using System.Collections.Generic;
using System;
using System.Text;
using System.Drawing;

namespace LB_VisionControls
{
    /// <summary>
    /// Line of text
    /// </summary>
    public class Line : IList<Char>
    {
        protected List<Char> chars;

        public string FoldingStartMarker { get; set; }
        public string FoldingEndMarker { get; set; }
        /// <summary>
        /// Text of line was changed
        /// </summary>
        public bool IsChanged { get; set; }
        /// <summary>
        /// Time of last visit of caret in this line
        /// </summary>
        /// <remarks>This property can be used for forward/backward navigating</remarks>
        public DateTime LastVisit { get; set; }
        /// <summary>
        /// Background brush.
        /// </summary>
        public Brush BackgroundBrush { get; set; }
        /// <summary>
        /// Unique ID
        /// </summary>
        public int UniqueId { get; private set; }
        /// <summary>
        /// Count of needed start spaces for AutoIndent
        /// </summary>
        public int AutoIndentSpacesNeededCount
        {
            get;
            internal set;
        }

        internal Line(int uid)
        {
            this.UniqueId = uid;
            chars = new List<Char>();
        }


        /// <summary>
        /// Clears style of chars, delete folding markers
        /// </summary>
        public void ClearStyle(StyleIndex styleIndex)
        {
            FoldingStartMarker = null;
            FoldingEndMarker = null;
            for (int i = 0; i < Count; i++)
            {
                Char c = this[i];
                c.style &= ~styleIndex;
                this[i] = c;
            }
        }

        /// <summary>
        /// Text of the line
        /// </summary>
        public virtual string Text
        {
            get
            {
                StringBuilder sb = new StringBuilder(Count);
                foreach (Char c in this)
                    sb.Append(c.c);
                return sb.ToString();
            }
        }

        /// <summary>
        /// Clears folding markers
        /// </summary>
        public void ClearFoldingMarkers()
        {
            FoldingStartMarker = null;
            FoldingEndMarker = null;
        }

        /// <summary>
        /// Count of start spaces
        /// </summary>
        public int StartSpacesCount
        {
            get
            {
                int spacesCount = 0;
                for (int i = 0; i < Count; i++)
                    if (this[i].c == ' ')
                        spacesCount++;
                    else
                        break;
                return spacesCount;
            }
        }

        public int IndexOf(Char item)
        {
            return chars.IndexOf(item);
        }

        public void Insert(int index, Char item)
        {
            chars.Insert(index, item);
        }

        public void RemoveAt(int index)
        {
            chars.RemoveAt(index);
        }

        public Char this[int index]
        {
            get
            {
                return chars[index];
            }
            set
            {
                chars[index] = value;
            }
        }

        public void Add(Char item)
        {
            chars.Add(item);
        }

        public void Clear()
        {
            chars.Clear();
        }

        public bool Contains(Char item)
        {
            return chars.Contains(item);
        }

        public void CopyTo(Char[] array, int arrayIndex)
        {
            chars.CopyTo(array, arrayIndex);
        }

        /// <summary>
        /// Chars count
        /// </summary>
        public int Count
        {
            get { return chars.Count; }
        }

        public bool IsReadOnly
        {
            get { return false; }
        }

        public bool Remove(Char item)
        {
            return chars.Remove(item);
        }

        public IEnumerator<Char> GetEnumerator()
        {
            return chars.GetEnumerator();
        }

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return chars.GetEnumerator() as System.Collections.IEnumerator;
        }

        public virtual void RemoveRange(int index, int count)
        {
            if (index >= Count)
                return;
            chars.RemoveRange(index, Math.Min(Count - index, count));
        }

        public virtual void TrimExcess()
        {
            chars.TrimExcess();
        }

        public virtual void AddRange(IEnumerable<Char> collection)
        {
            chars.AddRange(collection);
        }
    }

    public struct LineInfo
    {
        List<int> cutOffPositions;
        //Y coordinate of line on screen
        internal int startY;// = -1;
        /// <summary>
        /// Visible state
        /// </summary>
        public VisibleState VisibleState;

        public LineInfo(int startY)
        {
            cutOffPositions = null;
            VisibleState = VisibleState.Visible;
            this.startY = startY;
        }
        /// <summary>
        /// Positions for wordwrap cutoffs
        /// </summary>
        public List<int> CutOffPositions
        {
            get
            {
                if (cutOffPositions == null)
                    cutOffPositions = new List<int>();
                return cutOffPositions;
            }
        }

