/* This file is part of KDevelop
    Copyright (C) 2002, 2003 Roberto Raggi <roberto@kdevelop.org>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, see
    <http://www.gnu.org/licenses/>.
*/

#ifndef LEXER_H
#define LEXER_H

#undef QT_NO_CAST_TO_ASCII
#undef QT_NO_CAST_FROM_ASCII

#include "driver.h"
#include "debug_utils.h"

#include <qglobal.h>
#include <QString>
#include <qmap.h>
#include <qpair.h>
#include <hashedstring.h>

#define CHARTYPE QChar
#define DBG_LEXER DEBUG(QLatin1String("Lexer"))

enum Type {
    Token_eof = 0,
    Token_identifier = 1000,
    Token_number_literal,
    Token_char_literal,
    Token_string_literal,
    Token_whitespaces,
    Token_comment,
    Token_preproc,

    Token_assign = 2000,
    Token_ptrmem,
    Token_ellipsis,
    Token_scope,
    Token_shift,
    Token_eq,
    Token_leq,
    Token_geq,
    Token_incr,
    Token_decr,
    Token_arrow,

    Token_concat,

    Token_K_DCOP,
    Token_k_dcop,
    Token_k_dcop_signals,

    Token_Q_OBJECT,
    Token_signals,
    Token_slots,
    Token_emit,
    Token_foreach, // qt4 [erbsland]

    Token_and,
    Token_and_eq,
    Token_asm,
    Token_auto,
    Token_bitand,
    Token_bitor,
    Token_bool,
    Token_break,
    Token_case,
    Token_catch,
    Token_char,
    Token_class,
    Token_compl,
    Token_const,
    Token_const_expr,
    Token_const_cast,
    Token_continue,
    Token_default,
    Token_delete,
    Token_do,
    Token_double,
    Token_dynamic_cast,
    Token_else,
    Token_enum,
    Token_explicit,
    Token_export,
    Token_extern,
    Token_false,
    Token_float,
    Token_for,
    Token_friend,
    Token_goto,
    Token_if,
    Token_inline,
    Token_int,
    Token_long,
    Token_mutable,
    Token_namespace,
    Token_new,
    Token_not,
    Token_not_eq,
    Token_operator,
    Token_or,
    Token_or_eq,
    Token_override,
    Token_private,
    Token_protected,
    Token_public,
    Token_register,
    Token_reinterpret_cast,
    Token_return,
    Token_short,
    Token_signed,
    Token_sizeof,
    Token_static,
    Token_static_cast,
    Token_struct,
    Token_switch,
    Token_template,
    Token_this,
    Token_throw,
    Token_true,
    Token_try,
    Token_typedef,
    Token_typeid,
    Token_typename,
    Token_union,
    Token_unsigned,
    Token_using,
    Token_virtual,
    Token_void,
    Token_volatile,
    Token_wchar_t,
    Token_while,
    Token_xor,
    Token_xor_eq
};

enum SkipType {
    SkipWord,
    SkipWordAndArguments
};

struct LexerData;

class Token
{
    explicit Token(const QString &);
    Token(int type, int position, int length, const QString& text);
    Token(const Token& source);

    Token& operator = (const Token& source);
    bool operator == (const Token& token) const;
    operator int () const;

public:
    bool isNull() const;

    int type() const;
    void setType(int type);

    void getStartPosition(int* line, int* column) const;
    void setStartPosition(int line, int column);
    void getEndPosition(int* line, int* column) const;
    void setEndPosition(int line, int column);

    unsigned int length() const;
    void setLength(unsigned int length);

    int position() const;
    void setPosition(int position);

