// Scintilla source code edit control
/** @file LexCSS.cxx
 ** Lexer for Cascading Style Sheets
 ** Written by Jakub Vrána
 ** Improved by Philippe Lhoste (CSS2)
 **/
// Copyright 1998-2002 by Neil Hodgson <neilh@scintilla.org>
// The License.txt file describes the conditions under which this software may be distributed.

#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(const unsigned int ch) {
    /* FIXME:
     * The CSS spec allows "ISO 10646 characters U+00A1 and higher" to be treated as word chars.
     * Unfortunately, we are only getting string bytes here, and not full unicode characters. We cannot guarantee
     * that our byte is between U+0080 - U+00A0 (to return false), so we have to allow all characters U+0080 and higher
     */
    return ch >= 0x80 || isalnum(ch) || ch == '-' || ch == '_';
}

inline bool IsCssOperator(const int ch) {
    if (!((ch < 0x80) && isalnum(ch)) &&
        (ch == '{' || ch == '}' || ch == ':' || ch == ',' || ch == ';' ||
         ch == '.' || ch == '#' || ch == '!' || ch == '@' ||
         /* CSS2 */
         ch == '*' || ch == '>' || ch == '+' || ch == '=' || ch == '~' || ch == '|' ||
         ch == '[' || ch == ']' || ch == '(' || ch == ')')) {
        return true;
    }
    return false;
}

static void ColouriseCssDoc(unsigned int startPos, int length, int initStyle, WordList *keywordlists[], Accessor &styler) {
    WordList &css1Props = *keywordlists[0];
    WordList &pseudoClasses = *keywordlists[1];
    WordList &css2Props = *keywordlists[2];
    WordList &css3Props = *keywordlists[3];
    WordList &pseudoElements = *keywordlists[4];
    WordList &exProps = *keywordlists[5];
    WordList &exPseudoClasses = *keywordlists[6];
    WordList &exPseudoElements = *keywordlists[7];

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

    int lastState = -1; // before operator
    int lastStateC = -1; // before comment
    int lastStateS = -1; // before single-quoted/double-quoted string
    int op = ' '; // last operator
    int opPrev = ' '; // last operator

    for (; sc.More(); sc.Forward()) {
        if (sc.state == SCE_CSS_COMMENT && sc.Match('*', '/')) {
            if (lastStateC == -1) {
                // backtrack to get last state:
                // comments are like whitespace, so we must return to the previous state
                unsigned int i = startPos;
                for (; i > 0; i--) {
                    if ((lastStateC = styler.StyleAt(i-1)) != SCE_CSS_COMMENT) {
                        if (lastStateC == SCE_CSS_OPERATOR) {
                            op = styler.SafeGetCharAt(i-1);
                            opPrev = styler.SafeGetCharAt(i-2);
                            while (--i) {
                                lastState = styler.StyleAt(i-1);
                                if (lastState != SCE_CSS_OPERATOR && lastState != SCE_CSS_COMMENT)
                                    break;
                            }
                            if (i == 0)
                                lastState = SCE_CSS_DEFAULT;
                        }
                        break;
                    }
                }
                if (i == 0)
                    lastStateC = SCE_CSS_DEFAULT;
            }
            sc.Forward();
            sc.ForwardSetState(lastStateC);
        }

        if (sc.state == SCE_CSS_COMMENT)
            continue;

        if (sc.state == SCE_CSS_DOUBLESTRING || sc.state == SCE_CSS_SINGLESTRING) {
            if (sc.ch != (sc.state == SCE_CSS_DOUBLESTRING ? '\"' : '\''))
                continue;
            unsigned int i = sc.currentPos;
            while (i && styler[i-1] == '\\')
                i--;
            if ((sc.currentPos - i) % 2 == 1)
                continue;
            sc.ForwardSetState(lastStateS);
        }

