// Scintilla source code edit control
/** @file LexLout.cxx
 ** Lexer for the Basser Lout (>= version 3) typesetting language
 **/
// Copyright 2003 by Kein-Hong Man <mkh@pl.jaring.my>
// 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 int ch) {
    return (ch < 0x80) && (isalpha(ch) || ch == '@' || ch == '_');
}

static inline bool IsAnOther(const int ch) {
    return (ch < 0x80) && (ch == '{' || ch == '}' ||
    ch == '!' || ch == '$' || ch == '%' || ch == '&' || ch == '\'' ||
    ch == '(' || ch == ')' || ch == '*' || ch == '+' || ch == ',' ||
    ch == '-' || ch == '.' || ch == '/' || ch == ':' || ch == ';' ||
    ch == '<' || ch == '=' || ch == '>' || ch == '?' || ch == '[' ||
    ch == ']' || ch == '^' || ch == '`' || ch == '|' || ch == '~');
}

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

    WordList &keywords = *keywordlists[0];
    WordList &keywords2 = *keywordlists[1];
    WordList &keywords3 = *keywordlists[2];

    int visibleChars = 0;
    int firstWordInLine = 0;
    int leadingAtSign = 0;

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

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

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

        // Determine if the current state should terminate.
        if (sc.state == SCE_LOUT_COMMENT) {
            if (sc.atLineEnd) {
                sc.SetState(SCE_LOUT_DEFAULT);
                visibleChars = 0;
            }
        } else if (sc.state == SCE_LOUT_NUMBER) {
            if (!IsADigit(sc.ch) && sc.ch != '.') {
                sc.SetState(SCE_LOUT_DEFAULT);
            }
        } else if (sc.state == SCE_LOUT_STRING) {
            if (sc.ch == '\\') {
                if (sc.chNext == '\"' || sc.chNext == '\\') {
                    sc.Forward();
                }
            } else if (sc.ch == '\"') {
                sc.ForwardSetState(SCE_LOUT_DEFAULT);
            } else if (sc.atLineEnd) {
                sc.ChangeState(SCE_LOUT_STRINGEOL);
                sc.ForwardSetState(SCE_LOUT_DEFAULT);
                visibleChars = 0;
            }
        } else if (sc.state == SCE_LOUT_IDENTIFIER) {
            if (!IsAWordChar(sc.ch)) {
                char s[100];
                sc.GetCurrent(s, sizeof(s));

                if (leadingAtSign) {
                    if (keywords.InList(s)) {
                        sc.ChangeState(SCE_LOUT_WORD);
                    } else {
                        sc.ChangeState(SCE_LOUT_WORD4);
                    }
                } else if (firstWordInLine && keywords3.InList(s)) {
                    sc.ChangeState(SCE_LOUT_WORD3);
                }
                sc.SetState(SCE_LOUT_DEFAULT);
            }
        } else if (sc.state == SCE_LOUT_OPERATOR) {
            if (!IsAnOther(sc.ch)) {
                char s[100];
                sc.GetCurrent(s, sizeof(s));

                if (keywords2.InList(s)) {
                    sc.ChangeState(SCE_LOUT_WORD2);
                }
                sc.SetState(SCE_LOUT_DEFAULT);
            }
        }

        // Determine if a new state should be entered.
        if (sc.state == SCE_LOUT_DEFAULT) {
            if (sc.ch == '#') {
                sc.SetState(SCE_LOUT_COMMENT);
            } else if (sc.ch == '\"') {
                sc.SetState(SCE_LOUT_STRING);
            } else if (IsADigit(sc.ch) ||
                  (sc.ch == '.' && IsADigit(sc.chNext))) {
                sc.SetState(SCE_LOUT_NUMBER);
            } else if (IsAWordChar(sc.ch)) {
                firstWordInLine = (visibleChars == 0);
                leadingAtSign = (sc.ch == '@');
                sc.SetState(SCE_LOUT_IDENTIFIER);
            } else if (IsAnOther(sc.ch)) {
                sc.SetState(SCE_LOUT_OPERATOR);
            }
        }

        if (sc.atLineEnd) {
            // Reset states to begining of colourise so no surprises
            // if different sets of lines lexed.
            visibleChars = 0;
        }
        if (!IsASpace(sc.ch)) {
            visibleChars++;
        }
    }
    sc.Complete();
}

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

    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 foldCompact = styler.GetPropertyInt("fold.compact", 1) != 0;
    int styleNext = styler.StyleAt(startPos);
    char s[10];

    for (unsigned int i = startPos; i < endPos; i++) {
        char ch = chNext;
        chNext = styler.SafeGetCharAt(i + 1);
        int style = styleNext;
        styleNext = styler.StyleAt(i + 1);
        bool atEOL = (ch == '\r' && chNext != '\n') || (ch == '\n');

        if (style == SCE_LOUT_WORD) {
            if (ch == '@') {
                for (unsigned int j = 0; j < 8; j++) {
                    if (!IsAWordChar(styler[i + j])) {
                        break;
                    }
                    s[j] = styler[i + j];
                    s[j + 1] = '\0';
                }
                if (strcmp(s, "@Begin") == 0) {
                    levelCurrent++;
                } else if (strcmp(s, "@End") == 0) {
                    levelCurrent--;
                }
            }
        } else if (style == SCE_LOUT_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 loutWordLists[] = {
            "Predefined identifiers",
            "Predefined delimiters",
            "Predefined keywords",
            0,
        };

LexerModule lmLout(SCLEX_LOUT, ColouriseLoutDoc, "lout", FoldLoutDoc, loutWordLists);