    QString text() const;

private:
    int m_type;
    int m_position;
    int m_length;
    int m_startLine;
    int m_startColumn;
    int m_endLine;
    int m_endColumn;
    const QString & m_text;

    friend class Lexer;
    friend class Parser;
}; // class Token

class Lexer
{
public:
    explicit Lexer(Driver* driver);
    ~Lexer();

    bool recordComments() const;
    void setRecordComments(bool record);

    bool recordWhiteSpaces() const;
    void setRecordWhiteSpaces(bool record);

    bool reportWarnings() const;
    void setReportWarnings(bool enable);

    bool reportMessages() const;
    void setReportMessages(bool enable);

    bool skipWordsEnabled() const;
    void setSkipWordsEnabled(bool enabled);

    bool preprocessorEnabled() const;
    void setPreprocessorEnabled(bool enabled);

    void resetSkipWords();
    void addSkipWord(const QString& word, SkipType skipType=SkipWord, const QString& str = QString());

    QString source() const;
    void setSource(const QString& source);

    int index() const;
    void setIndex(int index);

    //returns the count of lines that wer skipped due to #ifdef's
    int skippedLines() const;

    void reset();

    const Token& tokenAt(int position) const;
    const Token& nextToken();
    const Token& lookAhead(int n) const;

    static int toInt(const Token& token);

    int tokenPosition(const Token& token) const;
    void getTokenPosition(const Token& token, int* line, int* col);

    int currentLine() const
    {
        return m_currentLine;
    }
    int currentColumn() const
    {
        return m_currentColumn;
    }

    inline const CHARTYPE* offset(int offset) const
    {
        Q_ASSERT(offset >= 0);
        Q_ASSERT(offset <= m_source.length());
        return m_source.unicode() + offset;
    }

    inline int getOffset(const QChar* p) const
    {
        const QChar* src = m_source.unicode();
        Q_ASSERT(p >= src);
        int result = int(p - src);
        Q_ASSERT(result <= m_source.length());
        return result;
    }

private:
    void setEndPtr(const QChar* c)
    {
        m_endPtr = c;
        if (m_ptr <  m_endPtr)
            m_currentChar = *m_ptr;
        else
            m_currentChar = 0;
    }
    const QChar currentChar() const;
    QChar peekChar(int n=1) const;
    int currentPosition() const;

    void insertCurrent(const QString& str);

    void tokenize();
    void nextToken(Token& token, bool stopOnNewline=false);
    void nextChar();
    void nextChar(int n);
    void skip(int l, int r);
    void readIdentifier();
    void readWhiteSpaces(bool skipNewLine=true, bool skipOnlyOnce=false);
    void readLineComment();
    void readMultiLineComment();
    void readCharLiteral();
    void readStringLiteral();
    void readNumberLiteral();

    int findOperator3() const;
    int findOperator2() const;
    bool eof() const;

    // preprocessor (based on an article of Al Stevens on Dr.Dobb's journal)
    int testIfLevel();
    int macroDefined();
    QString readArgument();

    int macroPrimary();
    int macroMultiplyDivide();
    int macroAddSubtract();
    int macroRelational();
    int macroEquality();
    int macroBoolAnd();
    int macroBoolXor();
    int macroBoolOr();
    int macroLogicalAnd();
    int macroLogicalOr();
    int macroExpression();

    void handleDirective(const QString& directive);
    void processDefine(Macro& macro);
    void processElse();
    void processElif();
    void processEndif();
    void processIf();
    void processIfdef();
    void processIfndef();
    void processInclude();
    void processUndef();

private:
    LexerData* d;
    Driver* m_driver;
    QVector<Token*> m_tokens;
    int m_size;
    int m_index;
    QString m_source;
    const QChar* m_ptr;
    const QChar* m_endPtr;
    QChar m_currentChar;
    bool m_recordComments;
    bool m_recordWhiteSpaces;
    bool m_startLine;
    QHash< HashedString, QPair<SkipType, QString> > m_words;


    int m_skippedLines;
    int m_currentLine;
    int m_currentColumn;
    bool m_skipWordsEnabled;

