eyes-and-ears/src/EyesAndEars.UWP/EyesAndEars.UWP/Services/DataServices.cs

using EyesAndEars.UWP.Models;
using System;
using System.Diagnostics;
using System.Text.Json;
using System.Threading.Tasks;
using Windows.Storage;
using Windows.UI;
using Windows.UI.Xaml.Media;

namespace EyesAndEars.UWP.Services {
    public static class DataServices {

        public static async Task<Device> UpdateDevice(string url, int deviceId) {
            try {
                var id = MapFactoryDeviceToGalleyDevice(deviceId); // Has note.
                var readingAPI = $"{url}/api/readings/latest/{id}";
                var statusAPI = $"{url}/api/status/latest/{deviceId}";
                var readingJSON = await WebServices.GetJSON(readingAPI);
                var statusJSON = await WebServices.GetJSON(statusAPI);
                var r = MapToLightReading(readingJSON);
                var s = MapToDeviceStatus(statusJSON);
                var c = UpdateStatusColour(s.status, r.reading);
                return new Device(deviceId, r, s, c);
            }
            catch (Exception e) {
                Debug.WriteLine(e.Message);
                return CreateFallBackDevice(deviceId);
            }
        }

        static SolidColorBrush UpdateStatusColour(string status, int reading) {
            try {
                if (status.Equals("on", StringComparison.OrdinalIgnoreCase)) {
                    /* Note: Reading values breakdown.
                     * =======================================
                     * 1. When testing the light meters, the base line for normal
                     * light is 48 or below. Anything above this is when one of
                     * the guys in the factory was welding. Becuase of this,
                     * I have set 0 to 48 as the 'default' status on the
                     * dashboard.
                     * 
                     * 2. During testing we noticed the light meters would
                     * return 'negative light' values. There is a reason for
                     * this but that is out of the scope of this project. This
                     * project just needs to process the data. The negative
                     * light values are when the lights in the factory are off.
                     * The light meter is still running but there is no light
                     * to measure. So, everything is fine but it looks broken.
                     * The 'LightSkyBlue' colour is used to help relay this
                     * bit of information.
                    */
                    if (reading > 0 && reading < 48) // On but no weld detected.
                        return new SolidColorBrush(Colors.LightSeaGreen);
                    if (reading > 48) // On and weld detected.
                        return new SolidColorBrush(Colors.DarkSeaGreen);
                    else {
                        // On but factory lights are off.
                        return new SolidColorBrush(Colors.LightSkyBlue);
                    }
                }
                else return new SolidColorBrush(Colors.DarkRed);            }
            catch (Exception e) {
                Debug.WriteLine(e.Message);
                return new SolidColorBrush(Colors.DarkOrange);
            }
        }

        /* Note: The Purpose of Mapping a Factory to a Gallery Device.
         * ================================================================
         * Every device in the project is paired up with another.
         * Factory1 => Gallery1 | Device1 => Device4
         * Factory2 => Gallery2 | Device2 => Device5
         * Factory3 => Gallery3 | Device3 => Device6 (Note in use at this time)
         * At the moment, when a device completes a status update, each one
         * is ran throught the "UpdateDevice" function (above). This means
         * the latest light reading for a light meter (factory) must be
         * retrieved when a galley-based device's status is updated.
         * From a strict point-of-view, the gallery device does not need it
         * so I should/could seperate out this functionality into seperate
         * functions. For now though, a light reading is still needed to be
         * retrieved because of the way the functions are called.
         * This function just maps/pairs the (factory) light reading to the
         * appropriate gallery device. By doing this, the gallery device
         * has extra information on its paired up light meter. One way I
         * have used that information is to show a small piece of text in
         * the gallery status box to quickly check the accuracy of the
         * synchronisation between the factory and gallery devices.
         */
        static int MapFactoryDeviceToGalleyDevice(int deviceId) {
            int id = 0;
            if (deviceId > 3) {
                switch (deviceId) {
                    case 4:
                        id = 1;
                        break;
                    case 5:
                        id = 2;
                        break;
                    case 6:
                        id = 3;
                        break;
                    default:
                        break;
                }
            }
            else {
                id = deviceId;
            }
            return id;
        }

        static LightReading MapToLightReading(string json) {
            try {
                var reading = JsonSerializer.Deserialize<LightReading>(json);
                return reading;
            }
            catch (Exception e) {
                Debug.WriteLine(e.Message);
                return CreateDefaultLightReading();
            }
        }

        static DeviceStatus MapToDeviceStatus(string json) {
            try {
                var status = JsonSerializer.Deserialize<DeviceStatus>(json);
                return status;
            }
            catch (Exception e) {
                Debug.WriteLine(e.Message);
                return CreateDefaultDeviceStatus();
            }
        }

        public static Device CreateFallBackDevice(int deviceId) {
            // "999" and "err" are acting as sentinals in this context.
            var r = new LightReading { id = 0, reading = 999, time = DateTime.Now };
            var s = new DeviceStatus { id = 0, status = "err", time = DateTime.Now };
            var c = new SolidColorBrush(Colors.DarkOrange);
            var d = new Device(deviceId, r, s, c);
            return d;
        }

        static LightReading CreateDefaultLightReading() =>
            new LightReading { id = 0, reading = 999, time = DateTime.Now };

        static DeviceStatus CreateDefaultDeviceStatus() =>
            new DeviceStatus { id = 0, status = "err", time = DateTime.Now };

        public static async Task SaveBaseURLAsync(string contents) {
            try {
                var storageFolder = ApplicationData.Current.LocalFolder;
                var baseURLFile = await storageFolder.CreateFileAsync("baseURL.txt",
                    CreationCollisionOption.ReplaceExisting);
                await FileIO.WriteTextAsync(baseURLFile, contents);
            }
            catch (Exception e) {
                Debug.WriteLine(e.Message);
            }
        }

        public static async Task<string> GetBaseURLAsync() {
            try {
                var storageFolder = ApplicationData.Current.LocalFolder;
                var baseURLFile = await storageFolder.GetFileAsync("baseURL.txt");
                var text = await FileIO.ReadTextAsync(baseURLFile);
                return text;
            }
            catch (Exception e) {
                Debug.WriteLine(e.Message);
                return "";
            }
            
        }
    }
}