// Copyright 1998-2019 Epic Games, Inc. All Rights Reserved.

using System;
using System.IO;
using System.Collections.Generic;
using System.Text;
using System.Reflection;
using System.Diagnostics;

namespace MemoryProfiler2
{
	/// <summary> The lower 2 bits of a pointer are piggy-bagged to store what kind of data follows it. This enum lists the possible types. </summary>
	public enum EProfilingPayloadType
	{
		TYPE_Malloc		= 0,
		TYPE_Free		= 1,
		TYPE_Realloc	= 2,
		TYPE_Other		= 3,
		// Don't add more than 4 values - we only have 2 bits to store this.
	}

	/// <summary> 
	///	The the case of TYPE_Other, this enum determines the subtype of the token.
	/// Mirrored in FMallocProfiler.h
	/// </summary>
	public enum EProfilingPayloadSubType
	{
		// Core marker types

		/// <summary> Marker used to determine when malloc profiler stream has ended. </summary> 
		SUBTYPE_EndOfStreamMarker = 0,

		/// <summary> Marker used to determine when we need to read data from the next file. </summary> 
		SUBTYPE_EndOfFileMarker = 1,

		/// <summary> Marker used to determine when a snapshot has been added. </summary> 
		SUBTYPE_SnapshotMarker = 2,

		/// <summary> Marker used to determine when a new frame has started. </summary> 
		SUBTYPE_FrameTimeMarker = 3,

		/// <summary> Not used. Only for backward compatibility. Use a new snapshot marker instead. </summary> 
		SUBTYPE_TextMarker = 4,

		// Marker types for periodic non-GMalloc memory status updates. Only for backward compatibility, replaced with SUBTYPE_MemoryAllocationStats

		/// <summary> Marker used to store the total amount of memory used by the game. </summary> 
		SUBTYPE_TotalUsed = 5,

		/// </summary> Marker used to store the total amount of memory allocated from the OS. </summary> 
		SUBTYPE_TotalAllocated = 6,

		/// <summary> Marker used to store the allocated in use by the application virtual memory. </summary> 
		SUBTYPE_CPUUsed = 7,

		/// <summary> Marker used to store the allocated from the OS/allocator, but not used by the application. </summary> 
		SUBTYPE_CPUSlack = 8,

		/// <summary> Marker used to store the alignment waste from a pooled allocator plus book keeping overhead. </summary> 
		SUBTYPE_CPUWaste = 9,

		/// <summary> Marker used to store the allocated in use by the application physical memory. </summary> 
		SUBTYPE_GPUUsed = 10,

		/// <summary> Marker used to store the allocated from the OS, but not used by the application. </summary> 
		SUBTYPE_GPUSlack = 11,

		/// <summary> Marker used to store the alignment waste from a pooled allocator plus book keeping overhead. </summary> 
		SUBTYPE_GPUWaste = 12,

		/// <summary> Marker used to store the overhead of the operating system. </summary> 
		SUBTYPE_OSOverhead = 13,

		/// <summary> Marker used to store the size of loaded executable, stack, static, and global object size. </summary> 
		SUBTYPE_ImageSize = 14,

		/// Version 3
		// Marker types for automatic snapshots.

		/// <summary> Marker used to determine when engine has started the cleaning process before loading a new level. </summary> 
		SUBTYPE_SnapshotMarker_LoadMap_Start = 21,

		/// <summary> Marker used to determine when a new level has started loading. </summary> 
		SUBTYPE_SnapshotMarker_LoadMap_Mid = 22,

		/// <summary> Marker used to determine when a new level has been loaded. </summary> 
		SUBTYPE_SnapshotMarker_LoadMap_End = 23,

		/// <summary> Marker used to determine when garbage collection has started. </summary> 
		SUBTYPE_SnapshotMarker_GC_Start = 24,

		/// <summary> Marker used to determine when garbage collection has finished. </summary> 
		SUBTYPE_SnapshotMarker_GC_End = 25,

		/// <summary> Marker used to determine when a new streaming level has been requested to load. </summary> 
		SUBTYPE_SnapshotMarker_LevelStream_Start = 26,

		/// <summary> Marker used to determine when a previously streamed level has been made visible. </summary> 
		SUBTYPE_SnapshotMarker_LevelStream_End = 27,

		/// <summary> Marker used to store a generic malloc statistics. @see FMallocProfiler::WriteMemoryAllocationStats </summary> 
		SUBTYPE_MemoryAllocationStats = 31,

