// Scintilla source code edit control
/** @file LexVerilog.cxx
 ** Lexer for Verilog.
 ** Written by Avi Yegudin, based on C++ lexer by Neil Hodgson
 **/
// 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 int ch) {
    return (ch < 0x80) && (isalnum(ch) || ch == '.' || ch == '_' || ch == '\''|| ch == '$');
}

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

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

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

    // Do not leak onto next line
    if (initStyle == SCE_V_STRINGEOL)
        initStyle = SCE_V_DEFAULT;

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

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

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

        // Handle line continuation generically.
        if (sc.ch == '\\') {
            if (sc.chNext == '\n' || sc.chNext == '\r') {
                sc.Forward();
                if (sc.ch == '\r' && sc.chNext == '\n') {
                    sc.Forward();
                }
                continue;
            }
        }

        // Determine if the current state should terminate.
        if (sc.state == SCE_V_OPERATOR) {
            sc.SetState(SCE_V_DEFAULT);
        } else if (sc.state == SCE_V_NUMBER) {
            if (!IsAWordChar(sc.ch)) {
                sc.SetState(SCE_V_DEFAULT);
            }
        } else if (sc.state == SCE_V_IDENTIFIER) {
            if (!IsAWordChar(sc.ch) || (sc.ch == '.')) {
                char s[100];
                                sc.GetCurrent(s, sizeof(s));
                if (keywords.InList(s)) {
                    sc.ChangeState(SCE_V_WORD);
                } else if (keywords2.InList(s)) {
                    sc.ChangeState(SCE_V_WORD2);
                } else if (keywords3.InList(s)) {
                    sc.ChangeState(SCE_V_WORD3);
                                } else if (keywords4.InList(s)) {
                    sc.ChangeState(SCE_V_USER);
                }
                sc.SetState(SCE_V_DEFAULT);
            }
        } else if (sc.state == SCE_V_PREPROCESSOR) {
                        if (!IsAWordChar(sc.ch)) {
                                sc.SetState(SCE_V_DEFAULT);
                        }
        } else if (sc.state == SCE_V_COMMENT) {
            if (sc.Match('*', '/')) {
                sc.Forward();
                sc.ForwardSetState(SCE_V_DEFAULT);
            }
        } else if (sc.state == SCE_V_COMMENTLINE || sc.state == SCE_V_COMMENTLINEBANG) {
            if (sc.atLineStart) {
                sc.SetState(SCE_V_DEFAULT);
            }
                } else if (sc.state == SCE_V_STRING) {
            if (sc.ch == '\\') {
                if (sc.chNext == '\"' || sc.chNext == '\'' || sc.chNext == '\\') {
                    sc.Forward();
                }
            } else if (sc.ch == '\"') {
                sc.ForwardSetState(SCE_V_DEFAULT);
            } else if (sc.atLineEnd) {
                sc.ChangeState(SCE_V_STRINGEOL);
                sc.ForwardSetState(SCE_V_DEFAULT);
            }
        }

        // Determine if a new state should be entered.
        if (sc.state == SCE_V_DEFAULT) {
            if (IsADigit(sc.ch) || (sc.ch == '\'') || (sc.ch == '.' && IsADigit(sc.chNext))) {
                sc.SetState(SCE_V_NUMBER);
            } else if (IsAWordStart(sc.ch)) {
                sc.SetState(SCE_V_IDENTIFIER);
            } else if (sc.Match('/', '*')) {
                                sc.SetState(SCE_V_COMMENT);
                sc.Forward();   // Eat the * so it isn't used for the end of the comment
            } else if (sc.Match('/', '/')) {
                if (sc.Match("//!"))    // Nice to have a different comment style
                    sc.SetState(SCE_V_COMMENTLINEBANG);
                else
                    sc.SetState(SCE_V_COMMENTLINE);
            } else if (sc.ch == '\"') {
                sc.SetState(SCE_V_STRING);
            } else if (sc.ch == '`') {
                sc.SetState(SCE_V_PREPROCESSOR);
                // Skip whitespace between ` and preprocessor word
                do {
                    sc.Forward();
                } while ((sc.ch == ' ' || sc.ch == '\t') && sc.More());
                if (sc.atLineEnd) {
                    sc.SetState(SCE_V_DEFAULT);
                }
            } else if (isoperator(static_cast<char>(sc.ch)) || sc.ch == '@' || sc.ch == '#') {
                sc.SetState(SCE_V_OPERATOR);
            }
        }
    }
    sc.Complete();
}

