// Scintilla source code edit control
/** @file LexBasic.cxx
 ** Lexer for BlitzBasic and PureBasic.
 ** Converted to lexer object and added further folding features/properties by "Udo Lechner" <dlchnr(at)gmx(dot)net>
 **/
// Copyright 1998-2003 by Neil Hodgson <neilh@scintilla.org>
// The License.txt file describes the conditions under which this software may be distributed.

// This tries to be a unified Lexer/Folder for all the BlitzBasic/BlitzMax/PurBasic basics
// and derivatives. Once they diverge enough, might want to split it into multiple
// lexers for more code clearity.
//
// Mail me (elias <at> users <dot> sf <dot> net) for any bugs.

// Folding only works for simple things like functions or types.

// You may want to have a look at my ctags lexer as well, if you additionally to coloring
// and folding need to extract things like label tags in your editor.

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

#ifdef _MSC_VER
#pragma warning(disable: 4786)
#endif

#include <string>
#include <map>

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

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

#ifdef SCI_NAMESPACE
using namespace Scintilla;
#endif

/* Bits:
 * 1  - whitespace
 * 2  - operator
 * 4  - identifier
 * 8  - decimal digit
 * 16 - hex digit
 * 32 - bin digit
 */
static int character_classification[128] =
{
    0,  0,  0,  0,  0,  0,  0,  0,  0,  1,  1,  0,  0,  1,  0,  0,
    0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
    1,  2,  0,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  10, 2,
    60, 60, 28, 28, 28, 28, 28, 28, 28, 28, 2,  2,  2,  2,  2,  2,
    2,  20, 20, 20, 20, 20, 20, 4,  4,  4,  4,  4,  4,  4,  4,  4,
    4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  2,  2,  2,  2,  4,
    2,  20, 20, 20, 20, 20, 20, 4,  4,  4,  4,  4,  4,  4,  4,  4,
    4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  2,  2,  2,  2,  0
};

static bool IsSpace(int c) {
    return c < 128 && (character_classification[c] & 1);
}

static bool IsOperator(int c) {
    return c < 128 && (character_classification[c] & 2);
}

static bool IsIdentifier(int c) {
    return c < 128 && (character_classification[c] & 4);
}

static bool IsDigit(int c) {
    return c < 128 && (character_classification[c] & 8);
}

static bool IsHexDigit(int c) {
    return c < 128 && (character_classification[c] & 16);
}

static bool IsBinDigit(int c) {
    return c < 128 && (character_classification[c] & 32);
}

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

static int CheckBlitzFoldPoint(char const *token, int &level) {
    if (!strcmp(token, "function") ||
        !strcmp(token, "type")) {
        level |= SC_FOLDLEVELHEADERFLAG;
        return 1;
    }
    if (!strcmp(token, "end function") ||
        !strcmp(token, "end type")) {
        return -1;
    }
    return 0;
}

static int CheckPureFoldPoint(char const *token, int &level) {
    if (!strcmp(token, "procedure") ||
        !strcmp(token, "enumeration") ||
        !strcmp(token, "interface") ||
        !strcmp(token, "structure")) {
        level |= SC_FOLDLEVELHEADERFLAG;
        return 1;
    }
    if (!strcmp(token, "endprocedure") ||
        !strcmp(token, "endenumeration") ||
        !strcmp(token, "endinterface") ||
        !strcmp(token, "endstructure")) {
        return -1;
    }
    return 0;
}

static int CheckFreeFoldPoint(char const *token, int &level) {
    if (!strcmp(token, "function") ||
        !strcmp(token, "sub") ||
        !strcmp(token, "type")) {
        level |= SC_FOLDLEVELHEADERFLAG;
        return 1;
    }
    if (!strcmp(token, "end function") ||
        !strcmp(token, "end sub") ||
        !strcmp(token, "end type")) {
        return -1;
    }
    return 0;
}

