using Microsoft.Diagnostics.Tracing.Session;
using ProfilerHelpers;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace Tracing
{
	static class Program
	{


		static public async Task<int> CreateTracingSession( bool noSampling, bool sortBySize, int topTypesLimit )
		{
			ShowHeader();

			try
			{

				TraceEventSession session = new TraceEventSession(
						"Tracing",
						TraceEventSessionOptions.Create
						);

				log.info( $"Create PerProcessProfilingState" );

				using( var processes = new PerProcessProfilingState() )
				{
					log.info( $"Create Memory profiler for session" );
					var profiler = new Memory( session, processes );

					log.info( $"Start task" );
					var task = profiler.StartAsync( noSampling );

					/*
					log.info( $"await the Continue" );
					await task.ContinueWith( ( t ) => {
						log.info( $"Task is done, Dispose" );
						session.Dispose();
					} );
					*/

					//log.info("Press ENTER to stop memory profiling");
					//Console.ReadLine();

					/*
					try
					{
						await task;
						ShowResults( processes, sortBySize, topTypesLimit );

						return 0;
					}
					catch( Exception x )
					{
						log.info( x.Message );
						ShowHelp();
					}
					*/
				}

				return -1;
			}
			catch( Exception x )
			{
				log.info( x.Message );
				ShowHelp();
			}

			return -2;
		}

		private static void ShowResults( PerProcessProfilingState processes, bool sortBySize, int topTypesLimit )
		{
			foreach( var pid in processes.Allocations.Keys )
			{
				// skip processes without symbol resolution
				if( !processes.Methods.ContainsKey( pid ) )
					continue;

				// skip processes without allocations
				if( !processes.Allocations[pid].GetAllAllocations().Any() )
					continue;

				ShowResults( GetProcessName( pid, processes.Names ), processes.Methods[pid], processes.Allocations[pid], sortBySize, topTypesLimit );
			}
		}

		private static string GetProcessName( int pid, Dictionary<int, string> names )
		{
			if( names.TryGetValue( pid, out var name ) )
				return name;

			return pid.ToString();
		}

		private static void ShowResults( string name, MethodStore methods, ProcessAllocations allocations, bool sortBySize, int topTypesLimit )
		{
			log.info( $"Memory allocations for {name}" );
			log.info( $"" );
			log.info( "---------------------------------------------------------" );
			log.info( "    Count        Size   Type" );
			log.info( "---------------------------------------------------------" );
			IEnumerable<AllocationInfo> types = ( sortBySize )
					? allocations.GetAllAllocations().OrderByDescending( a => a.Size )
					: allocations.GetAllAllocations().OrderByDescending( a => a.Count )
					;
			if( topTypesLimit != -1 )
				types = types.Take( topTypesLimit );

			foreach( var allocation in types )
			{
				log.info( $"{allocation.Count,9} {allocation.Size,11}   {allocation.TypeName}" );

				log.info( $"" );
				DumpStacks( allocation, methods );
				log.info( $"" );
			}
			log.info( $"" );
			log.info( $"" );
		}

		private static void DumpStacks( AllocationInfo allocation, MethodStore methods )
		{
			var stacks = allocation.Stacks.OrderByDescending( s => s.Count ).Take( 10 );
			foreach( var stack in stacks )
			{
				log.info( $"{stack.Count,6} allocations" );
				log.info( "----------------------------------" );
				DumpStack( stack.Stack, methods );
				log.info( $"" );
			}
		}

		private static void DumpStack( AddressStack stack, MethodStore methods )
		{
			var callstack = stack.Stack;
			for( int i = 0; i < Math.Min( 10, callstack.Count ); i++ )
			{
				log.info( $"       {methods.GetFullName( callstack[i] )}" );
			}
		}

		private static void ShowHeader()
		{
			log.info( "Tracing v1.0.0 - Sampled memory profiler for .NET applications" );
			log.info( "by Christophe Nasarre" );
			log.info( $"" );
		}
		private static void ShowHelp()
		{
			log.info( $"" );
			log.info( "Tracing shows sampled allocations of a given .NET application." );
			log.info( "Usage: Tracing  [-a (all allocations)] [-c (sort by count instead of default by size)] [-t <type count (instead of 3 types by default)>]" );
			log.info( "   Ex: Tracing -t -1     (all types sampled allocations sorted by size)" );
			log.info( "   Ex: Tracing -c -t 10  (allocations for top 10 types sorted by count)" );
			log.info( $"" );
		}
	}
}