		/// <summary> Start licensee-specific subtypes from here. </summary> 
		SUBTYPE_LicenseeBase = 50,

		/// <summary> Unknown the subtype of the token. </summary> 
		SUBTYPE_Unknown,
	};

	/// <summary> 
	/// Struct used to hold platform memory stats and allocator stats. Valid only for MemoryProfiler2.FProfileDataHeader.Version >= 4.
	/// @see FGenericPlatformMemory::GetStatsForMallocProfiler 
	/// @see FMalloc::GetAllocatorStats
	/// @todo add support for non-generic platform memory stats.
	/// </summary>
	public class FMemoryAllocationStatsV4
	{
		// Names of generic platform memory stats. @see FGenericPlatformMemory::GetStatsForMallocProfiler / GenericPlatformMemory.cpp
		
		/// <summary> The amount of actual physical memory, in bytes. </summary>
		static public string PlatformTotalPhysical = "Total Physical";

		/// <summary> The amount of virtual memory, in bytes. </summary>
		static public string PlatformTotalVirtual = "Total Virtual";

		/// <summary> The size of a page, in bytes. </summary>
		static public string PlatformPageSize = "Page Size";

		/// <summary> Approximate physical RAM in GB"; 1 on everything except PC. Used for "course tuning", like FPlatformMisc::NumberOfCores(). </summary>
		static public string PlatformTotalPhysicalGB = "Total Physical GB";

		/// <summary> The amount of physical memory currently available, in bytes. </summary>
		static public string PlatformAvailablePhysical = "Available Physical";

		/// <summary> The amount of virtual memory currently available, in bytes. </summary>
		static public string PlatformAvailableVirtual = "Available Virtual";

		/// <summary> The amount of physical memory used by the process, in bytes. </summary>
		static public string PlatformUsedPhysical = "Used Physical";

		/// <summary> The peak amount of physical memory used by the process, in bytes. </summary>
		static public string PlatformPeakUsedPhysical = "Peak Used Physical";

		/// <summary> Total amount of virtual memory used by the process. </summary>
		static public string PlatformUsedVirtual = "Used Virtual";

		/// <summary> The peak amount of virtual memory used by the process. </summary>
		static public string PlatformPeakUsedVirtual = "Peak Used Virtual";

		static public string MemoryProfilingOverhead = "Memory Profiling Overhead";

		// Names of malloc binned memory stats. @see FMallocBinned.GetAllocatorStats / MallocBinned.h

		static public string BinnedWasteCurrent = "Binned Waste Current";
		static public string BinnedUsedCurrent = "Binned Used Current";
		static public string BinnedSlackCurrent = "Binned Slack Current";

		private Dictionary<string, Int64> _Stats;

		public FMemoryAllocationStatsV4()
		{
			_Stats = new Dictionary<string, Int64>();
		}

		public FMemoryAllocationStatsV4( FMemoryAllocationStatsV4 Other )
		{
			this._Stats = new Dictionary<string, Int64>( Other._Stats );
		}

		public Int64 this[string StatName]
		{
			get
			{
				Int64 Value = 0;
				_Stats.TryGetValue(StatName, out Value);
				return Value;
			}
			set
			{
				_Stats[StatName] = value;
			}
		}

		public Int64 NumStats()
		{
			return _Stats.Count;
		}

		/// <summary> Returns a difference between old and new platform memory stats. </summary>
		public static FMemoryAllocationStatsV4 Diff( FMemoryAllocationStatsV4 Old, FMemoryAllocationStatsV4 New )
		{
			FMemoryAllocationStatsV4 Diff = new FMemoryAllocationStatsV4();

			var Keys = Old._Stats.Keys;

			foreach( string KeyValue in Keys )
			{
				Int64 OldValue = Old[KeyValue];
				Int64 NewValue = New[KeyValue];

				Diff[KeyValue] = NewValue - OldValue;
			}

			return Diff;
		}

		/// <summary> Creates a new copy of this class. </summary>
		public FMemoryAllocationStatsV4 DeepCopy()
		{
			FMemoryAllocationStatsV4 Copy = new FMemoryAllocationStatsV4(this);
			return Copy;
		}

