from asyncio.queues import Queue
import struct

class AsyncDataInputStream:
    def __init__(self, queue: Queue):
        self._queue = queue
        self._last = b''

    async def read_bytes(self, n: int) -> bytes:
        if len(self._last) < n:
            self._last += await self._queue.get()
        out, self._last = self._last[:n], self._last[n:]
        return out

    async def read(self) -> int:
        return (await self.read_bytes(1))[0]

    async def read_boolean(self) -> bool:
        return (await self.read()) != 0

    async def read_short(self) -> int:
        return struct.unpack('>h', await self.read_bytes(2))[0]

    async def read_ushort(self) -> int:
        return struct.unpack('>H', await self.read_bytes(2))[0]

    async def read_int(self) -> int:
        return struct.unpack('>i', await self.read_bytes(4))[0]

    async def read_uint(self) -> int:
        return struct.unpack('>I', await self.read_bytes(4))[0]

    async def read_long(self) -> int:
        return struct.unpack('>q', await self.read_bytes(8))[0]

    async def read_ulong(self) -> int:
        return struct.unpack('>Q', await self.read_bytes(8))[0]

    async def read_float(self) -> float:
        return struct.unpack('>f', await self.read_bytes(4))[0]

    async def read_double(self) -> float:
        return struct.unpack('>d', await self.read_bytes(8))[0]

    async def read_char(self) -> str:
        return chr(await self.read_ushort())

    async def read_varint(self, bits: int = 32) -> int:
        value: int = 0
        position: int = 0
        while True:
            byte = await self.read()
            value |= (byte & 0x7F) << position
            if ((byte & 0x80) == 0):
                break
            position += 7
            if position >= bits:
                raise ValueError('varint too big')
        return value

    async def read_string(self) -> str:
        size = await self.read_short()
        return (await self.read_bytes(size)).decode('utf-8')