    // preprocessor
    QVector<bool> m_skipping;
    QVector<bool> m_trueTest;
    int m_ifLevel;
    bool m_preprocessorEnabled;
    bool m_inPreproc;

    bool m_reportWarnings;
    bool m_reportMessages;

private:
    Lexer(const Lexer& source);
    void operator = (const Lexer& source);
};


inline Token::Token(const QString & text)
    : m_type(-1),
      m_position(0),
      m_length(0),
      m_startLine(0),
      m_startColumn(0),
      m_endLine(0),
      m_endColumn(0),
      m_text(text)
{
}

inline Token::Token(int type, int position, int length, const QString& text)
    : m_type(type),
      m_position(position),
      m_length(length),
      m_startLine(0),
      m_startColumn(0),
      m_endLine(0),
      m_endColumn(0),
      m_text(text)
{
    DBG_LEXER << type << position << length << text.mid(position, length);
}

inline Token::Token(const Token& source)
    : m_type(source.m_type),
      m_position(source.m_position),
      m_length(source.m_length),
      m_startLine(source.m_startLine),
      m_startColumn(source.m_startColumn),
      m_endLine(source.m_endLine),
      m_endColumn(source.m_endColumn),
      m_text(source.m_text)
{
}

inline Token& Token::operator = (const Token& source)
{
    m_type = source.m_type;
    m_position = source.m_position;
    m_length = source.m_length;
    m_startLine = source.m_startLine;
    m_startColumn = source.m_startColumn;
    m_endLine = source.m_endLine;
    m_endColumn = source.m_endColumn;
//    m_text = source.m_text;
    return (*this);
}

inline Token::operator int () const
{
    return m_type;
}

inline bool Token::operator == (const Token& token) const
{
    return m_type == token.m_type &&
           m_position == token.m_position &&
           m_length == token.m_length &&
           m_startLine == token.m_startLine &&
           m_startColumn == token.m_startColumn &&
           m_endLine == token.m_endLine &&
           m_endColumn == token.m_endColumn &&
           m_text == token.m_text;
}

inline bool Token::isNull() const
{
    return m_type == Token_eof || m_length == 0;
}

inline int Token::type() const
{
    return m_type;
}

inline void Token::setType(int type)
{
    m_type = type;
}

inline int Token::position() const
{
    return m_position;
}

inline QString Token::text() const
{
    return m_text.mid(m_position, m_length);
}

inline void Token::setStartPosition(int line, int column)
{
    m_startLine = line;
    m_startColumn = column;
}

inline void Token::setEndPosition(int line, int column)
{
    m_endLine = line;
    m_endColumn = column;
}

inline void Token::getStartPosition(int* line, int* column) const
{
    if (line) *line = m_startLine;
    if (column) *column = m_startColumn;
}

inline void Token::getEndPosition(int* line, int* column) const
{
    if (line) *line = m_endLine;
    if (column) *column = m_endColumn;
}

inline void Token::setPosition(int position)
{
    m_position = position;
}

inline unsigned int Token::length() const
{
    return m_length;
}

inline void Token::setLength(unsigned int length)
{
    m_length = length;
}

inline bool Lexer::recordComments() const
{
    return m_recordComments;
}

inline void Lexer::setRecordComments(bool record)
{
    m_recordComments = record;
}

inline bool Lexer::recordWhiteSpaces() const
{
    return m_recordWhiteSpaces;
}

inline void Lexer::setRecordWhiteSpaces(bool record)
{
    m_recordWhiteSpaces = record;
}

inline QString Lexer::source() const
{
    return m_source;
}

inline int Lexer::index() const
{
    return m_index;
}

inline void Lexer::setIndex(int index)
{
    m_index = index;
}

inline const Token& Lexer::nextToken()
{
    if (m_index < m_size)
        return *m_tokens[ m_index++ ];

    return *m_tokens[ m_index ];
}

inline const Token& Lexer::tokenAt(int n) const
{
    return *m_tokens[ qMin(n, m_size-1) ];
}

