# Auto-generated, do not edit

from msgcodec.codec import Codec
from msgcodec.messages import *
from typing import List
import io

class MessageCodec(Codec):

    def read_message_id(self, reader: io.BytesIO) -> int:
        """
        Read and return the first byte where the message id is encoded
        """
        id_ = self.read_uint(reader)
        return id_

    def encode(self, m: Message) -> bytes:
        ...

    def decode(self, b: bytes) -> Message:
        reader = io.BytesIO(b)
        return self.read_head_message(reader)

    @staticmethod
    def check_message_id(b: bytes) -> int:
        """
        todo: make it static and without reader. It's just the first byte
        Read and return the first byte where the message id is encoded
        """
        reader = io.BytesIO(b)
        id_ = Codec.read_uint(reader)

        return id_

    @staticmethod
    def decode_key(b) -> int:
        """
        Decode the message key (encoded with little endian)
        """
        try:
            decoded = int.from_bytes(b, "little", signed=False)
        except Exception as e:
            raise UnicodeDecodeError(f"Error while decoding message key (SessionID) from {b}\n{e}")
        return decoded

    def decode_detailed(self, b: bytes) -> List[Message]:
        reader = io.BytesIO(b)
        messages_list = list()
        messages_list.append(self.handler(reader, 0))
        if isinstance(messages_list[0], BatchMeta):
            # Old BatchMeta
            mode = 0
        elif isinstance(messages_list[0], BatchMetadata):
            # New BatchMeta
            mode = 1
        else:
            return messages_list
        while True:
            try:
                messages_list.append(self.handler(reader, mode))
            except IndexError:
                break
        return messages_list

    def handler(self, reader: io.BytesIO, mode=0) -> Message:
        message_id = self.read_message_id(reader)
        if mode == 1:
            # We skip the three bytes representing the length of message. It can be used to skip unwanted messages
            reader.read(3)
            return self.read_head_message(reader, message_id)
        elif mode == 0:
            # Old format with no bytes for message length
            return self.read_head_message(reader, message_id)
        else:
            raise IOError()

    def read_head_message(self, reader: io.BytesIO, message_id) -> Message:
<% $messages.each do |msg| %>
        if message_id == <%= msg.id %>:
            return <%= msg.name %>(
                <%= msg.attributes.map { |attr| 
                    "#{attr.name.snake_case}=self.read_#{attr.type.to_s}(reader)" }
                    .join ",\n                "
                %>
            )
<% end %>