// /app/static/js/modal-pagination.js

document.addEventListener('DOMContentLoaded', () => {
  const modal = document.getElementById('imageModal');
  const modalPrev = document.getElementById('modalPrev');
  const modalNext = document.getElementById('modalNext');
  const modalClose = document.getElementById('modalClose');
  const modalImageWrapper = document.querySelector('.modal-image-wrapper');

  let images = Array.from(document.querySelectorAll('.img-clickable'));
  let currentIndex = -1;
  let isZoomed = false;
  let isDragging = false;
  let startX, startY, scrollLeft, scrollTop;
  let dragStartX = 0;
  let dragStartY = 0;
  let dragMoved = false;

  const hasNextPageInput = document.getElementById('hasNextPage');
  const nextPageUrlInput = document.getElementById('nextPageUrl');
  const hasPrevPageInput = document.getElementById('hasPrevPage');
  const prevPageUrlInput = document.getElementById('prevPageUrl');

  function updateImage(index) {
    const img = images[index];
    const fileType = img.dataset.type || "image";
    modalImageWrapper.innerHTML = "";

    if (fileType === "video") {
      const video = document.createElement("video");
      video.src = img.dataset.full;
      video.controls = true;
      video.autoplay = true;
      video.style.maxWidth = "100%";
      video.style.maxHeight = "100%";
      modalImageWrapper.appendChild(video);
    } else {
      const image = document.createElement("img");
      image.src = img.dataset.full;
      image.alt = "Full View";
      image.setAttribute("draggable", "false");
      image.id = "modalImage";
      modalImageWrapper.appendChild(image);
    }

    currentIndex = index;
    resetZoom();
  }

  function openModal(index) {
    modal.classList.add('active');
    updateImage(index);
    history.replaceState({ modalIndex: index }, '', window.location.href);
  }

  function closeModal() {
    modal.classList.remove('active');
    modalImageWrapper.innerHTML = '';
    currentIndex = -1;
    resetZoom();
    history.replaceState({}, '', window.location.pathname + window.location.search);
  }

  function showNext() {
    if (currentIndex < images.length - 1) {
      updateImage(currentIndex + 1);
    } else if (hasNextPageInput?.value === "true") {
      fetch(nextPageUrlInput.value)
        .then(res => res.text())
        .then(html => {
          const parser = new DOMParser();
          const doc = parser.parseFromString(html, 'text/html');
          const newGallery = doc.querySelector('.gallery-grid');
          const newImages = doc.querySelectorAll('.img-clickable');

          if (newGallery && newImages.length > 0) {
            const gallery = document.querySelector('.gallery-grid');
            gallery.innerHTML = newGallery.innerHTML;

            images = Array.from(document.querySelectorAll('.img-clickable'));
            images.forEach((img, i) => {
              img.addEventListener('click', () => openModal(i));
            });

            hasNextPageInput.value = doc.getElementById('hasNextPage')?.value || "false";
            nextPageUrlInput.value = doc.getElementById('nextPageUrl')?.value || "";
            hasPrevPageInput.value = doc.getElementById('hasPrevPage')?.value || "false";
            prevPageUrlInput.value = doc.getElementById('prevPageUrl')?.value || "";

            history.pushState({}, '', nextPageUrlInput.value);
            openModal(0);
          }
        });
    }
  }

  function showPrev() {
    if (currentIndex > 0) {
      updateImage(currentIndex - 1);
    } else if (hasPrevPageInput?.value === "true") {
      fetch(prevPageUrlInput.value)
        .then(res => res.text())
        .then(html => {
          const parser = new DOMParser();
          const doc = parser.parseFromString(html, 'text/html');
          const newGallery = doc.querySelector('.gallery-grid');
          const newImages = doc.querySelectorAll('.img-clickable');

          if (newGallery && newImages.length > 0) {
            const gallery = document.querySelector('.gallery-grid');
            gallery.innerHTML = newGallery.innerHTML;