        if (sc.state == SCE_CSS_OPERATOR) {
            if (op == ' ') {
                unsigned int i = startPos;
                op = styler.SafeGetCharAt(i-1);
                opPrev = styler.SafeGetCharAt(i-2);
                while (--i) {
                    lastState = styler.StyleAt(i-1);
                    if (lastState != SCE_CSS_OPERATOR && lastState != SCE_CSS_COMMENT)
                        break;
                }
            }
            switch (op) {
            case '@':
                if (lastState == SCE_CSS_DEFAULT)
                    sc.SetState(SCE_CSS_DIRECTIVE);
                break;
            case '>':
            case '+':
                if (lastState == SCE_CSS_TAG || lastState == SCE_CSS_CLASS || lastState == SCE_CSS_ID ||
                    lastState == SCE_CSS_PSEUDOCLASS || lastState == SCE_CSS_EXTENDED_PSEUDOCLASS || lastState == SCE_CSS_UNKNOWN_PSEUDOCLASS)
                    sc.SetState(SCE_CSS_DEFAULT);
                break;
            case '[':
                if (lastState == SCE_CSS_TAG || lastState == SCE_CSS_DEFAULT || lastState == SCE_CSS_CLASS || lastState == SCE_CSS_ID ||
                    lastState == SCE_CSS_PSEUDOCLASS || lastState == SCE_CSS_EXTENDED_PSEUDOCLASS || lastState == SCE_CSS_UNKNOWN_PSEUDOCLASS)
                    sc.SetState(SCE_CSS_ATTRIBUTE);
                break;
            case ']':
                if (lastState == SCE_CSS_ATTRIBUTE)
                    sc.SetState(SCE_CSS_TAG);
                break;
            case '{':
                if (lastState == SCE_CSS_MEDIA)
                    sc.SetState(SCE_CSS_DEFAULT);
                else if (lastState == SCE_CSS_TAG || lastState == SCE_CSS_DIRECTIVE)
                    sc.SetState(SCE_CSS_IDENTIFIER);
                break;
            case '}':
                if (lastState == SCE_CSS_DEFAULT || lastState == SCE_CSS_VALUE || lastState == SCE_CSS_IMPORTANT ||
                    lastState == SCE_CSS_IDENTIFIER || lastState == SCE_CSS_IDENTIFIER2 || lastState == SCE_CSS_IDENTIFIER3)
                    sc.SetState(SCE_CSS_DEFAULT);
                break;
            case '(':
                if (lastState == SCE_CSS_PSEUDOCLASS)
                    sc.SetState(SCE_CSS_TAG);
                else if (lastState == SCE_CSS_EXTENDED_PSEUDOCLASS)
                    sc.SetState(SCE_CSS_EXTENDED_PSEUDOCLASS);
                break;
            case ')':
                if (lastState == SCE_CSS_TAG || lastState == SCE_CSS_DEFAULT || lastState == SCE_CSS_CLASS || lastState == SCE_CSS_ID ||
                    lastState == SCE_CSS_PSEUDOCLASS || lastState == SCE_CSS_EXTENDED_PSEUDOCLASS || lastState == SCE_CSS_UNKNOWN_PSEUDOCLASS ||
                    lastState == SCE_CSS_PSEUDOELEMENT || lastState == SCE_CSS_EXTENDED_PSEUDOELEMENT)
                    sc.SetState(SCE_CSS_TAG);
                break;
            case ':':
                if (lastState == SCE_CSS_TAG || lastState == SCE_CSS_DEFAULT || lastState == SCE_CSS_CLASS || lastState == SCE_CSS_ID ||
                    lastState == SCE_CSS_PSEUDOCLASS || lastState == SCE_CSS_EXTENDED_PSEUDOCLASS || lastState == SCE_CSS_UNKNOWN_PSEUDOCLASS ||
                    lastState == SCE_CSS_PSEUDOELEMENT || lastState == SCE_CSS_EXTENDED_PSEUDOELEMENT)
                    sc.SetState(SCE_CSS_PSEUDOCLASS);
                else if (lastState == SCE_CSS_IDENTIFIER || lastState == SCE_CSS_IDENTIFIER2 ||
                    lastState == SCE_CSS_IDENTIFIER3 || lastState == SCE_CSS_EXTENDED_IDENTIFIER ||
                    lastState == SCE_CSS_UNKNOWN_IDENTIFIER)
                    sc.SetState(SCE_CSS_VALUE);
                break;
            case '.':
                if (lastState == SCE_CSS_TAG || lastState == SCE_CSS_DEFAULT || lastState == SCE_CSS_CLASS || lastState == SCE_CSS_ID ||
                    lastState == SCE_CSS_PSEUDOCLASS || lastState == SCE_CSS_EXTENDED_PSEUDOCLASS || lastState == SCE_CSS_UNKNOWN_PSEUDOCLASS)
                    sc.SetState(SCE_CSS_CLASS);
                break;
            case '#':
                if (lastState == SCE_CSS_TAG || lastState == SCE_CSS_DEFAULT || lastState == SCE_CSS_CLASS || lastState == SCE_CSS_ID ||
                    lastState == SCE_CSS_PSEUDOCLASS || lastState == SCE_CSS_EXTENDED_PSEUDOCLASS || lastState == SCE_CSS_UNKNOWN_PSEUDOCLASS)
                    sc.SetState(SCE_CSS_ID);
                break;
            case ',':
            case '|':
            case '~':
                if (lastState == SCE_CSS_TAG)
                    sc.SetState(SCE_CSS_DEFAULT);
                break;
            case ';':
                if (lastState == SCE_CSS_DIRECTIVE)
                    sc.SetState(SCE_CSS_DEFAULT);
                else if (lastState == SCE_CSS_VALUE || lastState == SCE_CSS_IMPORTANT)
                    sc.SetState(SCE_CSS_IDENTIFIER);
                break;
            case '!':
                if (lastState == SCE_CSS_VALUE)
                    sc.SetState(SCE_CSS_IMPORTANT);
                break;
            }
        }

