Photo Album

// Photo Album — Virtualized 2D photo gallery
// Demonstrates withGrid + withMasonry + withScrollbar plugins
// Layout mode toggle: Grid ↔ Masonry

import { vlist, withGrid, withMasonry, withScrollbar } from "vlist";
import { createStats } from "../../stats.js";
import {
  ITEM_COUNT,
  ASPECT_RATIO,
  items,
  itemTemplate,
  currentMode,
  currentOrientation,
  currentColumns,
  currentGap,
  list,
  setList,
  setCreateView,
} from "../shared.js";
import "../controls.js";

// =============================================================================
// Stats — shared footer (progress, velocity, visible/total)
// =============================================================================

function getEffectiveItemHeight() {
  const container = document.getElementById("grid-container");
  if (!container || !list) return 200;
  const innerWidth = container.clientWidth - 2;
  const colWidth =
    (innerWidth - (currentColumns - 1) * currentGap) / currentColumns;
  if (currentMode === "masonry") return Math.round(colWidth * 1.05);
  return Math.round(colWidth * ASPECT_RATIO);
}

export const stats = createStats({
  getList: () => list,
  getTotal: () => ITEM_COUNT,
  getItemHeight: () => getEffectiveItemHeight(),
  container: "#grid-container",
});

// =============================================================================
// Create / Recreate
// =============================================================================

let firstVisibleIndex = 0;

function createView() {
  if (list) {
    list.destroy();
    setList(null);
  }

  const container = document.getElementById("grid-container");
  container.innerHTML = "";

  const orientation = currentOrientation;
  const columns = currentColumns;
  const gap = currentGap;

  if (currentMode === "grid") {
    createGridView(container, orientation, columns, gap);
  } else {
    createMasonryView(container, orientation, columns, gap);
  }

  // Wire events
  list.on("scroll", stats.scheduleUpdate);
  list.on("range:change", ({ range }) => {
    firstVisibleIndex =
      currentMode === "grid" ? range.start * currentColumns : range.start;
    stats.scheduleUpdate();
  });
  list.on("velocity:change", ({ velocity }) => stats.onVelocity(velocity));

  list.on("item:click", ({ item }) => {
    showDetail(item);
  });

  // Restore scroll position to first visible item
  if (firstVisibleIndex > 0) {
    list.scrollToIndex(firstVisibleIndex, "start");
  }

  stats.update();
  updateContext();
}

// Register createView so controls.js can call it
setCreateView(createView);

function createGridView(container, orientation, columns, gap) {
  if (orientation === "horizontal") {
    const innerHeight = container.clientHeight - 2;
    const colWidth = (innerHeight - (columns - 1) * gap) / columns;
    const height = Math.round(colWidth);

    setList(
      vlist({
        container: "#grid-container",
        ariaLabel: "Photo gallery",
        orientation,
        item: {
          height,
          width: (_index, ctx) =>
            ctx ? Math.round(ctx.columnWidth * (4 / 3)) : 200,
          template: itemTemplate,
        },
        items,
      })
        .use(withGrid({ columns, gap }))
        .use(withScrollbar({ autoHide: true }))
        .build(),
    );
  } else {
    setList(
      vlist({
        container: "#grid-container",
        ariaLabel: "Photo gallery",
        orientation,
        item: {
          height: (_index, ctx) =>
            ctx ? Math.round(ctx.columnWidth * ASPECT_RATIO) : 200,
          template: itemTemplate,
        },
        items,
      })
        .use(withGrid({ columns, gap }))
        .use(withScrollbar({ autoHide: true }))
        .build(),
    );
  }
}

function createMasonryView(container, orientation, columns, gap) {
  setList(
    vlist({
      container: "#grid-container",
      ariaLabel: "Photo gallery",
      orientation,
      item: {
        height: (_index, ctx) =>
          ctx ? Math.round(ctx.columnWidth * items[_index].aspectRatio) : 200,
        width:
          orientation === "horizontal"
            ? (_index, ctx) =>
                ctx
                  ? Math.round(ctx.columnWidth * items[_index].aspectRatio)
                  : 200
            : undefined,
        template: itemTemplate,
      },
      items,
    })
      .use(withMasonry({ columns, gap }))
      .use(withScrollbar({ autoHide: true }))
      .build(),
  );
}

// =============================================================================
// Photo detail (panel)
// =============================================================================

const detailEl = document.getElementById("photo-detail");

function showDetail(item) {
  detailEl.innerHTML = `
    <img
      class="detail__img"
      src="https://picsum.photos/id/${item.picId}/400/300"
      alt="${item.title}"
    />
    <div class="detail__meta">
      <strong>${item.title}</strong>
      <span>${item.category} · ♥ ${item.likes}</span>
    </div>
  `;
}

// =============================================================================
// Footer — right side (contextual)
// =============================================================================

const ftMode = document.getElementById("ft-mode");
const ftOrientation = document.getElementById("ft-orientation");

function updateContext() {
  ftMode.textContent = currentMode;
  ftOrientation.textContent = currentOrientation;
}

// =============================================================================
// Initialise
// =============================================================================

createView();

// Photo Album — Shared data, constants, template, and state
// Imported by all framework implementations to avoid duplication

// =============================================================================
// Constants
// =============================================================================

export const PHOTO_COUNT = 1084;
export const ITEM_COUNT = 600;
export const ASPECT_RATIO = 0.75; // 4:3 landscape

const CATEGORIES = [
  "Nature",
  "Urban",
  "Portrait",
  "Abstract",
  "Travel",
  "Food",
  "Animals",
  "Architecture",
  "Art",
  "Space",
];

