import gdb


class KstdUniquePtrPrinter(gdb.ValuePrinter):
    def __init__(self, val):
        self.__val = val
        self.__type = val.type.template_argument(0)

    def to_string(self):
        pointer = self.__val["pointer"]
        if int(pointer) == 0:
            return f"kstd::unique_ptr<{self.__type}> (empty)"
        return f"kstd::unique_ptr<{self.__type}>"

    def children(self):
        pointer = self.__val["pointer"]
        if int(pointer) != 0:
            yield ("get()", pointer.dereference())

    def display_hint(self):
        return None


class KstdSharedPtrPrinter(gdb.ValuePrinter):
    def __init__(self, val):
        self.__val = val
        self.__type = val.type.template_argument(0)

    def to_string(self):
        pointer = self.__val["pointer"]
        control_block = self.__val["control"]

        if int(pointer) == 0 or int(control_block) == 0:
            return f"shared_ptr<{self.__type}> (empty)"

        strong_refs = int(control_block["shared_count"]["_M_i"])
        weak_refs = int(control_block["weak_count"]["_M_i"])

        return (
            f"shared_ptr<{self.__type}> use count {strong_refs}, weak count {weak_refs}"
        )

    def children(self):
        pointer = self.__val["pointer"]
        control_block = self.__val["control"]

        if int(pointer) != 0:
            yield ("get()", pointer.dereference())

    def display_hint(self):
        return None


class KstdObserverPtrPrinter(gdb.ValuePrinter):
    def __init__(self, val):
        self.__val = val
        self.__type = val.type.template_argument(0)
        self.__pointer = val["m_ptr"]

    def to_string(self):
        return f"{(self.__pointer)}"

    def children(self):
        if int(self.__pointer) != 0:
            yield ("get()", self.__pointer.dereference())

    def display_hint(self):
        return None