/*

   This Source Code Form is subject to the terms of the Mozilla Public

   License, v. 2.0. If a copy of the MPL was not distributed with this

   file, You can obtain one at http://mozilla.org/MPL/2.0/.

 	Copyright (C) 2013 Michael Möller <mmoeller@openhardwaremonitor.org>

 */

 using System;

 using System.Collections.Generic;

 using System.Globalization;

 using System.IO;

 using System.Linq;

 using OpenHardwareMonitor.Hardware;

 namespace OpenHardwareMonitor.Utilities {

   public class Logger {

     private const string fileNameFormat = 

       "OpenHardwareMonitorLog-{0:yyyy-MM-dd}.csv";

     private readonly IComputer computer;

     private DateTime day = DateTime.MinValue;

     private string fileName;

     private string[] identifiers;

     private ISensor[] sensors;

     private DateTime lastLoggedTime = DateTime.MinValue;

     public Logger(IComputer computer) {

       this.computer = computer;

       this.computer.HardwareAdded += HardwareAdded;

       this.computer.HardwareRemoved += HardwareRemoved;      

     }

     private void HardwareRemoved(IHardware hardware) {

       hardware.SensorAdded -= SensorAdded;

       hardware.SensorRemoved -= SensorRemoved;

       foreach (ISensor sensor in hardware.Sensors)

         SensorRemoved(sensor);

       foreach (IHardware subHardware in hardware.SubHardware)

         HardwareRemoved(subHardware);

     }

     private void HardwareAdded(IHardware hardware) {

       foreach (ISensor sensor in hardware.Sensors)

         SensorAdded(sensor);

       hardware.SensorAdded += SensorAdded;

       hardware.SensorRemoved += SensorRemoved;

       foreach (IHardware subHardware in hardware.SubHardware)

         HardwareAdded(subHardware);

     }

     private void SensorAdded(ISensor sensor) {

       if (sensors == null)

         return;

       for (int i = 0; i < sensors.Length; i++) {

         if (sensor.Identifier.ToString() == identifiers[i])

           sensors[i] = sensor;

       }

     }

     private void SensorRemoved(ISensor sensor) {

       if (sensors == null)

         return;

       for (int i = 0; i < sensors.Length; i++) {

         if (sensor == sensors[i])

           sensors[i] = null;

       }

     }

     private static string GetFileName(DateTime date) {

       return AppDomain.CurrentDomain.BaseDirectory +

         Path.DirectorySeparatorChar + string.Format(fileNameFormat, date);

     }

     private bool OpenExistingLogFile() {

       if (!File.Exists(fileName))

         return false;

       try {

         String line;

         using (StreamReader reader = new StreamReader(fileName)) 

           line = reader.ReadLine(); 

         if (string.IsNullOrEmpty(line))

           return false;

         identifiers = line.Split(',').Skip(1).ToArray();

       } catch {

         identifiers = null;

         return false;

       }

       if (identifiers.Length == 0) {

         identifiers = null;

         return false;

       }

       sensors = new ISensor[identifiers.Length];

       SensorVisitor visitor = new SensorVisitor(sensor => {

         for (int i = 0; i < identifiers.Length; i++)

           if (sensor.Identifier.ToString() == identifiers[i])

             sensors[i] = sensor;

       });

       visitor.VisitComputer(computer);

       return true;

     }

     private void CreateNewLogFile() {

       IList<ISensor> list = new List<ISensor>();

       SensorVisitor visitor = new SensorVisitor(sensor => {

         list.Add(sensor);

       });

       visitor.VisitComputer(computer);

       sensors = list.ToArray();

       identifiers = sensors.Select(s => s.Identifier.ToString()).ToArray();

       using (StreamWriter writer = new StreamWriter(fileName, false)) {

         writer.Write(",");

         for (int i = 0; i < sensors.Length; i++) {

           writer.Write(sensors[i].Identifier);

           if (i < sensors.Length - 1)

             writer.Write(",");

           else

             writer.WriteLine();

         }

         writer.Write("Time,");

         for (int i = 0; i < sensors.Length; i++) {

           writer.Write('"');

           writer.Write(sensors[i].Name);

           writer.Write('"');

           if (i < sensors.Length - 1)

             writer.Write(",");

           else

             writer.WriteLine();

         }

       }

     }

     public TimeSpan LoggingInterval { get; set; }

     public void Log() {      

       var now = DateTime.Now;

       if (lastLoggedTime + LoggingInterval - new TimeSpan(5000000) > now)

         return;      

       if (day != now.Date || !File.Exists(fileName)) {

         day = now.Date;

         fileName = GetFileName(day);

         if (!OpenExistingLogFile())

           CreateNewLogFile();

       }

       try {

         using (StreamWriter writer = new StreamWriter(new FileStream(fileName,

           FileMode.Append, FileAccess.Write, FileShare.ReadWrite))) {

           writer.Write(now.ToString("G", CultureInfo.InvariantCulture));

           writer.Write(",");

           for (int i = 0; i < sensors.Length; i++) {

             if (sensors[i] != null) {

               float? value = sensors[i].Value;

               if (value.HasValue)

                 writer.Write(

                   value.Value.ToString("R", CultureInfo.InvariantCulture));

             }

             if (i < sensors.Length - 1)

               writer.Write(",");

             else

               writer.WriteLine();

           }

         }

       } catch (IOException) { }

       lastLoggedTime = now;

     }

   }

 }