// An individual named option for use in an OptionSet

// Options used for LexerBasic
struct OptionsBasic {
    bool fold;
    bool foldSyntaxBased;
    bool foldCommentExplicit;
    std::string foldExplicitStart;
    std::string foldExplicitEnd;
    bool foldExplicitAnywhere;
    bool foldCompact;
    OptionsBasic() {
        fold = false;
        foldSyntaxBased = true;
        foldCommentExplicit = false;
        foldExplicitStart = "";
        foldExplicitEnd   = "";
        foldExplicitAnywhere = false;
        foldCompact = true;
    }
};

static const char * const blitzbasicWordListDesc[] = {
    "BlitzBasic Keywords",
    "user1",
    "user2",
    "user3",
    0
};

static const char * const purebasicWordListDesc[] = {
    "PureBasic Keywords",
    "PureBasic PreProcessor Keywords",
    "user defined 1",
    "user defined 2",
    0
};

static const char * const freebasicWordListDesc[] = {
    "FreeBasic Keywords",
    "FreeBasic PreProcessor Keywords",
    "user defined 1",
    "user defined 2",
    0
};

struct OptionSetBasic : public OptionSet<OptionsBasic> {
    OptionSetBasic(const char * const wordListDescriptions[]) {
        DefineProperty("fold", &OptionsBasic::fold);

        DefineProperty("fold.basic.syntax.based", &OptionsBasic::foldSyntaxBased,
            "Set this property to 0 to disable syntax based folding.");

        DefineProperty("fold.basic.comment.explicit", &OptionsBasic::foldCommentExplicit,
            "This option enables folding explicit fold points when using the Basic lexer. "
            "Explicit fold points allows adding extra folding by placing a ;{ (BB/PB) or '{ (FB) comment at the start "
            "and a ;} (BB/PB) or '} (FB) at the end of a section that should be folded.");

        DefineProperty("fold.basic.explicit.start", &OptionsBasic::foldExplicitStart,
            "The string to use for explicit fold start points, replacing the standard ;{ (BB/PB) or '{ (FB).");

        DefineProperty("fold.basic.explicit.end", &OptionsBasic::foldExplicitEnd,
            "The string to use for explicit fold end points, replacing the standard ;} (BB/PB) or '} (FB).");

        DefineProperty("fold.basic.explicit.anywhere", &OptionsBasic::foldExplicitAnywhere,
            "Set this property to 1 to enable explicit fold points anywhere, not just in line comments.");

        DefineProperty("fold.compact", &OptionsBasic::foldCompact);

        DefineWordListSets(wordListDescriptions);
    }
};

class LexerBasic : public ILexer {
    char comment_char;
    int (*CheckFoldPoint)(char const *, int &);
    WordList keywordlists[4];
    OptionsBasic options;
    OptionSetBasic osBasic;
public:
    LexerBasic(char comment_char_, int (*CheckFoldPoint_)(char const *, int &), const char * const wordListDescriptions[]) :
               comment_char(comment_char_),
               CheckFoldPoint(CheckFoldPoint_),
               osBasic(wordListDescriptions) {
    }
    ~LexerBasic() {
    }
    void SCI_METHOD Release() {
        delete this;
    }
    int SCI_METHOD Version() const {
        return lvOriginal;
    }
    const char * SCI_METHOD PropertyNames() {
        return osBasic.PropertyNames();
    }
    int SCI_METHOD PropertyType(const char *name) {
        return osBasic.PropertyType(name);
    }
    const char * SCI_METHOD DescribeProperty(const char *name) {
        return osBasic.DescribeProperty(name);
    }
    int SCI_METHOD PropertySet(const char *key, const char *val);
    const char * SCI_METHOD DescribeWordListSets() {
        return osBasic.DescribeWordListSets();
    }
    int SCI_METHOD WordListSet(int n, const char *wl);
    void SCI_METHOD Lex(unsigned int startPos, int length, int initStyle, IDocument *pAccess);
    void SCI_METHOD Fold(unsigned int startPos, int length, int initStyle, IDocument *pAccess);

    void * SCI_METHOD PrivateCall(int, void *) {
        return 0;
    }
    static ILexer *LexerFactoryBlitzBasic() {
        return new LexerBasic(';', CheckBlitzFoldPoint, blitzbasicWordListDesc);
    }
    static ILexer *LexerFactoryPureBasic() {
        return new LexerBasic(';', CheckPureFoldPoint, purebasicWordListDesc);
    }
    static ILexer *LexerFactoryFreeBasic() {
        return new LexerBasic('\'', CheckFreeFoldPoint, freebasicWordListDesc );
    }
};

int SCI_METHOD LexerBasic::PropertySet(const char *key, const char *val) {
    if (osBasic.PropertySet(&options, key, val)) {
        return 0;
    }
    return -1;
}

