// Scintilla source code edit control
/** @file LexFortran.cxx
 ** Lexer for Fortran.
 ** Writen by Chuan-jian Shen, Last changed Sep. 2003
 **/
// Copyright 1998-2001 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 == '%');
}
/**********************************************/
static inline bool IsAWordStart(const int ch) {
    return (ch < 0x80) && (isalnum(ch));
}
/***************************************/
inline bool IsABlank(unsigned int ch) {
    return (ch == ' ') || (ch == 0x09) || (ch == 0x0b) ;
}
/***************************************/
inline bool IsALineEnd(char ch) {
    return ((ch == '\n') || (ch == '\r')) ;
}
/***************************************/
unsigned int GetContinuedPos(unsigned int pos, Accessor &styler) {
    while (!IsALineEnd(styler.SafeGetCharAt(pos++))) continue;
    if (styler.SafeGetCharAt(pos) == '\n') pos++;
    while (IsABlank(styler.SafeGetCharAt(pos++))) continue;
    char chCur = styler.SafeGetCharAt(pos);
    if (chCur == '&') {
        while (IsABlank(styler.SafeGetCharAt(++pos))) continue;
        return pos;
    } else {
        return pos;
    }
}
/***************************************/
static void ColouriseFortranDoc(unsigned int startPos, int length, int initStyle,
            WordList *keywordlists[], Accessor &styler, bool isFixFormat) {
    WordList &keywords = *keywordlists[0];
    WordList &keywords2 = *keywordlists[1];
    WordList &keywords3 = *keywordlists[2];
    /***************************************/
    int posLineStart = 0, numNonBlank = 0, prevState = 0;
    int endPos = startPos + length;
    /***************************************/
    // backtrack to the nearest keyword
    while ((startPos > 1) && (styler.StyleAt(startPos) != SCE_F_WORD)) {
        startPos--;
    }
    startPos = styler.LineStart(styler.GetLine(startPos));
    initStyle = styler.StyleAt(startPos - 1);
    StyleContext sc(startPos, endPos-startPos, initStyle, styler);
    /***************************************/
    for (; sc.More(); sc.Forward()) {
        // remember the start position of the line
        if (sc.atLineStart) {
            posLineStart = sc.currentPos;
            numNonBlank = 0;
            sc.SetState(SCE_F_DEFAULT);
        }
        if (!IsASpaceOrTab(sc.ch)) numNonBlank ++;
        /***********************************************/
        // Handle the fix format generically
        int toLineStart = sc.currentPos - posLineStart;
        if (isFixFormat && (toLineStart < 6 || toLineStart > 72)) {
            if ((toLineStart == 0 && (tolower(sc.ch) == 'c' || sc.ch == '*')) || sc.ch == '!') {
                if (sc.MatchIgnoreCase("cdec$") || sc.MatchIgnoreCase("*dec$") || sc.MatchIgnoreCase("!dec$") ||
                    sc.MatchIgnoreCase("cdir$") || sc.MatchIgnoreCase("*dir$") || sc.MatchIgnoreCase("!dir$") ||
                    sc.MatchIgnoreCase("cms$")  || sc.MatchIgnoreCase("*ms$")  || sc.MatchIgnoreCase("!ms$")  ||
                    sc.chNext == '$') {
                    sc.SetState(SCE_F_PREPROCESSOR);
                } else {
                    sc.SetState(SCE_F_COMMENT);
                }

                while (!sc.atLineEnd && sc.More()) sc.Forward(); // Until line end
            } else if (toLineStart > 72) {
                sc.SetState(SCE_F_COMMENT);
                while (!sc.atLineEnd && sc.More()) sc.Forward(); // Until line end
            } else if (toLineStart < 5) {
                if (IsADigit(sc.ch))
                    sc.SetState(SCE_F_LABEL);
                else
                    sc.SetState(SCE_F_DEFAULT);
            } else if (toLineStart == 5) {
                if (!IsASpace(sc.ch) && sc.ch != '0') {
                    sc.SetState(SCE_F_CONTINUATION);
                    sc.ForwardSetState(prevState);
                } else
                    sc.SetState(SCE_F_DEFAULT);
            }
            continue;
        }
        /***************************************/
        // Handle line continuation generically.
