// Scintilla source code edit control
/** @file LexCsound.cxx
 ** Lexer for Csound (Orchestra & Score)
 ** Written by Georg Ritter - <ritterfuture A T gmail D O T com>
 **/
// Copyright 1998-2003 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 == '?');
}

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

static inline bool IsCsoundOperator(char ch) {
    if (isascii(ch) && isalnum(ch))
        return false;
    // '.' left out as it is used to make up numbers
    if (ch == '*' || ch == '/' || ch == '-' || ch == '+' ||
        ch == '(' || ch == ')' || ch == '=' || ch == '^' ||
        ch == '[' || ch == ']' || ch == '<' || ch == '&' ||
        ch == '>' || ch == ',' || ch == '|' || ch == '~' ||
        ch == '%' || ch == ':')
        return true;
    return false;
}

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

    WordList &opcode = *keywordlists[0];
    WordList &headerStmt = *keywordlists[1];
    WordList &otherKeyword = *keywordlists[2];

    // Do not leak onto next line
    if (initStyle == SCE_CSOUND_STRINGEOL)
        initStyle = SCE_CSOUND_DEFAULT;

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

    for (; sc.More(); sc.Forward())
    {
        // 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_CSOUND_OPERATOR) {
            if (!IsCsoundOperator(static_cast<char>(sc.ch))) {
                sc.SetState(SCE_CSOUND_DEFAULT);
            }
        }else if (sc.state == SCE_CSOUND_NUMBER) {
            if (!IsAWordChar(sc.ch)) {
                sc.SetState(SCE_CSOUND_DEFAULT);
            }
        } else if (sc.state == SCE_CSOUND_IDENTIFIER) {
            if (!IsAWordChar(sc.ch) ) {
                char s[100];
                sc.GetCurrent(s, sizeof(s));

                if (opcode.InList(s)) {
                    sc.ChangeState(SCE_CSOUND_OPCODE);
                } else if (headerStmt.InList(s)) {
                    sc.ChangeState(SCE_CSOUND_HEADERSTMT);
                } else if (otherKeyword.InList(s)) {
                    sc.ChangeState(SCE_CSOUND_USERKEYWORD);
                } else if (s[0] == 'p') {
                    sc.ChangeState(SCE_CSOUND_PARAM);
                } else if (s[0] == 'a') {
                    sc.ChangeState(SCE_CSOUND_ARATE_VAR);
                } else if (s[0] == 'k') {
                    sc.ChangeState(SCE_CSOUND_KRATE_VAR);
                } else if (s[0] == 'i') { // covers both i-rate variables and i-statements
                    sc.ChangeState(SCE_CSOUND_IRATE_VAR);
                } else if (s[0] == 'g') {
                    sc.ChangeState(SCE_CSOUND_GLOBAL_VAR);
                }
                sc.SetState(SCE_CSOUND_DEFAULT);
            }
        }
        else if (sc.state == SCE_CSOUND_COMMENT ) {
            if (sc.atLineEnd) {
                sc.SetState(SCE_CSOUND_DEFAULT);
            }
        }
        else if ((sc.state == SCE_CSOUND_ARATE_VAR) ||
            (sc.state == SCE_CSOUND_KRATE_VAR) ||
        (sc.state == SCE_CSOUND_IRATE_VAR)) {
            if (!IsAWordChar(sc.ch)) {
                sc.SetState(SCE_CSOUND_DEFAULT);
            }
        }

        // Determine if a new state should be entered.
        if (sc.state == SCE_CSOUND_DEFAULT) {
            if (sc.ch == ';'){
                sc.SetState(SCE_CSOUND_COMMENT);
            } else if (isdigit(sc.ch) || (sc.ch == '.' && isdigit(sc.chNext))) {
                sc.SetState(SCE_CSOUND_NUMBER);
            } else if (IsAWordStart(sc.ch)) {
                sc.SetState(SCE_CSOUND_IDENTIFIER);
            } else if (IsCsoundOperator(static_cast<char>(sc.ch))) {
                sc.SetState(SCE_CSOUND_OPERATOR);
            } else if (sc.ch == 'p') {
                sc.SetState(SCE_CSOUND_PARAM);
            } else if (sc.ch == 'a') {
                sc.SetState(SCE_CSOUND_ARATE_VAR);
            } else if (sc.ch == 'k') {
                sc.SetState(SCE_CSOUND_KRATE_VAR);
            } else if (sc.ch == 'i') { // covers both i-rate variables and i-statements
                sc.SetState(SCE_CSOUND_IRATE_VAR);
            } else if (sc.ch == 'g') {
                sc.SetState(SCE_CSOUND_GLOBAL_VAR);
            }
        }
    }
    sc.Complete();
}

static void FoldCsoundInstruments(unsigned int startPos, int length, int /* initStyle */, WordList *[],
        Accessor &styler) {
    unsigned int lengthDoc = startPos + length;
    int visibleChars = 0;
    int lineCurrent = styler.GetLine(startPos);
    int levelPrev = styler.LevelAt(lineCurrent) & SC_FOLDLEVELNUMBERMASK;
    int levelCurrent = levelPrev;
    char chNext = styler[startPos];
    int stylePrev = 0;
    int styleNext = styler.StyleAt(startPos);
    for (unsigned int i = startPos; i < lengthDoc; 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 ((stylePrev != SCE_CSOUND_OPCODE) && (style == SCE_CSOUND_OPCODE)) {
            char s[20];
            unsigned int j = 0;
            while ((j < (sizeof(s) - 1)) && (iswordchar(styler[i + j]))) {
                s[j] = styler[i + j];
                j++;
            }
            s[j] = '\0';

            if (strcmp(s, "instr") == 0)
                levelCurrent++;
            if (strcmp(s, "endin") == 0)
                levelCurrent--;
        }

        if (atEOL) {
            int lev = levelPrev;
            if (visibleChars == 0)
                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++;
        stylePrev = style;
    }
    // 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 csoundWordListDesc[] = {
    "Opcodes",
    "Header Statements",
    "User keywords",
    0
};

LexerModule lmCsound(SCLEX_CSOUND, ColouriseCsoundDoc, "csound", FoldCsoundInstruments, csoundWordListDesc);
