package parsers

import (
    engine "github.com/tgckpg/mmqlengine/mmql/engine"
    stmtd "github.com/tgckpg/mmqlengine/mmql/statements"
)

/*
EXPECT: BUY
THEN EXPECT: [AmountStatement] OF [FinancialInstrumentStatement]
THEN EXPECT: FOR [AmountStatement]
THEN EXPECT: FROM [ExchangeType]
THEN OPT EXPECT: [ExchangeType]
THEN OPT EXPECT: [AND|OR]
    THEN EXPECT: [ActionExpression]
THEN OPT EXPECT: FOR EVERY
    THEN EXPECT: [AmountType] OF [FinancialInstrumentType]
    THEN EXPECT: [SOLD|BOUGHT] FROM [ExchangeType]
*/

func BuyStatement( lexer *engine.Lexer ) ( istmt stmtd.IStatement, err error ) {
    orderStmt := stmtd.OrderStatement{}
    orderStmt.Action = "BUY"

    // AmountStatement
    readAmount := engine.LexerExpect{
        Statements: true,
        Keywords: false,
        Brackets: false,
        Quotes: false,
        Key: "AMOUNT",
    }

    _amountStmt, err := lexer.ReadStatement( &readAmount )
    if err != nil {
        return
    }

    amountStmt := any( _amountStmt ).( stmtd.AmountStatement )
    orderStmt.SetAmount( &amountStmt )

    var fiStmt stmtd.FinancialInstrumentStatement

    // OF
    err = lexer.ReadKeyword( "OF" )
    if err != nil {
        // try read FOR
        err = lexer.ReadKeyword( "FOR" )
        if err != nil {
            return
        }

        // BUY 1 QQQ
        fiStmt := stmtd.FinancialInstrumentStatement{}
        fiStmt.Name = amountStmt.Unit()

        // Equivalent to BUY 1 UNIT OF QQQ
        amountStmt.SetUnit( "UNITS" )
    } else {
        // BUY 1 UNIT OF QQQ
        readFI := engine.LexerExpect{
            Statements: true,
            Keywords: false,
            Brackets: false,
            Quotes: false,
            Key: "FINANCIAL_INSTRUMENT",
        }

        _fiStmt, _err := lexer.ReadStatement( &readFI )
        if _err != nil {
            err = _err
            return
        }
        fiStmt = any( _fiStmt ).( stmtd.FinancialInstrumentStatement )

        // FOR
        err = lexer.ReadKeyword( "FOR" )
        if err != nil {
            return
        }
    }

    orderStmt.SetFinancialInstrument( &fiStmt )

    // FOR [AmountStatement]
    _forStmt, err := lexer.ReadStatement( &readAmount )
    if err != nil {
        return
    }

    forStmt := any( _forStmt ).( stmtd.AmountStatement )
    orderStmt.SetFor( &forStmt )

    istmt = orderStmt
    return
}