import { endpoints } from "./config.js";
import {
  getAnalyticsSessionId,
  getHashParam,
  getIsStaffPreview,
  getTableParam,
  setAnalyticsSessionId,
} from "./state.js";

const analyticsSessionKey = "karczma_analytics_session_id";

function getOrCreateAnalyticsSessionId() {
  let existing = localStorage.getItem(analyticsSessionKey);
  if (existing) return existing;

  let newId = "";
  if (window.crypto && crypto.randomUUID) {
    newId = crypto.randomUUID();
  } else {
    newId = `sess_${Date.now()}_${Math.random().toString(36).slice(2, 10)}`;
  }
  localStorage.setItem(analyticsSessionKey, newId);
  return newId;
}

setAnalyticsSessionId(getOrCreateAnalyticsSessionId());

function detectDeviceType() {
  const ua = navigator.userAgent || "";
  if (/iPad|iPhone|iPod/.test(ua) || (navigator.platform === "MacIntel" && navigator.maxTouchPoints > 1)) return "ios";
  if (/Android/i.test(ua)) return "android";
  return "other";
}

function detectBrowser() {
  const ua = navigator.userAgent || "";
  if (/Edg\//.test(ua)) return "edge";
  if (/OPR\//.test(ua)) return "opera";
  if (/Chrome\//.test(ua)) return "chrome";
  if (/Safari\//.test(ua)) return "safari";
  if (/Firefox\//.test(ua)) return "firefox";
  return "other";
}

function deriveZoneFromTable(tableValue) {
  const raw = String(tableValue || "").trim().toLowerCase();
  if (!raw) return null;

  if (raw.startsWith("t") || raw.includes("taras")) return "taras";
  if (raw.startsWith("k") || raw.includes("karczma")) return "karczma";
  return null;
}

export function trackEvent(eventName, payload = {}) {
  if (getIsStaffPreview()) {
    return;
  }

  const tableParam = getTableParam();
  const hashParam = getHashParam();

  const body = {
    eventName,
    sessionId: getAnalyticsSessionId(),
    tableId: tableParam || null,
    zone: deriveZoneFromTable(tableParam),
    qrHash: hashParam || null,
    deviceType: detectDeviceType(),
    browser: detectBrowser(),
    payload
  };

  const bodyString = JSON.stringify(body);

  try {
    if (navigator.sendBeacon) {
      const blob = new Blob([bodyString], { type: "application/json" });
      navigator.sendBeacon(endpoints.analytics, blob);
      return;
    }
  } catch {
    // fallback to fetch below
  }

  fetch(endpoints.analytics, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: bodyString,
    keepalive: true
  }).catch(() => {
    // best effort - ignore analytics errors
  });
}