package parser

// TokenType represents the type of a token
type TokenType int

const (
	// Literals
	IDENT TokenType = iota
	NUMBER
	STRING
	TRUE
	FALSE
	NIL

	// Operators
	ASSIGN // =
	PLUS   // +
	MINUS  // -
	STAR   // *
	SLASH  // /
	DOT    // .

	// Delimiters
	LPAREN   // (
	RPAREN   // )
	LBRACE   // {
	RBRACE   // }
	LBRACKET // [
	RBRACKET // ]
	COMMA    // ,

	// Keywords
	VAR
	IF
	THEN
	ELSEIF
	ELSE
	END
	ECHO
	FOR
	IN
	DO

	// Special
	EOF
	ILLEGAL
)

// Token represents a single token
type Token struct {
	Type    TokenType
	Literal string
	Line    int
	Column  int
}

// Precedence levels for Pratt parsing
type Precedence int

const (
	_ Precedence = iota
	LOWEST
	SUM     // +
	PRODUCT // *
	MEMBER  // table[key], table.key
	PREFIX  // -x, !x
	CALL    // function()
)

// precedences maps token types to their precedence levels
var precedences = map[TokenType]Precedence{
	PLUS:     SUM,
	MINUS:    SUM,
	SLASH:    PRODUCT,
	STAR:     PRODUCT,
	DOT:      MEMBER,
	LBRACKET: MEMBER,
}

// lookupIdent checks if an identifier is a keyword
func lookupIdent(ident string) TokenType {
	keywords := map[string]TokenType{
		"var":    VAR,
		"true":   TRUE,
		"false":  FALSE,
		"nil":    NIL,
		"if":     IF,
		"then":   THEN,
		"elseif": ELSEIF,
		"else":   ELSE,
		"end":    END,
		"echo":   ECHO,
		"for":    FOR,
		"in":     IN,
		"do":     DO,
	}

	if tok, ok := keywords[ident]; ok {
		return tok
	}
	return IDENT
}