// 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) LibreHardwareMonitor and Contributors.
// Partial Copyright (C) Michael Möller <mmoeller@openhardwaremonitor.org> and Contributors.
// All Rights Reserved.

using System;
using System.Collections.Generic;
using System.Management.Instrumentation;
using LibreHardwareMonitor.Hardware;

[assembly: Instrumented("root/LibreHardwareMonitor")]
[System.ComponentModel.RunInstaller(true)]
public class InstanceInstaller : DefaultManagementProjectInstaller { }

namespace LibreHardwareMonitor.Wmi
{
    /// <summary>
    /// The WMI Provider.
    /// This class is not exposed to WMI itself.
    /// </summary>
    public class WmiProvider : IDisposable
    {
        private List<IWmiObject> _activeInstances;

        public WmiProvider(IComputer computer)
        {
            _activeInstances = new List<IWmiObject>();
            foreach (IHardware hardware in computer.Hardware)
            {
                ComputerHardwareAdded(hardware);
            }
            computer.HardwareAdded += ComputerHardwareAdded;
            computer.HardwareRemoved += ComputerHardwareRemoved;
        }

        public void Update()
        {
            foreach (IWmiObject instance in _activeInstances)
                instance.Update();
        }

        #region Eventhandlers

        private void ComputerHardwareAdded(IHardware hardware)
        {
            if (!Exists(hardware.Identifier.ToString()))
            {
                foreach (ISensor sensor in hardware.Sensors)
                    HardwareSensorAdded(sensor);

                hardware.SensorAdded += HardwareSensorAdded;
                hardware.SensorRemoved += HardwareSensorRemoved;

                Hardware hw = new Hardware(hardware);
                _activeInstances.Add(hw);

                try
                {
                    Instrumentation.Publish(hw);
                }
                catch { }
            }

            foreach (IHardware subHardware in hardware.SubHardware)
                ComputerHardwareAdded(subHardware);
        }

        private void HardwareSensorAdded(ISensor data)
        {
            Sensor sensor = new Sensor(data);
            _activeInstances.Add(sensor);

            try
            {
                Instrumentation.Publish(sensor);
            }
            catch { }
        }

        private void ComputerHardwareRemoved(IHardware hardware)
        {
            hardware.SensorAdded -= HardwareSensorAdded;
            hardware.SensorRemoved -= HardwareSensorRemoved;

            foreach (ISensor sensor in hardware.Sensors)
                HardwareSensorRemoved(sensor);

            foreach (IHardware subHardware in hardware.SubHardware)
                ComputerHardwareRemoved(subHardware);

            RevokeInstance(hardware.Identifier.ToString());
        }

        private void HardwareSensorRemoved(ISensor sensor)
        {
            RevokeInstance(sensor.Identifier.ToString());
        }

        #endregion

        #region Helpers

        private bool Exists(string identifier)
        {
            return _activeInstances.Exists(h => h.Identifier == identifier);
        }

        private void RevokeInstance(string identifier)
        {
            int instanceIndex = _activeInstances.FindIndex(
              item => item.Identifier == identifier.ToString()
            );

            if (instanceIndex == -1)
                return;

            try
            {
                Instrumentation.Revoke(_activeInstances[instanceIndex]);
            }
            catch { }

            _activeInstances.RemoveAt(instanceIndex);
        }

        #endregion

        public void Dispose()
        {
            foreach (IWmiObject instance in _activeInstances)
            {
                try
                {
                    Instrumentation.Revoke(instance);
                }
                catch { }
            }
            _activeInstances = null;
        }
    }
}