mp3-com-meta-browser/script.js

338 lines
11 KiB
JavaScript

/*
Application bootstrap for the static, client-side metadata browser.
- Downloads a zipped SQLite DB (db.zip) with progress and unzips it in-memory
- Caches the uncompressed DB bytes in IndexedDB for reuse on next load
- Loads sql.js (WASM) and opens the database from the cached bytes
- Swaps interchangeable UX elements (views) in a viewport, with fade transitions
Assumptions:
- A ZIP archive is hosted at `/db.zip` containing a single `.sqlite` file.
- We use `fflate` (UMD) from a CDN to unzip after download (keeps implementation minimal).
- We use `sql.js` from a CDN; the WASM is located via `locateFile` (see initSql()).
- We store raw DB bytes in IndexedDB (localStorage is too small for large DBs).
*/
(function () {
// Use a relative URL so the app works when hosted under a subdirectory.
const DB_ZIP_URL = './db.zip';
const IDB_NAME = 'mp3com-meta-browser';
const IDB_STORE = 'files';
const IDB_KEY = 'mp3com-db-bytes-v1'; // bump if format changes
// Viewport layers
const $uxRoot = document.getElementById('ux-root');
const $uxOverlays = document.getElementById('ux-overlays');
// Fade helpers
function fadeIn(el) {
return new Promise((resolve) => {
el.classList.add('fade');
el.classList.add('fade-hidden');
requestAnimationFrame(() => {
el.classList.add('fade-visible');
el.classList.remove('fade-hidden');
const onEnd = (e) => {
if (e.propertyName === 'opacity') {
el.removeEventListener('transitionend', onEnd);
resolve();
}
};
el.addEventListener('transitionend', onEnd);
});
});
}
function fadeOut(el) {
return new Promise((resolve) => {
el.classList.add('fade');
el.classList.remove('fade-visible');
el.classList.add('fade-hidden');
const onEnd = (e) => {
if (e.propertyName === 'opacity') {
el.removeEventListener('transitionend', onEnd);
resolve();
}
};
el.addEventListener('transitionend', onEnd);
});
}
// UX Manager
const UX = (() => {
let currentBase = null; // { view, el }
const overlayStack = []; // [{ view, el, lastFocus }]
function ensureViewEl(view) {
if (!view || !view.el) throw new Error('Invalid view');
view.el.classList.add('ux-view');
return view.el;
}
async function replace(view) {
const el = ensureViewEl(view);
if (currentBase) {
await fadeOut(currentBase.el);
$uxRoot.removeChild(currentBase.el);
if (typeof currentBase.view.destroy === 'function') currentBase.view.destroy();
}
$uxRoot.appendChild(el);
await fadeIn(el);
currentBase = { view, el };
if (typeof view.onShow === 'function') view.onShow();
}
async function openOverlay(view) {
const el = ensureViewEl(view);
el.classList.add('ux-view--overlay');
const lastFocus = document.activeElement;
$uxOverlays.appendChild(el);
await fadeIn(el);
overlayStack.push({ view, el, lastFocus });
$uxRoot.setAttribute('aria-hidden', 'true');
if (typeof view.onShow === 'function') view.onShow();
}
async function closeTop() {
const top = overlayStack.pop();
if (!top) return;
const { view, el, lastFocus } = top;
await fadeOut(el);
if (el.parentNode) el.parentNode.removeChild(el);
if (typeof view.destroy === 'function') view.destroy();
if (overlayStack.length === 0) $uxRoot.removeAttribute('aria-hidden');
if (lastFocus && typeof lastFocus.focus === 'function') lastFocus.focus();
}
window.addEventListener('keydown', (e) => {
if (e.key === 'Escape' && overlayStack.length) {
e.preventDefault();
closeTop();
}
});
return { replace, openOverlay, closeTop };
})();
// --- IndexedDB helpers (minimal, no external deps) ---
function idbOpen() {
return new Promise((resolve, reject) => {
const req = indexedDB.open(IDB_NAME, 1);
req.onupgradeneeded = () => {
const db = req.result;
if (!db.objectStoreNames.contains(IDB_STORE)) db.createObjectStore(IDB_STORE);
};
req.onsuccess = () => resolve(req.result);
req.onerror = () => reject(req.error);
});
}
async function idbGet(key) {
const db = await idbOpen();
return new Promise((resolve, reject) => {
const tx = db.transaction(IDB_STORE, 'readonly');
const req = tx.objectStore(IDB_STORE).get(key);
req.onsuccess = () => resolve(req.result ?? null);
req.onerror = () => reject(req.error);
});
}
async function idbSet(key, value) {
const db = await idbOpen();
return new Promise((resolve, reject) => {
const tx = db.transaction(IDB_STORE, 'readwrite');
const req = tx.objectStore(IDB_STORE).put(value, key);
req.onsuccess = () => resolve();
req.onerror = () => reject(req.error);
});
}
// --- Download and unzip db.zip ---
let loader; // set after factory creation
async function fetchZipWithProgress(url) {
loader.setStep('Downloading database…');
loader.setDetail('Starting download');
const resp = await fetch(url, { cache: 'force-cache' });
if (!resp.ok || !resp.body) throw new Error('Failed to fetch DB archive');
const total = parseInt(resp.headers.get('content-length') || '0', 10) || 0;
const reader = resp.body.getReader();
