added internet time which is shown in the main first screen

.gitignore

@@ -3,3 +3,4 @@
 .vscode/c_cpp_properties.json
 .vscode/launch.json
 .vscode/ipch
+include/wifi_credentials.h

include/internet_time.h

@@ -0,0 +1,36 @@
+#ifndef INTERNET_TIME_H
+#define INTERNET_TIME_H
+
+#include <Arduino.h>
+
+struct InternetTimeInfo
+{
+  bool valid;
+  uint16_t year;
+  uint8_t month;
+  uint8_t day;
+  uint8_t hour;
+  uint8_t minute;
+};
+
+class InternetTime
+{
+public:
+  InternetTime();
+  void update(unsigned long now, bool wifiConnected);
+  InternetTimeInfo info() const;
+  bool consumeDirty();
+
+private:
+  void fetch(unsigned long now);
+  void updateCurrentTime(unsigned long now);
+  InternetTimeInfo infoFromEpoch(unsigned long epoch) const;
+
+  unsigned long lastEpoch_;
+  unsigned long lastSyncMillis_;
+  unsigned long nextAttempt_;
+  InternetTimeInfo current_;
+  bool dirty_;
+};
+
+#endif

include/menu.h

@@ -6,6 +6,7 @@
 
 enum class MenuAction
 {
+  ShowInternetDetails,
   ShowHelloWorld,
   BackToCarousel
 };

include/screens.h

@@ -4,9 +4,13 @@
 #include <U8g2lib.h>
 
 #include "am2302_sensor.h"
+#include "internet_time.h"
+#include "wifi_connection.h"
 
-void drawScreen1(U8G2 &u8g2);
+void setInternetTimeInfo(InternetTimeInfo timeInfo);
+void drawTimeScreen(U8G2 &u8g2);
 void drawHelloWorldScreen(U8G2 &u8g2);
+void drawInternetConnectionScreen(U8G2 &u8g2, WifiConnectionInfo wifiInfo);
 void setEnvironmentReading(Am2302Reading reading);
 void drawEnvironmentScreen(U8G2 &u8g2);
 void drawWeatherIconScreen(U8G2 &u8g2);

include/wifi_connection.h

@@ -0,0 +1,34 @@
+#ifndef WIFI_CONNECTION_H
+#define WIFI_CONNECTION_H
+
+#include <Arduino.h>
+#include <IPAddress.h>
+
+struct WifiConnectionInfo
+{
+  bool shieldAvailable;
+  bool connected;
+  IPAddress ipAddress;
+};
+
+class WifiConnection
+{
+public:
+  WifiConnection();
+  void begin(unsigned long now);
+  void update(unsigned long now);
+  WifiConnectionInfo info() const;
+  bool consumeDirty();
+
+private:
+  void connect(unsigned long now);
+  void recordStatus();
+
+  unsigned long nextAttempt_;
+  bool shieldAvailable_;
+  bool connected_;
+  IPAddress ipAddress_;
+  bool dirty_;
+};
+
+#endif

include/wifi_credentials.example.h

@@ -0,0 +1,10 @@
+#ifndef WIFI_CREDENTIALS_H
+#define WIFI_CREDENTIALS_H
+
+const char WIFI_SSID[] = "your-wifi-name";
+const char WIFI_PASSWORD[] = "your-wifi-password";
+
+// Offset from UTC in seconds. Examples: Finland winter 7200, Finland summer 10800.
+#define TIME_UTC_OFFSET_SECONDS 0
+
+#endif