        if (IsAWordChar(sc.ch)) {
            if (sc.state == SCE_CSS_DEFAULT)
                sc.SetState(SCE_CSS_TAG);
            continue;
        }

        if (sc.ch == '*' && sc.state == SCE_CSS_DEFAULT) {
            sc.SetState(SCE_CSS_TAG);
            continue;
        }

        if (IsAWordChar(sc.chPrev) && (
            sc.state == SCE_CSS_IDENTIFIER || sc.state == SCE_CSS_IDENTIFIER2 ||
            sc.state == SCE_CSS_IDENTIFIER3 || sc.state == SCE_CSS_EXTENDED_IDENTIFIER ||
            sc.state == SCE_CSS_UNKNOWN_IDENTIFIER ||
            sc.state == SCE_CSS_PSEUDOCLASS || sc.state == SCE_CSS_PSEUDOELEMENT ||
            sc.state == SCE_CSS_EXTENDED_PSEUDOCLASS || sc.state == SCE_CSS_EXTENDED_PSEUDOELEMENT ||
            sc.state == SCE_CSS_UNKNOWN_PSEUDOCLASS ||
            sc.state == SCE_CSS_IMPORTANT ||
            sc.state == SCE_CSS_DIRECTIVE
        )) {
            char s[100];
            sc.GetCurrentLowered(s, sizeof(s));
            char *s2 = s;
            while (*s2 && !IsAWordChar(*s2))
                s2++;
            switch (sc.state) {
            case SCE_CSS_IDENTIFIER:
            case SCE_CSS_IDENTIFIER2:
            case SCE_CSS_IDENTIFIER3:
            case SCE_CSS_EXTENDED_IDENTIFIER:
            case SCE_CSS_UNKNOWN_IDENTIFIER:
                if (css1Props.InList(s2))
                    sc.ChangeState(SCE_CSS_IDENTIFIER);
                else if (css2Props.InList(s2))
                    sc.ChangeState(SCE_CSS_IDENTIFIER2);
                else if (css3Props.InList(s2))
                    sc.ChangeState(SCE_CSS_IDENTIFIER3);
                else if (exProps.InList(s2))
                    sc.ChangeState(SCE_CSS_EXTENDED_IDENTIFIER);
                else
                    sc.ChangeState(SCE_CSS_UNKNOWN_IDENTIFIER);
                break;
            case SCE_CSS_PSEUDOCLASS:
            case SCE_CSS_PSEUDOELEMENT:
            case SCE_CSS_EXTENDED_PSEUDOCLASS:
            case SCE_CSS_EXTENDED_PSEUDOELEMENT:
            case SCE_CSS_UNKNOWN_PSEUDOCLASS:
                if (op == ':' && opPrev != ':' && pseudoClasses.InList(s2))
                    sc.ChangeState(SCE_CSS_PSEUDOCLASS);
                else if (opPrev == ':' && pseudoElements.InList(s2))
                    sc.ChangeState(SCE_CSS_PSEUDOELEMENT);
                else if ((op == ':' || (op == '(' && lastState == SCE_CSS_EXTENDED_PSEUDOCLASS)) && opPrev != ':' && exPseudoClasses.InList(s2))
                    sc.ChangeState(SCE_CSS_EXTENDED_PSEUDOCLASS);
                else if (opPrev == ':' && exPseudoElements.InList(s2))
                    sc.ChangeState(SCE_CSS_EXTENDED_PSEUDOELEMENT);
                else
                    sc.ChangeState(SCE_CSS_UNKNOWN_PSEUDOCLASS);
                break;
            case SCE_CSS_IMPORTANT:
                if (strcmp(s2, "important") != 0)
                    sc.ChangeState(SCE_CSS_VALUE);
                break;
            case SCE_CSS_DIRECTIVE:
                if (op == '@' && strcmp(s2, "media") == 0)
                    sc.ChangeState(SCE_CSS_MEDIA);
                break;
            }
        }

