// Scintilla source code edit control
/** @file LexVB.cxx
 ** Lexer for Visual Basic and VBScript.
 **/
// Copyright 1998-2005 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

// Internal state, highlighted as number
#define SCE_B_FILENUMBER SCE_B_DEFAULT+100


static bool IsVBComment(Accessor &styler, int pos, int len) {
    return len > 0 && styler[pos] == '\'';
}

static inline bool IsTypeCharacter(int ch) {
    return ch == '%' || ch == '&' || ch == '@' || ch == '!' || ch == '#' || ch == '$';
}

// Extended to accept accented characters
static inline bool IsAWordChar(int ch) {
    return ch >= 0x80 ||
           (isalnum(ch) || ch == '.' || ch == '_');
}

static inline bool IsAWordStart(int ch) {
    return ch >= 0x80 ||
           (isalpha(ch) || 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 ColouriseVBDoc(unsigned int startPos, int length, int initStyle,
                           WordList *keywordlists[], Accessor &styler, bool vbScriptSyntax) {

    WordList &keywords = *keywordlists[0];
    WordList &keywords2 = *keywordlists[1];
    WordList &keywords3 = *keywordlists[2];
    WordList &keywords4 = *keywordlists[3];

    styler.StartAt(startPos);

    int visibleChars = 0;
    int fileNbDigits = 0;

    // Do not leak onto next line
    if (initStyle == SCE_B_STRINGEOL || initStyle == SCE_B_COMMENT || initStyle == SCE_B_PREPROCESSOR) {
        initStyle = SCE_B_DEFAULT;
    }

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

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

        if (sc.state == SCE_B_OPERATOR) {
            sc.SetState(SCE_B_DEFAULT);
        } else if (sc.state == SCE_B_IDENTIFIER) {
            if (!IsAWordChar(sc.ch)) {
                // In Basic (except VBScript), a variable name or a function name
                // can end with a special character indicating the type of the value
                // held or returned.
                bool skipType = false;
                if (!vbScriptSyntax && IsTypeCharacter(sc.ch)) {
                    sc.Forward();   // Skip it
                    skipType = true;
                }
                if (sc.ch == ']') {
                    sc.Forward();
                }
                char s[100];
                sc.GetCurrentLowered(s, sizeof(s));
                if (skipType) {
                    s[strlen(s) - 1] = '\0';
                }
                if (strcmp(s, "rem") == 0) {
                    sc.ChangeState(SCE_B_COMMENT);
                } else {
                    if (keywords.InList(s)) {
                        sc.ChangeState(SCE_B_KEYWORD);
                    } else if (keywords2.InList(s)) {
                        sc.ChangeState(SCE_B_KEYWORD2);
                    } else if (keywords3.InList(s)) {
                        sc.ChangeState(SCE_B_KEYWORD3);
                    } else if (keywords4.InList(s)) {
                        sc.ChangeState(SCE_B_KEYWORD4);
                    }   // Else, it is really an identifier...
                    sc.SetState(SCE_B_DEFAULT);
                }
            }
        } else if (sc.state == SCE_B_NUMBER) {
            // We stop the number definition on non-numerical non-dot non-eE non-sign char
            // Also accepts A-F for hex. numbers
            if (!IsANumberChar(sc.ch) && !(tolower(sc.ch) >= 'a' && tolower(sc.ch) <= 'f')) {
                sc.SetState(SCE_B_DEFAULT);
            }
        } else if (sc.state == SCE_B_STRING) {
            // VB doubles quotes to preserve them, so just end this string
            // state now as a following quote will start again
            if (sc.ch == '\"') {
                if (sc.chNext == '\"') {
                    sc.Forward();
                } else {
                    if (tolower(sc.chNext) == 'c') {
                        sc.Forward();
                    }
                    sc.ForwardSetState(SCE_B_DEFAULT);
                }
            } else if (sc.atLineEnd) {
                visibleChars = 0;
                sc.ChangeState(SCE_B_STRINGEOL);
                sc.ForwardSetState(SCE_B_DEFAULT);
            }
        } else if (sc.state == SCE_B_COMMENT) {
            if (sc.atLineEnd) {
                visibleChars = 0;
                sc.ForwardSetState(SCE_B_DEFAULT);
            }
        } else if (sc.state == SCE_B_PREPROCESSOR) {
            if (sc.atLineEnd) {
                visibleChars = 0;
                sc.ForwardSetState(SCE_B_DEFAULT);
            }
        } else if (sc.state == SCE_B_FILENUMBER) {
            if (IsADigit(sc.ch)) {
                fileNbDigits++;
                if (fileNbDigits > 3) {
                    sc.ChangeState(SCE_B_DATE);
                }
            } else if (sc.ch == '\r' || sc.ch == '\n' || sc.ch == ',') {
                // Regular uses: Close #1; Put #1, ...; Get #1, ... etc.
                // Too bad if date is format #27, Oct, 2003# or something like that...
                // Use regular number state
                sc.ChangeState(SCE_B_NUMBER);
                sc.SetState(SCE_B_DEFAULT);
            } else if (sc.ch == '#') {
                sc.ChangeState(SCE_B_DATE);
                sc.ForwardSetState(SCE_B_DEFAULT);
            } else {
                sc.ChangeState(SCE_B_DATE);
            }
            if (sc.state != SCE_B_FILENUMBER) {
                fileNbDigits = 0;
            }
        } else if (sc.state == SCE_B_DATE) {
            if (sc.atLineEnd) {
                visibleChars = 0;
                sc.ChangeState(SCE_B_STRINGEOL);
                sc.ForwardSetState(SCE_B_DEFAULT);
            } else if (sc.ch == '#') {
                sc.ForwardSetState(SCE_B_DEFAULT);
            }
        }