src/internet_time.cpp

@@ -0,0 +1,142 @@
+#include "internet_time.h"
+
+#include <WiFi101.h>
+
+#include "wifi_credentials.h"
+
+#ifndef TIME_UTC_OFFSET_SECONDS
+#define TIME_UTC_OFFSET_SECONDS 0
+#endif
+
+namespace
+{
+const unsigned long retryInterval = 15000;
+const unsigned long refreshInterval = 3600000;
+const unsigned long secondsPerDay = 86400;
+
+bool isLeapYear(uint16_t year)
+{
+  return (year % 4 == 0 && year % 100 != 0) || year % 400 == 0;
+}
+
+uint8_t daysInMonth(uint16_t year, uint8_t month)
+{
+  const uint8_t days[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+  if (month == 2 && isLeapYear(year)) {
+    return 29;
+  }
+  return days[month - 1];
+}
+
+unsigned long applyTimeOffset(unsigned long epoch)
+{
+  if (TIME_UTC_OFFSET_SECONDS >= 0) {
+    return epoch + TIME_UTC_OFFSET_SECONDS;
+  }
+
+  const unsigned long offset = static_cast<unsigned long>(-TIME_UTC_OFFSET_SECONDS);
+  return epoch > offset ? epoch - offset : 0;
+}
+}
+
+InternetTime::InternetTime()
+    : lastEpoch_(0),
+      lastSyncMillis_(0),
+      nextAttempt_(0),
+      current_({false, 0, 0, 0, 0, 0}),
+      dirty_(true) {}
+
+void InternetTime::update(unsigned long now, bool wifiConnected)
+{
+  if (current_.valid) {
+    updateCurrentTime(now);
+  }
+
+  if (!wifiConnected) {
+    return;
+  }
+
+  if (now >= nextAttempt_) {
+    fetch(now);
+  }
+}
+
+InternetTimeInfo InternetTime::info() const
+{
+  return current_;
+}
+
+bool InternetTime::consumeDirty()
+{
+  const bool d = dirty_;
+  dirty_ = false;
+  return d;
+}
+
+void InternetTime::fetch(unsigned long now)
+{
+  const unsigned long epoch = WiFi.getTime();
+  nextAttempt_ = now + retryInterval;
+
+  if (epoch == 0) {
+    return;
+  }
+
+  lastEpoch_ = epoch;
+  lastSyncMillis_ = now;
+  nextAttempt_ = now + refreshInterval;
+  updateCurrentTime(now);
+}
+
+void InternetTime::updateCurrentTime(unsigned long now)
+{
+  const unsigned long elapsedSeconds = (now - lastSyncMillis_) / 1000;
+  const InternetTimeInfo updated = infoFromEpoch(lastEpoch_ + elapsedSeconds);
+
+  if (!current_.valid ||
+      current_.year != updated.year ||
+      current_.month != updated.month ||
+      current_.day != updated.day ||
+      current_.hour != updated.hour ||
+      current_.minute != updated.minute) {
+    current_ = updated;
+    dirty_ = true;
+  }
+}
+
+InternetTimeInfo InternetTime::infoFromEpoch(unsigned long epoch) const
+{
+  unsigned long adjustedEpoch = applyTimeOffset(epoch);
+  unsigned long days = adjustedEpoch / secondsPerDay;
+  unsigned long secondsToday = adjustedEpoch % secondsPerDay;
+
+  uint16_t year = 1970;
+  while (true) {
+    const uint16_t yearDays = isLeapYear(year) ? 366 : 365;
+    if (days < yearDays) {
+      break;
+    }
+    days -= yearDays;
+    year++;
+  }
+
+  uint8_t month = 1;
+  while (true) {
+    const uint8_t monthDays = daysInMonth(year, month);
+    if (days < monthDays) {
+      break;
+    }
+    days -= monthDays;
+    month++;
+  }
+
+  InternetTimeInfo info = {
+    true,
+    year,
+    month,
+    static_cast<uint8_t>(days + 1),
+    static_cast<uint8_t>(secondsToday / 3600),
+    static_cast<uint8_t>((secondsToday % 3600) / 60)
+  };
+  return info;
+}

src/main.cpp

@@ -4,8 +4,10 @@
 
 #include "am2302_sensor.h"
 #include "carousel.h"
+#include "internet_time.h"
 #include "menu.h"
 #include "screens.h"
+#include "wifi_connection.h"
 
 U8G2_SH1106_128X64_NONAME_F_HW_I2C u8g2(U8G2_R2, U8X8_PIN_NONE);
 
@@ -14,16 +16,19 @@ int lastButtonSelectState = LOW;
 uint8_t buttonNext = A4;
 uint8_t buttonSelect = A5;
 Am2302Sensor am2302(A3);
+WifiConnection wifiConnection;
+InternetTime internetTime;
 
 enum class AppMode
 {
   Carousel,
   Menu,
+  InternetDetails,
   HelloWorld
 };
 