        if (!isFixFormat && sc.ch == '&') {
            char chTemp = ' ';
            int j = 1;
            while (IsABlank(chTemp) && j<132) {
                chTemp = static_cast<char>(sc.GetRelative(j));
                j++;
            }
            if (chTemp == '!') {
                sc.SetState(SCE_F_CONTINUATION);
                if (sc.chNext == '!') sc.ForwardSetState(SCE_F_COMMENT);
            } else if (chTemp == '\r' || chTemp == '\n') {
                int currentState = sc.state;
                sc.SetState(SCE_F_CONTINUATION);
                sc.ForwardSetState(SCE_F_DEFAULT);
                while (IsASpace(sc.ch) && sc.More()) sc.Forward();
                if (sc.ch == '&') {
                    sc.SetState(SCE_F_CONTINUATION);
                    sc.Forward();
                }
                sc.SetState(currentState);
            }
        }
        /***************************************/
        // Determine if the current state should terminate.
        if (sc.state == SCE_F_OPERATOR) {
            sc.SetState(SCE_F_DEFAULT);
        } else if (sc.state == SCE_F_NUMBER) {
            if (!(IsAWordChar(sc.ch) || sc.ch=='\'' || sc.ch=='\"' || sc.ch=='.')) {
                sc.SetState(SCE_F_DEFAULT);
            }
        } else if (sc.state == SCE_F_IDENTIFIER) {
            if (!IsAWordChar(sc.ch) || (sc.ch == '%')) {
                char s[100];
                sc.GetCurrentLowered(s, sizeof(s));
                if (keywords.InList(s)) {
                    sc.ChangeState(SCE_F_WORD);
                } else if (keywords2.InList(s)) {
                    sc.ChangeState(SCE_F_WORD2);
                } else if (keywords3.InList(s)) {
                    sc.ChangeState(SCE_F_WORD3);
                }
                sc.SetState(SCE_F_DEFAULT);
            }
        } else if (sc.state == SCE_F_COMMENT || sc.state == SCE_F_PREPROCESSOR) {
            if (sc.ch == '\r' || sc.ch == '\n') {
                sc.SetState(SCE_F_DEFAULT);
            }
        } else if (sc.state == SCE_F_STRING1) {
            prevState = sc.state;
            if (sc.ch == '\'') {
                if (sc.chNext == '\'') {
                    sc.Forward();
                } else {
                    sc.ForwardSetState(SCE_F_DEFAULT);
                    prevState = SCE_F_DEFAULT;
                }
            } else if (sc.atLineEnd) {
                sc.ChangeState(SCE_F_STRINGEOL);
                sc.ForwardSetState(SCE_F_DEFAULT);
            }
        } else if (sc.state == SCE_F_STRING2) {
            prevState = sc.state;
            if (sc.atLineEnd) {
                sc.ChangeState(SCE_F_STRINGEOL);
                sc.ForwardSetState(SCE_F_DEFAULT);
            } else if (sc.ch == '\"') {
                if (sc.chNext == '\"') {
                    sc.Forward();
                } else {
                    sc.ForwardSetState(SCE_F_DEFAULT);
                    prevState = SCE_F_DEFAULT;
                }
            }
        } else if (sc.state == SCE_F_OPERATOR2) {
            if (sc.ch == '.') {
                sc.ForwardSetState(SCE_F_DEFAULT);
            }
        } else if (sc.state == SCE_F_CONTINUATION) {
            sc.SetState(SCE_F_DEFAULT);
        } else if (sc.state == SCE_F_LABEL) {
            if (!IsADigit(sc.ch)) {
                sc.SetState(SCE_F_DEFAULT);
            } else {
                if (isFixFormat && sc.currentPos-posLineStart > 4)
                    sc.SetState(SCE_F_DEFAULT);
                else if (numNonBlank > 5)
                    sc.SetState(SCE_F_DEFAULT);
            }
        }
        /***************************************/
        // Determine if a new state should be entered.
