package builtins

import (
	"monkey/internal/context"
	"monkey/internal/object"
	"monkey/internal/typing"
)

// Len ...
func Len(ctx context.Context, args ...object.Object) object.Object {
	if err := typing.Check(
		"len", args,
		typing.ExactArgs(1),
	); err != nil {
		return newError(err.Error())
	}

	switch obj := args[0].(type) {
	case object.String:
		return object.Integer{Value: int64(obj.Len())}
	case *object.Array:
		return object.Integer{Value: int64(obj.Len())}
	case *object.Hash:
		return object.Integer{Value: int64(obj.Len())}
	default:
		return newError("TypeError: object of type '%s' has no len()", args[0].Type())
	}
}