inline const Token& Lexer::lookAhead(int n) const
{
    Token &t = *m_tokens[ qMin(m_index + n, m_size-1) ];
    DBG_LEXER << t;
    return t;
}

inline int Lexer::tokenPosition(const Token& token) const
{
    return token.position();
}

inline void Lexer::nextChar()
{
    if (m_ptr >= m_endPtr) {
        m_currentChar = QChar();
        return;
    }
    if (*m_ptr == QLatin1Char('\n')) {
        ++m_currentLine;
        m_currentColumn = 0;
        m_startLine = true;
    } else {
        ++m_currentColumn;
    }
    ++m_ptr;

    if (m_ptr <  m_endPtr)
        m_currentChar = *m_ptr;
    else
        m_currentChar = QChar();
}

inline void Lexer::nextChar(int n)
{
    if (m_ptr + n >= m_endPtr) {
        m_ptr = m_endPtr;
        m_currentChar = QChar();
        return;
    }
    m_currentColumn += n;
    m_ptr += n;

    if (m_ptr <  m_endPtr)
        m_currentChar = *m_ptr;
    else
        m_currentChar = QChar();
}

inline void Lexer::readIdentifier()
{
    while (currentChar().isLetterOrNumber() || currentChar() == QLatin1Char('_'))
        nextChar();
}

inline void Lexer::readWhiteSpaces(bool skipNewLine, bool skipOnlyOnce)
{
    while (!currentChar().isNull()) {
        QChar ch = currentChar();

        if (ch == QLatin1Char('\n') && !skipNewLine) {
            break;
        } else if (ch.isSpace()) {
            nextChar();
        } else if (m_inPreproc && currentChar() == QLatin1Char('\\')) {
            nextChar();
            readWhiteSpaces(true, true);
        } else {
            break;
        }
        if (skipOnlyOnce && ch == QLatin1Char('\n')) {
            skipNewLine = false;
        }
    }
}

//little hack for better performance
inline bool isTodo(const QString& txt, int position)
{
    if (txt.length() < position + 4) return false;
    return (txt[ position ] == QLatin1Char('t') || txt[ position ] == QLatin1Char('T'))
           && (txt[ position+1 ] == QLatin1Char('o') || txt[ position+1 ] == QLatin1Char('O'))
           && (txt[ position+2 ] == QLatin1Char('d') || txt[ position+2 ] == QLatin1Char('D'))
           && (txt[ position+3 ] == QLatin1Char('o') || txt[ position+3 ] == QLatin1Char('O'));
}

inline bool isFixme(const QString& txt, int position)
{
    if (txt.length() < position + 5) return false;
    return (txt[ position ] == QLatin1Char('f') || txt[ position ] == QLatin1Char('F'))
           && (txt[ position+1 ] == QLatin1Char('i') || txt[ position+1 ] == QLatin1Char('I'))
           && (txt[ position+2 ] == QLatin1Char('x') || txt[ position+2 ] == QLatin1Char('X'))
           && (txt[ position+3 ] == QLatin1Char('m') || txt[ position+3 ] == QLatin1Char('M'))
           && (txt[ position+4 ] == QLatin1Char('e') || txt[ position+4 ] == QLatin1Char('E'));
}

inline void Lexer::readLineComment()
{
    while (!currentChar().isNull() && currentChar() != QLatin1Char('\n')) {
        if (m_reportMessages && isTodo(m_source, currentPosition())) {
            nextChar(4);
            QString msg;
            int line = m_currentLine;
            int col = m_currentColumn;

            while (!currentChar().isNull()) {
                if (currentChar() == QLatin1Char('*') && peekChar() == QLatin1Char('/'))
                    break;
                else if (currentChar() == QLatin1Char('\n'))
                    break;