static bool IsStreamCommentStyle(int style) {
    return style == SCE_V_COMMENT;
}

static bool IsCommentLine(int line, Accessor &styler) {
    int pos = styler.LineStart(line);
    int eolPos = styler.LineStart(line + 1) - 1;
    for (int i = pos; i < eolPos; i++) {
        char ch = styler[i];
        char chNext = styler.SafeGetCharAt(i + 1);
        int style = styler.StyleAt(i);
        if (ch == '/' && chNext == '/' &&
           (style == SCE_V_COMMENTLINE || style == SCE_V_COMMENTLINEBANG)) {
            return true;
        } else if (!IsASpaceOrTab(ch)) {
            return false;
        }
    }
    return false;
}
// Store both the current line's fold level and the next lines in the
// level store to make it easy to pick up with each increment
// and to make it possible to fiddle the current level for "} else {".
static void FoldNoBoxVerilogDoc(unsigned int startPos, int length, int initStyle,
                            Accessor &styler) {
    bool foldComment = styler.GetPropertyInt("fold.comment") != 0;
    bool foldPreprocessor = styler.GetPropertyInt("fold.preprocessor") != 0;
    bool foldCompact = styler.GetPropertyInt("fold.compact", 1) != 0;
    bool foldAtElse = styler.GetPropertyInt("fold.at.else", 0) != 0;
        // Verilog specific folding options:
        // fold_at_module -
        //      Generally used methodology in verilog code is
        //      one module per file, so folding at module definition is useless.
        // fold_at_brace/parenthese -
        //      Folding of long port lists can be convenient.
    bool foldAtModule = styler.GetPropertyInt("fold.verilog.flags", 0) != 0;
    bool foldAtBrace  = 1;
    bool foldAtParenthese  = 1;

