// Scintilla source code edit control

// @file LexMetapost.cxx - general context conformant metapost coloring scheme
// Author: Hans Hagen - PRAGMA ADE - Hasselt NL - www.pragma-ade.com
// Version: September 28, 2003
// Modified by instanton: July 10, 2007
// Folding based on keywordlists[]

// Copyright: 1998-2003 by Neil Hodgson <neilh@scintilla.org>
// The License.txt file describes the conditions under which this software may be distributed.

// This lexer is derived from the one written for the texwork environment (1999++) which in
// turn is inspired on texedit (1991++) which finds its roots in wdt (1986).

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <stdarg.h>
#include <assert.h>
#include <ctype.h>

#include <string>
#include <string_view>

#include "ILexer.h"
#include "Scintilla.h"
#include "SciLexer.h"

#include "WordList.h"
#include "LexAccessor.h"
#include "Accessor.h"
#include "StyleContext.h"
#include "CharacterSet.h"
#include "LexerModule.h"

using namespace Lexilla;

// val SCE_METAPOST_DEFAULT = 0
// val SCE_METAPOST_SPECIAL = 1
// val SCE_METAPOST_GROUP = 2
// val SCE_METAPOST_SYMBOL = 3
// val SCE_METAPOST_COMMAND = 4
// val SCE_METAPOST_TEXT = 5

// Definitions in SciTEGlobal.properties:
//
// Metapost Highlighting
//
// # Default
// style.metapost.0=fore:#7F7F00
// # Special
// style.metapost.1=fore:#007F7F
// # Group
// style.metapost.2=fore:#880000
// # Symbol
// style.metapost.3=fore:#7F7F00
// # Command
// style.metapost.4=fore:#008800
// # Text
// style.metapost.5=fore:#000000

// lexer.tex.comment.process=0

// Auxiliary functions:

static inline bool endOfLine(Accessor &styler, Sci_PositionU i) {
	return
      (styler[i] == '\n') || ((styler[i] == '\r') && (styler.SafeGetCharAt(i + 1) != '\n')) ;
}

static inline bool isMETAPOSTcomment(int ch) {
	return
      (ch == '%') ;
}

static inline bool isMETAPOSTone(int ch) {
	return
      (ch == '[') || (ch == ']') || (ch == '(') || (ch == ')') ||
      (ch == ':') || (ch == '=') || (ch == '<') || (ch == '>') ||
      (ch == '{') || (ch == '}') || (ch == '\'') || (ch == '\"') ;
}

static inline bool isMETAPOSTtwo(int ch) {
	return
      (ch == ';') || (ch == '$') || (ch == '@') || (ch == '#');
}

static inline bool isMETAPOSTthree(int ch) {
	return
      (ch == '.') || (ch == '-') || (ch == '+') || (ch == '/') ||
      (ch == '*') || (ch == ',') || (ch == '|') || (ch == '`') ||
      (ch == '!') || (ch == '?') || (ch == '^') || (ch == '&') ||
      (ch == '%') ;
}

static inline bool isMETAPOSTidentifier(int ch) {
	return
      ((ch >= 'a') && (ch <= 'z')) || ((ch >= 'A') && (ch <= 'Z')) ||
      (ch == '_') ;
}

static inline bool isMETAPOSTnumber(int ch) {
	return
      (ch >= '0') && (ch <= '9') ;
}

static inline bool isMETAPOSTstring(int ch) {
	return
      (ch == '\"') ;
}

static inline bool isMETAPOSTcolon(int ch) {
	return
		(ch == ':') ;
}

static inline bool isMETAPOSTequal(int ch) {
	return
		(ch == '=') ;
}

static int CheckMETAPOSTInterface(
    Sci_PositionU startPos,
    Sci_Position length,
    Accessor &styler,
	int defaultInterface) {

    char lineBuffer[1024] ;
	Sci_PositionU linePos = 0 ;

	// some day we can make something lexer.metapost.mapping=(none,0)(metapost,1)(mp,1)(metafun,2)...

    if (styler.SafeGetCharAt(0) == '%') {
        for (Sci_PositionU i = 0; i < startPos + length; i++) {
            lineBuffer[linePos++] = styler.SafeGetCharAt(i) ;
            if (endOfLine(styler, i) || (linePos >= sizeof(lineBuffer) - 1)) {
                lineBuffer[linePos] = '\0';
				if (strstr(lineBuffer, "interface=none")) {
                    return 0 ;
				} else if (strstr(lineBuffer, "interface=metapost") || strstr(lineBuffer, "interface=mp")) {
                    return 1 ;
				} else if (strstr(lineBuffer, "interface=metafun")) {
                    return 2 ;
				} else if (styler.SafeGetCharAt(1) == 'D' && strstr(lineBuffer, "%D \\module")) {
					// better would be to limit the search to just one line
					return 2 ;
                } else {
                    return defaultInterface ;
                }
            }
		}
    }

