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

namespace ST.Library.UI.STTextBox
{
 public abstract class TextStyleMonitor : ITextStyleMonitor
 {
 public static List<TextStyleRange> FillDefaultStyle(List<TextStyleRange> lst, int nTextLength, TextStyle style) {
 List<TextStyleRange> lstRet = new List<TextStyleRange>();
 int nIndex = 0;
 foreach (var tsr in lst) {
 if (nIndex != tsr.Index) {
 lstRet.Add(new TextStyleRange() {
 Index = nIndex,
 Length = tsr.Index - nIndex,
 Style = style
 });
 }
 lstRet.Add(new TextStyleRange() {
 Index = tsr.Index,
 Length = tsr.Length,
 Style = tsr.Style
 });
 nIndex = tsr.Index + tsr.Length;
 }
 if (nIndex < nTextLength) {
 lstRet.Add(new TextStyleRange() {
 Index = nIndex,
 Length = nTextLength - nIndex
 });
 }
 return lstRet;
 }

 public static TextStyleRange GetStyleFromCharIndex(int nIndex, List<TextStyleRange> lst) {
 if (lst == null || lst.Count == 0) {
 return TextStyleRange.Empty;
 }
 int nLeft = 0, nRight = lst.Count - 1, nMid = 0;
 while (nLeft <= nRight) {
 nMid = (nLeft + nRight) >> 1;
 if (lst[nMid].Index > nIndex) {
 nRight = nMid - 1;
 } else if (lst[nMid].Index + lst[nMid].Length <= nIndex) {
 nLeft = nMid + 1;
 } else {
 return lst[nMid];
 }
 }
 if (nIndex < lst[nMid].Index) {
 if (nMid == 0) return new TextStyleRange() { Index = 0, Length = lst[0].Index };
 return new TextStyleRange() {
 Index = lst[nMid - 1].Index + lst[nMid - 1].Length,
 Length = lst[nMid].Index - lst[nMid - 1].Index - lst[nMid - 1].Length
 };
 }
 if (nMid == lst.Count - 1) return new TextStyleRange() {
 Index = lst[nMid].Index + lst[nMid].Length, Length = int.MaxValue
 };
 return new TextStyleRange() {
 Index = lst[nMid].Index + lst[nMid].Length,
 Length = lst[nMid + 1].Index - lst[nMid].Index - lst[nMid].Length
 };
 }

 public abstract void Init(string strText);
 public abstract void OnSelectionChanged(TextManager textManager, int nStart, int nLen);
 public abstract void OnTextChanged(TextManager textManager, List<TextHistoryRecord> thrs);
 public abstract TextStyleRange GetStyleFromCharIndex(int nIndex);
 }
}