trpic/web/scripts/load_mixed/load_mixed.js

let gallery;
let sentinel;
let counter;
let countbox;
let select;
let observer;

let offset = 0;
let loading = false;
let hasMore = true;

const urlParams = new URLSearchParams(window.location.search);

let height = urlParams.get("height") || (window.innerWidth > 1600 ? 320 : 220);
let sort = urlParams.get("sort") || "time";
const limit = window.innerWidth > 1600 ? 50 : 20;

function resetGallery() {
  imgviewer.resetList();
  gallery.replaceChildren(gallery.firstElementChild);
  height = urlParams.get("height") || (window.innerWidth > 1600 ? 320 : 220);
  offset = 0;
  hasMore = true;
  loadMore();
}

async function loadMore() {
  if (loading || !hasMore) return;

  observer.unobserve(sentinel);
  loading = true;

  let url;
  let fromArtworks = false;

  switch (sort) {
    case "time":
    case "time-down":
    case "publish":
    case "publish-down":
      url = `/api/artworks?offset=${offset}&limit=${limit}&sort=${sort}`
      fromArtworks = true;
      break;
    default:
      url = `/api/files?offset=${offset}&limit=${limit}&sort=${sort}`
      break;
  }

  try {
    const res = await fetch(url);
    const data = await res.json();

    switch (res.status) {
      case 200:
        break;
      case 401:
        alert("Session expired");
        return;
      case 500:
        if (data.error) {
          hasMore = false;
          alert(`${data.msg}: ${data.error}`);
          return
        }
    }

    counter.textContent = data.total;

    if (fromArtworks) {
      appendArtworks(data.artworks);
      countbox.childNodes[2].nodeValue = " 个作品"
    } else {
      appendFiles(data.files);
      countbox.childNodes[2].nodeValue = " 张图片"
    }

    hasMore = data.offset + data.limit < data.total;
    offset += data.limit;
    if (!sort) sort = data.sort;
  } catch (err) {
    console.error(err);
    hasMore = false;
  } finally {
    loading = false;

    requestAnimationFrame(() => {
      observer.observe(sentinel);
    });
  }
}

function appendArtworks(artworks) {
  imgviewer.appendArtworks(artworks);
  for (const artwork of artworks) {
    let index = 0;
    for (const file of artwork.edges.files) {
      const fragment = document.createDocumentFragment();
      const jWidth = file.width * height / file.height;
      const jPadding = file.height / file.width * 100;
      const wrapper = document.createElement("div");
      wrapper.style.width = jWidth + "px";
      wrapper.style.flexGrow = jWidth;

      const i = document.createElement("i");
      i.style.paddingBottom = jPadding + "%";
      wrapper.appendChild(i);

      const img = document.createElement("img");
      img.loading = "lazy";
      img.decoding = "async";
      if (file.thumbed) {
        img.src = `/thumbnails/${file.id_str}.jpg`;
        img.dataset.highres = `/files/${file.id_str}.${file.ext}`;
      } else {
        img.src = `/files/${file.id_str}.${file.ext}`;
      }

      img.dataset.id_str = file.id_str;
      img.dataset.artwork_id = artwork.id;

      wrapper.appendChild(img);
      imgviewer.bindClickEvents(img);
      fragment.appendChild(wrapper);
      gallery.appendChild(fragment);
      index++;
    }
  }
}

function appendFiles(files) {
  imgviewer.appendFiles(files);
  const fragment = document.createDocumentFragment();

  for (const image of files) {
    const jWidth = image.width * height / image.height;
    const jPadding = image.height / image.width * 100;
    const wrapper = document.createElement("div");
    wrapper.style.width = jWidth + "px";
    wrapper.style.flexGrow = jWidth;

    const i = document.createElement("i");
    i.style.paddingBottom = jPadding + "%";
    if (sort == "size" || sort == "size-down") {
      const span = document.createElement("span");
      const p = document.createElement("p");
      p.textContent = `${image.ext} | ${image.thumbed ? "☇ " : ""}${image.size_str}`;
      span.appendChild(p);
      i.appendChild(span);
    }
    wrapper.appendChild(i);

    const img = document.createElement("img");
    img.loading = "lazy";
    img.decoding = "async";
    img.src = image.thumbed ? `/thumbnails/${image.id_str}.jpg` : `/files/${image.id_str}.${image.ext}`;

    let artwork = image.edges.artwork;

    img.dataset.id_str = image.id_str;
    img.dataset.artwork_id = artwork.id;

    wrapper.appendChild(img);
    imgviewer.bindClickEvents(img);
    fragment.appendChild(wrapper);
  }

  gallery.appendChild(fragment);
}

document.addEventListener("DOMContentLoaded", () => {
  gallery = document.getElementById("gallery");
  sentinel = document.getElementById("sentinel");
  counter = document.getElementById("count");
  countbox = document.getElementById("count-box");
  select = document.getElementById('sort-select')

  select.value = sort

  select.addEventListener('change', () => {
    urlParams.set("sort", sort = select.value);
    history.replaceState(null, null, `/?${urlParams.toString()}`);
    resetGallery()
  })

  observer = new IntersectionObserver(
    (entries) => {
      if (entries[0].isIntersecting) {
        loadMore();
      }
    },
    {
      root: null,
      rootMargin: "800px", // 提前 800px 加载
      threshold: 0,
    }
  );

  observer.observe(sentinel);
});

document.addEventListener("error", (e) => {
  let target = e.target;
  const tagName = target.tagName || "";
  const curTimes = Number(target.dataset.retryTimes) || 0;
  if (tagName.toLowerCase() === "img") {
    if (curTimes >= 5) {
      target.alt = "loading failed";
    } else {
      setTimeout(() => {
        target.dataset.retryTimes = curTimes + 1;
        target.src = target.src;
      }, 10000);
    }
  } else {
    target = null;
  }
}, true);