From b557d9f0dfbdb3fb9a4d3d6e6ad28f34ac50935e Mon Sep 17 00:00:00 2001
From: Chad <chad@localhost>
Date: Mon, 20 Apr 2026 13:47:56 -0500
Subject: [PATCH] Fix countdown timer overflow using modulo arithmetic

---
 src/main.cpp | 58 +++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 39 insertions(+), 19 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 4ad53b0..5a94399 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1178,8 +1178,13 @@ indexY += 65;
   }
   lcd.drawString("WiFi: " + wifiStatus, 20, SCREEN_HEIGHT - 20);
 
-  int secondsLeft = (REFRESH_INTERVAL - (millis() - lastRefresh)) / 1000;
-  if (secondsLeft < 0) secondsLeft = 0;
+  unsigned long elapsed = millis() - lastRefresh;
+  int secondsLeft;
+  if (lastRefresh == 0) {
+    secondsLeft = 0;
+  } else {
+    secondsLeft = (REFRESH_INTERVAL - (elapsed % REFRESH_INTERVAL)) / 1000;
+  }
   int mins = secondsLeft / 60;
   int secs = secondsLeft % 60;
   char timeStr[8];
@@ -1862,8 +1867,13 @@ void drawHardMoneyDetailScreen() {
   lcd.drawString("WiFi: " + wifiStatus, 20, SCREEN_HEIGHT - 20);
 
   lcd.setTextDatum(textdatum_t::middle_center);
-  int secondsLeft = (REFRESH_INTERVAL - (millis() - lastRefresh)) / 1000;
-  if (secondsLeft < 0) secondsLeft = 0;
+  unsigned long elapsed = millis() - lastRefresh;
+  int secondsLeft;
+  if (lastRefresh == 0) {
+    secondsLeft = 0;
+  } else {
+    secondsLeft = (REFRESH_INTERVAL - (elapsed % REFRESH_INTERVAL)) / 1000;
+  }
   int mins = secondsLeft / 60;
   int secs = secondsLeft % 60;
   char timeStr[8];
@@ -2064,13 +2074,18 @@ void setup() {
 }
 
 void drawFooterCountdown() {
-  int secondsLeft = (REFRESH_INTERVAL - (millis() - lastRefresh)) / 1000;
-  if (secondsLeft < 0) secondsLeft = 0;
+  unsigned long elapsed = millis() - lastRefresh;
+  int secondsLeft;
+  if (lastRefresh == 0) {
+    secondsLeft = 0;
+  } else {
+    secondsLeft = (REFRESH_INTERVAL - (elapsed % REFRESH_INTERVAL)) / 1000;
+  }
   int mins = secondsLeft / 60;
   int secs = secondsLeft % 60;
   char timeStr[8];
   sprintf(timeStr, "%d:%02d", mins, secs);
-  
+
   lcd.setFont(&fonts::DejaVu18);
   lcd.setTextColor(TFT_WHITE, TFT_ORANGE);
   lcd.setTextDatum(textdatum_t::middle_center);
@@ -2142,18 +2157,23 @@ if (currentScreen == SCREEN_DASHBOARD && millis() - lastCountdownUpdate >= 1000)
   drawFooterCountdown();
 }
 if (currentScreen == SCREEN_HARD_MONEY_DETAIL && millis() - lastCountdownUpdate >= 1000) {
-  lastCountdownUpdate = millis();
-  lcd.setFont(&fonts::DejaVu18);
-  lcd.setTextColor(TFT_WHITE, TFT_ORANGE);
-  lcd.setTextDatum(textdatum_t::middle_center);
-  int secondsLeft = (REFRESH_INTERVAL - (millis() - lastRefresh)) / 1000;
-  if (secondsLeft < 0) secondsLeft = 0;
-  int mins = secondsLeft / 60;
-  int secs = secondsLeft % 60;
-  char timeStr[8];
-  sprintf(timeStr, "%d:%02d", mins, secs);
-  lcd.drawString(String(timeStr), SCREEN_WIDTH / 2, SCREEN_HEIGHT - 20);
-}
+    lastCountdownUpdate = millis();
+    lcd.setFont(&fonts::DejaVu18);
+    lcd.setTextColor(TFT_WHITE, TFT_ORANGE);
+    lcd.setTextDatum(textdatum_t::middle_center);
+    unsigned long elapsed = millis() - lastRefresh;
+    int secondsLeft;
+    if (lastRefresh == 0) {
+      secondsLeft = 0;
+    } else {
+      secondsLeft = (REFRESH_INTERVAL - (elapsed % REFRESH_INTERVAL)) / 1000;
+    }
+    int mins = secondsLeft / 60;
+    int secs = secondsLeft % 60;
+    char timeStr[8];
+    sprintf(timeStr, "%d:%02d", mins, secs);
+    lcd.drawString(String(timeStr), SCREEN_WIDTH / 2, SCREEN_HEIGHT - 20);
+  }
 
   if (currentScreen == SCREEN_HARD_MONEY_DETAIL) {
     if (hmNeedsRefresh || !btcHmLoaded || !goldHmLoaded || !silverHmLoaded) {