// Scintilla source code edit control
/** @file LexMatlab.cxx
** Lexer for Matlab.
** Written by José Fonseca
**
** Changes by Christoph Dalitz 2003/12/04:
**   - added support for Octave
**   - Strings can now be included both in single or double quotes
**
** Changes by John Donoghue 2012/04/02
**   - added block comment (and nested block comments)
**   - added ... displayed as a comment
**   - removed unused IsAWord functions
**   - added some comments
**
** Changes by John Donoghue 2014/08/01
**   - fix allowed transpose ' after {} operator
**
** Changes by John Donoghue 2016/11/15
**   - update matlab code folding
**
** Changes by John Donoghue 2017/01/18
**   - update matlab block comment detection
**/
// Copyright 1998-2001 by Neil Hodgson <neilh@scintilla.org>
// The License.txt file describes the conditions under which this software may be distributed.

#include <Platform.h>
#include <Scintilla.h>
#include <scintilla-internal.h>
#pragma hdrstop

#ifdef SCI_NAMESPACE
using namespace Scintilla;
#endif

static bool IsMatlabCommentChar(int c)
{
	return (c == '%');
}

static bool IsOctaveCommentChar(int c)
{
	return oneof2(c, '%', '#');
}

static inline int LowerCase(int c)
{
	return (c >= 'A' && c <= 'Z') ? ('a' + c - 'A') : c;
}

static int CheckKeywordFoldPoint(char * str)
{
	if(sstreq(str, "if") || sstreq(str, "for") || sstreq(str, "switch") || sstreq(str, "try") || sstreq(str, "do") || sstreq(str, "parfor") || sstreq(str, "function"))
		return 1;
	else if(strncmp("end", str, 3) == 0 || sstreq(str, "until"))
		return -1;
	else
		return 0;
}

static bool IsSpaceToEOL(Sci_Position startPos, Accessor & styler)
{
	Sci_Position line = styler.GetLine(startPos);
	Sci_Position eol_pos = styler.LineStart(line + 1) - 1;
	for(Sci_Position i = startPos; i < eol_pos; i++) {
		char ch = styler[i];
		if(!IsASpace(ch)) return false;
	}
	return true;
}

static void ColouriseMatlabOctaveDoc(Sci_PositionU startPos, Sci_Position length, int initStyle,
    WordList * keywordlists[], Accessor & styler, bool (* IsCommentChar)(int), bool ismatlab)
{
	WordList &keywords = *keywordlists[0];
	styler.StartAt(startPos);
	// boolean for when the ' is allowed to be transpose vs the start/end
	// of a string
	bool transpose = false;
	// approximate position of first non space character in a line
	int nonSpaceColumn = -1;
	// approximate column position of the current character in a line
	int column = 0;
	// use the line state of each line to store the block comment depth
	Sci_Position curLine = styler.GetLine(startPos);
	int commentDepth = curLine > 0 ? styler.GetLineState(curLine-1) : 0;
	StyleContext sc(startPos, length, initStyle, styler);
	for(; sc.More(); sc.Forward(), column++) {
		if(sc.atLineStart) {
			// set the line state to the current commentDepth
			curLine = styler.GetLine(sc.currentPos);
			styler.SetLineState(curLine, commentDepth);

			// reset the column to 0, nonSpace to -1 (not set)
			column = 0;
			nonSpaceColumn = -1;
		}

		// save the column position of first non space character in a line
		if((nonSpaceColumn == -1) && (!IsASpace(sc.ch))) {
			nonSpaceColumn = column;
		}