		/// <summary> Converts this memory allocation statistics to its equivalent string representation. </summary>
		public override string ToString()
		{
			StringBuilder StrBuilder = new StringBuilder( 1024 );

			foreach( KeyValuePair<string, Int64> KeyPairValue in _Stats )
			{
				StrBuilder.AppendLine( string.Format( "	{0}: {1}", KeyPairValue.Key, MainWindow.FormatSizeString2( KeyPairValue.Value ) ) );
			}

			return StrBuilder.ToString();
		}

		
	};

	/// <summary>
	/// Variable sized token emitted by capture code. The parsing code ReadNextToken deals with this and updates
	/// internal data. The calling code is responsible for only accessing member variables associated with the type.
	/// </summary>
	public class FStreamToken
	{
		// Parsing configuration

		/// <summary> Mask of pointer field to get a real pointer (the two LSB are type fields, and the top bits may be a pool index. </summary>
		public static UInt64 PointerMask = 0xFFFFFFFFFFFFFFFCUL;

		public const UInt64 TypeMask = 0x3UL;
		public static int PoolShift = 64;

		/// <summary> Whether to decode the script callstacks. </summary>
		public static bool bDecodeScriptCallstacks;

		/// <summary> Version of the stream, same as FProfileDataHeader.Version  </summary>
		public static uint Version;

		/// <summary> Position in the stream. </summary>
		public ulong StreamIndex = 0;

		/// <summary> Type of token. </summary>
		public EProfilingPayloadType Type;

		/// <summary> Subtype of token if it's of TYPE_Other. </summary>
		public EProfilingPayloadSubType SubType;

		/// <summary> Pointer in the case of alloc / free. </summary>
		public UInt64 Pointer;

		/// <summary> Old pointer in the case of realloc. </summary>
		public UInt64 OldPointer;

		/// <summary> New pointer in the case of realloc. </summary>
		public UInt64 NewPointer;

		/// <summary> Index into callstack array. </summary>
		public Int32 CallStackIndex;

		/// <summary> Index into tags array. </summary>
		public Int32 TagsIndex;

		/// <summary> Size of allocation in alloc / realloc case. </summary>
		public Int32 Size;

		/// <summary> Payload if type is TYPE_Other. </summary>
		public UInt32 Payload;

		/// <summary> Payload data if type is TYPE_Other and subtype is SUBTYPE_SnapshotMarker or SUBTYPE_TextMarker. Index into array of unique names. </summary>
		public int TextIndex;

		/// <summary> Payload data if type is TYPE_Other and subtype is SUBTYPE_FrameTimeMarker. Current delta time in seconds. </summary>
		public float DeltaTime;

		/// <summary> Total time, increased every time DeltaTime has been read. </summary>
		public float TotalTime = 0.0f;

		/// <summary> Time between two consecutive snapshot markers. </summary>
		public float ElapsedTime = 0.0f;

		/// <summary> Memory pool. </summary>
		public EMemoryPool Pool;

		/// <summary> Platform dependent memory metrics. </summary>
		public List<long> Metrics = new List<long>();

		/// <summary> A list of indices into the name table, one for each loaded level including persistent level. </summary>
		public List<int> LoadedLevels = new List<int>();

		/// <summary> Generic memory allocation stats for V4. </summary>
		public FMemoryAllocationStatsV4 MemoryAllocationStats4 = new FMemoryAllocationStatsV4();

		/// <summary> Index into script callstack array. </summary>
		public int ScriptCallstackIndex;

		/// <summary> Index into script-object type array. </summary>
		public int ScriptObjectTypeIndex;

		/// <summary> Reads a script callstack. </summary>
		/// <param name="BinaryStream"> Stream to serialize data from </param>
		void ReadScriptCallstack( BinaryReader BinaryStream )
		{
			if( bDecodeScriptCallstacks )
			{
				ScriptCallstackIndex = BinaryStream.ReadUInt16();
				bool bAllocatingScriptObject = ( ScriptCallstackIndex & 0x8000 ) != 0;

				ScriptCallstackIndex = ScriptCallstackIndex & 0x7FFF;
				if( ScriptCallstackIndex == 0x7FFF )
				{
					ScriptCallstackIndex = -1;
				}

				if( bAllocatingScriptObject )
				{
					int ScriptObjectTypeCompactedName = BinaryStream.ReadInt32();
					ScriptObjectTypeIndex = ScriptObjectTypeCompactedName & 0x00FFFFFF;
					// Number is always 0.
					int ScriptObjectTypeNumber = ( ScriptObjectTypeCompactedName & 0x7FFFFFFF ) >> 24;
				}
			}
		}