int SCI_METHOD LexerBasic::WordListSet(int n, const char *wl) {
    WordList *wordListN = 0;
    switch (n) {
    case 0:
        wordListN = &keywordlists[0];
        break;
    case 1:
        wordListN = &keywordlists[1];
        break;
    case 2:
        wordListN = &keywordlists[2];
        break;
    case 3:
        wordListN = &keywordlists[3];
        break;
    }
    int firstModification = -1;
    if (wordListN) {
        WordList wlNew;
        wlNew.Set(wl);
        if (*wordListN != wlNew) {
            wordListN->Set(wl);
            firstModification = 0;
        }
    }
    return firstModification;
}

void SCI_METHOD LexerBasic::Lex(unsigned int startPos, int length, int initStyle, IDocument *pAccess) {
    LexAccessor styler(pAccess);

    bool wasfirst = true, isfirst = true; // true if first token in a line
    styler.StartAt(startPos);

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

    // Can't use sc.More() here else we miss the last character
    for (; ; sc.Forward()) {
        if (sc.state == SCE_B_IDENTIFIER) {
            if (!IsIdentifier(sc.ch)) {
                // Labels
                if (wasfirst && sc.Match(':')) {
                    sc.ChangeState(SCE_B_LABEL);
                    sc.ForwardSetState(SCE_B_DEFAULT);
                } else {
                    char s[100];
                    int kstates[4] = {
                        SCE_B_KEYWORD,
                        SCE_B_KEYWORD2,
                        SCE_B_KEYWORD3,
                        SCE_B_KEYWORD4,
                    };
                    sc.GetCurrentLowered(s, sizeof(s));
                    for (int i = 0; i < 4; i++) {
                        if (keywordlists[i].InList(s)) {
                            sc.ChangeState(kstates[i]);
                        }
                    }
                    // Types, must set them as operator else they will be
                    // matched as number/constant
                    if (sc.Match('.') || sc.Match('$') || sc.Match('%') ||
                        sc.Match('#')) {
                        sc.SetState(SCE_B_OPERATOR);
                    } else {
                        sc.SetState(SCE_B_DEFAULT);
                    }
                }
            }
        } else if (sc.state == SCE_B_OPERATOR) {
            if (!IsOperator(sc.ch) || sc.Match('#'))
                sc.SetState(SCE_B_DEFAULT);
        } else if (sc.state == SCE_B_LABEL) {
            if (!IsIdentifier(sc.ch))
                sc.SetState(SCE_B_DEFAULT);
        } else if (sc.state == SCE_B_CONSTANT) {
            if (!IsIdentifier(sc.ch))
                sc.SetState(SCE_B_DEFAULT);
        } else if (sc.state == SCE_B_NUMBER) {
            if (!IsDigit(sc.ch))
                sc.SetState(SCE_B_DEFAULT);
        } else if (sc.state == SCE_B_HEXNUMBER) {
            if (!IsHexDigit(sc.ch))
                sc.SetState(SCE_B_DEFAULT);
        } else if (sc.state == SCE_B_BINNUMBER) {
            if (!IsBinDigit(sc.ch))
                sc.SetState(SCE_B_DEFAULT);
        } else if (sc.state == SCE_B_STRING) {
            if (sc.ch == '"') {
                sc.ForwardSetState(SCE_B_DEFAULT);
            }
            if (sc.atLineEnd) {
                sc.ChangeState(SCE_B_ERROR);
                sc.SetState(SCE_B_DEFAULT);
            }
        } else if (sc.state == SCE_B_COMMENT || sc.state == SCE_B_PREPROCESSOR) {
            if (sc.atLineEnd) {
                sc.SetState(SCE_B_DEFAULT);
            }
        }

        if (sc.atLineStart)
            isfirst = true;

        if (sc.state == SCE_B_DEFAULT || sc.state == SCE_B_ERROR) {
            if (isfirst && sc.Match('.')) {
                sc.SetState(SCE_B_LABEL);
            } else if (isfirst && sc.Match('#')) {
                wasfirst = isfirst;
                sc.SetState(SCE_B_IDENTIFIER);
            } else if (sc.Match(comment_char)) {
                // Hack to make deprecated QBASIC '$Include show
                // up in freebasic with SCE_B_PREPROCESSOR.
                if (comment_char == '\'' && sc.Match(comment_char, '$'))
                    sc.SetState(SCE_B_PREPROCESSOR);
                else
                    sc.SetState(SCE_B_COMMENT);
            } else if (sc.Match('"')) {
                sc.SetState(SCE_B_STRING);
            } else if (IsDigit(sc.ch)) {
                sc.SetState(SCE_B_NUMBER);
            } else if (sc.Match('$')) {
                sc.SetState(SCE_B_HEXNUMBER);
            } else if (sc.Match('%')) {
                sc.SetState(SCE_B_BINNUMBER);
            } else if (sc.Match('#')) {
                sc.SetState(SCE_B_CONSTANT);
            } else if (IsOperator(sc.ch)) {
                sc.SetState(SCE_B_OPERATOR);
            } else if (IsIdentifier(sc.ch)) {
                wasfirst = isfirst;
                sc.SetState(SCE_B_IDENTIFIER);
            } else if (!IsSpace(sc.ch)) {
                sc.SetState(SCE_B_ERROR);
            }
        }

