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

namespace pmtest_client
{
    public class CommandLineSplit
    {
        public static IEnumerable<string> SplitArgs(string commandLine)
        {
            var result = new StringBuilder();

            var quoted = false;
            var escaped = false;
            var started = false;
            var allowcaret = false;
            for (int i = 0; i < commandLine.Length; i++)
            {
                var chr = commandLine[i];

                if (chr == '^' && !quoted)
                {
                    if (allowcaret)
                    {
                        result.Append(chr);
                        started = true;
                        escaped = false;
                        allowcaret = false;
                    }
                    else if (i + 1 < commandLine.Length && commandLine[i + 1] == '^')
                    {
                        allowcaret = true;
                    }
                    else if (i + 1 == commandLine.Length)
                    {
                        result.Append(chr);
                        started = true;
                        escaped = false;
                    }
                }
                else if (escaped)
                {
                    result.Append(chr);
                    started = true;
                    escaped = false;
                }
                else if (chr == '"')
                {
                    quoted = !quoted;
                    started = true;
                }
                else if (chr == '\\' && i + 1 < commandLine.Length && commandLine[i + 1] == '"')
                {
                    escaped = true;
                }
                else if (chr == ' ' && !quoted)
                {
                    if (started) yield return result.ToString();
                    result.Clear();
                    started = false;
                }
                else
                {
                    result.Append(chr);
                    started = true;
                }
            }

            if (started) yield return result.ToString();
        }
    }
}