    return defaultInterface ;
}

static void ColouriseMETAPOSTDoc(
    Sci_PositionU startPos,
    Sci_Position length,
    int,
    WordList *keywordlists[],
    Accessor &styler) {

	styler.StartAt(startPos) ;
	styler.StartSegment(startPos) ;

	bool processComment   = styler.GetPropertyInt("lexer.metapost.comment.process",   0) == 1 ;
    int  defaultInterface = styler.GetPropertyInt("lexer.metapost.interface.default", 1) ;

	int currentInterface = CheckMETAPOSTInterface(startPos,length,styler,defaultInterface) ;

	// 0  no keyword highlighting
	// 1  metapost keyword hightlighting
	// 2+ metafun keyword hightlighting

	int extraInterface = 0 ;

	if (currentInterface != 0) {
		extraInterface = currentInterface ;
	}

	WordList &keywords  = *keywordlists[0] ;
	WordList kwEmpty;
	WordList &keywords2 = (extraInterface > 0) ? *keywordlists[extraInterface - 1] : kwEmpty;

	StyleContext sc(startPos, length, SCE_METAPOST_TEXT, styler) ;

	char key[100] ;

    bool inTeX     = false ;
	bool inComment = false ;
	bool inString  = false ;
	bool inClause  = false ;

	bool going = sc.More() ; // needed because of a fuzzy end of file state

	for (; going; sc.Forward()) {

		if (! sc.More()) { going = false ; } // we need to go one behind the end of text

		if (inClause) {
			sc.SetState(SCE_METAPOST_TEXT) ;
			inClause = false ;
		}

		if (inComment) {
			if (sc.atLineEnd) {
				sc.SetState(SCE_METAPOST_TEXT) ;
				inTeX = false ;
				inComment = false ;
				inClause = false ;
				inString = false ; // not correct but we want to stimulate one-lines
			}
		} else if (inString) {
			if (isMETAPOSTstring(sc.ch)) {
				sc.SetState(SCE_METAPOST_SPECIAL) ;
				sc.ForwardSetState(SCE_METAPOST_TEXT) ;
				inString = false ;
			} else if (sc.atLineEnd) {
				sc.SetState(SCE_METAPOST_TEXT) ;
				inTeX = false ;
				inComment = false ;
				inClause = false ;
				inString = false ; // not correct but we want to stimulate one-lines
			}
		} else {
			if ((! isMETAPOSTidentifier(sc.ch)) && (sc.LengthCurrent() > 0)) {
				if (sc.state == SCE_METAPOST_COMMAND) {
					sc.GetCurrent(key, sizeof(key)) ;
					if ((strcmp(key,"btex") == 0) || (strcmp(key,"verbatimtex") == 0)) {
    					sc.ChangeState(SCE_METAPOST_GROUP) ;
						inTeX = true ;
					} else if (inTeX) {
						if (strcmp(key,"etex") == 0) {
	    					sc.ChangeState(SCE_METAPOST_GROUP) ;
							inTeX = false ;
						} else {
	    					sc.ChangeState(SCE_METAPOST_TEXT) ;
						}
					} else {
						if (keywords && keywords.InList(key)) {
    						sc.ChangeState(SCE_METAPOST_COMMAND) ;
						} else if (keywords2 && keywords2.InList(key)) {
							sc.ChangeState(SCE_METAPOST_EXTRA) ;
						} else {
							sc.ChangeState(SCE_METAPOST_TEXT) ;
						}
					}
				}
			}
			if (isMETAPOSTcomment(sc.ch)) {
				if (! inTeX) {
					sc.SetState(SCE_METAPOST_SYMBOL) ;
					sc.ForwardSetState(SCE_METAPOST_DEFAULT) ;
					inComment = ! processComment ;
				} else {
					sc.SetState(SCE_METAPOST_TEXT) ;
				}
			} else if (isMETAPOSTstring(sc.ch)) {
				if (! inTeX) {
					sc.SetState(SCE_METAPOST_SPECIAL) ;
					if (! isMETAPOSTstring(sc.chNext)) {
						sc.ForwardSetState(SCE_METAPOST_TEXT) ;
					}
					inString = true ;
				} else {
					sc.SetState(SCE_METAPOST_TEXT) ;
				}
			} else if (isMETAPOSTcolon(sc.ch)) {
				if (! inTeX) {
					if (! isMETAPOSTequal(sc.chNext)) {
						sc.SetState(SCE_METAPOST_COMMAND) ;
						inClause = true ;
					} else {
						sc.SetState(SCE_METAPOST_SPECIAL) ;
					}
				} else {
					sc.SetState(SCE_METAPOST_TEXT) ;
				}
			} else if (isMETAPOSTone(sc.ch)) {
				if (! inTeX) {
					sc.SetState(SCE_METAPOST_SPECIAL) ;
				} else {
					sc.SetState(SCE_METAPOST_TEXT) ;
				}
			} else if (isMETAPOSTtwo(sc.ch)) {
				if (! inTeX) {
					sc.SetState(SCE_METAPOST_GROUP) ;
				} else {
					sc.SetState(SCE_METAPOST_TEXT) ;
				}
			} else if (isMETAPOSTthree(sc.ch)) {
				if (! inTeX) {
					sc.SetState(SCE_METAPOST_SYMBOL) ;
				} else {
					sc.SetState(SCE_METAPOST_TEXT) ;
				}
			} else if (isMETAPOSTidentifier(sc.ch)) {
				if (sc.state != SCE_METAPOST_COMMAND) {
					sc.SetState(SCE_METAPOST_TEXT) ;
					sc.ChangeState(SCE_METAPOST_COMMAND) ;
				}
			} else if (isMETAPOSTnumber(sc.ch)) {
				// rather redundant since for the moment we don't handle numbers
				sc.SetState(SCE_METAPOST_TEXT) ;
			} else if (sc.atLineEnd) {
				sc.SetState(SCE_METAPOST_TEXT) ;
				inTeX = false ;
				inComment = false ;
				inClause = false ;
				inString = false ;
			} else {
				sc.SetState(SCE_METAPOST_TEXT) ;
			}
		}

