namespace NTERA.Interpreter
{
    public enum Token
    {
        Unknown = 0,

        Identifer,
        Value,

        [LexerCharacter('#', LexerType.Real)]
        Sharp,
        [LexerCharacter('@', LexerType.Real)]
        Function,

        [LexerKeyword("DIM")]
        Dim,
        [LexerKeyword("CONST")]
        Const,
        [LexerKeyword("FUNCTION")]
        ReturnFunction,

        //Eralang print keywords 
        [LexerKeyword("DRAWLINE", false)]
        DrawLine,
        [LexerKeyword("CUSTOMDRAWLINE", true)]
        CustomDrawLine,
        [LexerKeyword("DRAWLINEFORM", true)]
        DrawLineForm,
        [LexerKeyword("PRINT", true)]
        Print,
        [LexerKeyword("PRINTL", true)]
        PrintL,
        [LexerKeyword("PRINTFORM", true)]
        PrintForm,
        [LexerKeyword("PRINTFORML", true)]
        PrintFormL,
        [LexerKeyword("HTML_PRINT", true)]
        PrintHtml,
        [LexerKeyword("PRINT_IMG", true)]
        PrintImg,
        [LexerKeyword("PRINTBUTTON", false)]
        PrintButton,
        [LexerKeyword("ALIGNMENT", true)]
        Alignment,
        [LexerKeyword("SETCOLOR", false)]
        SetColor,
        [LexerKeyword("RESETCOLOR", false)]
        ResetColor,

        //Eralang arithmetic keywords
        [LexerKeyword("TIMES")]
        Times,

        //Standard BASIC keywords
        [LexerKeyword("IF")]
        If,
        [LexerKeyword("ENDIF")]
        EndIf,
        [LexerKeyword("THEN")]
        Then,
        [LexerKeyword("ELSE")]
        Else,
        [LexerKeyword("FOR")]
        For,
        [LexerKeyword("TO")]
        To,
        [LexerKeyword("NEXT")]
        Next,
        [LexerKeyword("INPUT")]
        Input,
        [LexerKeyword("LET")]
        Let,
        [LexerKeyword("GOSUB")]
        Gosub,
        [LexerKeyword("RETURN")]
        Return,
        [LexerKeyword("REM")]
        Rem,
        [LexerKeyword("END")]
        End,

        [LexerCharacter('\n', LexerType.Both)]
        NewLine,
        [LexerCharacter(':', LexerType.Real)]
        Colon,
        [LexerCharacter(',', LexerType.Both)]
        Comma,
        
        Plus,
        Append,
        [LexerCharacter('-', LexerType.Real)]
        Minus,
        [LexerCharacter('/', LexerType.Real)]
        Slash,
        [LexerCharacter('*', LexerType.Real)]
        Asterisk,
        [LexerCharacter('^', LexerType.Real)]
        Caret,
        [LexerCharacter('=', LexerType.Real)]
        Equal,
        Less,
        More,
        NotEqual,
        LessEqual,
        MoreEqual,
        [LexerKeyword("OR")]
        [LexerCharacter('|', LexerType.Real)]
        Or,
        [LexerKeyword("AND")]
        [LexerCharacter('&', LexerType.Real)]
        And,
        [LexerCharacter('!', LexerType.Real)]
        Not,

        [LexerCharacter('(', LexerType.Real)]
        LParen,
        [LexerCharacter(')', LexerType.Real)]
        RParen,
        
        EOF = -1   //End Of File
    }

    public static class TokenEnumExtensions
    {
        public static bool IsUnary(this Token token)
        {
            return token == Token.Plus
                || token == Token.Minus;
        }

        public static bool IsArithmetic(this Token token)
        {
            return token == Token.Plus
                || token == Token.Minus
                || token == Token.Slash
                || token == Token.Asterisk
                || token == Token.Caret
                || token == Token.Equal
                || token == Token.NotEqual
                || token == Token.Less
                || token == Token.LessEqual
                || token == Token.More
                || token == Token.MoreEqual
                || token == Token.Or
                || token == Token.And
                || token == Token.Not;
        }

        public static bool IsStringOp(this Token token)
        {
            return token == Token.Plus;
        }
    }
}