using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ICSharpCode.Decompiler.Tests.FSharpPatterns
{
	public class ToolLocator
	{
		public static string FindTool(string fileName)
		{
			var allPaths = FindPathForDotNetFramework().Concat(FindPathForWindowsSdk());
			return allPaths.Select(dir => Path.Combine(dir, fileName)).FirstOrDefault(File.Exists);
		}

		private static IEnumerable<string> FindPathForWindowsSdk()
		{
			string[] windowsSdkPaths = new[]
			{
				@"Microsoft SDKs\Windows\v8.0A\bin\NETFX 4.0 Tools\",
				@"Microsoft SDKs\Windows\v8.0A\bin\",
				@"Microsoft SDKs\Windows\v8.0\bin\NETFX 4.0 Tools\",
				@"Microsoft SDKs\Windows\v8.0\bin\",
				@"Microsoft SDKs\Windows\v7.1A\bin\NETFX 4.0 Tools\",
				@"Microsoft SDKs\Windows\v7.1A\bin\",
				@"Microsoft SDKs\Windows\v7.0A\bin\NETFX 4.0 Tools\",
				@"Microsoft SDKs\Windows\v7.0A\bin\",
				@"Microsoft SDKs\Windows\v6.1A\bin\",
				@"Microsoft SDKs\Windows\v6.0A\bin\",
				@"Microsoft SDKs\Windows\v6.0\bin\",
				@"Microsoft.NET\FrameworkSDK\bin"
			};

			foreach (var possiblePath in windowsSdkPaths)
			{
				string fullPath = string.Empty;

				// Check alternate program file paths as well as 64-bit versions.
				if (Environment.Is64BitProcess)
				{
					fullPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles), possiblePath, "x64");
					if (Directory.Exists(fullPath))
					{
						yield return fullPath;
					}

					fullPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86), possiblePath, "x64");
					if (Directory.Exists(fullPath))
					{
						yield return fullPath;
					}
				}

				fullPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles), possiblePath);
				if (Directory.Exists(fullPath))
				{
					yield return fullPath;
				}

				fullPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86), possiblePath);
				if (Directory.Exists(fullPath))
				{
					yield return fullPath;
				}
			}
		}
		
		private static IEnumerable<string> FindPathForDotNetFramework()
		{
			string[] frameworkPaths = new[]
			{
				@"Microsoft.NET\Framework\v4.0.30319",
				@"Microsoft.NET\Framework\v2.0.50727"
			};

			foreach (var possiblePath in frameworkPaths)
			{
				string fullPath = string.Empty;

				if (Environment.Is64BitProcess)
				{
					fullPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Windows), possiblePath.Replace(@"\Framework\", @"\Framework64\"));
					if (Directory.Exists(fullPath))
					{
						yield return fullPath;
					}
				}

				fullPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Windows), possiblePath);
				if (Directory.Exists(fullPath))
				{
					yield return fullPath;
				}
			}
		}
	}
}