        if (sc.state == SCE_F_DEFAULT) {
            if (sc.ch == '!') {
                if (sc.MatchIgnoreCase("!dec$") || sc.MatchIgnoreCase("!dir$") ||
                    sc.MatchIgnoreCase("!ms$") || sc.chNext == '$') {
                    sc.SetState(SCE_F_PREPROCESSOR);
                } else {
                    sc.SetState(SCE_F_COMMENT);
                }
            } else if ((!isFixFormat) && IsADigit(sc.ch) && numNonBlank == 1) {
                sc.SetState(SCE_F_LABEL);
            } else if (IsADigit(sc.ch) || (sc.ch == '.' && IsADigit(sc.chNext))) {
                sc.SetState(SCE_F_NUMBER);
            } else if ((tolower(sc.ch) == 'b' || tolower(sc.ch) == 'o' ||
                        tolower(sc.ch) == 'z') && (sc.chNext == '\"' || sc.chNext == '\'')) {
                sc.SetState(SCE_F_NUMBER);
                sc.Forward();
            } else if (sc.ch == '.' && isalpha(sc.chNext)) {
                sc.SetState(SCE_F_OPERATOR2);
            } else if (IsAWordStart(sc.ch)) {
                sc.SetState(SCE_F_IDENTIFIER);
            } else if (sc.ch == '\"') {
                sc.SetState(SCE_F_STRING2);
            } else if (sc.ch == '\'') {
                sc.SetState(SCE_F_STRING1);
            } else if (isoperator(static_cast<char>(sc.ch))) {
                sc.SetState(SCE_F_OPERATOR);
            }
        }
    }
    sc.Complete();
}
/***************************************/
// To determine the folding level depending on keywords
static int classifyFoldPointFortran(const char* s, const char* prevWord, const char chNextNonBlank) {
    int lev = 0;
    if ((strcmp(prevWord, "else") == 0 && strcmp(s, "if") == 0) || strcmp(s, "elseif") == 0)
        return -1;
    if (strcmp(s, "associate") == 0 || strcmp(s, "block") == 0
        || strcmp(s, "blockdata") == 0 || strcmp(s, "select") == 0
        || strcmp(s, "do") == 0 || strcmp(s, "enum") ==0
        || strcmp(s, "function") == 0 || strcmp(s, "interface") == 0
        || strcmp(s, "module") == 0 || strcmp(s, "program") == 0
        || strcmp(s, "subroutine") == 0 || strcmp(s, "then") == 0
        || (strcmp(s, "type") == 0 && chNextNonBlank != '(') ){
            if (strcmp(prevWord, "end") == 0)
                lev = 0;
            else
                lev = 1;
    } else if ((strcmp(s, "end") == 0 && chNextNonBlank != '=')
        || strcmp(s, "endassociate") == 0 || strcmp(s, "endblock") == 0
        || strcmp(s, "endblockdata") == 0 || strcmp(s, "endselect") == 0
        || strcmp(s, "enddo") == 0 || strcmp(s, "endenum") ==0
        || strcmp(s, "endif") == 0 || strcmp(s, "endforall") == 0
        || strcmp(s, "endfunction") == 0 || strcmp(s, "endinterface") == 0
        || strcmp(s, "endmodule") == 0 || strcmp(s, "endprogram") == 0
        || strcmp(s, "endsubroutine") == 0 || strcmp(s, "endtype") == 0
        || strcmp(s, "endwhere") == 0
        || (strcmp(s, "procedure") == 0 && strcmp(prevWord,"module")==0) ) { // Take care of the module procedure statement
            lev = -1;
    } else if (strcmp(prevWord, "end") == 0 && strcmp(s, "if") == 0){ // end if
            lev = 0;
    }
    return lev;
}
// Folding the code
static void FoldFortranDoc(unsigned int startPos, int length, int initStyle,
                           Accessor &styler, bool isFixFormat) {
    //
    // bool foldComment = styler.GetPropertyInt("fold.comment") != 0;
    // Do not know how to fold the comment at the moment.
    //
    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];
    char chNextNonBlank;
    int styleNext = styler.StyleAt(startPos);
    int style = initStyle;
    /***************************************/
    int lastStart = 0;
    char prevWord[32] = "";
    char Label[6] = "";
    // Variables for do label folding.
    static int doLabels[100];
    static int posLabel=-1;
    /***************************************/
    for (unsigned int i = startPos; i < endPos; i++) {
        char ch = chNext;
        chNext = styler.SafeGetCharAt(i + 1);
        chNextNonBlank = chNext;
        unsigned int j=i+1;
        while(IsABlank(chNextNonBlank) && j<endPos) {
            j ++ ;
            chNextNonBlank = styler.SafeGetCharAt(j);
        }
        int stylePrev = style;
        style = styleNext;
        styleNext = styler.StyleAt(i + 1);
        bool atEOL = (ch == '\r' && chNext != '\n') || (ch == '\n');
        //
        if (stylePrev == SCE_F_DEFAULT && (style == SCE_F_WORD || style == SCE_F_LABEL)) {
            // Store last word and label start point.
            lastStart = i;
        }
        /***************************************/
        if (style == SCE_F_WORD) {
            if(iswordchar(ch) && !iswordchar(chNext)) {
                char s[32];
                unsigned int k;
                for(k=0; (k<31 ) && (k<i-lastStart+1 ); k++) {
                    s[k] = static_cast<char>(tolower(styler[lastStart+k]));
                }
                s[k] = '\0';
                // Handle the forall and where statement and structure.