// Variable aspect ratios for masonry mode (height/width)
const ASPECT_RATIOS = [0.75, 1.0, 1.33, 1.5, 0.66];

// =============================================================================
// Data
// =============================================================================

export const items = Array.from({ length: ITEM_COUNT }, (_, i) => {
  const picId = i % PHOTO_COUNT;
  const category = CATEGORIES[i % CATEGORIES.length];
  return {
    id: i + 1,
    title: `Photo ${i + 1}`,
    category,
    likes: Math.floor(Math.abs(Math.sin(i * 2.1)) * 500),
    picId,
    aspectRatio: ASPECT_RATIOS[i % ASPECT_RATIOS.length],
  };
});

// =============================================================================
// Template
// =============================================================================

export const itemTemplate = (item) => `
  <div class="card">
    <img
      class="card__img"
      src="https://picsum.photos/id/${item.picId}/300/225"
      alt="${item.title}"
      loading="lazy"
      decoding="async"
    />
    <div class="card__overlay">
      <span class="card__title">${item.title}</span>
      <span class="card__category">${item.category}</span>
    </div>
    <div class="card__likes">♥ ${item.likes}</div>
  </div>
`;

// =============================================================================
// State — mutable, shared across script.js and controls.js
// =============================================================================

export let currentMode = "grid";
export let currentOrientation = "vertical";
export let currentColumns = 4;
export let currentGap = 8;
export let list = null;

export function setCurrentMode(v) {
  currentMode = v;
}
export function setCurrentOrientation(v) {
  currentOrientation = v;
}
export function setCurrentColumns(v) {
  currentColumns = v;
}
export function setCurrentGap(v) {
  currentGap = v;
}
export function setList(v) {
  list = v;
}

// =============================================================================
// View lifecycle — set by each variant's script.js
// =============================================================================

let _createView = () => {};

export function createView() {
  _createView();
}

export function setCreateView(fn) {
  _createView = fn;
}

/* Photo Album — shared styles for all variants (javascript, react, vue, svelte)
   Common styles (.container, h1, .description, .stats, footer)
   are provided by example/example.css using shell.css design tokens.
   Panel system (.split-layout, .split-panel, .panel-*)
   is also provided by example/example.css. */

/* Grid container */
#grid-container {
    height: 600px;
    margin: 0 auto;
}

/* Horizontal orientation - swap dimensions */
#grid-container.vlist--horizontal {
    height: 300px;
    width: 100%;
}

#grid-container.vlist--horizontal .vlist-viewport {
    overflow-x: auto;
    overflow-y: hidden;
}

/* ============================================================================
   Grid Info Bar
   ============================================================================ */

.grid-info {
    padding: 8px 14px;
    margin-bottom: 16px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: var(--bg-card);
    font-size: 13px;
    color: var(--text-muted);
}

.grid-info strong {
    color: var(--text);
}

/* ============================================================================
   Control Buttons (columns / gap)
   ============================================================================ */

.ctrl-btn {
    padding: 6px 14px;
    border: 1px solid var(--border);
    border-radius: 6px;
    background: var(--bg-card);
    color: var(--text-muted);
    font-size: 13px;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: all 0.15s ease;
    min-width: 36px;
    text-align: center;
}

.ctrl-btn:hover {
    border-color: var(--accent);
    color: var(--accent-text);
}

.ctrl-btn--active {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
}

/* ============================================================================
   Photo Card (inside grid items)
   ============================================================================ */

.card {
    position: relative;
    width: 100%;
    height: 100%;
    overflow: hidden;
    border-radius: 8px;
    background: var(--bg-card);
    cursor: pointer;
}

.card__img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    transition: transform 0.25s ease;
}

.card:hover .card__img {
    transform: scale(1.05);
}

.card__overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 24px 8px 8px;
    background: linear-gradient(transparent, rgba(0, 0, 0, 0.7));
    display: flex;
    flex-direction: column;
    gap: 2px;
    opacity: 0;
    transition: opacity 0.2s ease;
}

.card:hover .card__overlay {
    opacity: 1;
}

.card__title {
    font-size: 12px;
    font-weight: 600;
    color: white;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.card__category {
    font-size: 10px;
    color: rgba(255, 255, 255, 0.7);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.card__likes {
    position: absolute;
    top: 6px;
    right: 6px;
    padding: 2px 8px;
    border-radius: 10px;
    background: rgba(0, 0, 0, 0.5);
    color: white;
    font-size: 11px;
    font-weight: 600;
    opacity: 0;
    transition: opacity 0.2s ease;
}

.card:hover .card__likes {
    opacity: 1;
}

/* ============================================================================
   Photo Detail (panel)
   ============================================================================ */

.detail__img {
    width: 100%;
    border-radius: 8px;
    display: block;
    margin-bottom: 8px;
}

.detail__meta {
    display: flex;
    flex-direction: column;
    gap: 2px;
    font-size: 13px;
}

.detail__meta strong {
    font-weight: 600;
}

.detail__meta span {
    font-size: 12px;
    color: var(--text-muted);
}

/* ============================================================================
   vlist grid overrides — remove item borders/padding for photo cards
   ============================================================================ */

#grid-container .vlist-item {
    padding: 0;
    border: none;
    background: transparent;
}

#grid-container .vlist-item:hover {
    background: transparent;
}

/* ============================================================================
   Responsive
   ============================================================================ */

@media (max-width: 820px) {
    #grid-container {
        height: 400px;
    }

    #grid-container.vlist--horizontal {
        height: 250px;
    }
}