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

namespace ST.Library.UI.STTextBox
{
 public abstract class TextBoundary : ITextBoundary
 {
 public enum Type
 {
 Other,
 Double_Quote,
 Single_Quote,
 Hebrew_Letter,
 CR,
 LF,
 Newline,
 Extend,
 Regional_Indicator,
 Format,
 Katakana,
 ALetter,
 MidLetter,
 MidNum,
 MidNumLet,
 Numeric,
 ExtendNumLet,
 ZWJ,
 WSegSpace,
 Extended_Pictographic,
 Control,
 SpacingMark,
 L,
 V,
 T,
 LV,
 LVT,
 Prepend,
 E_Base,
 E_Modifier,
 Glue_After_Zwj,
 E_Base_GAZ,
 Custom_Property_Ascii
 }

 protected struct RangeInfo
 {
 public int Start;
 public int End;
 public int Type;
 }

 public List<string> Split(string strText) {
 List<string> lst_result = new List<string>(strText.Length);
 this.SplitPrivate(strText, lst_result, 0, null, null);
 return lst_result;
 }

 public int GetCount(string strText) {
 int nLen = this.SplitPrivate(strText, null, 0, null, null);
 return nLen;
 }

 public void Each(string strText, EachVoidCallBack cb) {
 this.SplitPrivate(strText, null, 0, cb, null);
 }

 public void Each(string strText, int nIndex, EachVoidCallBack cb) {
 this.SplitPrivate(strText, null, nIndex, cb, null);
 }

 public void Each(string strText, EachBoolCallBack cb) {
 this.SplitPrivate(strText, null, 0, null, cb);
 }

 public void Each(string strText, int nIndex, EachBoolCallBack cb) {
 this.SplitPrivate(strText, null, nIndex, null, cb);
 }

 public static int GetCodePoint(string strText, int nIndex) {
 if (strText[nIndex] < '\uD800' || strText[nIndex] > '\uDFFF') {
 return strText[nIndex];
 }
 if (char.IsHighSurrogate(strText, nIndex)) {
 if (nIndex + 1 >= strText.Length) {
 return 0;
 }
 } else {
 if (--nIndex < 0) {
 return 0;
 }
 }
 return ((strText[nIndex] & 0x03FF) << 10) + (strText[nIndex + 1] & 0x03FF) + 0x10000;
 }

 private int SplitPrivate(string strText, List<string> lst_result, int nIndexCurrent, EachVoidCallBack cb_void, EachBoolCallBack cb_bool) {
 int nCounter = 0;
 List<int> lst_history_break_type = new List<int>();
 if (string.IsNullOrEmpty(strText) || nIndexCurrent >= strText.Length) {
 return 0;
 }
 int nIndexCharStart = 0, nCharLen = 0, nLastCharLen = 0;
 int nCodePoint = 0;
 int nLeftBreakType = 0, nRightBreakType = 0;

 while (nIndexCurrent < strText.Length && char.IsLowSurrogate(strText, nIndexCurrent)) {
 nIndexCurrent++;
 nCharLen++;
 }
 if (nCharLen != 0) {
 nCounter++;
 if (!this.CharCompleted(strText, nIndexCurrent - nCharLen, nCharLen, lst_result, cb_void, cb_bool)) {
 return nCounter;
 }
 }
 nIndexCharStart = nIndexCurrent;
 nCodePoint = TextBoundary.GetCodePoint(strText, nIndexCurrent);
 nLastCharLen = nCodePoint >= 0x10000 ? 2 : 1; // >= 0x10000 is double char
 nLeftBreakType = this.GetBreakProperty(nCodePoint);
 nIndexCurrent += nLastCharLen;
 nCharLen = nLastCharLen;
 lst_history_break_type.Add(nLeftBreakType);
 while (nIndexCurrent < strText.Length) {
 nCodePoint = TextBoundary.GetCodePoint(strText, nIndexCurrent);
 nLastCharLen = nCodePoint >= 0x10000 ? 2 : 1; // >= 0x10000 is double char
 nRightBreakType = this.GetBreakProperty(nCodePoint);
 if (this.ShouldBreak(nRightBreakType, lst_history_break_type)) {
 nCounter++;
 if (!this.CharCompleted(strText, nIndexCharStart, nCharLen, lst_result, cb_void, cb_bool)) {
 return nCounter;
 }
 nIndexCharStart = nIndexCurrent;
 nCharLen = nLastCharLen;
 lst_history_break_type.Clear();
 } else {
 nCharLen += nLastCharLen;
 }
 lst_history_break_type.Add(nRightBreakType);
 nIndexCurrent += nLastCharLen;
 nLeftBreakType = nRightBreakType;
 }
 if (nCharLen != 0) {
 nCounter++;
 this.CharCompleted(strText, nIndexCharStart, nCharLen, lst_result, cb_void, cb_bool);
 }
 return nCounter;
 }

 private bool CharCompleted(string strText, int nIndex, int nLen, List<string> lst_result, EachVoidCallBack cb_void, EachBoolCallBack cb_bool) {
 //return value...[true:continue]...[false:break]
 if (lst_result != null) {
 lst_result.Add(strText.Substring(nIndex, nLen));
 }
 if (cb_void != null) {
 cb_void(strText, nIndex, nLen);
 } else if (cb_bool != null && !cb_bool(strText, nIndex, nLen)) {
 return false;
 }
 return true;
 }

 protected abstract bool ShouldBreak(int nRightBreakType, List<int> lstHistoryBreakType);

 protected abstract int GetBreakProperty(int nCodePoint);

 protected static int BinarySearchRangeFromList(int nStart, int nEnd, int nValue, List<RangeInfo> lst) {
 if (nEnd < nStart) {
 return 0;
 }
 int nMid = nStart + (nEnd - nStart) / 2;
 if (lst[nMid].Start > nValue) {
 return TextBoundary.BinarySearchRangeFromList(nStart, nMid - 1, nValue, lst);
 } else if (lst[nMid].End < nValue) {
 return TextBoundary.BinarySearchRangeFromList(nMid + 1, nEnd, nValue, lst);
 } else {
 return lst[nMid].Type;
 }
 }
 }
}