        if (sc.ch != '.' && sc.ch != ':' && sc.ch != '#' && (
            sc.state == SCE_CSS_CLASS || sc.state == SCE_CSS_ID ||
            (sc.ch != '(' && sc.ch != ')' && ( /* This line of the condition makes it possible to extend pseudo-classes with parentheses */
                sc.state == SCE_CSS_PSEUDOCLASS || sc.state == SCE_CSS_PSEUDOELEMENT ||
                sc.state == SCE_CSS_EXTENDED_PSEUDOCLASS || sc.state == SCE_CSS_EXTENDED_PSEUDOELEMENT ||
                sc.state == SCE_CSS_UNKNOWN_PSEUDOCLASS
            ))
        ))
            sc.SetState(SCE_CSS_TAG);

        if (sc.Match('/', '*')) {
            lastStateC = sc.state;
            sc.SetState(SCE_CSS_COMMENT);
            sc.Forward();
        } else if ((sc.state == SCE_CSS_VALUE || sc.state == SCE_CSS_ATTRIBUTE)
            && (sc.ch == '\"' || sc.ch == '\'')) {
            lastStateS = sc.state;
            sc.SetState((sc.ch == '\"' ? SCE_CSS_DOUBLESTRING : SCE_CSS_SINGLESTRING));
        } else if (IsCssOperator(sc.ch)
            && (sc.state != SCE_CSS_ATTRIBUTE || sc.ch == ']')
            && (sc.state != SCE_CSS_VALUE || sc.ch == ';' || sc.ch == '}' || sc.ch == '!')
            && ((sc.state != SCE_CSS_DIRECTIVE && sc.state != SCE_CSS_MEDIA) || sc.ch == ';' || sc.ch == '{')
        ) {
            if (sc.state != SCE_CSS_OPERATOR)
                lastState = sc.state;
            sc.SetState(SCE_CSS_OPERATOR);
            op = sc.ch;
            opPrev = sc.chPrev;
        }
    }

    sc.Complete();
}

static void FoldCSSDoc(unsigned int startPos, int length, int, WordList *[], Accessor &styler) {
    bool foldComment = styler.GetPropertyInt("fold.comment") != 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];
    bool inComment = (styler.StyleAt(startPos-1) == SCE_CSS_COMMENT);
    for (unsigned int i = startPos; i < endPos; i++) {
        char ch = chNext;
        chNext = styler.SafeGetCharAt(i + 1);
        int style = styler.StyleAt(i);
        bool atEOL = (ch == '\r' && chNext != '\n') || (ch == '\n');
        if (foldComment) {
            if (!inComment && (style == SCE_CSS_COMMENT))
                levelCurrent++;
            else if (inComment && (style != SCE_CSS_COMMENT))
                levelCurrent--;
            inComment = (style == SCE_CSS_COMMENT);
        }
        if (style == SCE_CSS_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 cssWordListDesc[] = {
    "CSS1 Properties",
    "Pseudo-classes",
    "CSS2 Properties",
    "CSS3 Properties",
    "Pseudo-elements",
    "Browser-Specific CSS Properties",
    "Browser-Specific Pseudo-classes",
    "Browser-Specific Pseudo-elements",
    0
};

LexerModule lmCss(SCLEX_CSS, ColouriseCssDoc, "css", FoldCSSDoc, cssWordListDesc);
