// Copyright (c) Microsoft Corporation.

// Licensed under the MIT License.

#if NET6_0

using System;

using System.Collections.Generic;

using System.IO;

using System.Management.Automation;

using System.Management.Automation.Language;

using BenchmarkDotNet.Attributes;

using MicroBenchmarks;

namespace Engine

{

[BenchmarkCategory(Categories.Engine, Categories.Internal)]

public class Compiler

{

private static readonly Dictionary<string, ScriptBlockAst> s_scriptBlocksDict;

private static readonly List<string> s_functionNames;

private ScriptBlockAst _currentAst;

static Compiler()

{

string pattern = string.Format("{0}test{0}perf{0}benchmarks", Path.DirectorySeparatorChar);

string location = typeof(Compiler).Assembly.Location;

string testFilePath = null;

int start = location.IndexOf(pattern, StringComparison.Ordinal);

if (start > 0)

{

testFilePath = Path.Join(location.AsSpan(0, start + pattern.Length), "assets", "compiler.test.ps1");

}

var topScriptBlockAst = Parser.ParseFile(testFilePath, tokens: out _, errors: out _);

var allFunctions = topScriptBlockAst.FindAll(ast => ast is FunctionDefinitionAst, searchNestedScriptBlocks: false);

s_scriptBlocksDict = new Dictionary<string, ScriptBlockAst>(capacity: 16);

s_functionNames = new List<string>(capacity: 16);

foreach (FunctionDefinitionAst function in allFunctions)

{

s_functionNames.Add(function.Name);

s_scriptBlocksDict.Add(function.Name, function.Body);

}

}

[ParamsSource(nameof(FunctionName))]

public string FunctionsToCompile { get; set; }

public IEnumerable<string> FunctionName() => s_functionNames;

[GlobalSetup(Target = nameof(CompileFunction))]

public void GlobalSetup()

{

_currentAst = s_scriptBlocksDict[FunctionsToCompile];

// Run it once to get the C# code jitted.

// The first call to this takes relatively too long, which makes the BDN's heuristic incorrectly

// believe that there is no need to run many ops in each iteration. However, the subsequent runs

// of this method is much faster than the first run, and this causes 'MinIterationTime' warnings

// to our benchmarks and make the benchmark results not reliable.

// Calling this method once in 'GlobalSetup' is a workaround.

// See https://github.com/dotnet/BenchmarkDotNet/issues/837#issuecomment-828600157

CompileFunction();

}

[Benchmark]

public bool CompileFunction()

{

var compiledData = new CompiledScriptBlockData(_currentAst, isFilter: false);

return compiledData.Compile(true);

}

}

}

#endif