from .stream_interface import IStream
import asyncio

class Stream(IStream):

    def __init__(self, peer_id, maddr):
        self.peer_id = peer_id

        ip = maddr.get_protocol_value("ip4")
        port = maddr.get_protocol_value("tcp")

        # look up peer_id -> multiaddr in peer store
        # parse multiaddr and set_protocol based on it
        # open connection to multiaddr
        # save connection to stream's state
        self.open_connection(ip, port)

    async def open_connection(self, ip, port):
        self.reader, self.writer = await asyncio.open_connection(ip, port)

    def protocol(self):
        """
        :return: protocol id that stream runs on
        """
        return self.protocol_id

    def set_protocol(self, protocol_id):
        """
        :param protocol_id: protocol id that stream runs on
        :return: true if successful
        """
        self.protocol_id = protocol_id

    def read(self):
        """
        read from stream
        :return: bytes of input
        """
        return self.reader.read(-1)

    def write(self, _bytes):
        """
        write to stream
        :return: number of bytes written
        """
        return self.write_to_stream(_bytes)

    async def write_to_stream(self, _bytes):
        to_return = self.writer.write(_bytes)
        await self.writer.drain()
        return to_return

    def close(self):
        """
        close stream
        :return: true if successful
        """
        self.writer.close()