// Zoom indipendente per foto e attività.
(() => {
  "use strict";

  const STORAGE = {
    photos: "galleryZoomPhotos",
    activities: "galleryZoomActivities"
  };

  const MIN_SCALE = 0.65;
  const MAX_SCALE = 2.5;
  const STEP = 0.1;

  function getScale(mode) {
    const value = Number(localStorage.getItem(STORAGE[mode]));
    return Number.isFinite(value) && value >= MIN_SCALE && value <= MAX_SCALE
      ? value
      : 1;
  }

  function setScale(mode, value) {
    const scale = Math.max(MIN_SCALE, Math.min(MAX_SCALE, value));
    localStorage.setItem(STORAGE[mode], String(scale));
    window.GalleryRenderer?.refreshLayout?.();
  }

  function currentMode() {
    return window.state?.mode === "activities" ? "activities" : "photos";
  }

  function getMinTile(activities, base) {
    return base * getScale(activities ? "activities" : "photos");
  }

  // Desktop: Ctrl + rotellina.
  window.addEventListener("wheel", (event) => {
    if (!event.ctrlKey) return;

    const gallery = document.getElementById("gallery");
    if (!gallery || !gallery.contains(event.target)) return;

    event.preventDefault();
    const mode = currentMode();
    const direction = event.deltaY < 0 ? 1 : -1;
    setScale(mode, getScale(mode) + direction * STEP);
  }, { passive: false });

  // Smartphone/tablet: pinch a due dita nella galleria.
  let pinchStartDistance = 0;
  let pinchStartScale = 1;
  let pinchMode = "photos";
  let pinchActive = false;

  function distance(touches) {
    const dx = touches[0].clientX - touches[1].clientX;
    const dy = touches[0].clientY - touches[1].clientY;
    return Math.hypot(dx, dy);
  }

  function isGalleryTouch(event) {
    const gallery = document.getElementById("gallery");
    return gallery && gallery.contains(event.target);
  }

  document.addEventListener("touchstart", (event) => {
    if (event.touches.length !== 2 || !isGalleryTouch(event)) return;

    pinchActive = true;
    pinchMode = currentMode();
    pinchStartDistance = distance(event.touches);
    pinchStartScale = getScale(pinchMode);
  }, { passive: true });

  document.addEventListener("touchmove", (event) => {
    if (!pinchActive || event.touches.length !== 2 || !isGalleryTouch(event)) return;

    event.preventDefault();
    const currentDistance = distance(event.touches);
    if (pinchStartDistance <= 0) return;

    const ratio = currentDistance / pinchStartDistance;
    const scale = Math.round((pinchStartScale * ratio) * 100) / 100;
    const bounded = Math.max(MIN_SCALE, Math.min(MAX_SCALE, scale));

    localStorage.setItem(STORAGE[pinchMode], String(bounded));
    window.GalleryRenderer?.refreshLayout?.();
  }, { passive: false });

  document.addEventListener("touchend", (event) => {
    if (event.touches.length < 2) pinchActive = false;
  }, { passive: true });

  document.addEventListener("touchcancel", () => {
    pinchActive = false;
  }, { passive: true });

  window.GalleryZoom = Object.freeze({
    getMinTile,
    getScale: (mode) => getScale(mode)
  });
})();