// ****************************************************************

// This is free software licensed under the NUnit license. You may

// obtain a copy of the license at http://nunit.org

// ****************************************************************



using System;

using System.Collections.Generic;

using System.Text;

using System.Collections;



namespace NUnit.UiException.CodeFormatters

{

    /// <summary>

    /// (formerly named CSTokenCollection)

    /// 

    /// Manages an ordered collection of ClassifiedToken present in one line of text.

    /// </summary>

    public class ClassifiedTokenCollection

    {

        /// <summary>

        /// Target location when building a ClassifiedToken instance on the fly.

        /// </summary>

        protected ClassifiedToken _token;



        /// <summary>

        /// Keeps tracks of the data source.

        /// </summary>

        protected FormattedCode.CodeInfo _info;



        /// <summary>

        /// Store the current line startingPosition.

        /// </summary>

        protected int _lineIndex;



        /// <summary>

        /// This class requires subclassing.

        /// </summary>

        protected ClassifiedTokenCollection()

        {

            _token = new InternalToken();

        }



        /// <summary>

        /// Gets the number of ClassifiedToken present in this line of text.

        /// </summary>

        public int Count

        {

            get

            {

                int count;



                if (_lineIndex + 1 < _info.LineArray.Count)

                {

                    count = _info.LineArray[_lineIndex + 1] -

                            _info.LineArray[_lineIndex];

                }

                else

                {

                    count = _info.IndexArray.Count -

                            _info.LineArray[_lineIndex];

                }



                return (count);

            }

        }



        /// <summary>

        /// Gets the ClassifiedToken instance at the specified startingPosition.

        /// Warning: this indexer always return the same instance.

        /// To keep data safe, it is strongly recommanded to make

        /// a deep copy of the returned ClassifiedToken.

        /// </summary>

        /// <param name="startingPosition">A zero based value in the range: [0 - Count[</param>

        /// <returns>The ClassifiedToken at this startingPosition.</returns>

        public ClassifiedToken this[int index]

        {

            get

            {

                InternalToken result;



                result = (InternalToken)_token;

                _populateToken(_lineIndex, index, result);



                return (result); 

            }

        }



        /// <summary>

        /// Gets the part of the text at the given position.

        /// The returned string can be composed of one or severals words 

        /// all with the same style.

        /// </summary>

        private void _populateToken(int lineIndex, int tokenIndex, InternalToken output)

        {

            int tagZero;

            int tagStart;

            int tagEnd;

            int strIndex_start;

            int strIndex_end;

            string res;

            ClassificationTag tag;



            //

            // Gets value of tagStart and tagEnd

            // from which string indexes can be extracted 

            //



            tagZero = _info.LineArray[lineIndex];

            tagStart = tagZero + tokenIndex;

            tagEnd = tagStart + 1;



            strIndex_start = _info.IndexArray[tagStart];



            if (tagEnd < _info.IndexArray.Count)

            {

                strIndex_end = _info.IndexArray[tagEnd];

                res = _info.Text.Substring(strIndex_start, strIndex_end - strIndex_start);

            }

            else

                res = _info.Text.Substring(strIndex_start);



            //

            // Check the need to trimEnd() the resulting string.

            // We only want to trimEnd when current string is the

            // last part of the current line. Intermediary strings

            // must not be trimed end. At display time this would

            // lead to introduce bad shifting of text sequences.

            //



            if (res.EndsWith("\n"))

                res = res.TrimEnd();



            //

            // Convert the byte code into a ClassificationTag

            // for this string sequence

            //



            tag = _getTagFromByteValue(_info.TagArray[tagStart]);



            // and populate result



            output.Setup(res, tag);



            return;

        }



        /// <summary>

        /// Converts the given value into the matching ClassificationTag.

        /// </summary>

        private ClassificationTag _getTagFromByteValue(byte value)

        {

            switch (value)

            {

                case 0: return (ClassificationTag.Code);

                case 1: return (ClassificationTag.Keyword);

                case 2: return (ClassificationTag.Comment);

                case 3: return (ClassificationTag.String);

                default:

                    UiExceptionHelper.CheckTrue(false, "should not reach this code", "value");

                    break;

            }



            return (ClassificationTag.Code);

        }



        /// <summary>

        /// Return a string filled with the text present at the current line startingPosition.

        /// </summary>

        public string Text

        {

            get

            {

                int index_start;

                int index_start_ptr; 

                int index_end;

                int index_end_ptr;

                string text;

                

                index_start_ptr = _info.LineArray[_lineIndex];

                index_start = _info.IndexArray[index_start_ptr];



                if (_lineIndex + 1 >= _info.LineArray.Count)

                    index_end = _info.Text.Length;

                else

                {

                    index_end_ptr = _info.LineArray[_lineIndex + 1];

                    index_end = _info.IndexArray[index_end_ptr];

                }



                if (index_end - index_start < 0)

                    throw new Exception(

                        "ClassifiedTokenCollection: Text: error: calling substring with negative length");



                text = _info.Text.Substring(index_start, index_end - index_start);

                text = text.TrimEnd();



                return (text);

            }

        }



        #region InternalToken



        class InternalToken : 

            ClassifiedToken

        {

            public InternalToken()

            {

            }



            public void Setup(string text, ClassificationTag tag)

            {

                _text = text;

                _tag = tag;

            }

        }



        #endregion                   

    }

}