Added functionality to align display refreshes

TRMNL.cpp

@@ -1,6 +1,8 @@
 #include "TRMNL.h"
 #include "helpers.h"
 
+#include <time.h>
+
 using std::list;
 using std::map;
 using std::optional;
@@ -11,11 +13,13 @@ using nlohmann::json;
 TRMNL::TRMNL(const string& id,
 	const string& api_key,
 	const string& friendly_id,
-	int refresh_rate)
+	int refresh_rate,
+	bool is_refresh_aligned)
 : m_id(id),
 m_api_key(api_key),
 m_friendly_id(friendly_id),
 m_refresh_rate(refresh_rate),
+m_is_refresh_aligned(is_refresh_aligned),
 m_update_handler()
 {}
 
@@ -52,6 +56,65 @@ int TRMNL::refresh_rate() const
 	return m_refresh_rate;
 }
 
+bool TRMNL::is_refresh_aligned() const
+{
+	return m_is_refresh_aligned;
+}
+
+int TRMNL::get_next_refresh(int min_time, int offset) const
+{
+	if (!m_is_refresh_aligned)
+	{
+		return m_refresh_rate;
+	}
+
+	if (min_time > m_refresh_rate)
+	{
+		min_time = m_refresh_rate;
+	}
+
+	int result = 0;
+	time_t curr = time(nullptr);
+	struct tm* now = localtime(&curr);
+
+	int tmp_refresh = m_refresh_rate;
+	bool align_minutes = false;
+	bool align_hours = false;
+
+	if (0 == m_refresh_rate % 60)
+	{
+		align_minutes = true;
+		tmp_refresh /= 60;
+
+		if (0 == tmp_refresh % 60)
+		{
+			align_hours = true;
+			tmp_refresh /= 60;
+		}
+	}
+
+	if (align_minutes)
+	{
+		now->tm_sec = 0;
+		now->tm_min += 1;
+	}
+
+	if (align_hours)
+	{
+		now->tm_min = 0;
+		now->tm_hour += 1;
+	}
+
+	time_t next = mktime(now);
+	result = next - curr + offset;
+	while (result < min_time)
+	{
+		result += m_refresh_rate;
+	}
+
+	return result;
+}
+
 void TRMNL::id(const std::string& id)
 {
 	m_id = id;
@@ -88,6 +151,15 @@ void TRMNL::refresh_rate(int refresh_rate)
 	}
 }
 
+void TRMNL::is_refresh_aligned(bool to_align)
+{
+	m_is_refresh_aligned = to_align;
+	if (m_update_handler)
+	{
+		m_update_handler(*this);
+	}
+}
+
 void TRMNL::set_update_handler(std::function<void (const TRMNL& trmnl)> handler)
 {
 	m_update_handler = handler;