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#include "rppexpressionbuilder.h"

#include "tokens.h"

#include "rpp.h"

QT_BEGIN_NAMESPACE

using namespace TokenEngine;

namespace Rpp {

ExpressionBuilder::ExpressionBuilder(const TokenList &tokenList, const QVector<Type> &typeList, TypedPool<Item> *memoryPool)

:i(0)

,m_tokenList(tokenList)

,m_typeList(typeList)

,m_memoryPool(memoryPool)

{}

Rpp::Expression *ExpressionBuilder::parse()

{

    if(unary_expression_lookup())

        return conditional_expression();

    else

        return createIntLiteral(0);

}

Type ExpressionBuilder::next()

{

    if(!hasNext())

        return Token_eof;

    return typeAt(i++);

}

inline bool ExpressionBuilder::test(int token)

{

    if (i < m_tokenList.count() && typeAt(i) == token) {

        ++i;

        return true;

    }

    return false;

}

inline bool ExpressionBuilder::moreTokens(int delta)

{

    return (i + delta < m_tokenList.count());

}

inline Type ExpressionBuilder::lookup(int k)

{

    const int l = i - 1 + k;

    return l < m_tokenList.count() ? typeAt(l) : Token_eof;

}

Expression *ExpressionBuilder::conditional_expression()

{

    Expression *value = logical_OR_expression();

    if (test('?')) {

        Expression *leftExpression = conditional_expression();

        Expression *rightExpression;

        if(test(':'))

            rightExpression = conditional_expression();

        else

            rightExpression = createIntLiteral(0);

        return createConditionalExpression(value, leftExpression, rightExpression);

    }

    return value;

}

Expression *ExpressionBuilder::logical_OR_expression()

{

    Expression *value = logical_AND_expression();

    if (test(Token_or))

        return createBinaryExpression(Expression::OrOp, value, logical_OR_expression());

    return value;

}

Expression *ExpressionBuilder::logical_AND_expression()

{

    Expression *value = inclusive_OR_expression();

    if (test(Token_and))

        return createBinaryExpression(Expression::AndOp, value, logical_AND_expression());

    return value;

}

Expression *ExpressionBuilder::inclusive_OR_expression()

{

    Expression *value = exclusive_OR_expression();

    if (test('|'))

        return createBinaryExpression('|', value, inclusive_OR_expression());

    return value;

}

Expression *ExpressionBuilder::exclusive_OR_expression()

{

    Expression *value = AND_expression();

    if (test('^'))

        return createBinaryExpression('^', value, exclusive_OR_expression());

    return value;

}

Expression *ExpressionBuilder::AND_expression()

{

    Expression *value = equality_expression();

    if (test('&'))

        return createBinaryExpression('&', value, AND_expression());

    return value;

}

Expression *ExpressionBuilder::equality_expression()

{

    Expression *value = relational_expression();

    switch (next()) {

    case Token_eq:

        return createBinaryExpression(Expression::EqOp, value, equality_expression());

    case Token_not_eq:

        return createBinaryExpression(Expression::NotEqOp, value, equality_expression());

    default:

        prev();

        return value;

    }

}

Expression *ExpressionBuilder::relational_expression()

{

    Expression *value = shift_expression();

    switch (next()) {

    case '<':

        return createBinaryExpression('<', value, relational_expression());

    case '>':

        return createBinaryExpression('>', value, relational_expression());

    case Token_leq:

        return createBinaryExpression(Expression::LtEqOp, value, relational_expression());

    case Token_geq:

        return createBinaryExpression(Expression::GtEqOp, value, relational_expression());

    default:

        prev();

        return value;

    }

}

Expression *ExpressionBuilder::shift_expression()

{

    Expression *value = additive_expression();

    switch (next()) {

    case Token_left_shift:

        return createBinaryExpression(Expression::LShiftOp, value, shift_expression());

    case Token_right_shift:

        return createBinaryExpression(Expression::RShiftOp, value, shift_expression());

    default:

        prev();

        return value;

