Cache every played or saved video on the server via background jobs with a validation gate and a Broken re-download button

server/db.js

@@ -9,6 +9,7 @@
  *   users         — one row per fingerprint; tracks last app version seen
  *   playlists     — one row per fingerprint; full playlist JSON blob
  *   video_history — one row per (fingerprint, video_id); recent 200 entries
+ *   media_cache   — one row per server-cached video file (see media-cache.js)
  * ========================================================================== */
 
 import { createClient } from '@libsql/client';
@@ -81,9 +82,110 @@ export async function initDb() {
 
     CREATE INDEX IF NOT EXISTS idx_inbox_to
       ON playlist_inbox (to_name, created_at DESC);
+
+    -- Server-side media cache: one validated mp4 per video under MEDIA_DIR.
+    -- The file on disk is <video_id>.<gen>.mp4 (+ .m4a audio sidecar); gen
+    -- bumps on every replacement so a URL carrying ?g= always maps to the
+    -- same bytes. Timestamps here are ms epochs (backoff math needs ms).
+    CREATE TABLE IF NOT EXISTS media_cache (
+      video_id    TEXT    PRIMARY KEY,
+      status      TEXT    NOT NULL DEFAULT 'queued', -- queued|downloading|validating|ready|failed
+      gen         INTEGER NOT NULL DEFAULT 0,
+      size        INTEGER NOT NULL DEFAULT 0,        -- mp4 + m4a bytes
+      height      INTEGER NOT NULL DEFAULT 0,
+      vcodec      TEXT,
+      acodec      TEXT,
+      duration    REAL    NOT NULL DEFAULT 0,
+      optimized   INTEGER NOT NULL DEFAULT 0,
+      meta        TEXT    NOT NULL DEFAULT '{}',
+      priority    INTEGER NOT NULL DEFAULT 1,
+      auto        INTEGER NOT NULL DEFAULT 0,
+      attempts    INTEGER NOT NULL DEFAULT 0,
+      error       TEXT,
+      retry_at    INTEGER NOT NULL DEFAULT 0,
+      created_at  INTEGER NOT NULL DEFAULT 0,
+      updated_at  INTEGER NOT NULL DEFAULT 0,
+      last_access INTEGER NOT NULL DEFAULT 0,
+      hits        INTEGER NOT NULL DEFAULT 0
+    );
+
+    CREATE INDEX IF NOT EXISTS idx_media_lru
+      ON media_cache (status, last_access);
   `);
 }
 
+// ---- Media cache -------------------------------------------------------------
+
+const MEDIA_COLS = new Set([
+  'status', 'gen', 'size', 'height', 'vcodec', 'acodec', 'duration', 'optimized',
+  'meta', 'priority', 'auto', 'attempts', 'error', 'retry_at', 'created_at',
+  'updated_at', 'last_access', 'hits',
+]);
+
+function rowToObj(res, row) {
+  const o = {};
+  res.columns.forEach((c, i) => { o[c] = row[i]; });
+  return o;
+}
+
+export async function getMedia(videoId) {
+  const r = await db.execute({ sql: 'SELECT * FROM media_cache WHERE video_id = ?', args: [videoId] });
+  return r.rows[0] ? rowToObj(r, r.rows[0]) : null;
+}
+
+// Insert or partially update a media row. Unknown keys are ignored.
+export async function upsertMedia(videoId, fields) {
+  const cols = Object.keys(fields).filter((k) => MEDIA_COLS.has(k));
+  const all = ['video_id', ...cols];
+  const set = cols.length ? 'DO UPDATE SET ' + cols.map((c) => `${c} = excluded.${c}`).join(', ') : 'DO NOTHING';
+  await db.execute({
+    sql: `INSERT INTO media_cache (${all.join(', ')}) VALUES (${all.map(() => '?').join(', ')})
+          ON CONFLICT(video_id) ${set}`,
+    args: [videoId, ...cols.map((c) => fields[c] ?? null)],
+  });
+}
+
+export async function deleteMedia(videoId) {
+  await db.execute({ sql: 'DELETE FROM media_cache WHERE video_id = ?', args: [videoId] });
+}
+
+export async function listMedia() {
+  const r = await db.execute('SELECT * FROM media_cache');
+  return r.rows.map((row) => rowToObj(r, row));
+}
+
+// Ready rows, least-recently-played first — the eviction order.
+export async function listMediaLru() {
+  const r = await db.execute(
+    "SELECT video_id, size, last_access FROM media_cache WHERE status = 'ready' ORDER BY last_access ASC",
+  );
+  return r.rows.map((row) => rowToObj(r, row));
+}
+
+export async function touchMedia(videoId, now) {
+  await db.execute({
+    sql: 'UPDATE media_cache SET last_access = ?, hits = hits + 1 WHERE video_id = ?',
+    args: [now, videoId],
+  });
+}
+
+export async function mediaStats() {
+  const r = await db.execute(
+    `SELECT
+       SUM(CASE WHEN status = 'ready' THEN 1 ELSE 0 END)    AS count,
+       SUM(CASE WHEN status = 'ready' THEN size ELSE 0 END) AS bytes,
+       SUM(CASE WHEN status IN ('queued','downloading','validating') THEN 1 ELSE 0 END) AS pending,
+       SUM(CASE WHEN status = 'failed' THEN 1 ELSE 0 END)   AS failed,
+       SUM(CASE WHEN status = 'ready' AND optimized = 1 THEN 1 ELSE 0 END) AS optimized
+     FROM media_cache`,
+  );
+  const o = r.rows[0] ? rowToObj(r, r.rows[0]) : {};
+  return {
+    count: o.count || 0, bytes: o.bytes || 0, pending: o.pending || 0,
+    failed: o.failed || 0, optimized: o.optimized || 0,
+  };
+}
+
 // ---- Profiles (named cross-device sync; the name acts as the passkey) ------
 
 // Insert a new profile. Returns false when the name is already taken.