// Scintilla source code edit control
/** @file LexPOV.cxx
 ** Lexer for POV-Ray SDL (Persistance of Vision Raytracer, Scene Description Language).
 ** Written by Philippe Lhoste but this is mostly a derivative of LexCPP...
 **/
// Copyright 1998-2005 by Neil Hodgson <neilh@scintilla.org>
// The License.txt file describes the conditions under which this software may be distributed.

// Some points that distinguish from a simple C lexer:
// Identifiers start only by a character.
// No line continuation character.
// Strings are limited to 256 characters.
// Directives are similar to preprocessor commands,
// but we match directive keywords and colorize incorrect ones.
// Block comments can be nested (code stolen from my code in LexLua).

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

#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"

#ifdef SCI_NAMESPACE
using namespace Scintilla;
#endif

static inline bool IsAWordChar(int ch) {
    return ch < 0x80 && (isalnum(ch) || ch == '_');
}

static inline bool IsAWordStart(int ch) {
    return ch < 0x80 && isalpha(ch);
}

static inline bool IsANumberChar(int ch) {
    // Not exactly following number definition (several dots are seen as OK, etc.)
    // but probably enough in most cases.
    return (ch < 0x80) &&
            (isdigit(ch) || toupper(ch) == 'E' ||
             ch == '.' || ch == '-' || ch == '+');
}

static void ColourisePovDoc(
    unsigned int startPos,
    int length,
    int initStyle,
    WordList *keywordlists[],
    Accessor &styler) {

    WordList &keywords1 = *keywordlists[0];
    WordList &keywords2 = *keywordlists[1];
    WordList &keywords3 = *keywordlists[2];
    WordList &keywords4 = *keywordlists[3];
    WordList &keywords5 = *keywordlists[4];
    WordList &keywords6 = *keywordlists[5];
    WordList &keywords7 = *keywordlists[6];
    WordList &keywords8 = *keywordlists[7];

    int currentLine = styler.GetLine(startPos);
    // Initialize the block comment /* */ nesting level, if we are inside such a comment.
    int blockCommentLevel = 0;
    if (initStyle == SCE_POV_COMMENT) {
        blockCommentLevel = styler.GetLineState(currentLine - 1);
    }

    // Do not leak onto next line
    if (initStyle == SCE_POV_STRINGEOL || initStyle == SCE_POV_COMMENTLINE) {
        initStyle = SCE_POV_DEFAULT;
    }

    short stringLen = 0;

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

    for (; sc.More(); sc.Forward()) {
        if (sc.atLineEnd) {
            // Update the line state, so it can be seen by next line
            currentLine = styler.GetLine(sc.currentPos);
            if (sc.state == SCE_POV_COMMENT) {
                // Inside a block comment, we set the line state
                styler.SetLineState(currentLine, blockCommentLevel);
            } else {
                // Reset the line state
                styler.SetLineState(currentLine, 0);
            }
        }

        if (sc.atLineStart && (sc.state == SCE_POV_STRING)) {
            // Prevent SCE_POV_STRINGEOL from leaking back to previous line
            sc.SetState(SCE_POV_STRING);
        }

        // Determine if the current state should terminate.
        if (sc.state == SCE_POV_OPERATOR) {
            sc.SetState(SCE_POV_DEFAULT);
        } else if (sc.state == SCE_POV_NUMBER) {
            // We stop the number definition on non-numerical non-dot non-eE non-sign char
            if (!IsANumberChar(sc.ch)) {
                sc.SetState(SCE_POV_DEFAULT);
            }
        } else if (sc.state == SCE_POV_IDENTIFIER) {
            if (!IsAWordChar(sc.ch)) {
                char s[100];
                sc.GetCurrent(s, sizeof(s));
                if (keywords2.InList(s)) {
                    sc.ChangeState(SCE_POV_WORD2);
                } else if (keywords3.InList(s)) {
                    sc.ChangeState(SCE_POV_WORD3);
                } else if (keywords4.InList(s)) {
                    sc.ChangeState(SCE_POV_WORD4);
                } else if (keywords5.InList(s)) {
                    sc.ChangeState(SCE_POV_WORD5);
                } else if (keywords6.InList(s)) {
                    sc.ChangeState(SCE_POV_WORD6);
                } else if (keywords7.InList(s)) {
                    sc.ChangeState(SCE_POV_WORD7);
                } else if (keywords8.InList(s)) {
                    sc.ChangeState(SCE_POV_WORD8);
                }
                sc.SetState(SCE_POV_DEFAULT);
            }
        } else if (sc.state == SCE_POV_DIRECTIVE) {
            if (!IsAWordChar(sc.ch)) {
                char s[100];
                char *p;
                sc.GetCurrent(s, sizeof(s));
                p = s;
                // Skip # and whitespace between # and directive word
                do {
                    p++;
                } while ((*p == ' ' || *p == '\t') && *p != '\0');
                if (!keywords1.InList(p)) {
                    sc.ChangeState(SCE_POV_BADDIRECTIVE);
                }
                sc.SetState(SCE_POV_DEFAULT);
            }
        } else if (sc.state == SCE_POV_COMMENT) {
            if (sc.Match('/', '*')) {
                blockCommentLevel++;
                sc.Forward();
            } else if (sc.Match('*', '/') && blockCommentLevel > 0) {
                blockCommentLevel--;
                sc.Forward();
                if (blockCommentLevel == 0) {
                    sc.ForwardSetState(SCE_POV_DEFAULT);
                }
            }
        } else if (sc.state == SCE_POV_COMMENTLINE) {
            if (sc.atLineEnd) {
                sc.ForwardSetState(SCE_POV_DEFAULT);
            }
        } else if (sc.state == SCE_POV_STRING) {
            if (sc.ch == '\\') {
                stringLen++;
                if (strchr("abfnrtuv0'\"", sc.chNext)) {
                    // Compound characters are counted as one.
                    // Note: for Unicode chars \u, we shouldn't count the next 4 digits...
                    sc.Forward();
                }
            } else if (sc.ch == '\"') {
                sc.ForwardSetState(SCE_POV_DEFAULT);
            } else if (sc.atLineEnd) {
                sc.ChangeState(SCE_POV_STRINGEOL);
                sc.ForwardSetState(SCE_POV_DEFAULT);
            } else {
                stringLen++;
            }
            if (stringLen > 256) {
                // Strings are limited to 256 chars
                sc.SetState(SCE_POV_STRINGEOL);
            }
        } else if (sc.state == SCE_POV_STRINGEOL) {
            if (sc.ch == '\\') {
                if (sc.chNext == '\"' || sc.chNext == '\\') {
                    sc.Forward();
                }
            } else if (sc.ch == '\"') {
                sc.ForwardSetState(SCE_C_DEFAULT);
            } else if (sc.atLineEnd) {
                sc.ForwardSetState(SCE_POV_DEFAULT);
            }
        }