    unsigned int endPos = startPos + length;
    int visibleChars = 0;
    int lineCurrent = styler.GetLine(startPos);
    int levelCurrent = SC_FOLDLEVELBASE;
    if (lineCurrent > 0)
        levelCurrent = styler.LevelAt(lineCurrent-1) >> 16;
    int levelMinCurrent = levelCurrent;
    int levelNext = levelCurrent;
    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 && IsStreamCommentStyle(style)) {
            if (!IsStreamCommentStyle(stylePrev)) {
                levelNext++;
            } else if (!IsStreamCommentStyle(styleNext) && !atEOL) {
                // Comments don't end at end of line and the next character may be unstyled.
                levelNext--;
            }
        }
        if (foldComment && atEOL && IsCommentLine(lineCurrent, styler))
        {
            if (!IsCommentLine(lineCurrent - 1, styler)
                && IsCommentLine(lineCurrent + 1, styler))
                levelNext++;
            else if (IsCommentLine(lineCurrent - 1, styler)
                     && !IsCommentLine(lineCurrent+1, styler))
                levelNext--;
        }
        if (foldComment && (style == SCE_V_COMMENTLINE)) {
            if ((ch == '/') && (chNext == '/')) {
                char chNext2 = styler.SafeGetCharAt(i + 2);
                if (chNext2 == '{') {
                    levelNext++;
                } else if (chNext2 == '}') {
                    levelNext--;
                }
            }
        }
        if (foldPreprocessor && (style == SCE_V_PREPROCESSOR)) {
            if (ch == '`') {
                unsigned int j = i + 1;
                while ((j < endPos) && IsASpaceOrTab(styler.SafeGetCharAt(j))) {
                    j++;
                }
                if (styler.Match(j, "if")) {
                    levelNext++;
                } else if (styler.Match(j, "end")) {
                    levelNext--;
                }
            }
        }
                if (style == SCE_V_OPERATOR) {
                    if (foldAtParenthese) {
            if (ch == '(') {
                levelNext++;
            } else if (ch == ')') {
                levelNext--;
            }
                    }
        }
                if (style == SCE_V_OPERATOR) {
                    if (foldAtBrace) {
            if (ch == '{') {
                levelNext++;
            } else if (ch == '}') {
                levelNext--;
            }
                    }
        }
                if (style == SCE_V_WORD && stylePrev != SCE_V_WORD) {
                        unsigned int j = i;
                        if (styler.Match(j, "case") ||
                            styler.Match(j, "casex") ||
                            styler.Match(j, "casez") ||
                            styler.Match(j, "class") ||
                            styler.Match(j, "function") ||
                            styler.Match(j, "generate") ||
                            styler.Match(j, "covergroup") ||
                            styler.Match(j, "package") ||
                            styler.Match(j, "primitive") ||
                            styler.Match(j, "program") ||
                            styler.Match(j, "sequence") ||
                            styler.Match(j, "specify") ||
                            styler.Match(j, "table") ||
                            styler.Match(j, "task") ||
                            styler.Match(j, "fork") ||
                            (styler.Match(j, "module") && foldAtModule) ||
                            styler.Match(j, "begin")) {
                                levelNext++;
                        } else if (styler.Match(j, "endcase") ||
                                   styler.Match(j, "endclass") ||
                                   styler.Match(j, "endfunction") ||
                                   styler.Match(j, "endgenerate") ||
                                   styler.Match(j, "endgroup") ||
                                   styler.Match(j, "endpackage") ||
                                   styler.Match(j, "endprimitive") ||
                                   styler.Match(j, "endprogram") ||
                                   styler.Match(j, "endsequence") ||
                                   styler.Match(j, "endspecify") ||
                                   styler.Match(j, "endtable") ||
                                   styler.Match(j, "endtask") ||
                                   styler.Match(j, "join") ||
                                   styler.Match(j, "join_any") ||
                                   styler.Match(j, "join_none") ||
                                   (styler.Match(j, "endmodule") && foldAtModule) ||
                                   (styler.Match(j, "end") && !IsAWordChar(styler.SafeGetCharAt(j+3)))) {
                                levelNext--;
                        }
        }
        if (atEOL) {
            int levelUse = levelCurrent;
            if (foldAtElse) {
                levelUse = levelMinCurrent;
            }
            int lev = levelUse | levelNext << 16;
            if (visibleChars == 0 && foldCompact)
                lev |= SC_FOLDLEVELWHITEFLAG;
            if (levelUse < levelNext)
                lev |= SC_FOLDLEVELHEADERFLAG;
            if (lev != styler.LevelAt(lineCurrent)) {
                styler.SetLevel(lineCurrent, lev);
            }
            lineCurrent++;
            levelCurrent = levelNext;
            levelMinCurrent = levelCurrent;
            visibleChars = 0;
        }
        if (!isspacechar(ch))
            visibleChars++;
    }
}

static void FoldVerilogDoc(unsigned int startPos, int length, int initStyle, WordList *[],
                       Accessor &styler) {
    FoldNoBoxVerilogDoc(startPos, length, initStyle, styler);
}

static const char * const verilogWordLists[] = {
            "Primary keywords and identifiers",
            "Secondary keywords and identifiers",
            "System Tasks",
            "User defined tasks and identifiers",
            "Unused",
            0,
        };


LexerModule lmVerilog(SCLEX_VERILOG, ColouriseVerilogDoc, "verilog", FoldVerilogDoc, verilogWordLists);
