From 05db37343dad059f6fa77db93b07c292d2a8ac15 Mon Sep 17 00:00:00 2001
From: Mike Shoup <mike+gitlab@shoup.io>
Date: Sun, 7 Oct 2018 21:57:41 +0000
Subject: [PATCH] Resolve "Change temperature logic"

---
 html/js/thermostat.js |  4 +--
 thermostat.go         | 58 +++++++++++++++++++++----------------------
 2 files changed, 30 insertions(+), 32 deletions(-)

diff --git a/html/js/thermostat.js b/html/js/thermostat.js
index cd2f3e7..c7f8fde 100644
--- a/html/js/thermostat.js
+++ b/html/js/thermostat.js
@@ -49,8 +49,8 @@ function renderThermostats() {
                     var hightemp = parseFloat(configData.hightemp).toFixed(1) + "°C";
                     var lowtemp = parseFloat(configData.lowtemp).toFixed(1) + "°C";
                 }
-                configText = "Chills when > " + hightemp + " for " + configData.coolminutes + " minutes.<br />";
-                configText += "Heats when < " + lowtemp + " for " + configData.heatminutes + " minutes.";
+                configText = "Chills for " + configData.coolminutes + " minutes when > " + hightemp + ".<br />";
+                configText += "Heats for " + configData.heatminutes + " minutes when < " + lowtemp + ".";
 
                 var configp = $("<p></p>").html(configText);
                 var configdiv = $("<div></div>").addClass("seven columns").append(configp);
diff --git a/thermostat.go b/thermostat.go
index f5ab612..172fe7e 100644
--- a/thermostat.go
+++ b/thermostat.go
@@ -63,6 +63,11 @@ func ProcessSensor(sensor Sensor, state State) (State, error) {
 		log.Panicln(err)
 	}
 
+	// When things reach the right temperature, set the duration to the future
+	// TODO: Better handling of this. Changed should maintain when the state changed.
+	//       Probably need a new flag in the State struct.
+	future := time.Date(2999, 1, 1, 0, 0, 0, 0, time.UTC)
+
 	state.When = time.Now()
 
 	// Initialize the pins
@@ -74,45 +79,38 @@ func ProcessSensor(sensor Sensor, state State) (State, error) {
 	// Calculate duration
 	duration := time.Since(state.Changed).Minutes()
 
-	// When things reach the right temperature, set the duration to the future
-	// TODO: Better handling of this. Changed should maintain when the state changed.
-	//       Probably need a new flag in the State struct.
-	future := time.Date(2999, 1, 1, 0, 0, 0, 0, time.UTC)
-
 	switch {
 	case temp > sensor.HighTemp && temp < sensor.LowTemp:
 		log.Println("Invalid state! Temperature is too high AND too low!")
-	// Temperature is high enough, turn off
-	case temp > sensor.LowTemp && state.Heating:
-		PinSwitch(hpin, false, sensor.HeatInvert)
-		state.Heating = false
-		state.Changed = future
-	// Temperature is too high and the cooling switch is still on, do nothing
-	case temp > sensor.HighTemp && state.Cooling:
-		break
-	// Temperature is too high, but duration hasn't been counted
-	case temp > sensor.HighTemp && duration < 0:
-		state.Changed = time.Now()
-	// Temperature is too high and the duration has been long enough, start cooling
-	case temp > sensor.HighTemp && duration > sensor.CoolMinutes:
+	// Temperature too high, start cooling
+	case temp > sensor.HighTemp:
 		PinSwitch(cpin, true, sensor.CoolInvert)
 		state.Cooling = true
-		state.Changed = time.Now()
-	// Temperature is low enough, stop cooling
-	case temp < sensor.HighTemp && state.Cooling:
+		PinSwitch(hpin, false, sensor.HeatInvert) // Ensure the heater is off
+		state.Heating = false
+		state.Changed = future
+	// Temperature too low, start heating
+	case temp < sensor.LowTemp:
+		PinSwitch(hpin, true, sensor.HeatInvert)
+		state.Heating = true
+		PinSwitch(cpin, false, sensor.CoolInvert) // Ensure the chiller is off
+		state.Cooling = false
+		state.Changed = future
+	// Temperature is good and cooling has been happening long enough
+	case temp < sensor.HighTemp && state.Cooling && duration > sensor.CoolMinutes:
 		PinSwitch(cpin, false, sensor.CoolInvert)
 		state.Cooling = false
 		state.Changed = future
-	// Temperature is too low and the heating switch is on, do nothing
-	case temp < sensor.LowTemp && state.Heating:
-		break
-	// Temperature is too low, but duration hasn't been counted
-	case temp < sensor.LowTemp && duration < 0:
+	// Temperature is good and heating has been happening long enough
+	case temp > sensor.LowTemp && state.Heating && duration > sensor.HeatMinutes:
+		PinSwitch(hpin, false, sensor.HeatInvert)
+		state.Heating = false
+		state.Changed = future
+	// Temperature just crossed high threshold
+	case temp < sensor.HighTemp && state.Cooling && duration < 0:
 		state.Changed = time.Now()
-	// Temperature is too low and the duration has been long enough, start heating
-	case temp < sensor.LowTemp && duration > sensor.HeatMinutes:
-		PinSwitch(hpin, true, sensor.HeatInvert)
-		state.Heating = true
+	// Temperature just crossed low threshold
+	case temp > sensor.LowTemp && state.Heating && duration < 0:
 		state.Changed = time.Now()
 	default:
 		break