#include "config.h"
#include "parser.h"
#include "lexer.h"
#include "number.h"
#include "datafiles.h"

#include <bu/sio.h>
#include <stdlib.h>


Parser::Parser( Lexer &lex, Bu::Stream &rOut ) :
    lex( lex ),
    rOut( rOut )
{
}

Parser::~Parser()
{
}

void Parser::parse()
{
    for(;;)
    {
        lex.nextToken();
        if( lex[0].eType == Token::tEndOfInput )
            break;

        exprR();
        reduce();

        printState("Final");

        tsParse.clear();
        tsScript.clear();
    }
}

void Parser::exprR()
{
    exprP();
    expr();
}

void Parser::expr()
{
    Bu::sio << "::expr " << lex[0] << Bu::sio.nl;
    if( lex[0].eType == Token::tEndOfInput )
        return;

    switch( lex[0].eType )
    {
        case Token::tEquals:
            throw Bu::ExceptionBase("misplaced equals.");
            break;

        case Token::tPlus:
        case Token::tMinus:
        case Token::tMultiply:
        case Token::tDivide:
        case Token::tModulus:
            Token t = lex[0];
            lex.nextToken();
            Bu::sio << "->expr " << t << " " << lex[0] << Bu::sio.nl;
            if( lex[0].eType == Token::tOpenParen )
            {
                exprP();
                shift( t );
                reduce();
                expr();
            }
            else
            {
                if( lex[0].eType == Token::tNumber ||
                    lex[0].eType == Token::tVariable )
                {
                    Bu::sio << "->expr " << t <<
                        " " << lex[0] <<
                        " " << lex[1] <<
                        Bu::sio.nl;
                    shift( lex[0] );
                    if( lex[1].eType&Token::mMetaOperator )
                    {
                        if( getPriority(lex[1].eType) <=
                            getPriority(t.eType) )
                        {
                            shift( t );
                            reduce();
                            printState("reduce");
                            lex.nextToken();
                            expr();
                        }
                        else
                        {
                            printState("no reduce");
                            lex.nextToken();
                            expr();
                            if( !tsParse.isEmpty() &&
                                tsParse.peek().eType != Token::tComputedValue )
                            {
                                reduce();
                                printState("no reduce reduce");
                            }
                            shift( t );
                            printState("post no reduce");
                        }
                    }
                    else
                    {
                        shift( t );
                        lex.nextToken();
                        printState("no next op");
                    }
                }
                else if( lex[0].eType == Token::tMinus )
                {
                    // This is negation
                    Bu::sio << "next token: " << lex[0] << Bu::sio.nl;
                    printState("inline-negate");
                    exprP();
                    printState("inline-negate-post");
                    shift( t );
                    printState("inline-negate-post2");

                    Bu::sio << "??? " << lex[0] << Bu::sio.nl;
                }
            }
            break;
    }
}

void Parser::exprP()
{
    if( lex[0].eType == Token::tVariable &&
        lex[1].eType == Token::tEquals )
    {
        Token t = lex[0];
        lex.nextToken( 2 );
        exprR();
        reduce();
        printState("pre-equals");
        shift( t );
        shift( Token( Token::tEquals ) );
        printState("post-equals");
        reduce();
        printState("post-equals-reduce");
        return;
    }

    switch( lex[0].eType )
    {
        case Token::tNumber:
        case Token::tVariable:
            shift( lex[0] );
            lex.nextToken();
            break;

        case Token::tOpenParen:
            shift( lex[0] );
            lex.nextToken();
            exprR();
            if( lex[0].eType != Token::tCloseParen )
            {
                Bu::sio << "::exprP " << lex[0] << Bu::sio.nl;
                throw Bu::ExceptionBase("Expected close paren");
            }
            shift( lex[0] );
            printState("closeParen");
            reduce();
            lex.nextToken();
            printState("post closeParen");
            break;

