From b659d26ad1846fb2c63ae5564792ad68346b86d7 Mon Sep 17 00:00:00 2001
From: Dione <dione@localhost>
Date: Wed, 10 Jun 2026 19:17:32 +0000
Subject: [PATCH] fix: Date.UTC spread operator and EMA for rolling sats chart

---
 index.html | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/index.html b/index.html
index dc92f78..b4e790b 100644
--- a/index.html
+++ b/index.html
@@ -1571,24 +1571,24 @@ function setupCumulCard(cutoff) {
 
 function setupSatsCard(cutoff) {
     const DAY_MS = 86400000;
-    /* Derive daily balances (latest snapshot per day) */
+    /* Derive daily balances (latest snapshot per day) using UTC date strings */
     const dailyBalances = {};
     const selectedAddr = getSelectedAddresses() || [];
     selectedAddr.forEach(addr => {
         const snaps = addressSnapshots[addr] || [];
         snaps.forEach(snap => {
-            const dateStr = snap.block_timestamp.slice(0, 10);
+            const utcTs = new Date(snap.block_timestamp).getTime();
+            const dateStr = new Date(utcTs).toISOString().slice(0, 10);
             const btcVal = getTokenAmount(snap?.wallet?.cbBTC, 'cbBTC') + getTokenAmount(snap?.collateral?.cbBTC, 'cbBTC');
-            const ts = new Date(snap.block_timestamp).getTime();
-            if (!dailyBalances[dateStr] || ts > dailyBalances[dateStr].ts) {
-                dailyBalances[dateStr] = { ts, dateStr, btcVal };
+            if (!dailyBalances[dateStr] || utcTs > dailyBalances[dateStr].ts) {
+                dailyBalances[dateStr] = { ts: utcTs, dateStr, btcVal };
             } else {
                 dailyBalances[dateStr].btcVal += btcVal;
             }
         });
     });
 
-    /* Sort by date, compute daily delta (acquisition), then fill continuous timeline */
+    /* Sort by date, compute daily delta (acquisition) */
     const sortedDays = Object.values(dailyBalances).sort((a, b) => a.dateStr.localeCompare(b.dateStr));
     const dailyDeltas = {};
     sortedDays.forEach((d, i) => {
@@ -1596,29 +1596,31 @@ function setupSatsCard(cutoff) {
         dailyDeltas[d.dateStr] = d.btcVal - prevBalance;
     });
 
-    /* Fill continuous daily timeline so no days are skipped */
-    const firstDate = new Date(sortedDays[0].dateStr).getTime();
-    const lastDate = new Date(sortedDays[sortedDays.length - 1].dateStr).getTime();
+    /* Fill continuous daily timeline — iterate every day from first to last */
+    const firstUTC = Date.UTC(new Date(sortedDays[0].dateStr).getUTCFullYear(), new Date(sortedDays[0].dateStr).getUTCMonth(), new Date(sortedDays[0].dateStr).getUTCDate());
+    const lastUTC = Date.UTC(new Date(sortedDays[sortedDays.length - 1].dateStr).getUTCFullYear(), new Date(sortedDays[sortedDays.length - 1].dateStr).getUTCMonth(), new Date(sortedDays[sortedDays.length - 1].dateStr).getUTCDate());
     const continuousDays = [];
-    for (let t = firstDate; t <= lastDate; t += DAY_MS) {
+    for (let t = firstUTC; t <= lastUTC; t += DAY_MS) {
         const ds = new Date(t).toISOString().slice(0, 10);
         continuousDays.push({ ts: t, dateStr: ds, delta: dailyDeltas[ds] || 0 });
     }
 
-    /* 30-day rolling average of daily deltas */
+    /* Exponentially weighted moving average — older days decay so average drops when there are no acquisitions */
     const filtered = continuousDays.filter(d => d.ts >= cutoff);
-    const rollingAvg = [];
+    const halfLife = 7;
+    const decay = Math.pow(0.5, 1 / halfLife);
+    let ewmaVal = filtered[0]?.delta || 0;
+    const emaSats = [];
     for (let i = 0; i < filtered.length; i++) {
-        const window = filtered.slice(Math.max(0, i - 29), i + 1);
-        const avgSats = Math.round(window.reduce((s, d) => s + d.delta, 0) / window.length * 1e8);
-        rollingAvg.push([filtered[i].ts, avgSats]);
+        ewmaVal = filtered[i].delta + decay * ewmaVal;
+        emaSats.push([filtered[i].ts, Math.round(ewmaVal * 1e8)]);
     }
 
-    const latestAvg = rollingAvg.length > 0 ? rollingAvg[rollingAvg.length - 1][1] : 0;
+    const latestAvg = emaSats.length > 0 ? emaSats[emaSats.length - 1][1] : 0;
     document.getElementById('avg-sats-val').innerText = new Intl.NumberFormat('en-US').format(Math.round(latestAvg));
     const options = {
         chart: { id: 'instance-sats', type: 'area', height: 200, background: 'transparent', toolbar: { show: false }, sparkline: { enabled: false }, zoom: { enabled: true, type: 'x', autoScaleYaxis: true }, animations: { enabled: false } },
-        series: [{ name: 'Avg Sats/Day', data: rollingAvg }],
+        series: [{ name: 'Avg Sats/Day', data: emaSats }],
         dataLabels: { enabled: false },
         colors: [orangeBrandColor],
         stroke: { curve: 'smooth', width: 2 },