	}

	sc.Complete();

}

// Hooks info the system:

static const char * const metapostWordListDesc[] = {
	"MetaPost",
	"MetaFun",
	0
} ;

static int classifyFoldPointMetapost(const char* s,WordList *keywordlists[]) {
	WordList& keywordsStart=*keywordlists[3];
	WordList& keywordsStop1=*keywordlists[4];

	if (keywordsStart.InList(s)) {return 1;}
	else if (keywordsStop1.InList(s)) {return -1;}
	return 0;

}

static int ParseMetapostWord(Sci_PositionU pos, Accessor &styler, char *word)
{
  int length=0;
  char ch=styler.SafeGetCharAt(pos);
  *word=0;

  while(isMETAPOSTidentifier(ch) && isalpha(ch) && length<100){
          word[length]=ch;
          length++;
          ch=styler.SafeGetCharAt(pos+length);
  }
  word[length]=0;
  return length;
}

static void FoldMetapostDoc(Sci_PositionU startPos, Sci_Position length, int, WordList *keywordlists[], Accessor &styler)
{
	bool foldCompact = styler.GetPropertyInt("fold.compact", 1) != 0;
	Sci_PositionU endPos = startPos+length;
	int visibleChars=0;
	Sci_Position lineCurrent=styler.GetLine(startPos);
	int levelPrev=styler.LevelAt(lineCurrent) & SC_FOLDLEVELNUMBERMASK;
	int levelCurrent=levelPrev;
	char chNext=styler[startPos];

	char buffer[100]="";

	for (Sci_PositionU i=startPos; i < endPos; i++) {
		char ch=chNext;
		chNext=styler.SafeGetCharAt(i+1);
		char chPrev=styler.SafeGetCharAt(i-1);
		bool atEOL = (ch == '\r' && chNext != '\n') || (ch == '\n');

		if(i==0 || chPrev == '\r' || chPrev=='\n'|| chPrev==' '|| chPrev=='(' || chPrev=='$')
		{
            ParseMetapostWord(i, styler, buffer);
			levelCurrent += classifyFoldPointMetapost(buffer,keywordlists);
		}

		if (atEOL) {
			int lev = levelPrev;
			if (visibleChars == 0 && foldCompact)
				lev |= SC_FOLDLEVELWHITEFLAG;
			if ((levelCurrent > levelPrev) && (visibleChars > 0))
				lev |= SC_FOLDLEVELHEADERFLAG;
			if (lev != styler.LevelAt(lineCurrent)) {
				styler.SetLevel(lineCurrent, lev);
			}
			lineCurrent++;
			levelPrev = levelCurrent;
			visibleChars = 0;
		}

		if (!isspacechar(ch))
			visibleChars++;
	}
	// Fill in the real level of the next line, keeping the current flags as they will be filled in later
	int flagsNext = styler.LevelAt(lineCurrent) & ~SC_FOLDLEVELNUMBERMASK;
	styler.SetLevel(lineCurrent, levelPrev | flagsNext);

}


LexerModule lmMETAPOST(SCLEX_METAPOST, ColouriseMETAPOSTDoc, "metapost", FoldMetapostDoc, metapostWordListDesc);