		/// <summary> Reads additional data required for GCM callstacks. </summary>
		/// <param name="BinaryStream"> Stream to serialize data from </param>
		bool ReadGCMData(BinaryReader BinaryStream, ref UInt32 UnsignedSize )
		{
			// @see FMallocGcmProfiler.h
			const UInt32 GCM_MEMORY_PROFILER_ID_BIT = 0x80000000;
			bool bHasGCMData = false;

			if( ( UnsignedSize & GCM_MEMORY_PROFILER_ID_BIT ) == GCM_MEMORY_PROFILER_ID_BIT )
			{
				// Lower five bits are EAllocationType, upper three bits are EMemoryPool
				byte AllocationType = BinaryStream.ReadByte();
				Pool = FMemoryPoolInfo.ConvertToMemoryPoolFlag( ( EMemoryPoolSerialized )( AllocationType & 0xe0 ) );

				UnsignedSize &= ~GCM_MEMORY_PROFILER_ID_BIT;

				bHasGCMData = true;
			}

			return bHasGCMData;
		}

		/// <summary> Reads platform dependent memory metrics. </summary>
		/// <param name="BinaryStream"> Stream to serialize data from </param>
		void ReadMetrics(BinaryReader BinaryStream)
		{
			// Read the metrics 
			int NumMetrics = BinaryStream.ReadByte();
			for (int i = 0; i < NumMetrics; i++)
			{
				Metrics.Add(BinaryStream.ReadInt64());
			}
		}

		/// <summary> Reads names of all loaded levels. </summary>
		/// <param name="BinaryStream"> Stream to serialize data from </param>
		void ReadLoadedLevels( BinaryReader BinaryStream )
		{
			// Read the currently loaded levels
			int NumLevels = BinaryStream.ReadInt16();
			for( int LevelIndex = 0; LevelIndex < NumLevels; LevelIndex++ )
			{
				int LevelNameIndex = BinaryStream.ReadInt32();

				LoadedLevels.Add( LevelNameIndex );
			}
		}

		/// <summary> Reads generic memory allocations stats. </summary>
		/// <param name="BinaryStream"> Stream to serialize data from </param>
		private void ReadMemoryAllocationsStats( BinaryReader BinaryStream )
		{
			// Read Platform Memory and Allocator Stats
			// @see FMallocProfiler::WriteMemoryAllocationStats
			int StatsNum = BinaryStream.ReadByte();

			for( int StatIndex = 0; StatIndex < StatsNum; StatIndex++ )
			{
				int NameIndex = BinaryStream.ReadInt32();
				Int64 StatValue = BinaryStream.ReadInt64();
				string StatName = FStreamInfo.GlobalInstance.NameArray[NameIndex];

				MemoryAllocationStats4[StatName] = StatValue;
			}	
		}

		/// <summary> Updates the token with data read from passed in stream and returns whether we've reached the end. </summary>
		/// <param name="BinaryStream"> Stream to serialize data from </param>
		public bool ReadNextToken( BinaryReader BinaryStream )
		{
			bool bReachedEndOfStream = false;

			// Initialize to defaults.
			SubType = EProfilingPayloadSubType.SUBTYPE_Unknown;
			TextIndex = -1;

			// Read the pointer and convert to token type by looking at lowest 2 bits. Pointers are always
			// 4 byte aligned so need to clear them again after the conversion.
			UInt64 RawPointerData = BinaryStream.ReadUInt64();

			Pool = EMemoryPool.MEMPOOL_Main;
			Type = (EProfilingPayloadType)(RawPointerData & TypeMask);
			Pointer = RawPointerData & PointerMask;

			Metrics.Clear();
			LoadedLevels.Clear();
			CallStackIndex = -1;
			TagsIndex = -1;
			ScriptCallstackIndex = -1;
			ScriptObjectTypeIndex = -1;

			NewPointer = 0;
			OldPointer = 0;
			Size = -1;
			Payload = 0;
			DeltaTime = -1.0f;

			// Serialize based on token type.
			switch( Type )
			{
				// Malloc
				case EProfilingPayloadType.TYPE_Malloc:
				{
					// Get the call stack index.
					CallStackIndex = BinaryStream.ReadInt32();

					// Get the tags index.
					if (Version >= 7)
					{
						TagsIndex = BinaryStream.ReadInt32();
					}