        if (sc.state == SCE_B_DEFAULT) {
            if (sc.ch == '\'') {
                sc.SetState(SCE_B_COMMENT);
            } else if (sc.ch == '\"') {
                sc.SetState(SCE_B_STRING);
            } else if (sc.ch == '#' && visibleChars == 0) {
                // Preprocessor commands are alone on their line
                sc.SetState(SCE_B_PREPROCESSOR);
            } else if (sc.ch == '#') {
                // It can be a date literal, ending with #, or a file number, from 1 to 511
                // The date literal depends on the locale, so anything can go between #'s.
                // Can be #January 1, 1993# or #1 Jan 93# or #05/11/2003#, etc.
                // So we set the FILENUMBER state, and switch to DATE if it isn't a file number
                sc.SetState(SCE_B_FILENUMBER);
            } else if (sc.ch == '&' && tolower(sc.chNext) == 'h') {
                // Hexadecimal number
                sc.SetState(SCE_B_NUMBER);
                sc.Forward();
            } else if (sc.ch == '&' && tolower(sc.chNext) == 'o') {
                // Octal number
                sc.SetState(SCE_B_NUMBER);
                sc.Forward();
            } else if (IsADigit(sc.ch) || (sc.ch == '.' && IsADigit(sc.chNext))) {
                sc.SetState(SCE_B_NUMBER);
            } else if (IsAWordStart(sc.ch) || (sc.ch == '[')) {
                sc.SetState(SCE_B_IDENTIFIER);
            } else if (isoperator(static_cast<char>(sc.ch)) || (sc.ch == '\\')) {   // Integer division
                sc.SetState(SCE_B_OPERATOR);
            }
        }

        if (sc.atLineEnd) {
            visibleChars = 0;
        }
        if (!IsASpace(sc.ch)) {
            visibleChars++;
        }
    }

