using System;

/// <header>
/// <wox>
///     <version>1.0</version>
///     <author>Carlos R. Jaimez Gonzalez</author>
///     <author>Simon M. Lucas</author>
///     <site>http://woxserializer.sourceforge.net/</site>
/// </wox>
/// <wox>
///     <version>1.5</version>
///     <author>Steven M Lewis</author>
/// </wox>
/// <wox>
///     <version>2.0</version>
///     <author>George A Smith</author>
///     <svn>http://woxserializer.sourceforge.net/</svn>
///     <note>XML form for vs 2 is more compact and therefor incompatible with vs 1</note>
/// </wox>
/// </header>

namespace wox.serial
{
    public class CharSource
    {
        private readonly string mSource;
        private int mFrom;
        private readonly int mTo;

        public CharSource(string pSource, int pFrom)
        {
            mSource = pSource ?? "";
            if ((mFrom = pFrom) < 0)
            {
                throw new ArgumentException("'From' not allowed to be negative");
            }
            mTo = mSource.Length;
        }

        public CharSource(string pSource)
            : this(pSource, 0)
        {
        }

        public CharSource(string pSource, int pFrom, int pTo)
            : this(pSource, pFrom)
        {
            if (pTo > mTo)
            {
                throw new ArgumentException("'To' not allowed to be greater than the length of the 'Source' string");
            }
            if (pTo < 0)
            {
                mTo += pTo;
            }
            else
            {
                mTo = pTo;
            }
        }

        public bool AnyRemaining()
        {
            return (mFrom < mTo);
        }

        public int Peek()
        {
            return AnyRemaining() ? mSource[mFrom] : -1;
        }

        public int Get()
        {
            return AnyRemaining() ? mSource[mFrom++] : -1;
        }

        public string GetUpTo(char c)
        {
            int at = mSource.IndexOf(c, mFrom);
            if (at == -1)
            {
                return "";
            }
            string rv = mSource.Substring(mFrom, at);
            mFrom = at;
            return rv;
        }

        public bool ConsumeSpaces()
        {
            while (Peek() == ' ')
            {
                mFrom++;
            }
            return AnyRemaining();
        }

        public string GetUpToNonVisible7BitAscii()
        {
            if (!AnyRemaining())
            {
                return "";
            }
            int zFrom = mFrom;
            for (int c = Peek(); (c != -1) && ((' ' < c) && (c <= 126)); c = Peek())
            {
                mFrom++;
            }
            return mSource.Substring(zFrom, mFrom);
        }

        public bool ConsumeNonVisible7BitAscii()
        {
            for (int c = Peek(); (c != -1) && ((c <= ' ') || (126 < c)); c = Peek())
            {
                mFrom++;
            }
            return AnyRemaining();
        }

        public int GetFrom()
        {
            return mFrom;
        }

        public int GetLastFrom()
        {
            return mFrom - 1;
        }

        public override string ToString()
        {
            return mSource.Substring(mFrom, mTo);
        }
    }
}