Added backlog replay threshold, currently one day

firmware/inc/backlog.h

@@ -45,6 +45,10 @@
  * Address offset in memory
  */
 #define BACKLOG_ADDRESS 0
+/**
+ * Defines the number of backlogs that should be valid before we start replaying
+ */
+#define BACKLOG_REPLAY_THRESHOLD	24    /* One day */
 
 void record_backlog(tracker_datapoint* dp);
 struct tracker_datapoint* get_backlog(void);

firmware/src/backlog.c

@@ -226,6 +226,23 @@ struct tracker_datapoint* read_check_backlog_item(uint16_t index)
 
   return (struct tracker_datapoint*)buffer;
 }
+/**
+ * Returns the number of backlogs indicated as valid in is_backlog_valid.
+ *
+ * Should correspond with the actual number of valid backlogs
+ */
+uint16_t is_backlog_valid_count(void)
+{
+  uint16_t i, count = 0;
+
+  for (i = 0; i < BACKLOG_COUNT; i++) {
+    if (is_backlog_valid[i] == BACKLOG_VALID_FLAG) {
+      count++;
+    }
+  }
+
+  return count;
+}
 /**
  * Gets a valid backlog item. Returns NULL if none available.
  */
@@ -238,6 +255,11 @@ struct tracker_datapoint* get_backlog(void)
     load_is_backlog_valid();
   }
 
+  /* Return early if we haven't reached our replay threshold */
+  if (is_backlog_valid_count() < BACKLOG_REPLAY_THRESHOLD) {
+    return NULL;
+  }
+
   for (i = 0; i < BACKLOG_COUNT; i++) {
 
     /* Find an read index we think is valid */