Process Monitor - initial POC implementation

This is probably overengineered. The same could be done cross platform only using Processes.GetProcesses. I did it this way because initially i wanted to use Wmi events for process start and stop. This requires admin though, so i decided to not use it.

src/Artemis.Core/Services/ProcessMonitor/Events/ProcessEventArgs.cs

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+using System;
+
+namespace Artemis.Core.Services
+{
+    public class ProcessEventArgs : EventArgs
+    {
+        public string ProcessName { get; }
+
+        public ProcessEventArgs(string name)
+        {
+            ProcessName = name;
+        }
+    }
+}

src/Artemis.Core/Services/ProcessMonitor/Interfaces/IProcessMonitorService.cs

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+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Artemis.Core.Services
+{
+    public interface IProcessMonitorService : IArtemisService
+    {
+        void AddProcessWatcher(ProcessWatcher provider);
+        void RemoveProcessWatcher(ProcessWatcher provider);
+
+        IEnumerable<string> GetRunningProcesses();
+
+        event EventHandler<ProcessEventArgs> ProcessStarted;
+
+        event EventHandler<ProcessEventArgs> ProcessStopped;
+    }
+}

src/Artemis.Core/Services/ProcessMonitor/ProcessMonitorService.cs

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+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+
+namespace Artemis.Core.Services
+{
+    public class ProcessMonitorService : IProcessMonitorService
+    {
+        private readonly List<ProcessWatcher> _watchers = new List<ProcessWatcher>();
+        public event EventHandler<ProcessEventArgs> ProcessStarted;
+        public event EventHandler<ProcessEventArgs> ProcessStopped;
+
+        public void AddProcessWatcher(ProcessWatcher watcher)
+        {
+            watcher.ProcessStarted += ProviderOnProcessStarted;
+            watcher.ProcessStopped += ProviderOnProcessStopped;
+            _watchers.Add(watcher);
+        }
+
+        public void RemoveProcessWatcher(ProcessWatcher watcher)
+        {
+            if (!_watchers.Contains(watcher))
+                return;
+
+            _watchers.Remove(watcher);
+            watcher.ProcessStarted -= ProviderOnProcessStarted;
+            watcher.ProcessStopped -= ProviderOnProcessStopped;
+        }
+
+        public IEnumerable<string> GetRunningProcesses()
+        {
+            return _watchers.SelectMany(w => w.GetRunningProcesses());
+        }
+
+        private void ProviderOnProcessStopped(object? sender, ProcessEventArgs e)
+        {
+            ProcessStopped?.Invoke(this, e);
+        }
+
+        private void ProviderOnProcessStarted(object? sender, ProcessEventArgs e)
+        {
+            ProcessStarted?.Invoke(this, e);
+        }
+    }
+}

src/Artemis.Core/Services/ProcessMonitor/ProcessWatcher.cs

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+using System;
+using System.Collections.Generic;
+
+namespace Artemis.Core.Services
+{
+    /// <summary>
+    ///     Class that provides info on running processes, including events on event start and stop
+    /// </summary>
+    public abstract class ProcessWatcher
+    {
+        public event EventHandler<ProcessEventArgs> ProcessStarted;
+        public event EventHandler<ProcessEventArgs> ProcessStopped;
+
+        public abstract IEnumerable<string> GetRunningProcesses();
+
+        public virtual void OnProcessStarted(string processName)
+        {
+            ProcessStarted?.Invoke(this, new ProcessEventArgs(processName));
+        }
+
+        public virtual void OnProcessStopped(string processName)
+        {
+            ProcessStopped?.Invoke(this, new ProcessEventArgs(processName));
+        }
+    }
+}