#!/usr/bin/python

import json

from typing import Union, Optional
from pathlib import Path
from contextlib import asynccontextmanager as acm

import pynng

from pynng import TLSConfig

from ..types import SkynetRPCRequest, SkynetRPCResponse
from ..constants import *


class ConfigRequestFormatError(BaseException):
    ...

class ConfigUnknownAttribute(BaseException):
    ...

class ConfigUnknownAlgorithm(BaseException):
    ...

class ConfigUnknownUpscaler(BaseException):
    ...

class ConfigSizeDivisionByEight(BaseException):
    ...


async def rpc_call(
    sock,
    uid: Union[int, str],
    method: str,
    params: dict = {}
):
    req = SkynetRPCRequest(
        uid=uid,
        method=method,
        params=params
    )
    await sock.asend(
        json.dumps(
            req.to_dict()).encode())

    return SkynetRPCResponse(
        **json.loads(
            (await sock.arecv_msg()).bytes.decode()))


@acm
async def open_skynet_rpc(
    rpc_address: str = DEFAULT_RPC_ADDR,
    security: bool = False,
    cert_name: Optional[str] = None,
    key_name: Optional[str] = None
):
    tls_config = None
    if security:
        # load tls certs
        if not key_name:
            key_name = certs_name
        certs_dir = Path(DEFAULT_CERTS_DIR).resolve()
        skynet_cert = (certs_dir / 'brain.cert').read_text()
        tls_cert = (certs_dir / f'{cert_name}.cert').read_text()
        tls_key = (certs_dir / f'{key_name}.key').read_text()
        rpc_address = 'tls+' + rpc_address
        tls_config = TLSConfig(
            TLSConfig.MODE_CLIENT,
            own_key_string=tls_key,
            own_cert_string=tls_cert,
            ca_string=skynet_cert)

    with pynng.Req0() as sock:
        if security:
            sock.tls_config = tls_config

        sock.dial(rpc_address)
        async def _rpc_call(*args, **kwargs):
            return await rpc_call(sock, *args, **kwargs)

        yield _rpc_call


def validate_user_config_request(req: str):
    params = req.split(' ')

    if len(params) < 3:
        raise ConfigRequestFormatError('config request format incorrect')

    else:
        try:
            attr = params[1]

            if attr == 'algo':
                val = params[2]
                if val not in ALGOS:
                    raise ConfigUnknownAlgorithm(f'no algo named {val}')

            elif attr == 'step':
                val = int(params[2])
                val = max(min(val, MAX_STEP), MIN_STEP)

            elif attr  == 'width':
                val = max(min(int(params[2]), MAX_WIDTH), 16)
                if val % 8 != 0:
                    raise ConfigSizeDivisionByEight(
                        'size must be divisible by 8!')

            elif attr  == 'height':
                val = max(min(int(params[2]), MAX_HEIGHT), 16)
                if val % 8 != 0:
                    raise ConfigSizeDivisionByEight(
                        'size must be divisible by 8!')

            elif attr == 'seed':
                val = params[2]
                if val == 'auto':
                    val = None
                else:
                    val = int(params[2])

            elif attr == 'guidance':
                val = float(params[2])
                val = max(min(val, MAX_GUIDANCE), 0)

            elif attr == 'upscaler':
                val = params[2]
                if val == 'off':
                    val = None
                elif val != 'x4':
                    raise ConfigUnknownUpscaler(
                        f'\"{val}\" is not a valid upscaler')

            else:
                raise ConfigUnknownAttribute(
                    f'\"{attr}\" not a configurable parameter')

            return attr, val, f'config updated! {attr} to {val}'

        except ValueError:
            raise ValueError(f'\"{val}\" is not a number silly')