        if (!IsSpace(sc.ch))
            isfirst = false;

        if (!sc.More())
            break;
    }
    sc.Complete();
}


void SCI_METHOD LexerBasic::Fold(unsigned int startPos, int length, int /* initStyle */, IDocument *pAccess) {

    if (!options.fold)
        return;

    LexAccessor styler(pAccess);

    int line = styler.GetLine(startPos);
    int level = styler.LevelAt(line);
    int go = 0, done = 0;
    int endPos = startPos + length;
    char word[256];
    int wordlen = 0;
    const bool userDefinedFoldMarkers = !options.foldExplicitStart.empty() && !options.foldExplicitEnd.empty();
    int cNext = styler[startPos];

    // Scan for tokens at the start of the line (they may include
    // whitespace, for tokens like "End Function"
    for (int i = startPos; i < endPos; i++) {
        int c = cNext;
        cNext = styler.SafeGetCharAt(i + 1);
        bool atEOL = (c == '\r' && cNext != '\n') || (c == '\n');
        if (options.foldSyntaxBased && !done && !go) {
            if (wordlen) { // are we scanning a token already?
                word[wordlen] = static_cast<char>(LowerCase(c));
                if (!IsIdentifier(c)) { // done with token
                    word[wordlen] = '\0';
                    go = CheckFoldPoint(word, level);
                    if (!go) {
                        // Treat any whitespace as single blank, for
                        // things like "End   Function".
                        if (IsSpace(c) && IsIdentifier(word[wordlen - 1])) {
                            word[wordlen] = ' ';
                            if (wordlen < 255)
                                wordlen++;
                        }
                        else // done with this line
                            done = 1;
                    }
                } else if (wordlen < 255) {
                    wordlen++;
                }
            } else { // start scanning at first non-whitespace character
                if (!IsSpace(c)) {
                    if (IsIdentifier(c)) {
                        word[0] = static_cast<char>(LowerCase(c));
                        wordlen = 1;
                    } else // done with this line
                        done = 1;
                }
            }
        }
        if (options.foldCommentExplicit && ((styler.StyleAt(i) == SCE_B_COMMENT) || options.foldExplicitAnywhere)) {
            if (userDefinedFoldMarkers) {
                if (styler.Match(i, options.foldExplicitStart.c_str())) {
                    level |= SC_FOLDLEVELHEADERFLAG;
                    go = 1;
                } else if (styler.Match(i, options.foldExplicitEnd.c_str())) {
                    go = -1;
                }
            } else {
                if (c == comment_char) {
                    if (cNext == '{') {
                        level |= SC_FOLDLEVELHEADERFLAG;
                        go = 1;
                    } else if (cNext == '}') {
                        go = -1;
                    }
                }
            }
        }
        if (atEOL) { // line end
            if (!done && wordlen == 0 && options.foldCompact) // line was only space
                level |= SC_FOLDLEVELWHITEFLAG;
            if (level != styler.LevelAt(line))
                styler.SetLevel(line, level);
            level += go;
            line++;
            // reset state
            wordlen = 0;
            level &= ~SC_FOLDLEVELHEADERFLAG;
            level &= ~SC_FOLDLEVELWHITEFLAG;
            go = 0;
            done = 0;
        }
    }
}

LexerModule lmBlitzBasic(SCLEX_BLITZBASIC, LexerBasic::LexerFactoryBlitzBasic, "blitzbasic", blitzbasicWordListDesc);

LexerModule lmPureBasic(SCLEX_PUREBASIC, LexerBasic::LexerFactoryPureBasic, "purebasic", purebasicWordListDesc);

LexerModule lmFreeBasic(SCLEX_FREEBASIC, LexerBasic::LexerFactoryFreeBasic, "freebasic", freebasicWordListDesc);
