// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System;
using Microsoft.Build.Locator;
using Roslyn.Test.Utilities;
using System.IO;
using System.Diagnostics.CodeAnalysis;
#if NETCOREAPP
using System.Text.Json.Nodes;
#endif
 
namespace Microsoft.CodeAnalysis.MSBuild.UnitTests
{
    internal partial class DotNetSdkMSBuildInstalled : ExecutionCondition
    {
        public static string? SdkPath { get; private set; } = null;
 
#if NETCOREAPP
        private static string? VersionString { get; } = null;
 
        static DotNetSdkMSBuildInstalled()
        {
            var solutionFolder = GetSolutionFolder();
 
            if (!TryGetSDKVersion(solutionFolder, out var version))
            {
                return;
            }
 
            if (TryGetSdkPath(solutionFolder, version, out var sdkPath, out var msbuildPath))
            {
                MSBuildLocator.RegisterMSBuildPath(msbuildPath);
                SdkPath = sdkPath;
            }
 
            VersionString = version;
            return;
 
            static bool TryGetSDKVersion(
                string solutionFolder,
                [NotNullWhen(true)] out string? version)
            {
                var globalJsonPath = Path.Combine(solutionFolder, "global.json");
                var globalJsonString = File.ReadAllText(globalJsonPath);
                version = JsonNode.Parse(globalJsonString)
                    ?["sdk"]
                    ?["version"]
                    ?.GetValue<string>();
                return version is not null;
            }
 
            static bool TryGetSdkPath(
                string solutionFolder,
                string version,
                [NotNullWhen(true)] out string? sdkPath,
                [NotNullWhen(true)] out string? msbuildPath)
            {
                sdkPath = null;
                msbuildPath = null;
 
                // use the local SDK if its there
                var sdkFolder = Path.Combine(solutionFolder, ".dotnet");
                var localSDK = Path.Combine(sdkFolder, "sdk", version);
                if (Directory.Exists(localSDK))
                {
                    sdkPath = sdkFolder;
                    msbuildPath = localSDK;
                    return true;
                }
 
                // check if sdk is installed
                var programFilesSDKFolder = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles), "dotnet");
                var programFilesSDK = Path.Combine(
                    programFilesSDKFolder, "sdk", version);
                if (Directory.Exists(programFilesSDK))
                {
                    sdkPath = programFilesSDKFolder;
                    msbuildPath = programFilesSDK;
                    return true;
                }
 
                var specifiedSDKPath = Environment.GetEnvironmentVariable("DOTNET_INSTALL_DIR");
                if (string.IsNullOrEmpty(specifiedSDKPath))
                {
                    return false;
                }
 
                var specifiedSDKFolder = Path.Combine(
                specifiedSDKPath,
                "dotnet", "sdk", version);
                if (Directory.Exists(specifiedSDKFolder))
                {
                    sdkPath = specifiedSDKPath;
                    msbuildPath = specifiedSDKFolder;
                    return true;
                }
 
                return false;
            }
 
            static string GetSolutionFolder()
            {
                // Expected assembly path:
                //  <solutionFolder>\artifacts\bin\Microsoft.CodeAnalysis.Workspaces.MSBuild.UnitTests\<Configuration>\<TFM>\Microsoft.CodeAnalysis.Workspaces.MSBuild.UnitTests.dll
                var assemblyLocation = typeof(DotNetSdkMSBuildInstalled).Assembly.Location;
                var solutionFolder = Directory.GetParent(assemblyLocation)
                    ?.Parent?.Parent?.Parent?.Parent?.Parent?.FullName;
                Assumes.NotNull(solutionFolder);
                return solutionFolder;
            }
        }
#endif
 
        public DotNetSdkMSBuildInstalled()
        {
        }
 
        public override bool ShouldSkip
            => SdkPath is null;
 
        public override string SkipReason
#if NETCOREAPP
            => $"Could not locate .NET SDK version {VersionString}.";
#else
            => $"Test runs on .NET Core only.";
#endif
    }
}