					// Get the size of an allocation.
					UInt32 UnsignedSize = BinaryStream.ReadUInt32();

					// Read GCM data if any.
					bool bHasGCMData = ReadGCMData( BinaryStream, ref UnsignedSize );

					// If GCM doesn't exist read script callstack.
					if( bHasGCMData == false )
					{
						ReadScriptCallstack( BinaryStream );
					}
					Size = ( int )UnsignedSize;
					break;
				}
				

				// Free
				case EProfilingPayloadType.TYPE_Free:
				{
					break;
				}

				// Realloc
				case EProfilingPayloadType.TYPE_Realloc:
				{
					OldPointer = Pointer;
					NewPointer = BinaryStream.ReadUInt64();
					CallStackIndex = BinaryStream.ReadInt32();

					// Get the tags index.
					if (Version >= 7)
					{
						TagsIndex = BinaryStream.ReadInt32();
					}

					UInt32 UnsignedSize = BinaryStream.ReadUInt32();
					bool bHasGCMData = ReadGCMData( BinaryStream, ref UnsignedSize );
					if( bHasGCMData == false )
					{
						ReadScriptCallstack( BinaryStream );
					}
					Size = ( int )UnsignedSize;
					break;
				}
				

				// Other
				case EProfilingPayloadType.TYPE_Other:
				{
					SubType = ( EProfilingPayloadSubType )BinaryStream.ReadInt32();
					Payload = BinaryStream.ReadUInt32();

					// Read subtype.
					switch( SubType )
					{
						// End of stream!
						case EProfilingPayloadSubType.SUBTYPE_EndOfStreamMarker:
						{
							ReadMemoryAllocationsStats( BinaryStream );
							ReadLoadedLevels( BinaryStream );
							bReachedEndOfStream = true;
							break;
						}
						

						case EProfilingPayloadSubType.SUBTYPE_EndOfFileMarker:
						{
							break;
						}

						case EProfilingPayloadSubType.SUBTYPE_SnapshotMarker_LoadMap_Start:
						case EProfilingPayloadSubType.SUBTYPE_SnapshotMarker_LoadMap_Mid:
						case EProfilingPayloadSubType.SUBTYPE_SnapshotMarker_LoadMap_End:
						case EProfilingPayloadSubType.SUBTYPE_SnapshotMarker_GC_Start:
						case EProfilingPayloadSubType.SUBTYPE_SnapshotMarker_GC_End:
						case EProfilingPayloadSubType.SUBTYPE_SnapshotMarker_LevelStream_Start:
						case EProfilingPayloadSubType.SUBTYPE_SnapshotMarker_LevelStream_End:
						case EProfilingPayloadSubType.SUBTYPE_SnapshotMarker:
						{
							TextIndex = ( int )Payload;

							ReadMemoryAllocationsStats( BinaryStream );
							ReadLoadedLevels( BinaryStream );
							break;
						}
						

						case EProfilingPayloadSubType.SUBTYPE_FrameTimeMarker:
						{
							DeltaTime = BitConverter.ToSingle( System.BitConverter.GetBytes( Payload ), 0 );
							TotalTime += DeltaTime;
							ElapsedTime += DeltaTime;
							break;
						}

						case EProfilingPayloadSubType.SUBTYPE_TextMarker:
						{
							TextIndex = ( int )Payload;
							break;
						}

						case EProfilingPayloadSubType.SUBTYPE_MemoryAllocationStats:
						{
							ReadMemoryAllocationsStats( BinaryStream );
							break;
						}

						case EProfilingPayloadSubType.SUBTYPE_TotalUsed:
						case EProfilingPayloadSubType.SUBTYPE_TotalAllocated:
						case EProfilingPayloadSubType.SUBTYPE_CPUUsed:
						case EProfilingPayloadSubType.SUBTYPE_CPUSlack:
						case EProfilingPayloadSubType.SUBTYPE_CPUWaste:
						case EProfilingPayloadSubType.SUBTYPE_GPUUsed:
						case EProfilingPayloadSubType.SUBTYPE_GPUSlack:
						case EProfilingPayloadSubType.SUBTYPE_GPUWaste:
						case EProfilingPayloadSubType.SUBTYPE_ImageSize:
						case EProfilingPayloadSubType.SUBTYPE_OSOverhead:
						{
							break;
						}

						default:
						{
							throw new InvalidDataException();
						}
					}
					break;
				}
			}

			return !bReachedEndOfStream;
		}
	}
}