                msg += currentChar();
                nextChar();
            }
            m_driver->addProblem(m_driver->currentFileName(), Problem(msg, line, col, Problem::Level_Todo));
        } else if (m_reportMessages && isFixme(m_source, currentPosition())) {
            nextChar(5);
            QString msg;
            int line = m_currentLine;
            int col = m_currentColumn;

            while (!currentChar().isNull()) {
                if (currentChar() == QLatin1Char('*') && peekChar() == QLatin1Char('/'))
                    break;
                else if (currentChar() == QLatin1Char('\n'))
                    break;

                msg += currentChar();
                nextChar();
            }
            m_driver->addProblem(m_driver->currentFileName(), Problem(msg, line, col, Problem::Level_Fixme));
        } else
            nextChar();
    }
}

inline void Lexer::readMultiLineComment()
{
    while (!currentChar().isNull()) {
        if (currentChar() == QLatin1Char('*') && peekChar() == QLatin1Char('/')) {
            nextChar(2);
            return;
        } else if (m_reportMessages && isTodo(m_source, currentPosition())) {
            nextChar(4);
            QString msg;
            int line = m_currentLine;
            int col = m_currentColumn;

            while (!currentChar().isNull()) {
                if (currentChar() == QLatin1Char('*') && peekChar() == QLatin1Char('/'))
                    break;
                else if (currentChar() == QLatin1Char('\n'))
                    break;
                msg += currentChar();
                nextChar();
            }
            m_driver->addProblem(m_driver->currentFileName(), Problem(msg, line, col, Problem::Level_Todo));
        } else if (m_reportMessages && isFixme(m_source, currentPosition())) {
            nextChar(5);
            QString msg;
            int line = m_currentLine;
            int col = m_currentColumn;

            while (!currentChar().isNull()) {
                if (currentChar() == QLatin1Char('*') && peekChar() == QLatin1Char('/'))
                    break;
                else if (currentChar() == QLatin1Char('\n'))
                    break;

                msg += currentChar();
                nextChar();
            }
            m_driver->addProblem(m_driver->currentFileName(), Problem(msg, line, col, Problem::Level_Fixme));
        } else
            nextChar();
    }
}

inline void Lexer::readCharLiteral()
{
    if (currentChar() == QLatin1Char('\''))
        nextChar(); // skip '
    else if (currentChar() == QLatin1Char('L') && peekChar() == QLatin1Char('\''))
        nextChar(2); // slip L'
    else
        return;

    while (!currentChar().isNull()) {
        int len = getOffset(m_endPtr) - currentPosition();

        if (len>=2 && (currentChar() == QLatin1Char('\\') && peekChar() == QLatin1Char('\''))) {
            nextChar(2);
        } else if (len>=2 && (currentChar() == QLatin1Char('\\') && peekChar() == QLatin1Char('\\'))) {
            nextChar(2);
        } else if (currentChar() == QLatin1Char('\'')) {
            nextChar();
            break;
        } else {
            nextChar();
        }
    }
}

inline void Lexer::readStringLiteral()
{
    if (currentChar() != QLatin1Char('"'))
        return;

    nextChar(); // skip "

    while (!currentChar().isNull()) {
        int len = getOffset(m_endPtr) - currentPosition();

        if (len>=2 && currentChar() == QLatin1Char('\\') && peekChar() == QLatin1Char('"')) {
            nextChar(2);
        } else if (len>=2 && currentChar() == QLatin1Char('\\') && peekChar() == QLatin1Char('\\')) {
            nextChar(2);
        } else if (currentChar() == QLatin1Char('"')) {
            nextChar();
            break;
        } else {
            nextChar();
        }
    }
}

inline void Lexer::readNumberLiteral()
{
    while (currentChar().isLetterOrNumber() || currentChar() == QLatin1Char('.'))
        nextChar();
}

inline int Lexer::findOperator3() const
{
    int n = getOffset(m_endPtr) - currentPosition();