        // Determine if a new state should be entered.
        if (sc.state == SCE_POV_DEFAULT) {
            if (IsADigit(sc.ch) || (sc.ch == '.' && IsADigit(sc.chNext))) {
                sc.SetState(SCE_POV_NUMBER);
            } else if (IsAWordStart(sc.ch)) {
                sc.SetState(SCE_POV_IDENTIFIER);
            } else if (sc.Match('/', '*')) {
                blockCommentLevel = 1;
                sc.SetState(SCE_POV_COMMENT);
                sc.Forward();   // Eat the * so it isn't used for the end of the comment
            } else if (sc.Match('/', '/')) {
                sc.SetState(SCE_POV_COMMENTLINE);
            } else if (sc.ch == '\"') {
                sc.SetState(SCE_POV_STRING);
                stringLen = 0;
            } else if (sc.ch == '#') {
                sc.SetState(SCE_POV_DIRECTIVE);
                // Skip whitespace between # and directive word
                do {
                    sc.Forward();
                } while ((sc.ch == ' ' || sc.ch == '\t') && sc.More());
                if (sc.atLineEnd) {
                    sc.SetState(SCE_POV_DEFAULT);
                }
            } else if (isoperator(static_cast<char>(sc.ch))) {
                sc.SetState(SCE_POV_OPERATOR);
            }
        }
    }
    sc.Complete();
}

static void FoldPovDoc(
    unsigned int startPos,
    int length,
    int initStyle,
    WordList *[],
    Accessor &styler) {

    bool foldComment = styler.GetPropertyInt("fold.comment") != 0;
    bool foldDirective = styler.GetPropertyInt("fold.directive") != 0;
    bool foldCompact = styler.GetPropertyInt("fold.compact", 1) != 0;
    unsigned int endPos = startPos + length;
    int visibleChars = 0;
    int lineCurrent = styler.GetLine(startPos);
    int levelPrev = styler.LevelAt(lineCurrent) & SC_FOLDLEVELNUMBERMASK;
    int levelCurrent = levelPrev;
    char chNext = styler[startPos];
    int styleNext = styler.StyleAt(startPos);
    int style = initStyle;
    for (unsigned int i = startPos; i < endPos; i++) {
        char ch = chNext;
        chNext = styler.SafeGetCharAt(i + 1);
        int stylePrev = style;
        style = styleNext;
        styleNext = styler.StyleAt(i + 1);
        bool atEOL = (ch == '\r' && chNext != '\n') || (ch == '\n');
        if (foldComment && (style == SCE_POV_COMMENT)) {
            if (stylePrev != SCE_POV_COMMENT) {
                levelCurrent++;
            } else if ((styleNext != SCE_POV_COMMENT) && !atEOL) {
                // Comments don't end at end of line and the next character may be unstyled.
                levelCurrent--;
            }
        }
        if (foldComment && (style == SCE_POV_COMMENTLINE)) {
            if ((ch == '/') && (chNext == '/')) {
                char chNext2 = styler.SafeGetCharAt(i + 2);
                if (chNext2 == '{') {
                    levelCurrent++;
                } else if (chNext2 == '}') {
                    levelCurrent--;
                }
            }
        }
        if (foldDirective && (style == SCE_POV_DIRECTIVE)) {
            if (ch == '#') {
                unsigned int j=i+1;
                while ((j<endPos) && IsASpaceOrTab(styler.SafeGetCharAt(j))) {
                    j++;
                }
            }
        }
        if (style == SCE_POV_OPERATOR) {
            if (ch == '{') {
                levelCurrent++;
            } else if (ch == '}') {
                levelCurrent--;
            }
        }
        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);
}

static const char * const povWordLists[] = {
    "Language directives",
    "Objects & CSG & Appearance",
    "Types & Modifiers & Items",
    "Predefined Identifiers",
    "Predefined Functions",
    "User defined 1",
    "User defined 2",
    "User defined 3",
    0,
};

LexerModule lmPOV(SCLEX_POV, ColourisePovDoc, "pov", FoldPovDoc, povWordLists);