            images = Array.from(document.querySelectorAll('.img-clickable'));
            images.forEach((img, i) => {
              img.addEventListener('click', () => openModal(i));
            });

            hasNextPageInput.value = doc.getElementById('hasNextPage')?.value || "false";
            nextPageUrlInput.value = doc.getElementById('nextPageUrl')?.value || "";
            hasPrevPageInput.value = doc.getElementById('hasPrevPage')?.value || "false";
            prevPageUrlInput.value = doc.getElementById('prevPageUrl')?.value || "";

            history.pushState({}, '', prevPageUrlInput.value);
            openModal(images.length - 1);
          }
        });
    }
  }

  function toggleZoom() {
    const isImage = modalImageWrapper.querySelector('img') !== null;
    if (!isImage) return;
    isZoomed = !isZoomed;
    modalImageWrapper.classList.toggle('zoomed', isZoomed);
    modalImageWrapper.style.cursor = isZoomed ? 'grab' : '';
    if (!isZoomed) {
      modalImageWrapper.scrollLeft = 0;
      modalImageWrapper.scrollTop = 0;
    }
  }

  function resetZoom() {
    isZoomed = false;
    modalImageWrapper.classList.remove('zoomed');
    modalImageWrapper.scrollLeft = 0;
    modalImageWrapper.scrollTop = 0;
    modalImageWrapper.style.cursor = '';
  }

  modalImageWrapper.addEventListener('mousedown', (e) => {
    const isImage = modalImageWrapper.querySelector('img') !== null;
    if (!isZoomed || !isImage) return;
    isDragging = true;
    dragMoved = false;
    modalImageWrapper.style.cursor = 'grabbing';
    startX = e.pageX - modalImageWrapper.offsetLeft;
    startY = e.pageY - modalImageWrapper.offsetTop;
    scrollLeft = modalImageWrapper.scrollLeft;
    scrollTop = modalImageWrapper.scrollTop;
    dragStartX = e.pageX;
    dragStartY = e.pageY;
  });

  modalImageWrapper.addEventListener('mouseleave', () => {
    isDragging = false;
    const isImage = modalImageWrapper.querySelector('img') !== null;
    if (isZoomed && isImage) modalImageWrapper.style.cursor = 'grab';
  });

  modalImageWrapper.addEventListener('mouseup', () => {
    isDragging = false;
    const isImage = modalImageWrapper.querySelector('img') !== null;
    if (isZoomed && isImage) modalImageWrapper.style.cursor = 'grab';
  });

  modalImageWrapper.addEventListener('mousemove', (e) => {
    const isImage = modalImageWrapper.querySelector('img') !== null;
    if (!isDragging || !isZoomed || !isImage) return;
    e.preventDefault();
    dragMoved = true;
    const x = e.pageX - modalImageWrapper.offsetLeft;
    const y = e.pageY - modalImageWrapper.offsetTop;
    const walkX = x - startX;
    const walkY = y - startY;
    modalImageWrapper.scrollLeft = scrollLeft - walkX;
    modalImageWrapper.scrollTop = scrollTop - walkY;
  });

  modalImageWrapper.addEventListener('click', (e) => {
    if (dragMoved) {
      dragMoved = false;
      return;
    }
    toggleZoom();
  });

  modalClose?.addEventListener('click', closeModal);
  modalPrev?.addEventListener('click', showPrev);
  modalNext?.addEventListener('click', showNext);

  modal.addEventListener('click', (e) => {
    if (e.target === modal) closeModal();
  });

  document.addEventListener('keydown', (e) => {
    if (!modal.classList.contains('active')) return;
    if (e.key === 'ArrowRight') showNext();
    if (e.key === 'ArrowLeft') showPrev();
    if (e.key === 'Escape') closeModal();
  });

  images.forEach((img, index) => {
    img.addEventListener('click', () => openModal(index));
  });

  window.addEventListener('popstate', () => {
    if (modal.classList.contains('active')) {
      closeModal();
    } else {
      location.reload();
    }
  });
});