    if (n >= 3) {
        char ch  = currentChar().toLatin1();
        char ch1 = peekChar().toLatin1();
        char ch2 = peekChar(2).toLatin1();

        if (ch == '<' && ch1 == '<' && ch2 == '=') return Token_assign;
        else if (ch == '>' && ch1 == '>' && ch2 == '=') return Token_assign;
        else if (ch == '-' && ch1 == '>' && ch2 == '*') return Token_ptrmem;
        else if (ch == '.' && ch1 == '.' && ch2 == '.') return Token_ellipsis;
    }

    return -1;
}

inline int Lexer::findOperator2() const
{
    int n = getOffset(m_endPtr) - currentPosition();

    if (n>=2) {
        char ch = currentChar().toLatin1(), ch1 = peekChar().toLatin1();

        if (ch == ':' && ch1 == ':') return Token_scope;
        else if (ch == '.' && ch1 == '*') return Token_ptrmem;
        else if (ch == '+' && ch1 == '=') return Token_assign;
        else if (ch == '-' && ch1 == '=') return Token_assign;
        else if (ch == '*' && ch1 == '=') return Token_assign;
        else if (ch == '/' && ch1 == '=') return Token_assign;
        else if (ch == '%' && ch1 == '=') return Token_assign;
        else if (ch == '^' && ch1 == '=') return Token_assign;
        else if (ch == '&' && ch1 == '=') return Token_assign;
        else if (ch == '|' && ch1 == '=') return Token_assign;
        else if (ch == '<' && ch1 == '<') return Token_shift;
        //else if(ch == '>' && ch1 == '>') return Token_shift;
        else if (ch == '=' && ch1 == '=') return Token_eq;
        else if (ch == '!' && ch1 == '=') return Token_eq;
        else if (ch == '<' && ch1 == '=') return Token_leq;
        else if (ch == '>' && ch1 == '=') return Token_geq;
        else if (ch == '&' && ch1 == '&') return Token_and;
        else if (ch == '|' && ch1 == '|') return Token_or;
        else if (ch == '+' && ch1 == '+') return Token_incr;
        else if (ch == '-' && ch1 == '-') return Token_decr;
        else if (ch == '-' && ch1 == '>') return Token_arrow;
        else if (ch == '#' && ch1 == '#') return Token_concat;
    }

    return -1;
}

inline bool Lexer::skipWordsEnabled() const
{
    return m_skipWordsEnabled;
}

inline void Lexer::setSkipWordsEnabled(bool enabled)
{
    m_skipWordsEnabled = enabled;
}

inline bool Lexer::preprocessorEnabled() const
{
    return m_preprocessorEnabled;
}

inline void Lexer::setPreprocessorEnabled(bool enabled)
{
    m_preprocessorEnabled = enabled;
}

inline int Lexer::currentPosition() const
{
    return getOffset(m_ptr);
}

inline const QChar Lexer::currentChar() const
{
    return m_currentChar;
}

inline QChar Lexer::peekChar(int n) const
{
    const QChar* p = m_ptr + n;

    if (p <  m_endPtr)
        return *p;
    else
        return QChar();
}

inline bool Lexer::eof() const
{
    return m_ptr >= m_endPtr;
}

inline bool Lexer::reportWarnings() const
{
    return m_reportWarnings;
}

inline void Lexer::setReportWarnings(bool enable)
{
    m_reportWarnings = enable;
}

inline bool Lexer::reportMessages() const
{
    return m_reportMessages;
}

inline void Lexer::setReportMessages(bool enable)
{
    m_reportMessages = enable;
}

inline void Lexer::insertCurrent(const QString& str)
{
    int posi = currentPosition();
    m_source.insert(posi, str);

    m_ptr = offset(posi);
    m_endPtr = offset(m_source.length());
    if (m_ptr < m_endPtr)
        m_currentChar = *m_ptr;
    else
        m_currentChar = QChar();
}

#endif