From 7570d0c13178c15fdce3e92c681cce76d53799ce Mon Sep 17 00:00:00 2001
From: Jan Tuomi <jans.tuomi@gmail.com>
Date: Tue, 19 Sep 2017 21:04:48 +0300
Subject: [PATCH] Add filtering to coffee data

---
 coffee_scale/mqtt.py               | 25 ++++++++++++++++++++-----
 coffee_scale/templates/coffee.html |  5 ++++-
 coffee_scale/views.py              |  4 ++--
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/coffee_scale/mqtt.py b/coffee_scale/mqtt.py
index f69f503..76751bc 100644
--- a/coffee_scale/mqtt.py
+++ b/coffee_scale/mqtt.py
@@ -8,9 +8,10 @@ MQTT_HOST = "mqtt.sik.party"
 TOPIC_TEMP = "sik/kiltahuone/kahvivaaka/temperature"
 TOPIC_WEIGHT = "sik/kiltahuone/kahvivaaka/weight"
 
-BREWING_DIFFERENTIAL = 60
+BREWING_DIFFERENTIAL_MIN = 60
 # setting down the pan creates at least 800 g of weight
-BREWING_DIFFERENTIAL_ERROR_MAX = 800
+BREWING_DIFFERENTIAL_MAX = 180
+
 WEIGHT_DEQUE_LENGTH = 20
 weight_deque = deque(maxlen=WEIGHT_DEQUE_LENGTH)
 latest = {
@@ -18,6 +19,17 @@ latest = {
 }
 
 
+def calc_averaged_weight():
+    if len(weight_deque) > 2:
+        half = []
+        for i in range(0, int(len(weight_deque) / 2)):
+            half.append(weight_deque[i])
+
+        return sum(half) / len(half)
+    else:
+        return 0
+
+
 def on_connect(client, userdata, flags, rc):
     logging.info('Subscribing to all topics on mqtt.sik.party.')
     client.subscribe("#")
@@ -28,8 +40,10 @@ def on_message(client, userdata, msg):
         latest['temp'] = float(msg.payload.decode('utf-8'))
     elif msg.topic == TOPIC_WEIGHT:
         weight = float(msg.payload.decode('utf-8'))
-        latest['weight'] = weight
-        weight_deque.appendleft(weight)
+
+        # avoid showing erroneous data from an empty scale
+        if weight > 50:  # g
+            weight_deque.appendleft(weight)
 
 
 def on_disconnect(client, userdata, rc):
@@ -49,13 +63,14 @@ def get_latest():
     if len(weight_deque) < WEIGHT_DEQUE_LENGTH:
         brewing = False
     else:
-        if BREWING_DIFFERENTIAL < diff < BREWING_DIFFERENTIAL_ERROR_MAX:
+        if BREWING_DIFFERENTIAL_MIN < diff < BREWING_DIFFERENTIAL_MAX:
             brewing = True
             latest['last_brew'] = datetime.datetime.now()
         else:
             brewing = False
 
     latest['brewing'] = brewing
+    latest['weight'] = calc_averaged_weight()
     return latest
 
 
diff --git a/coffee_scale/templates/coffee.html b/coffee_scale/templates/coffee.html
index 72bc9c2..2d5ee2b 100644
--- a/coffee_scale/templates/coffee.html
+++ b/coffee_scale/templates/coffee.html
@@ -233,7 +233,10 @@ function setData(cups, temp, opa, timeFromUpdate, timeFromBrew, brewing){
   formatBrewTime();
   if($("#text").html() == "+" && !brewing)
     $("body").addClass("coffeeready");
-  len = cups.toString().length;
+
+  cups = Number(cups).toFixed(1);
+  var cupsString = cups.toString();
+  len = cupsString.length;
   $("#text").html(cups);
 }
 
diff --git a/coffee_scale/views.py b/coffee_scale/views.py
index d35cd22..fcfbc50 100644
--- a/coffee_scale/views.py
+++ b/coffee_scale/views.py
@@ -18,12 +18,12 @@ def get_cups_from_weight(weight):
     cups = 10 * (weight - EMPTY) / (FULL - EMPTY)
 
     cups = round(cups, 1)
-    if cups < 0:
+    if cups < 0.5:
         cups = 0
     if cups > 10:
         cups = 10
 
-    logging.debug("Coffee cups: {}, weight: {}".format(cups, weight))
+    # logging.debug("Coffee cups: {}, weight: {}".format(cups, weight))
     return cups