const chunks = [];
let received = 0;
loader.setProgress(0, total || undefined);
while (true) {
const { done, value } = await reader.read();
if (done) break;
chunks.push(value);
received += value.byteLength;
loader.setProgress(received, total || undefined);
if (total) loader.setDetail(`${((received / total) * 100).toFixed(1)}% • ${formatBytes(received)} / ${formatBytes(total)}`);
else loader.setDetail(`${formatBytes(received)} downloaded`);
}
const zipBytes = concatUint8(chunks, received);
return zipBytes;
}
function concatUint8(chunks, totalLen) {
const out = new Uint8Array(totalLen);
let offset = 0;
for (const c of chunks) {
out.set(c, offset);
offset += c.byteLength;
}
return out;
}
function formatBytes(bytes) {
const units = ['B', 'KB', 'MB', 'GB'];
let i = 0;
let val = bytes;
while (val >= 1024 && i < units.length - 1) {
val /= 1024;
i++;
}
return `${val.toFixed(i === 0 ? 0 : 1)} ${units[i]}`;
}
async function unzipSqlite(zipBytes) {
loader.setStep('Unpacking database…');
loader.setDetail('Decompressing ZIP');
const { unzipSync } = window.fflate || {};
if (!unzipSync) throw new Error('Unzip library not loaded');
const files = unzipSync(zipBytes);
const names = Object.keys(files);
if (!names.length) throw new Error('Empty ZIP archive');
let choice = names.find((n) => /\.sqlite$/i.test(n)) || names[0];
const dbBytes = files[choice];
loader.setDetail(`Unpacked ${choice}${formatBytes(dbBytes.byteLength)}`);
loader.setProgress(100, 100);
return dbBytes;
}
// --- SQL.js init ---
async function initSql() {
if (typeof initSqlJs !== 'function') throw new Error('sql.js not loaded');
loader.setStep('Initializing SQLite…');
loader.setDetail('Loading WASM');
const SQL = await initSqlJs({
locateFile: (file) => `https://cdnjs.cloudflare.com/ajax/libs/sql.js/1.10.2/${file}`,
});
return SQL;
}
// --- Templates & Views ---
function instantiateTemplate(id) {
const tpl = document.getElementById(id);
if (!tpl || !('content' in tpl)) throw new Error(`Missing template: ${id}`);
const frag = tpl.content.cloneNode(true);
const root = frag.firstElementChild;
return root;
}
function createLoaderView() {
const el = instantiateTemplate('tpl-loader');
const $step = el.querySelector('[data-ref="step"]');
const $detail = el.querySelector('[data-ref="detail"]');
const $progress = el.querySelector('[data-ref="progress"]');
return {
kind: 'base',
el,
setStep(text) { $step.textContent = text; },
setDetail(text) { $detail.textContent = text; },
setProgress(value, max) {
if (typeof max === 'number' && max > 0) {
$progress.max = max;
$progress.value = value;
const pct = Math.floor((value / max) * 100);
$progress.textContent = pct + '%';
} else {
$progress.removeAttribute('max');
$progress.value = 0;
$progress.textContent = '…';
}
},
destroy() {},
};
}
function createSearchView(db) {
const el = instantiateTemplate('tpl-search');
const $form = el.querySelector('[data-ref="form"]');
const $q = el.querySelector('[data-ref="q"]');
const $results = el.querySelector('[data-ref="results"]');
function renderStub(qVal) {
if (!qVal) {
$results.innerHTML = '<p class="has-text-grey">Type to search…</p>';
} else {
$results.innerHTML = `<p class="has-text-grey">Search stub — ready for query: <code>${escapeHtml(qVal)}</code></p>`;
}
}
function enable() {
$q.disabled = false;
$q.removeAttribute('aria-disabled');
$q.focus();
}
$form.addEventListener('submit', (e) => e.preventDefault());
$q.addEventListener('input', () => {
const q = $q.value.trim();
renderStub(q);
// Future: db.prepare / db.exec queries
});
renderStub('');
return {
kind: 'base',
el,
onShow() { enable(); },
destroy() {},
};
}
// --- Main bootstrap ---
loader = createLoaderView();
UX.replace(loader);
(async function main() {
try {
loader.setStep('Checking cache…');
loader.setDetail('Looking for cached database');
let dbBytes = await idbGet(IDB_KEY);
if (dbBytes) {
loader.setStep('Using cached database');
loader.setDetail(`Found ${formatBytes(dbBytes.byteLength)} in IndexedDB`);
loader.setProgress(100, 100);
} else {
const zipBytes = await fetchZipWithProgress(DB_ZIP_URL);
dbBytes = await unzipSqlite(zipBytes);
loader.setDetail('Caching database for future loads');
await idbSet(IDB_KEY, dbBytes);
}
const SQL = await initSql();
loader.setDetail('Opening database');
const db = new SQL.Database(dbBytes);
const search = createSearchView(db);
await UX.replace(search);
window.__db = db;
} catch (err) {
console.error(err);
try {
loader.setStep('Initialization failed');
loader.setDetail(String(err && err.message ? err.message : err));
const pb = loader.el.querySelector('[data-ref="progress"]');
if (pb) { pb.classList.remove('is-primary'); pb.classList.add('is-danger'); }
} catch (_) {}
}
})();
function escapeHtml(s) {
return s
.replace(/&/g, '&amp;')
.replace(/</g, '&lt;')
.replace(/>/g, '&gt;')
.replace(/\"/g, '&quot;')
.replace(/'/g, '&#039;');
}
})();