		// check for end of states
		if(sc.state == SCE_MATLAB_OPERATOR) {
			if(sc.chPrev == '.') {
				if(oneof4(sc.ch, '*', '/', '\\', '^')) {
					sc.ForwardSetState(SCE_MATLAB_DEFAULT);
					transpose = false;
				}
				else if(sc.ch == '\'') {
					sc.ForwardSetState(SCE_MATLAB_DEFAULT);
					transpose = true;
				}
				else if(sc.ch == '.' && sc.chNext == '.') {
					// we werent an operator, but a '...'
					sc.ChangeState(SCE_MATLAB_COMMENT);
					transpose = false;
				}
				else {
					sc.SetState(SCE_MATLAB_DEFAULT);
				}
			}
			else {
				sc.SetState(SCE_MATLAB_DEFAULT);
			}
		}
		else if(sc.state == SCE_MATLAB_KEYWORD) {
			if(!isalnum(sc.ch) && sc.ch != '_') {
				char s[100];
				sc.GetCurrentLowered(s, sizeof(s));
				if(keywords.InList(s)) {
					sc.SetState(SCE_MATLAB_DEFAULT);
					transpose = false;
				}
				else {
					sc.ChangeState(SCE_MATLAB_IDENTIFIER);
					sc.SetState(SCE_MATLAB_DEFAULT);
					transpose = true;
				}
			}
		}
		else if(sc.state == SCE_MATLAB_NUMBER) {
			if(!isdec(sc.ch) && sc.ch != '.' && !oneof2(sc.ch, 'e', 'E') && !((sc.ch == '+' || sc.ch == '-') && (sc.chPrev == 'e' || sc.chPrev == 'E'))) {
				sc.SetState(SCE_MATLAB_DEFAULT);
				transpose = true;
			}
		}
		else if(sc.state == SCE_MATLAB_STRING) {
			if(sc.ch == '\'') {
				if(sc.chNext == '\'')
					sc.Forward();
				else
					sc.ForwardSetState(SCE_MATLAB_DEFAULT);
			}
		}
		else if(sc.state == SCE_MATLAB_DOUBLEQUOTESTRING) {
			if(sc.ch == '\\') {
				if(oneof3(sc.chNext, '\"', '\'', '\\')) {
					sc.Forward();
				}
			}
			else if(sc.ch == '\"') {
				sc.ForwardSetState(SCE_MATLAB_DEFAULT);
			}
		}
		else if(sc.state == SCE_MATLAB_COMMAND) {
			if(sc.atLineEnd) {
				sc.SetState(SCE_MATLAB_DEFAULT);
				transpose = false;
			}
		}
		else if(sc.state == SCE_MATLAB_COMMENT) {
			// end or start of a nested a block comment?
			if(IsCommentChar(sc.ch) && sc.chNext == '}' && nonSpaceColumn == column && IsSpaceToEOL(sc.currentPos+2, styler)) {
				if(commentDepth > 0) 
					commentDepth--;
				curLine = styler.GetLine(sc.currentPos);
				styler.SetLineState(curLine, commentDepth);
				sc.Forward();
				if(commentDepth == 0) {
					sc.ForwardSetState(SCE_D_DEFAULT);
					transpose = false;
				}
			}
			else if(IsCommentChar(sc.ch) && sc.chNext == '{' && nonSpaceColumn == column && IsSpaceToEOL(sc.currentPos+2, styler)) {
				commentDepth++;
				curLine = styler.GetLine(sc.currentPos);
				styler.SetLineState(curLine, commentDepth);
				sc.Forward();
				transpose = false;
			}
			else if(commentDepth == 0) {
				// single line comment
				if(sc.atLineEnd || oneof2(sc.ch, '\r', '\n')) {
					sc.SetState(SCE_MATLAB_DEFAULT);
					transpose = false;
				}
			}
		}
		// check start of a new state
		if(sc.state == SCE_MATLAB_DEFAULT) {
			if(IsCommentChar(sc.ch)) {
				// ncrement depth if we are a block comment
				if(sc.chNext == '{' && nonSpaceColumn == column) {
					if(IsSpaceToEOL(sc.currentPos+2, styler)) {
						commentDepth++;
					}
				}
				curLine = styler.GetLine(sc.currentPos);
				styler.SetLineState(curLine, commentDepth);
				sc.SetState(SCE_MATLAB_COMMENT);
			}
			else if(sc.ch == '!' && sc.chNext != '=') {
				sc.SetState(ismatlab ? SCE_MATLAB_COMMAND : SCE_MATLAB_OPERATOR);
			}
			else if(sc.ch == '\'') {
				sc.SetState(transpose ? SCE_MATLAB_OPERATOR : SCE_MATLAB_STRING);
			}
			else if(sc.ch == '"') {
				sc.SetState(SCE_MATLAB_DOUBLEQUOTESTRING);
			}
			else if(isdec(sc.ch) || (sc.ch == '.' && isdec(sc.chNext))) {
				sc.SetState(SCE_MATLAB_NUMBER);
			}
			else if(isalpha(sc.ch)) {
				sc.SetState(SCE_MATLAB_KEYWORD);
			}
			else if(isoperator(static_cast<char>(sc.ch)) || sc.ch == '@' || sc.ch == '\\') {
				transpose = LOGIC(oneof3(sc.ch, ')', ']', '}'));
				sc.SetState(SCE_MATLAB_OPERATOR);
			}
			else {
				transpose = false;
			}
		}
	}
	sc.Complete();
}