    }

}

Expression *ExpressionBuilder::additive_expression()

{

    Expression *value = multiplicative_expression();

    switch (next()) {

    case '+':

        return createBinaryExpression('+', value, additive_expression());

    case '-':

        return createBinaryExpression('-', value, additive_expression());

    default:

        prev();

        return value;

    }

}

Expression *ExpressionBuilder::multiplicative_expression()

{

    Expression *value = unary_expression();

    switch (next()) {

    case '*':

        return createBinaryExpression('*', value, multiplicative_expression());

    case '%':

        return createBinaryExpression('%', value, multiplicative_expression());

    case '/':

        return createBinaryExpression('/', value, multiplicative_expression());

    default:

        prev();

        return value;

    };

}

Expression *ExpressionBuilder::unary_expression()

{

    switch (next()) {

    case '+':

        return createUnaryExpression('+', unary_expression());

    case '-':

        return createUnaryExpression('-',  unary_expression());

    case '!':

        return createUnaryExpression('!',  unary_expression());

    case '~':

        return createUnaryExpression('~', unary_expression());

    case Token_defined:

    {

        int identifierIndex  = 0;

        if (test(Token_identifier)) {

            identifierIndex = i - 1;

        } else if (test('(')) {

            if (test(Token_identifier))

                identifierIndex = i -1;

            test(')');

        }

        return createMacroReference(MacroReference::DefinedRef, createTokenList(identifierIndex));

    }

    default:

        prev();

        return primary_expression();

    }

}

bool ExpressionBuilder::unary_expression_lookup()

{

    Type t = lookup();

    return (primary_expression_lookup()

            || t == '+'

            || t == '-'

            || t == '!'

            || t == '~'

            || t == Token_defined);

}

Expression *ExpressionBuilder::primary_expression()

{

    Expression *value;

    if (test('(')) {

        if (moreTokens(1))

            value = conditional_expression();

        else

            value = createIntLiteral(0); // Syntax error.

        test(')');

    } else {

        next();

        bool ok;

        int val  = QString::fromLatin1(lexem()).toInt(&ok, 0);

        if(ok)

            value = createIntLiteral(val);

        else

            value = createMacroReference(MacroReference::ValueRef, createTokenList(i -1));

    }

    return value;

}

bool ExpressionBuilder::primary_expression_lookup()

{

    Type t = lookup();

    return (t == Token_identifier

            || t == Token_number_literal

/*            || t == PP_FLOATING_LITERAL*/

            || t == '(');

}

/*

    Creates a tokenList containing one token

*/

TokenList ExpressionBuilder::createTokenList(int tokenIndex) const

{

    return TokenList(m_tokenList.tokenContainer(tokenIndex),

        QVector<int>() << m_tokenList.containerIndex(tokenIndex));

}

/*

    Node cration helper functions

*/

UnaryExpression *ExpressionBuilder::createUnaryExpression(int op, Expression *expression)

{

    return new (m_memoryPool->allocate(sizeof(UnaryExpression))) UnaryExpression(op, expression);

}

BinaryExpression *ExpressionBuilder::createBinaryExpression(int op, Expression *leftExpresson, Expression *rightExpression)

{

    return new (m_memoryPool->allocate(sizeof(BinaryExpression))) BinaryExpression(op, leftExpresson, rightExpression);

}

ConditionalExpression *ExpressionBuilder::createConditionalExpression(Expression *condition, Expression *leftExpression, Expression *rightExpression)

{

    return new (m_memoryPool->allocate(sizeof(ConditionalExpression))) ConditionalExpression(condition, leftExpression, rightExpression);

}

MacroReference *ExpressionBuilder::createMacroReference(MacroReference::Type type, TokenEngine::TokenList token)

{

    return new (m_memoryPool->allocate(sizeof(MacroReference))) MacroReference(token, type);

}

IntLiteral *ExpressionBuilder::createIntLiteral(const int arg)

{

    return new (m_memoryPool->allocate(sizeof(IntLiteral))) IntLiteral(arg);

}

}

QT_END_NAMESPACE