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

namespace FileWatcher
{
    class Utils
    {
        public static string ProgramFilesx86()
        {
            if (8 == IntPtr.Size
                || (!String.IsNullOrEmpty(Environment.GetEnvironmentVariable("PROCESSOR_ARCHITEW6432"))))
            {
                return Environment.GetEnvironmentVariable("ProgramFiles(x86)");
            }

            return Environment.GetEnvironmentVariable("ProgramFiles");
        }

        public static string ProgramFilesx64()
        {
            return Environment.GetEnvironmentVariable("ProgramW6432");
        }

        /// <summary>
        /// Gets the program default, Program Fils(x86) when program is compiled
        /// for 32 bit Windows, and Program Files when program is compiled for 
        /// 64bit Windows.
        /// </summary>
        /// <returns></returns>
        public static string ProgramFiles()
        {
            return Environment.GetEnvironmentVariable("ProgramFiles");
        }

        /// <summary>
        /// Returns Windows/System32 or Windows/SysWOW64 depending on your program
        /// </summary>
        /// <returns></returns>
        public static string SystemDirectory()
        {
            return Environment.SystemDirectory;
        }

        /// <summary>
        /// Creates a relative path from one file or folder to another.
        /// </summary>
        /// <param name="fromPath">Contains the directory that defines the start of the relative path.</param>
        /// <param name="toPath">Contains the path that defines the endpoint of the relative path.</param>
        /// <param name="dontEscape">Boolean indicating whether to add uri safe escapes to the relative path</param>
        /// <returns>The relative path from the start directory to the end path.</returns>
        /// <exception cref="ArgumentNullException"></exception>
        public static String MakeRelativePath(String fromPath, String toPath)
        {
            if (String.IsNullOrEmpty(fromPath)) throw new ArgumentNullException("fromPath");
            if (String.IsNullOrEmpty(toPath)) throw new ArgumentNullException("toPath");

            // If path doesn't end with '\\' it's assumed to be a file.
            if (fromPath.EndsWith("\\") == false)
            {
                fromPath += "\\";
            }

            Uri fromUri = new Uri(fromPath);
            Uri toUri = new Uri(toPath);

            Uri relativeUri = fromUri.MakeRelativeUri(toUri);
            String relativePath = Uri.UnescapeDataString(relativeUri.ToString());

            return relativePath.Replace('/', Path.DirectorySeparatorChar);
        }
    }
}