static void ColouriseMatlabDoc(Sci_PositionU startPos, Sci_Position length, int initStyle,
    WordList * keywordlists[], Accessor & styler)
{
	ColouriseMatlabOctaveDoc(startPos, length, initStyle, keywordlists, styler, IsMatlabCommentChar, true);
}

static void ColouriseOctaveDoc(Sci_PositionU startPos, Sci_Position length, int initStyle,
    WordList * keywordlists[], Accessor & styler)
{
	ColouriseMatlabOctaveDoc(startPos, length, initStyle, keywordlists, styler, IsOctaveCommentChar, false);
}

static void FoldMatlabOctaveDoc(Sci_PositionU startPos, Sci_Position length, int initStyle,
    WordList *[], Accessor & styler,
    bool (* IsComment)(int ch))
{
	Sci_PositionU endPos = startPos + length;
	int visibleChars = 0;
	Sci_Position lineCurrent = styler.GetLine(startPos);
	int levelCurrent = SC_FOLDLEVELBASE;
	if(lineCurrent > 0)
		levelCurrent = styler.LevelAt(lineCurrent-1) >> 16;
	int levelNext = levelCurrent;
	char chNext = styler[startPos];
	int styleNext = styler.StyleAt(startPos);
	int style = initStyle;
	char word[100];
	int wordlen = 0;
	for(Sci_PositionU i = startPos; i < endPos; i++) {
		char ch = chNext;
		chNext = styler.SafeGetCharAt(i + 1);
		style = styleNext;
		styleNext = styler.StyleAt(i + 1);
		bool atEOL = (ch == '\r' && chNext != '\n') || (ch == '\n');

		// a line that starts with a comment
		if(style == SCE_MATLAB_COMMENT && IsComment(ch) && visibleChars == 0) {
			// start/end of block comment
			if(chNext == '{' && IsSpaceToEOL(i+2, styler))
				levelNext++;
			if(chNext == '}' && IsSpaceToEOL(i+2, styler))
				levelNext--;
		}
		// keyword
		if(style == SCE_MATLAB_KEYWORD) {
			word[wordlen++] = static_cast<char>(LowerCase(ch));
			if(wordlen == 100) {   // prevent overflow
				word[0] = '\0';
				wordlen = 1;
			}
			if(styleNext !=  SCE_MATLAB_KEYWORD) {
				word[wordlen] = '\0';
				wordlen = 0;

				levelNext += CheckKeywordFoldPoint(word);
			}
		}
		if(!IsASpace(ch))
			visibleChars++;
		if(atEOL || (i == endPos-1)) {
			int levelUse = levelCurrent;
			int lev = levelUse | levelNext << 16;
			if(visibleChars == 0)
				lev |= SC_FOLDLEVELWHITEFLAG;
			if(levelUse < levelNext)
				lev |= SC_FOLDLEVELHEADERFLAG;
			if(lev != styler.LevelAt(lineCurrent)) {
				styler.SetLevel(lineCurrent, lev);
			}
			lineCurrent++;
			levelCurrent = levelNext;
			if(atEOL && (i == static_cast<Sci_PositionU>(styler.Length() - 1))) {
				// There is an empty line at end of file so give it same level and empty
				styler.SetLevel(lineCurrent, (levelCurrent | levelCurrent << 16) | SC_FOLDLEVELWHITEFLAG);
			}
			visibleChars = 0;
		}
	}
}

static void FoldMatlabDoc(Sci_PositionU startPos, Sci_Position length, int initStyle,
    WordList * keywordlists[], Accessor & styler)
{
	FoldMatlabOctaveDoc(startPos, length, initStyle, keywordlists, styler, IsMatlabCommentChar);
}

static void FoldOctaveDoc(Sci_PositionU startPos, Sci_Position length, int initStyle,
    WordList * keywordlists[], Accessor & styler)
{
	FoldMatlabOctaveDoc(startPos, length, initStyle, keywordlists, styler, IsOctaveCommentChar);
}

static const char * const matlabWordListDesc[] = {
	"Keywords",
	0
};

static const char * const octaveWordListDesc[] = {
	"Keywords",
	0
};

LexerModule lmMatlab(SCLEX_MATLAB, ColouriseMatlabDoc, "matlab", FoldMatlabDoc, matlabWordListDesc);

LexerModule lmOctave(SCLEX_OCTAVE, ColouriseOctaveDoc, "octave", FoldOctaveDoc, octaveWordListDesc);
