From 79b54b3a7554024d29047fe71cb46bfb2cf60a4a Mon Sep 17 00:00:00 2001
From: jpirnay <jens@pirnay.com>
Date: Thu, 12 Mar 2026 00:37:13 +0100
Subject: [PATCH] fix: Init lastSleepImage (edge case) (#1360)
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## Summary

* **What is the goal of this PR?** fix edge case for definition

## Additional Context

If loadFromFile() returns false (no state file exists — first boot, or
SD missing), lastSleepImage is never set and contains garbage.
[SleepActivity.cpp:83] then uses it in a while comparison to avoid
repeating the same image. The JSON path (doc["lastSleepImage"] |
(uint8_t)0) handles it, but only if the file exists.

---

### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? _** NO **_
---
 src/CrossPointState.cpp                     | 2 +-
 src/CrossPointState.h                       | 3 ++-
 src/JsonSettingsIO.cpp                      | 2 +-
 src/activities/boot_sleep/SleepActivity.cpp | 2 +-
 4 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/CrossPointState.cpp b/src/CrossPointState.cpp
index 232860cd..af8bdda5 100644
--- a/src/CrossPointState.cpp
+++ b/src/CrossPointState.cpp
@@ -63,7 +63,7 @@ bool CrossPointState::loadFromBinaryFile() {
   if (version >= 2) {
     serialization::readPod(inputFile, lastSleepImage);
   } else {
-    lastSleepImage = 0;
+    lastSleepImage = UINT8_MAX;
   }
 
   if (version >= 3) {
diff --git a/src/CrossPointState.h b/src/CrossPointState.h
index 35a9a871..1de89838 100644
--- a/src/CrossPointState.h
+++ b/src/CrossPointState.h
@@ -1,4 +1,5 @@
 #pragma once
+#include <cstdint>
 #include <iosfwd>
 #include <string>
 
@@ -8,7 +9,7 @@ class CrossPointState {
 
  public:
   std::string openEpubPath;
-  uint8_t lastSleepImage;
+  uint8_t lastSleepImage = UINT8_MAX;  // UINT8_MAX = unset sentinel
   uint8_t readerActivityLoadCount = 0;
   bool lastSleepFromReader = false;
   ~CrossPointState() = default;
diff --git a/src/JsonSettingsIO.cpp b/src/JsonSettingsIO.cpp
index 4a563142..a0458043 100644
--- a/src/JsonSettingsIO.cpp
+++ b/src/JsonSettingsIO.cpp
@@ -87,7 +87,7 @@ bool JsonSettingsIO::loadState(CrossPointState& s, const char* json) {
   }
 
   s.openEpubPath = doc["openEpubPath"] | std::string("");
-  s.lastSleepImage = doc["lastSleepImage"] | (uint8_t)0;
+  s.lastSleepImage = doc["lastSleepImage"] | (uint8_t)UINT8_MAX;
   s.readerActivityLoadCount = doc["readerActivityLoadCount"] | (uint8_t)0;
   s.lastSleepFromReader = doc["lastSleepFromReader"] | false;
   return true;
diff --git a/src/activities/boot_sleep/SleepActivity.cpp b/src/activities/boot_sleep/SleepActivity.cpp
index 0b2c1825..d6a566df 100644
--- a/src/activities/boot_sleep/SleepActivity.cpp
+++ b/src/activities/boot_sleep/SleepActivity.cpp
@@ -80,7 +80,7 @@ void SleepActivity::renderCustomSleepScreen() const {
       // Generate a random number between 1 and numFiles
       auto randomFileIndex = random(numFiles);
       // If we picked the same image as last time, reroll
-      while (numFiles > 1 && randomFileIndex == APP_STATE.lastSleepImage) {
+      while (numFiles > 1 && APP_STATE.lastSleepImage != UINT8_MAX && randomFileIndex == APP_STATE.lastSleepImage) {
         randomFileIndex = random(numFiles);
       }
       APP_STATE.lastSleepImage = randomFileIndex;