From 9c9fb4f6e7b03cff5e654d27455f12a5ac857956 Mon Sep 17 00:00:00 2001
From: n0m1s <n0m1s@homnomnom.fr>
Date: Sat, 11 Jan 2020 23:40:18 +0100
Subject: [PATCH] NTP & RTC clock handling

---
 clock.cpp | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 clock.h   | 34 +++++++++++++++++++++
 lamp.ino  |  9 ++++--
 3 files changed, 130 insertions(+), 2 deletions(-)
 create mode 100644 clock.cpp
 create mode 100644 clock.h

diff --git a/clock.cpp b/clock.cpp
new file mode 100644
index 0000000..f80536e
--- /dev/null
+++ b/clock.cpp
@@ -0,0 +1,89 @@
+#include "clock.h"
+
+#include <ESP8266WiFi.h>
+#include <DS1307RTC.h>
+
+Clock::Clock(ClockSettings const& settings):
+    m_settings(settings),
+    m_last_NTP_check(0),
+    m_NTP_waiting_for_response(false),
+    m_UDP(),
+    m_NTP_ip()
+{
+    setSyncProvider(RTC.get);
+    m_UDP.begin(NTP_PORT);
+}
+
+void Clock::internet_update()
+{
+    ntp_update();
+}
+
+void Clock::ntp_update()
+{
+    bool need_to_ask = false;
+    if(timeStatus() != timeSet)
+        need_to_ask = !m_NTP_waiting_for_response;
+    else if(m_NTP_waiting_for_response)
+    {
+        //5 minutes timeout for the NTP response
+        if((now() - m_last_NTP_check) > 5*60)
+            m_NTP_waiting_for_response = false;
+    }
+    else
+        need_to_ask = (now() - m_last_NTP_check) > m_settings.cooldown();
+
+    if(need_to_ask) ntp_ask();
+    ntp_checkResponse();
+}
+
+void Clock::ntp_ask()
+{
+    if(!WiFi.hostByName(m_settings.server(), m_NTP_ip))
+    {
+        Serial.print("DNS lookup for \"");
+        Serial.print(m_settings.server());
+        Serial.println("\" failed");
+        return;
+    }
+
+    Serial.print("time server IP: \"");
+    Serial.print(m_NTP_ip);
+    Serial.println("\"");
+
+    Serial.println("Sending NTP request...");
+    //creating the NTP packet
+    memset(m_NTP_buffer, 0, NTP_BUFFER_SIZE);
+    m_NTP_buffer[0] = 0b11100011; //LI, version, mode
+    m_UDP.beginPacket(m_NTP_ip, NTP_PORT);
+    m_UDP.write(m_NTP_buffer, NTP_BUFFER_SIZE);
+    m_UDP.endPacket();
+
+    m_last_NTP_check = now();
+    m_NTP_waiting_for_response = true;
+}
+
+void Clock::ntp_checkResponse()
+{
+    //no packet available
+    if(m_UDP.parsePacket() == 0)
+        return;
+
+    m_NTP_waiting_for_response = false;
+
+    m_UDP.read(m_NTP_buffer, NTP_BUFFER_SIZE);
+
+    time_t NTP_time = (m_NTP_buffer[40] << 24) |
+                      (m_NTP_buffer[41] << 16) |
+                      (m_NTP_buffer[42] << 8)  |
+                      (m_NTP_buffer[43]);
+
+    time_t UNIX_time = NTP_time - 2208988800UL;
+
+    m_last_NTP_check = UNIX_time;
+    RTC.set(UNIX_time);
+    setTime(UNIX_time);
+
+    Serial.print("Time: ");
+    Serial.println(UNIX_time);
+}
diff --git a/clock.h b/clock.h
new file mode 100644
index 0000000..e4a08aa
--- /dev/null
+++ b/clock.h
@@ -0,0 +1,34 @@
+#ifndef CLOCK_H
+#define CLOCK_H
+
+#include <WiFiUdp.h>
+
+#include "clock_settings.h"
+
+unsigned int const NTP_BUFFER_SIZE = 48;
+unsigned int const NTP_PORT = 123;
+
+class Clock
+{
+    public:
+        Clock(ClockSettings const& settings);
+
+        void internet_update();
+
+    protected:
+        void ntp_update();
+        void ntp_ask();
+        void ntp_checkResponse();
+
+    protected:
+        ClockSettings const& m_settings;
+
+        time_t    m_last_NTP_check;
+        bool      m_NTP_waiting_for_response;
+
+        WiFiUDP   m_UDP;
+        IPAddress m_NTP_ip;
+        uint8_t   m_NTP_buffer[NTP_BUFFER_SIZE];
+};
+
+#endif //CLOCK_H
diff --git a/lamp.ino b/lamp.ino
index 1ca6994..ae5d21b 100644
--- a/lamp.ino
+++ b/lamp.ino
@@ -1,8 +1,10 @@
 #include "settings.h"
 #include "wifi.h"
+#include "clock.h"
 
 Settings const* settings = nullptr;
-Wifi  * wifi  = nullptr;
+Wifi  * wifi = nullptr;
+Clock * clk  = nullptr;
 
 bool ok = true;
 
@@ -21,11 +23,14 @@ void setup() {
     else
         Serial.println(" OK");
 
-    wifi  = new Wifi(settings->wifi);
+    wifi = new Wifi(settings->wifi);
+    clk  = new Clock(settings->clock);
 }
 
 void loop() {
     if(!ok) {delay(3600000); return;}
 
     wifi->keep_alive_connection();
+    if(wifi->is_connected())
+        clk->internet_update();
 }