#include "scriptengine.h"
#include "lexer.h"
#include "parser.h"
#include "expression.h"

#include <bu/staticmembuf.h>
#include <bu/exceptionbase.h>
#include <bu/sio.h>

#include <stdlib.h>

ScriptEngine::ScriptEngine() :
    bRunning( true )
{
}

ScriptEngine::~ScriptEngine()
{
}

void ScriptEngine::exec( const Bu::String &sExpr )
{
    Bu::StaticMemBuf mb( sExpr.getStr(), sExpr.getSize() );
    exec( sExpr );
}

void ScriptEngine::exec( Bu::Stream &sInput )
{
    Lexer l( sInput );
    Parser p( l );
    Expression *pExp = p.parse();
    exec( pExp );
    delete pExp;
}

void ScriptEngine::exec( Expression *pExpr )
{
    NumStack sNums;

    for( Expression::iterator i = pExpr->begin(); i; i++ )
    {
//        Bu::sio << (*i).eType << " - " << sNums << Bu::sio.nl;
        if( ((*i).eType&Token::mMetaCmd) )
        {
            command( i );
            continue;
        }
        switch( (*i).eType )
        {
            case Token::tNumber:
                sNums.push( *(*i).nVal );
                break;

            case Token::tVariable:
                if( hVarState.has( *(*i).sVal ) )
                {
                    sNums.push( hVarState[*(*i).sVal] );
                }
                else
                {
                    if( sigError.isSet() )
                        sigError(
                            Bu::String("No such variable: $%1").
                                arg(*(*i).sVal)
                            );
                    return;
                }
                break;

            case Token::tPlus:
                {
                    Number b = sNums.peekPop();
                    Number a = sNums.peekPop();
                    sNums.push( a + b );
                }
                break;

            case Token::tMinus:
                {
                    Number b = sNums.peekPop();
                    Number a = sNums.peekPop();
                    sNums.push( a - b );
                }
                break;

            case Token::tDivide:
                {
                    Number b = sNums.peekPop();
                    Number a = sNums.peekPop();
                    sNums.push( a / b );
                }
                break;

            case Token::tMultiply:
                {
                    Number b = sNums.peekPop();
                    Number a = sNums.peekPop();
                    sNums.push( a * b );
                }
                break;

            case Token::tNegate:
                sNums.push( -sNums.peekPop() );
                break;
        }
    }

    if( sigNumResult.isSet() && !sNums.isEmpty() )
        sigNumResult( sNums.peekPop() );
}

void ScriptEngine::command( Expression::iterator &i )
{
    switch( (*i).eType )
    {
        case Token::tCmdExit:
            bRunning = false;
            return;

        case Token::tCmdScale:
            {
                if( !(++i) )
                {
                    if( sigError.isSet() )
                        sigError("You must provide a positive integer.");
                    return;
                }
                int32_t iScale = strtol( (*i).sVal->getStr(), 0, 10 );
                if( iScale < 0 )
                {
                    if( sigError.isSet() )
                        sigError("You must provide a positive integer.");
                    return;
                }
                if( sigMessage.isSet() )
                    sigMessage(Bu::String("Changed scale to: %1").arg( iScale ));
                for( VarHash::iterator j = hVarState.begin(); j; j++ )
                    (*j).setScale( iScale );
                i++;
            }
            break;

        case Token::tCmdRadix:
            {
                if( !(++i) )
                {
                    if( sigError.isSet() )
                        sigError("You must provide a positive integer.");
                    return;
                }
                int32_t iRadix = strtol( (*i).sVal->getStr(), 0, 10 );
                if( iRadix < 0 )
                {
                    if( sigError.isSet() )
                        sigError("You must provide a positive integer.");
                    return;
                }
                if( sigMessage.isSet() )
                    sigMessage(Bu::String("Changed radix to: %1").arg( iRadix ));
                hVarState.clear();
//                for( VarHash::iterator i = hVarState.begin(); i; i++ )
//                    (*i).setRadix( iRadix );
                i++;
            }
            break;

        case Token::tCmdExtended:
            /*
    else if( sCmd == "vars" )
    {
    }
    else if( sCmd == "help" || sCmd == "?" )
    {
    }
    else
    {
    }*/
            break;
    }

    if( (*i).eType != Token::tCmdEndParams )
        sigError("Too many parameters.");
}