    if (sc.state == SCE_B_IDENTIFIER && !IsAWordChar(sc.ch)) {
        // In Basic (except VBScript), a variable name or a function name
        // can end with a special character indicating the type of the value
        // held or returned.
        bool skipType = false;
        if (!vbScriptSyntax && IsTypeCharacter(sc.ch)) {
            sc.Forward();   // Skip it
            skipType = true;
        }
        if (sc.ch == ']') {
            sc.Forward();
        }
        char s[100];
        sc.GetCurrentLowered(s, sizeof(s));
        if (skipType) {
            s[strlen(s) - 1] = '\0';
        }
        if (strcmp(s, "rem") == 0) {
            sc.ChangeState(SCE_B_COMMENT);
        } else {
            if (keywords.InList(s)) {
                sc.ChangeState(SCE_B_KEYWORD);
            } else if (keywords2.InList(s)) {
                sc.ChangeState(SCE_B_KEYWORD2);
            } else if (keywords3.InList(s)) {
                sc.ChangeState(SCE_B_KEYWORD3);
            } else if (keywords4.InList(s)) {
                sc.ChangeState(SCE_B_KEYWORD4);
            }   // Else, it is really an identifier...
            sc.SetState(SCE_B_DEFAULT);
        }
    }

    sc.Complete();
}

static void FoldVBDoc(unsigned int startPos, int length, int,
                           WordList *[], Accessor &styler) {
    int endPos = startPos + length;

    // Backtrack to previous line in case need to fix its fold status
    int lineCurrent = styler.GetLine(startPos);
    if (startPos > 0) {
        if (lineCurrent > 0) {
            lineCurrent--;
            startPos = styler.LineStart(lineCurrent);
        }
    }
    int spaceFlags = 0;
    int indentCurrent = styler.IndentAmount(lineCurrent, &spaceFlags, IsVBComment);
    char chNext = styler[startPos];
    for (int i = startPos; i < endPos; i++) {
        char ch = chNext;
        chNext = styler.SafeGetCharAt(i + 1);

        if ((ch == '\r' && chNext != '\n') || (ch == '\n') || (i == endPos)) {
            int lev = indentCurrent;
            int indentNext = styler.IndentAmount(lineCurrent + 1, &spaceFlags, IsVBComment);
            if (!(indentCurrent & SC_FOLDLEVELWHITEFLAG)) {
                // Only non whitespace lines can be headers
                if ((indentCurrent & SC_FOLDLEVELNUMBERMASK) < (indentNext & SC_FOLDLEVELNUMBERMASK)) {
                    lev |= SC_FOLDLEVELHEADERFLAG;
                } else if (indentNext & SC_FOLDLEVELWHITEFLAG) {
                    // Line after is blank so check the next - maybe should continue further?
                    int spaceFlags2 = 0;
                    int indentNext2 = styler.IndentAmount(lineCurrent + 2, &spaceFlags2, IsVBComment);
                    if ((indentCurrent & SC_FOLDLEVELNUMBERMASK) < (indentNext2 & SC_FOLDLEVELNUMBERMASK)) {
                        lev |= SC_FOLDLEVELHEADERFLAG;
                    }
                }
            }
            indentCurrent = indentNext;
            styler.SetLevel(lineCurrent, lev);
            lineCurrent++;
        }
    }
}

static void ColouriseVBNetDoc(unsigned int startPos, int length, int initStyle,
                           WordList *keywordlists[], Accessor &styler) {
    ColouriseVBDoc(startPos, length, initStyle, keywordlists, styler, false);
}

static void ColouriseVBScriptDoc(unsigned int startPos, int length, int initStyle,
                           WordList *keywordlists[], Accessor &styler) {
    ColouriseVBDoc(startPos, length, initStyle, keywordlists, styler, true);
}

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

LexerModule lmVB(SCLEX_VB, ColouriseVBNetDoc, "vb", FoldVBDoc, vbWordListDesc);
LexerModule lmVBScript(SCLEX_VBSCRIPT, ColouriseVBScriptDoc, "vbscript", FoldVBDoc, vbWordListDesc);

