From 38d794300b7063b1dbca1100ee30e434c30d690f Mon Sep 17 00:00:00 2001
From: Holger Wirtz <wirtz@parasitstudio.de>
Date: Mon, 12 Oct 2020 09:16:30 +0200
Subject: [PATCH] Added summer/wintertime detection.

---
 WLAN_Thermometer.ino | 72 +++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 64 insertions(+), 8 deletions(-)

diff --git a/WLAN_Thermometer.ino b/WLAN_Thermometer.ino
index aecc789..e030dd9 100644
--- a/WLAN_Thermometer.ino
+++ b/WLAN_Thermometer.ino
@@ -11,6 +11,7 @@
 #include <looper.h>
 #include <RunningMedian.h>
 #include <ESPDateTime.h>
+#include <Time.h>
 
 #define MDNS_NAME             "wlanthermometer"
 #define AP_SSID_CONFIG_NAME   "WLANTHERMOMETER-Config"
@@ -29,9 +30,9 @@
 LiquidCrystal_I2C lcd(LCD_I2C_ADDR, LCD_COL, LCD_ROW);
 looper sched;
 RunningMedian samples = RunningMedian(MEDIAN_SAMPLES);
-float temp_min = (analogRead(TEMP_SENS_PIN) / 2048.0) * 330.0;
-float temp_max = temp_min;
-float temp = (analogRead(TEMP_SENS_PIN) / 2048.0) * 330.0;
+float temp_min;
+float temp_max;
+float temp;
 bool led_state;
 String header;
 WiFiServer server(80);
@@ -59,8 +60,13 @@ void setup()
   WiFi.mode(WIFI_STA); // explicitly set mode, esp defaults to STA+AP
 
   WiFiManager wm;
+  bool bounce[2];
 
-  if (digitalRead(AP_DATA_RESET_PIN) != LOW)
+  bounce[0] = digitalRead(AP_DATA_RESET_PIN);
+  delay(50);
+  bounce[1] = digitalRead(AP_DATA_RESET_PIN);
+
+  if (bounce[1] == LOW && bounce[0] == LOW)
   {
     wm.resetSettings();
     DEBUG_MSG("Resetting AP data\n");
@@ -117,7 +123,7 @@ void setup()
 
   lcd.setCursor(0, 3);
   lcd.print("Getting time...");
-  DateTime.setTimeZone(2);
+  DateTime.setTimeZone(1);
   DateTime.begin(NTP_TIMEOUT);
   while (!DateTime.isTimeValid())
   {
@@ -130,6 +136,10 @@ void setup()
   sched.addJob(show_temperature, KRATE_TEMP);
   sched.addJob(show_time, KRATE_TIME);
 
+  temp_min = (analogRead(TEMP_SENS_PIN) / 2048.0) * 330.0;
+  temp_max = temp_min;
+  temp = (analogRead(TEMP_SENS_PIN) / 2048.0) * 330.0;
+
   lcd.clear();
   show_time();
   show_temperature();
@@ -213,10 +223,19 @@ void show_time(void)
   DateTimeParts p = DateTime.getParts();
   char dt[21];
 
-  Serial.println(DateTime.format(DateFormatter::DATE_ONLY));
-  Serial.println(DateTime.format(DateFormatter::TIME_ONLY));
+  if (is_wintertime(DateTime.getTime()) == false)
+  {
+    sprintf(dt, "%02d.%02d.%4d  %02d:%02d:%02d", p.getMonthDay(), p.getMonth() + 1, p.getYear(), p.getHours() + 1, p.getMinutes(), p.getSeconds());
+    Serial.print(dt);
+    Serial.println(" Summertime");
+  }
+  else
+  {
+    sprintf(dt, "%02d.%02d.%4d  %02d:%02d:%02d", p.getMonthDay(), p.getMonth() + 1, p.getYear(), p.getHours(), p.getMinutes(), p.getSeconds());
+    Serial.print(dt);
+    Serial.println(" Wintertime");
+  }
 
-  sprintf(dt, "%02d.%02d.%4d  %02d:%02d:%02d", p.getMonthDay(), p.getMonth() + 1, p.getYear(), p.getHours(), p.getMinutes(), p.getSeconds());
   lcd.setCursor(0, 0);
   lcd.print(dt);
 
@@ -262,3 +281,40 @@ void show_temperature(void)
   lcd.print("Maximum:    ");
   lcd.print(temp_max);
 }
+
+bool is_wintertime(time_t t)
+{
+  // Sommerzeit/Winterzeit http://manfred.wilzeck.de/Datum_berechnen.html#Jahreszahl
+  // Tag = 31 – ( 4 + Jahr*5 / 4) MOD 7  ' Datum Tag für Beginn Sommerzeit (Jahr 4-stellig)
+  // Tag = 31 – ( 1 + Jahr*5 / 4) MOD 7  ' Datum Tag für Ende Sommerzeit (Jahr 4-stellig)
+  tmElements_t tm;
+  byte day_of_switch[2];
+  time_t switch_secs[2];
+  byte i;
+
+  day_of_switch[0] = 31 - (4 + year(t) * 5 / 4) % 7; // winter->summer
+  day_of_switch[1] = 31 - (1 + year(t) * 5 / 4) % 7; // summer->winter
+
+  for (i = 0; i < 2; i++)
+  {
+    tm.Second = 0;
+    if (i == 0)
+      tm.Hour = 2;
+    else
+      tm.Hour = 3;
+    tm.Minute = 0;
+    tm.Day = day_of_switch[i];
+    if (i == 0)
+      tm.Month = 3;
+    else
+      tm.Month = 10;
+    tm.Year = year(t) - 1970;
+
+    switch_secs[i] = makeTime(tm);
+  }
+
+  if (t >= switch_secs[0] && t < switch_secs[1])
+    return (false);
+  else
+    return (true);
+}