 Screen screens[] = {
-  { drawScreen1 },
+  { drawTimeScreen },
   { drawEnvironmentScreen },
   { drawWeatherIconScreen }
 };
@@ -36,6 +41,7 @@ void setup() {
   pinMode(buttonNext, INPUT);
   pinMode(buttonSelect, INPUT);
   am2302.begin();
+  wifiConnection.begin(millis());
 
   u8g2.begin();
   u8g2.clearBuffer();
@@ -52,6 +58,9 @@ void openMenu()
 void selectMenuOption()
 {
   switch (menu.select()) {
+    case MenuAction::ShowInternetDetails:
+      appMode = AppMode::InternetDetails;
+      break;
     case MenuAction::ShowHelloWorld:
       appMode = AppMode::HelloWorld;
       break;
@@ -73,6 +82,7 @@ void handleNextButton()
     case AppMode::Menu:
       menu.nextOption();
       break;
+    case AppMode::InternetDetails:
     case AppMode::HelloWorld:
       break;
   }
@@ -82,6 +92,7 @@ void handleSelectButton()
 {
   switch (appMode) {
     case AppMode::Carousel:
+    case AppMode::InternetDetails:
     case AppMode::HelloWorld:
       openMenu();
       break;
@@ -103,6 +114,8 @@ bool displayNeedsRedraw()
       return carousel.consumeDirty();
     case AppMode::Menu:
       return menu.consumeDirty();
+    case AppMode::InternetDetails:
+      return wifiConnection.consumeDirty();
     case AppMode::HelloWorld:
       return false;
   }
@@ -119,6 +132,9 @@ void drawActiveView()
     case AppMode::Menu:
       menu.draw(u8g2);
       break;
+    case AppMode::InternetDetails:
+      drawInternetConnectionScreen(u8g2, wifiConnection.info());
+      break;
     case AppMode::HelloWorld:
       drawHelloWorldScreen(u8g2);
       break;
@@ -127,6 +143,16 @@ void drawActiveView()
 
 void loop(){
   const unsigned long now = millis();
+  wifiConnection.update(now);
+  internetTime.update(now, wifiConnection.info().connected);
+
+  if (internetTime.consumeDirty()) {
+    setInternetTimeInfo(internetTime.info());
+    if (appMode == AppMode::Carousel) {
+      carousel.requestRedraw();
+    }
+  }
+
   if (appMode == AppMode::Carousel) {
     carousel.update(now);
   }

src/menu.cpp

@@ -3,6 +3,7 @@
 namespace
 {
 const char *menuOptions[] = {
+  "Internet",
   "Hello world",
   "Back"
 };
@@ -13,6 +14,8 @@ MenuAction actionForIndex(size_t index)
 {
   switch (index) {
     case 0:
+      return MenuAction::ShowInternetDetails;
+    case 1:
       return MenuAction::ShowHelloWorld;
     default:
       return MenuAction::BackToCarousel;
@@ -30,7 +33,7 @@ void Menu::draw(U8G2 &u8g2)
   u8g2.drawStr(0, 12, "Menu");
 
   for (size_t i = 0; i < menuOptionCount; i++) {
-    const uint8_t y = 32 + (i * 18);
+    const uint8_t y = 28 + (i * 14);
     if (i == selectedIndex_) {
       u8g2.drawStr(0, y, ">");
     }

src/screens.cpp

@@ -3,6 +3,15 @@
 namespace
 {
 Am2302Reading environmentReading = {0.0F, 0.0F, false};
+InternetTimeInfo internetTimeInfo = {false, 0, 0, 0, 0, 0};
+
+void printTwoDigits(U8G2 &u8g2, uint8_t value)
+{
+  if (value < 10) {
+    u8g2.print("0");
+  }
+  u8g2.print(value);
+}
 
 void drawSun(U8G2 &u8g2, uint8_t x, uint8_t y)
 {
@@ -27,10 +36,33 @@ void drawCloud(U8G2 &u8g2, uint8_t x, uint8_t y)
 }
 }
 