        /// <summary>
        /// Count of wordwrap string count for this line
        /// </summary>
        public int WordWrapStringsCount
        {
            get
            {
                switch (VisibleState)
                {
                    case VisibleState.Visible:
                        if (cutOffPositions == null)
                            return 1;
                        else
                            return cutOffPositions.Count + 1;
                    case VisibleState.Hidden: return 0;
                    case VisibleState.StartOfHiddenBlock: return 1;
                }

                return 0;
            }
        }

        internal int GetWordWrapStringStartPosition(int iWordWrapLine)
        {
            return iWordWrapLine == 0 ? 0 : CutOffPositions[iWordWrapLine - 1];
        }

        internal int GetWordWrapStringFinishPosition(int iWordWrapLine, Line line)
        {
            if (WordWrapStringsCount <= 0)
                return 0;
            return iWordWrapLine == WordWrapStringsCount - 1 ? line.Count - 1 : CutOffPositions[iWordWrapLine] - 1;
        }

        /// <summary>
        /// Gets index of wordwrap string for given char position
        /// </summary>
        public int GetWordWrapStringIndex(int iChar)
        {
            if (cutOffPositions == null || cutOffPositions.Count == 0) return 0;
            for (int i = 0; i < cutOffPositions.Count; i++)
                if (cutOffPositions[i] >/*>=*/ iChar)
                    return i;
            return cutOffPositions.Count;
        }

        /// <summary>
        /// Calculates wordwrap cutoffs
        /// </summary>
        internal void CalcCutOffs(int maxCharsPerLine, bool allowIME, bool charWrap, Line line)
        {
            int segmentLength = 0;
            int cutOff = 0;
            CutOffPositions.Clear();

            for (int i = 0; i < line.Count; i++)
            {
                char c = line[i].c;
                if (charWrap)
                {
                    //char wrapping
                    cutOff = Math.Min(i + 1, line.Count - 1);
                }
                else
                {
                    //word wrapping
                    if (allowIME && isCJKLetter(c))//in CJK languages cutoff can be in any letter
                    {
                        cutOff = i;
                    }
                    else
                        if (!char.IsLetterOrDigit(c) && c != '_')
                        cutOff = Math.Min(i + 1, line.Count - 1);
                }

                segmentLength++;

                if (segmentLength == maxCharsPerLine)
                {
                    if (cutOff == 0 || (cutOffPositions.Count > 0 && cutOff == cutOffPositions[cutOffPositions.Count - 1]))
                        cutOff = i + 1;
                    CutOffPositions.Add(cutOff);
                    segmentLength = 1 + i - cutOff;
                }
            }
        }

        private bool isCJKLetter(char c)
        {
            int code = Convert.ToInt32(c);
            return
            (code >= 0x3300 && code <= 0x33FF) ||
            (code >= 0xFE30 && code <= 0xFE4F) ||
            (code >= 0xF900 && code <= 0xFAFF) ||
            (code >= 0x2E80 && code <= 0x2EFF) ||
            (code >= 0x31C0 && code <= 0x31EF) ||
            (code >= 0x4E00 && code <= 0x9FFF) ||
            (code >= 0x3400 && code <= 0x4DBF) ||
            (code >= 0x3200 && code <= 0x32FF) ||
            (code >= 0x2460 && code <= 0x24FF) ||
            (code >= 0x3040 && code <= 0x309F) ||
            (code >= 0x2F00 && code <= 0x2FDF) ||
            (code >= 0x31A0 && code <= 0x31BF) ||
            (code >= 0x4DC0 && code <= 0x4DFF) ||
            (code >= 0x3100 && code <= 0x312F) ||
            (code >= 0x30A0 && code <= 0x30FF) ||
            (code >= 0x31F0 && code <= 0x31FF) ||
            (code >= 0x2FF0 && code <= 0x2FFF) ||
            (code >= 0x1100 && code <= 0x11FF) ||
            (code >= 0xA960 && code <= 0xA97F) ||
            (code >= 0xD7B0 && code <= 0xD7FF) ||
            (code >= 0x3130 && code <= 0x318F) ||
            (code >= 0xAC00 && code <= 0xD7AF);

        }
    }

    public enum VisibleState : byte
    {
        Visible, StartOfHiddenBlock, Hidden
    }

    public enum IndentMarker
    {
        None,
        Increased,
        Decreased
    }
}