: string): boolean {
  const url = `${getProtocolPathPrefix()}/protocol/webcal?url=${encodeURIComponent(raw)}&fallback=1`;
  const opened = window.open(url, "_blank");
  if (!opened) return false;
  opened.opener = null;
  return true;
}

function shouldOpenFallbackAppTab(): boolean {
  const standalone = window.matchMedia?.("(display-mode: standalone)").matches
    || (navigator as StandaloneNavigator).standalone === true;
  return !standalone && window.history.length > 1;
}

interface WebcalProtocolClientProps {
  openingText: string;
}

export function WebcalProtocolClient({ openingText }: WebcalProtocolClientProps) {
  useEffect(() => {
    const params = new URLSearchParams(window.location.search);
    const raw = params.get("url");
    const isFallbackAppTab = params.get("fallback") === "1";

    if (raw) {
      const parsed = parseWebcal(raw);
      if (parsed) {
        if (!isFallbackAppTab
          && useSettingsStore.getState().protocolOpenMode === "new-tab"
          && shouldOpenFallbackAppTab()
          && openFallbackAppTab(raw)) {
          returnToSourcePage();
          return;
        }

        savePendingWebcal(parsed);
      }
    }

    window.location.replace(`${getProtocolPathPrefix()}/calendar`);
  }, []);

  return (
    <main className="flex min-h-screen items-center justify-center">
      <p>{openingText}</p>
    </main>
  );
}