-void drawScreen1(U8G2 &u8g2)
+void setInternetTimeInfo(InternetTimeInfo timeInfo)
 {
-  u8g2.setFont(u8g2_font_ncenB14_tr);
-  u8g2.drawStr(0, 20, "Screen 1");
+  internetTimeInfo = timeInfo;
+}
+
+void drawTimeScreen(U8G2 &u8g2)
+{
+  if (!internetTimeInfo.valid) {
+    u8g2.setFont(u8g2_font_6x12_tr);
+    u8g2.drawStr(0, 24, "Time has not");
+    u8g2.drawStr(0, 40, "been updated");
+    return;
+  }
+
+  u8g2.setFont(u8g2_font_6x12_tr);
+  u8g2.setCursor(0, 14);
+  printTwoDigits(u8g2, internetTimeInfo.day);
+  u8g2.print(".");
+  printTwoDigits(u8g2, internetTimeInfo.month);
+  u8g2.print(".");
+  u8g2.print(internetTimeInfo.year);
+
+  u8g2.setFont(u8g2_font_ncenB24_tr);
+  u8g2.setCursor(0, 54);
+  printTwoDigits(u8g2, internetTimeInfo.hour);
+  u8g2.print(":");
+  printTwoDigits(u8g2, internetTimeInfo.minute);
 }
 
 void drawHelloWorldScreen(U8G2 &u8g2)
@@ -40,6 +72,28 @@ void drawHelloWorldScreen(U8G2 &u8g2)
   u8g2.drawStr(0, 54, "world");
 }
 
+void drawInternetConnectionScreen(U8G2 &u8g2, WifiConnectionInfo wifiInfo)
+{
+  u8g2.setFont(u8g2_font_6x12_tr);
+  u8g2.drawStr(0, 12, "Internet");
+
+  if (!wifiInfo.shieldAvailable) {
+    u8g2.drawStr(0, 34, "WiFi shield missing");
+    return;
+  }
+
+  if (!wifiInfo.connected) {
+    u8g2.setFont(u8g2_font_ncenB14_tr);
+    u8g2.drawStr(0, 42, "Disconnected");
+    return;
+  }
+
+  u8g2.drawStr(0, 32, "Connected");
+  u8g2.drawStr(0, 48, "IP address:");
+  u8g2.setCursor(0, 64);
+  u8g2.print(wifiInfo.ipAddress);
+}
+
 void setEnvironmentReading(Am2302Reading reading)
 {
   environmentReading = reading;

src/wifi_connection.cpp

@@ -0,0 +1,84 @@
+#include "wifi_connection.h"
+
+#include <WiFi101.h>
+
+#include "wifi_credentials.h"
+
+namespace
+{
+const unsigned long reconnectInterval = 30000;
+}
+
+WifiConnection::WifiConnection()
+    : nextAttempt_(0),
+      shieldAvailable_(true),
+      connected_(false),
+      ipAddress_(0, 0, 0, 0),
+      dirty_(true) {}
+
+void WifiConnection::begin(unsigned long now)
+{
+  shieldAvailable_ = WiFi.status() != WL_NO_SHIELD;
+  connect(now);
+  recordStatus();
+}
+
+void WifiConnection::update(unsigned long now)
+{
+  if (!shieldAvailable_) {
+    return;
+  }
+
+  if (WiFi.status() == WL_CONNECTED) {
+    recordStatus();
+    return;
+  }
+
+  if (now >= nextAttempt_) {
+    connect(now);
+  }
+
+  recordStatus();
+}
+
+WifiConnectionInfo WifiConnection::info() const
+{
+  WifiConnectionInfo current = {
+    shieldAvailable_,
+    connected_,
+    ipAddress_
+  };
+  return current;
+}
+
+bool WifiConnection::consumeDirty()
+{
+  const bool d = dirty_;
+  dirty_ = false;
+  return d;
+}
+
+void WifiConnection::connect(unsigned long now)
+{
+  if (!shieldAvailable_) {
+    return;
+  }
+
+  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
+  nextAttempt_ = now + reconnectInterval;
+}
+
+void WifiConnection::recordStatus()
+{
+  const bool currentConnected = WiFi.status() == WL_CONNECTED;
+  IPAddress currentIpAddress(0, 0, 0, 0);
+  if (currentConnected) {
+    currentIpAddress = WiFi.localIP();
+  }
+
+  if (connected_ != currentConnected || ipAddress_ != currentIpAddress) {
+    connected_ = currentConnected;
+    ipAddress_ = currentIpAddress;
+    dirty_ = true;
+  }
+}