                if (strcmp(s, "forall") == 0 || strcmp(s, "where") == 0) {
                    if (strcmp(prevWord, "end") != 0) {
                        j = i + 1;
                        char chBrace = '(', chSeek = ')', ch1 = styler.SafeGetCharAt(j);
                        // Find the position of the first (
                        while (ch1 != chBrace && j<endPos) {
                            j++;
                            ch1 = styler.SafeGetCharAt(j);
                        }
                        char styBrace = styler.StyleAt(j);
                        int depth = 1;
                        char chAtPos;
                        char styAtPos;
                        while (j<endPos) {
                            j++;
                            chAtPos = styler.SafeGetCharAt(j);
                            styAtPos = styler.StyleAt(j);
                            if (styAtPos == styBrace) {
                                if (chAtPos == chBrace) depth++;
                                if (chAtPos == chSeek) depth--;
                                if (depth == 0) break;
                            }
                        }
                        while (j<endPos) {
                            j++;
                            chAtPos = styler.SafeGetCharAt(j);
                            styAtPos = styler.StyleAt(j);
                            if (styAtPos == SCE_F_COMMENT || IsABlank(chAtPos)) continue;
                            if (isFixFormat) {
                                if (!IsALineEnd(chAtPos)) {
                                    break;
                                } else {
                                    if (lineCurrent < styler.GetLine(styler.Length()-1)) {
                                        j = styler.LineStart(lineCurrent+1);
                                        if (styler.StyleAt(j+5) == SCE_F_CONTINUATION) {
                                            j += 5;
                                            continue;
                                        } else {
                                            levelCurrent++;
                                            break;
                                        }
                                    }
                                }
                            } else {
                                if (chAtPos == '&' && styler.StyleAt(j) == SCE_F_CONTINUATION) {
                                    j = GetContinuedPos(j+1, styler);
                                    continue;
                                } else if (IsALineEnd(chAtPos)) {
                                    levelCurrent ++;
                                    break;
                                } else {
                                    break;
                                }
                            }
                        }
                    }
                } else {
                    levelCurrent += classifyFoldPointFortran(s, prevWord, chNextNonBlank);
                    // Store the do Labels into array
                    if (strcmp(s, "do") == 0 && IsADigit(chNextNonBlank)) {
                        unsigned int k = 0;
                        for (i=j; (i<j+5 && i<endPos); i++) {
                            ch = styler.SafeGetCharAt(i);
                            if (IsADigit(ch))
                                Label[k++] = ch;
                            else
                                break;
                        }
                        Label[k] = '\0';
                        posLabel ++;
                        doLabels[posLabel] = atoi(Label);
                    }
                }
                strcpy(prevWord, s);
            }
        } else if (style == SCE_F_LABEL) {
            if(IsADigit(ch) && !IsADigit(chNext)) {
                for(j = 0; ( j < 5 ) && ( j < i-lastStart+1 ); j++) {
                    ch = styler.SafeGetCharAt(lastStart + j);
                    if (IsADigit(ch) && styler.StyleAt(lastStart+j) == SCE_F_LABEL)
                        Label[j] = ch;
                    else
                        break;
                }
                Label[j] = '\0';
                while (doLabels[posLabel] == atoi(Label) && posLabel > -1) {
                    levelCurrent--;
                    posLabel--;
                }
            }
        }
        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;
            strcpy(prevWord, "");
        }
        /***************************************/
        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 FortranWordLists[] = {
    "Primary keywords and identifiers",
    "Intrinsic functions",
    "Extended and user defined functions",
    0,
};
/***************************************/
static void ColouriseFortranDocFreeFormat(unsigned int startPos, int length, int initStyle, WordList *keywordlists[],
                            Accessor &styler) {
    ColouriseFortranDoc(startPos, length, initStyle, keywordlists, styler, false);
}
/***************************************/
static void ColouriseFortranDocFixFormat(unsigned int startPos, int length, int initStyle, WordList *keywordlists[],
                            Accessor &styler) {
    ColouriseFortranDoc(startPos, length, initStyle, keywordlists, styler, true);
}
/***************************************/
static void FoldFortranDocFreeFormat(unsigned int startPos, int length, int initStyle,
        WordList *[], Accessor &styler) {
    FoldFortranDoc(startPos, length, initStyle,styler, false);
}
/***************************************/
static void FoldFortranDocFixFormat(unsigned int startPos, int length, int initStyle,
        WordList *[], Accessor &styler) {
    FoldFortranDoc(startPos, length, initStyle,styler, true);
}
/***************************************/
LexerModule lmFortran(SCLEX_FORTRAN, ColouriseFortranDocFreeFormat, "fortran", FoldFortranDocFreeFormat, FortranWordLists);
LexerModule lmF77(SCLEX_F77, ColouriseFortranDocFixFormat, "f77", FoldFortranDocFixFormat, FortranWordLists);