        case Token::tMinus:
            lex.nextToken();
            exprP();
            shift( Token( Token::tNegate ) );     
            reduce();
            break;
    }
}
/*
case Token::tCommand:
    lex.setMode( Lexer::modeCommand );
    if( *t.sVal == "exit" || *t.sVal == "quit" )
        return;
    else if( *t.sVal == "scale" )
    {
        Token t2 = lex.nextToken();
        if( t2.eType == Token::tEndOfLine )
        {
            Bu::println( rOut, "Current scale: %1").
                arg( lex.getScale() );
        }
        else if( t2.eType == Token::tString )
        {
            int32_t i = strtol( t2.sVal->getStr(), 0, 10 );
            lex.setScale( i );
            if( i < 0 )
            {
                Bu::println( rOut, "ERROR: You must provide a "
                    "positive integer or zero as the parameter "
                    "to scale.");
            }
            else
            {
                Bu::println( rOut, "Scale changed to: %1").
                    arg( lex.getScale() );
                for( VarHash::iterator i = hVars.begin(); i; i++ )
                    (*i).setScale( lex.getScale() );
                nZero = Number( lex.getScale(), lex.getRadix() );
            }
        }
        else
        {
            Bu::println( rOut, "ERROR: You must provide a number "
                "as the parameter to scale.");
        }
    }
    else if( *t.sVal == "radix" )
    {
        Token t2 = lex.nextToken();
        if( t2.eType == Token::tEndOfLine )
        {
            Bu::println( rOut, "Current radix: %1").
                arg( lex.getRadix() );
        }
        else if( t2.eType == Token::tString )
        {
            int32_t i = strtol( t2.sVal->getStr(), 0, 10 );
            if( i < 2 || i > 36 )
                Bu::println( rOut, "ERROR: Radix must be between "
                        "2 and 36 inclusive");
            else
            {
                lex.setRadix( i );
                Bu::println( rOut, "Radix changed to: %1").
                    arg( lex.getRadix() );
                hVars.clear();
                nZero = Number( lex.getScale(), lex.getRadix() );
            }
        }
        else
        {
            Bu::println( rOut, "You must provide a number as "
                    "the parameter to radix.");
        }
    }
    else if( *t.sVal == "vars" )
    {
        Bu::println( rOut, "Declared variables:");
        for( VarHash::iterator i = hVars.begin(); i; i++ )
        {
            Bu::println( rOut, " - %1 = %2").
                arg( i.getKey() ).arg( *i );
        }
        Bu::println( rOut, "");
    }
    else if( *t.sVal == "help" || *t.sVal == "h" || *t.sVal == "?" )
    {
        Bu::println( rOut, Datafiles::getString("parserhelp.txt") );
    }
    else
    {
        Bu::println( rOut, "ERROR: Unknown command '%1'").
            arg( *t.sVal );
    }
    lex.setMode( Lexer::modeNormal );
    break;
*/

void Parser::shift( const Token &t )
{
    tsParse.push( t );
}

void Parser::reduce()
{
    if( tsParse.isEmpty() || tsParse.peek().eType == Token::tOpenParen )
        return;
    Token tOp = tsParse.peekPop();
    switch( tOp.eType )
    {
        case Token::tNumber:
        case Token::tVariable:
            tsScript.append( tOp );
            tsParse.push( Token( Token::tComputedValue ) );
            break;

        case Token::tComputedValue:
            tsParse.push( Token( Token::tComputedValue ) );
            break;

        case Token::tPlus:
        case Token::tMinus:
        case Token::tDivide:
        case Token::tMultiply:
        case Token::tModulus:
        case Token::tEquals:
            for(int j = 0; j < 2; j++ )
            {
                Token t = tsParse.peekPop();
                if( t.eType == Token::tNumber ||
                    t.eType == Token::tVariable )
                {
                    tsScript.append( t );
                }
                else if( t.eType == Token::tComputedValue )
                {
                    // Nope, we don't care
                }
            }
            tsScript.append( tOp );
            shift( Token( Token::tComputedValue ) );
            break;

        case Token::tNegate:
            {
                Token t = tsParse.peekPop();
                if( t.eType != Token::tComputedValue )
                    tsScript.append( t );
                tsScript.append( tOp );
                shift( Token( Token::tComputedValue ) );
            }
            break;

        case Token::tCloseParen:
            if( tsParse.peek().eType != Token::tComputedValue )
            {
                printState("paren-innerReduce-pre");
                reduce();
                printState("paren-innerReduce-post");
            }
            tsParse.pop();
            if( tsParse.peek().eType == Token::tOpenParen )
            {
                tsParse.pop();
                shift( Token( Token::tComputedValue ) );
            }
            else
            {
                throw Bu::ExceptionBase("Error?");
            }
            break;
    }
}

int Parser::reqTokens( Token::Type eType )
{
    switch( eType )
    {
        case Token::tPlus:
        case Token::tMinus:
        case Token::tDivide:
        case Token::tMultiply:
        case Token::tModulus:
        case Token::tEquals:
            return 2;

        case Token::tOpenParen:
            return 0;

        case Token::tCloseParen:
            return 1;

        default:
            return 0;
    }
}

int Parser::getPriority( Token::Type eType )
{
    switch( eType )
    {
        case Token::tNumber:
        case Token::tVariable:
        case Token::tCommand:
            return 0;

        case Token::tPlus:
        case Token::tMinus:
            return 1;

        case Token::tDivide:
        case Token::tMultiply:
        case Token::tModulus:
            return 2;

        case Token::tOpenParen:
        case Token::tCloseParen:
            return 3;

        case Token::tEndOfLine:
        case Token::tEndOfInput:
        case Token::tEquals:
            return -1;

        default:
            throw Bu::ExceptionBase("Invalid type in getPriority");
    }
}

void Parser::printState( const Bu::String &sTag )
{
    Bu::sio << "----------------" << Bu::sio.nl;
    Bu::sio << sTag << " stack:";
    for( TokenStack::iterator i = tsParse.begin(); i; i++ )
    {
        Bu::sio << " " << (*i);
    }
    Bu::sio << Bu::sio.nl;
    Bu::sio << sTag << " script:";
    for( TokenStack::iterator i = tsScript.begin(); i; i++ )
    {
        Bu::sio << " " << (*i);
    }
    Bu::sio << Bu::sio.nl;
    Bu::sio << "----------------" << Bu::sio.nl;
}