from typing import overload

from .Utils import uint_le, u8_le, u16_le, u32_le


class FileAllocationEntry:
    @overload
    def __init__(self, offset: int = 0, length: int = 0, /):
        ...

    @overload
    def __init__(self, data: bytes|None = None, /):
        ...

    def __init__(self, *args):
        if len(args) == 2:
            self.start = args[0]
            self.end = args[0] + args[1]
        elif not args or args[0] is None:
            self.start = 0
            self.end = 0
        else:
            data = args[0]
            self.start = uint_le(data[:4])
            self.end = uint_le(data[4:8])


    def encode(self) -> bytes:
        return b''.join([u32_le(self.start), u32_le(self.end)])

    __bytes__ = encode


    def __len__(self):
        return 8


class DirectoryTableEntry:
    @overload
    def __init__(self, start: int, file_id: int, parent_id: int, /):
        ...

    @overload
    def __init__(self, data: bytes|None = None, /):
        ...

    def __init__(self, *args):
        if len(args) == 3:
            self.start = args[0]
            self.file_id = args[1]
            self.parent_id = args[2]
        elif not args or args[0] is None:
            self.start = 0
            self.file_id = 0
            self.parent_id = 0
        else:
            data = args[0]
            self.start = uint_le(data[:4])
            self.file_id = uint_le(data[4:6])
            self.parent_id = uint_le(data[6:8])


    def encode(self) -> bytes:
        return b''.join([
            u32_le(self.start),
            u16_le(self.file_id),
            u16_le(self.parent_id)
        ])

    __bytes__ = encode


    def __len__(self):
        return 8


class EntryNameTableEntry:
    @overload
    def __init__(self, length: int = 0, /):
        ...

    @overload
    def __init__(self, data: bytes|None = None, /):
        ...

    def __init__(self, arg = 0):
        if isinstance(arg, int):
            self.entry_name_length = arg
        elif isinstance(arg, bytes):
            self.entry_name_length = arg[0]
        else:
            self.entry_name_length = 0


    def encode(self) -> bytes:
        return u8_le(self.entry_name_length)

    __bytes__ = encode


class EntryNameTableEndOfDirectoryEntry(EntryNameTableEntry):
    def __init__(self, *_):
        super().__init__()


    def __len__(self):
        return 1


class EntryNameTableFileEntry(EntryNameTableEntry):
    @overload
    def __init__(self, name: str = '', /):
        ...

    @overload
    def __init__(self, data: bytes|None = None, /):
        ...

    def __init__(self, arg = ''):
        if arg is None:
            super().__init__()
            return
        elif isinstance(arg, str):
            super().__init__(len(arg))
            self.entry_name = arg
        else:
            super().__init__(arg)
            self.entry_name = arg[1:self.entry_name_length+1].decode('shift-jis')


    def encode(self) -> bytes:
        self.__init__(self.entry_name)
        return b''.join([
            super().encode(),
            self.entry_name.encode('shift-jis')
        ])


    def __len__(self):
        return self.entry_name_length + 1


class EntryNameTableDirectoryEntry(EntryNameTableEntry):
    @overload
    def __init__(self, name: str = '', directory_id: int = 0, /):
        ...

    @overload
    def __init__(self, data: bytes|None = None, /):
        ...

    def __init__(self, *args):
        if len(args) == 2:
            super().__init__(len(args[0]) | 0x80)
            self.entry_name = args[0]
            self.directory_id = args[1]
        elif not args or args[0] is None:
            super().__init__()
            self.entry_name = ''
            self.directory_id = 0
        else:
            data = args[0]
            super().__init__(data[:1])
            enl = self.entry_name_length ^ 0x80
            self.entry_name = data[1 : enl+1].decode('shift-jis')
            self.directory_id = uint_le(data[enl+1 : enl+3])


    def encode(self) -> bytes:
        return b''.join([
            super().encode(),
            self.entry_name.encode('shift-jis'),
            u16_le(self.directory_id)
        ])


    def __len__(self):
        return (self.entry_name_length ^ 0x80) + 3