1 files changed, 102 insertions, 0 deletions
diff --git a/pollutometer-api/PollutometerWebApi/AqiCalculator.cs b/pollutometer-api/PollutometerWebApi/AqiCalculator.cs
new file mode 100644
index 0000000..58f6194
--- /dev/null
+++ b/pollutometer-api/PollutometerWebApi/AqiCalculator.cs
@@ -0,0 +1,102 @@
+using PollutometerWebApi.Models;
+
+namespace PollutometerWebApi
+{
+    public static class AqiCalculator
+    {
+        public static Aqi CalculateAqi(Reading reading)
+        {
+            double[,,] breakpoints =
+            {
+                {
+                    {0, 4.4},
+                    {4.5, 9.4},
+                    {9.5, 12.4},
+                    {12.5, 15.4},
+                    {15.5, 30.4},
+                    {30.5, 40.4},
+                    {40.5, 50.4}
+                },
+                {
+                    {0.000, 0.034},
+                    {0.035, 0.144},
+                    {0.145, 0.224},
+                    {0.225, 0.304},
+                    {0.305, 0.604},
+                    {0.605, 0.804},
+                    {0.805, 1.004}
+                },
+                {
+                    {0, 0.05},
+                    {0.08, 0.10},
+                    {0.15, 0.20},
+                    {0.25, 0.31},
+                    {0.65, 1.24},
+                    {1.25, 1.64},
+                    {1.65, 2.04}
+                },
+                {
+                    {0, 50},
+                    {51, 100},
+                    {101, 150},
+                    {151, 200},
+                    {201, 300},
+                    {301, 400},
+                    {401, 500}
+                }
+            };
+
+            double i, c = 0, cLow = 0, cHigh = 0, iLow = 0, iHigh = 0;
+            Aqi aqi = new Aqi();
+           
+            for (int x = 0; x < 4; x++)
+            {
+                switch (x)
+                {
+                    case 0:
+                        c = reading.Co;
+                        break;
+                    case 1:
+                        c = reading.So;
+                        break;
+                    case 2:
+                        c = reading.No;
+                        break;
+                }
+
+                for (int y = 0; y < 7; y++)
+				{
+					if (c >= breakpoints[x, y, 0] && c <= breakpoints[x, y, 1])
+					{
+						cLow = breakpoints[x, y, 0];
+						cHigh = breakpoints[x, y, 1];
+						iLow = breakpoints[3, y, 0];
+						iHigh = breakpoints[3, y, 1];
+                        break;
+					}
+				}
+
+                i = (iHigh - iLow) / (cHigh - cLow) * (c - cLow) + iLow;
+
+                if (i > aqi.Value)
+                { 
+                    aqi.Value = i;
+                    switch (x)
+                    {
+                        case 0:
+                            aqi.GasName = "CO";
+                            break;
+                        case 1:
+                            aqi.GasName = "SO";
+                            break;
+                        case 2:
+                            aqi.GasName = "NO";
+                            break;
+                    }
+                }
+            }
+
+            return aqi;
+        }
+    }
+}