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

namespace TableParser
{
    [TestFixture]
    public class QuotedFieldTaskTests
    {
        [TestCase("''", 0, "", 2)]
        [TestCase("'q'", 0, "q", 3)]
        [TestCase("\"qw'e", 0, "qw'e", 5)]
        [TestCase("q \"'w'\"\"'", 2, "'w'", 5)]
        [TestCase(@"'q\' w'", 0, "q' w", 7)]
        public void Test(string line, int startIndex, string expectedValue, int expectedLength)
        {
            var actualToken = QuotedFieldTask.ReadQuotedField(line, startIndex);
            Assert.AreEqual(new Token(expectedValue, startIndex, expectedLength), actualToken);
        }
    }

    class QuotedFieldTask
    {
        public static Token ReadQuotedField(string line, int startIndex)
        {
            var tokenString = new StringBuilder();
            var quote = line[startIndex];
            var index = startIndex + 1;

            for (; index < line.Length; index++)
            {
                if (line[index] == quote)
                    break;

                if (line[index] == '\\')
                    index++;

                tokenString.Append(line[index]);
            }

            if (index < line.Length)
                index++;

            return new Token(tokenString.ToString(), startIndex, index - startIndex);
        }
    }
}