using System;

namespace AIDiagnosisDemo.GC
{
    internal class GcAdapter : IGcAdapter
    {
        private static GcAdapter _instance;

        public bool IsManualGc { get; set; }

        public static GcAdapter Instance
        {
            get
            {
                if (_instance == null)
                {
                    _instance = new GcAdapter();
                }

                return _instance;
            }
        }

        private GcAdapter()
        {
            IsManualGc = true;
        }

        public void SuppressFinalize(object obj)
        {
            if (IsManualGc)
            {
                System.GC.SuppressFinalize(obj);
            }
        }

        public void RegisterForFullGCNotification(int maxGenerationThreshold, int largeObjectHeapThreshold)
        {
            if (IsManualGc)
            {
                try
                {
                    System.GC.RegisterForFullGCNotification(maxGenerationThreshold, largeObjectHeapThreshold);
                }
                catch (Exception e)
                {
                    // ignored
                }
            }
        }

        public GCNotificationStatus WaitForFullGCApproach()
        {
            if (IsManualGc)
            {
                return System.GC.WaitForFullGCApproach();
            }

            return GCNotificationStatus.Canceled;
        }

        public GCNotificationStatus WaitForFullGCComplete()
        {
            if (IsManualGc)
            {
                return System.GC.WaitForFullGCComplete();
            }

            return GCNotificationStatus.Canceled;
        }

        public void WaitForPendingFinalizers()
        {
            if (IsManualGc)
            {
                System.GC.WaitForPendingFinalizers();
            }
        }

        public int CollectionCount(int generation)
        {
            if (IsManualGc)
            {
                return System.GC.CollectionCount(generation);
            }

            return 0;
        }

        public void Collect()
        {
            if (IsManualGc)
            {
                System.GC.Collect();
            }
        }

        public void Collect(int generation)
        {
            if (IsManualGc)
            {
                System.GC.Collect(generation);
            }
        }

        public void CancelFullGCNotification()
        {
            if (IsManualGc)
            {// TODO for net standard,this method is not implemented !!!!
                try
                {
                    System.GC.CancelFullGCNotification();
                }
                catch (Exception e)
                {
                    // ignored
                }
            }
        }

        public void EndNoGCRegion()
        {
            if (IsManualGc)
            {
                System.GC.EndNoGCRegion();
            }
        }
    }
}