feat: queue offline Today-to-Week moves (Closes #1233)

frontend/today-week-reschedule.js

@@ -17,29 +17,47 @@ function createTodayWeekReschedule({
     return login ? storagePrefix + encodeURIComponent(login) : '';
   }
 
-  function persist(record) {
+  function validRecord(value) {
+    return typeof value?.body?.operation_id === 'string' &&
+      Array.isArray(value?.today?.ids) && Array.isArray(value?.week?.days);
+  }
+
+  function readQueue() {
+    const key = storageKey();
+    if (!key || !storage) return [];
+    try {
+      const value = JSON.parse(storage.getItem(key) || 'null');
+      if (Array.isArray(value?.records)) return value.records.filter(validRecord);
+      return validRecord(value) ? [value] : [];
+    } catch (_error) { return []; }
+  }
+
+  function saveQueue(records) {
     const key = storageKey();
     if (!key || !storage) return false;
-    try { storage.setItem(key, JSON.stringify(record)); return true; }
+    try {
+      if (!records.length) storage.removeItem(key);
+      else storage.setItem(key, JSON.stringify({version:2, records}));
+      return true;
+    }
     catch (_error) { return false; }
   }
 
+  function persist(record) { return saveQueue([...readQueue(), record]); }
+
   function pending() {
     const key = storageKey();
     if (!key || !storage) return null;
-    try {
-      const value = JSON.parse(storage.getItem(key) || 'null');
-      return typeof value?.body?.operation_id === 'string' &&
-        Array.isArray(value?.today?.ids) && Array.isArray(value?.week?.days) ? value : null;
-    } catch (_error) { return null; }
+    return readQueue()[0] || null;
   }
 
   function resume() {
-    const record = pending();
+    const records = readQueue();
+    const record = records[records.length - 1];
     if (!record) return null;
     adoptToday(record.today);
     week.adopt(record.week);
-    return {...record, sync_pending:true};
+    return {...record, sync_pending:true, pending_count:records.length};
   }
 
   async function restoreConflict(error) {
@@ -54,18 +72,29 @@ function createTodayWeekReschedule({
 
   function flush() {
     if (flushing) return flushing;
-    const record = pending();
-    if (!record) return Promise.resolve(false);
-    const key = storageKey();
-    flushing = api('api/v1/week/reschedule', {
-      method:'POST', headers:{'Content-Type':'application/json'}, body:JSON.stringify(record.body),
-    }).then(result => {
-      adoptToday(result.today);
-      week.adopt(result.week);
-      const latest = pending();
-      if (latest?.body?.operation_id === record.body.operation_id) storage.removeItem(key);
-      return {...result, sync_pending:false};
-    }).catch(restoreConflict).finally(() => { flushing = null; });
+    if (!pending()) return Promise.resolve(false);
+    flushing = (async () => {
+      let result = null;
+      while (true) {
+        const records = readQueue();
+        const record = records[0];
+        if (!record) return result ? {...result, sync_pending:false, pending_count:0} : false;
+        try {
+          result = await api('api/v1/week/reschedule', {
+            method:'POST', headers:{'Content-Type':'application/json'}, body:JSON.stringify(record.body),
+          });
+        } catch (error) { await restoreConflict(error); }
+        adoptToday(result.today);
+        week.adopt(result.week);
+        const latest = readQueue();
+        if (latest[0]?.body?.operation_id !== record.body.operation_id) continue;
+        const remaining = latest.slice(1).map((entry, index) => index ? entry : ({
+          ...entry,
+          body:{...entry.body, today_revision:result.today.revision, week_revision:result.week.revision},
+        }));
+        if (!saveQueue(remaining)) throw new Error('Move synced, but its local queue could not be updated.');
+      }
+    })().finally(() => { flushing = null; });
     return flushing;
   }
 
@@ -92,16 +121,22 @@ function createTodayWeekReschedule({
 
   async function open(identity) {
     let today;
-    let offline = false;
-    try { today = await api('api/v1/today'); }
-    catch (error) {
-      if (error?.status === 401 || error?.status === 403) throw error;
-      today = getToday?.(); offline = true;
+    const queued = readQueue().length;
+    let offline = Boolean(queued);
+    if (queued) {
+      today = getToday?.();
+    } else {
+      try { today = await api('api/v1/today'); }
+      catch (error) {
+        if (error?.status === 401 || error?.status === 403) throw error;
+        today = getToday?.(); offline = true;
+      }
     }
     if (!identity || !today?.ids?.includes(identity)) {
       throw new Error('The active Today item changed. Reopen rescheduling.');
     }
-    const loaded = await week.load();
+    const loaded = queued ? week.state?.() : await week.load();
+    if (!loaded) throw new Error('Reload Today before rescheduling another saved move.');
     if (loaded?.sync_pending) {
       throw new Error('Reconnect before rescheduling Today into Week Ahead.');
     }
@@ -168,11 +203,11 @@ function createTodayWeekReschedule({
     }
     if (current.offline) {
       current = null;
-      return {...optimistic, sync_pending:true};
+      return {...optimistic, sync_pending:true, pending_count:readQueue().length};
     }
     let result;
     try {
-      result = await api('api/v1/week/reschedule', {
+      result = admitted ? await flush() : await api('api/v1/week/reschedule', {
         method:'POST', headers:{'Content-Type':'application/json'}, body:JSON.stringify(body),
       });
     } catch(error) {
@@ -185,7 +220,6 @@ function createTodayWeekReschedule({
     }
     adoptToday(result.today);
     week.adopt(result.week);
-    if (admitted && pending()?.body?.operation_id === body.operation_id) storage.removeItem(storageKey());
     current = null;
     return result;
   }