import random
import base64
import json
import os
import datetime


def generate_random_id(_s=set()):
    while (new_id := base64.b32encode(bytearray(random.randint(0, 0xFF) for _ in range(10)))[:16].decode().lower()) in _s:
        pass
    _s.add(new_id)
    return new_id


class Model(object):
    class ApiMethod:
        dict = dict()

        def __init__(self, fun):
            self.dict[fun.__name__] = fun

        def __contains__(self, item):
            return item in self.dict

    def __init__(self, filename="tehmodel.json"):
        self.sockets = {}  # mapping: client -> socket
        self.filename = filename
        self.model = None
        if os.path.isfile(filename):
            with open(filename) as f:
                try:
                    self.model = json.load(f)
                except:
                    self.model = {}
        else:
            self.model = {}
        self.assert_model()

    def assert_model(self):
        if not "clients" in self.model:
            self.model["clients"] = {}
        if not "sessions" in self.model:
            self.model["sessions"] = {}

    @ApiMethod
    async def test_api(self, clientid):
        print(f'test_api {clientid=}')

    @ApiMethod
    async def test_yeet(self, clientid):
        raise Exception('yeet')

    @ApiMethod
    async def change_username(self, clientid, username) -> str:
        self.model["clients"][clientid]["username"] = username
        await self.send_state(clientid)

    @ApiMethod
    async def create_session(self, clientid) -> str:
        sessionname = generate_random_id()
        newsession = {"id": sessionname, "owner": clientid, "clients": []}
        self.model["sessions"][sessionname] = newsession
        await self.send_state(clientid)

    @ApiMethod
    async def join_session(self, clientid, sessionid):
        if sessionid in self.model["sessions"]:
            # remove old session
            if "session" in self.model["clients"][clientid]:
                oldsession = self.model["clients"][clientid]["session"]
                self.model["sessions"][oldsession]["clients"].remove(clientid)

            self.model["sessions"][sessionid]["clients"].append(clientid)
            self.model["clients"][clientid]["session"] = sessionid
            await self.send_state(clientid)
        else:
            raise Exception(f"Session {sessionid} does not exist")

    async def send_state(self, clientid):
        # TODO: compute state, send to client
        session = "No session"
        if "session" in self.model["clients"][clientid]:
            session = self.model["clients"][clientid]["session"]
        allsessions = [ name for name in self.model["sessions"] ]
        username = self.model["clients"][clientid]["username"] if "username" in self.model["clients"][clientid] else "Joe"
        data = {"currentsession": session, "allsessions": allsessions, "username": username}
        for socket in self.sockets[clientid]:
            await socket.send_json(data)

    def save(self):
        with open(self.filename, "w") as f:
            json.dump(self.model, f)
        if not os.path.isdir("backups"):
            try:
                os.mkdir("backups")
            except FileExistsError:
                print("backups is a file, no directory. Please delete yourself")
        datestring = datetime.datetime.strftime(datetime.datetime.now(), "%Y-%m-%d-%H%M%S")
        with open(f"backups/{datestring}_{self.filename}", "w") as f:
            json.dump(self.model, f)

    def exists_client(self, clientid: str) -> bool:
        return clientid in self.model["clients"]

    def create_client(self, name="Joe") -> str:
        clientname = generate_random_id()
        newclient = {"id": clientname, "username": name}
        self.model["clients"][clientname] = newclient
        return clientname

    async def subscribe(self, clientid, socket):
        if not clientid in self.sockets:
            self.sockets[clientid] = []
        self.sockets[clientid].append(socket)
        await self.send_state(clientid)

    def unsubscribe(self, socket):
        for client in self.sockets:
            if socket in self.sockets[client]:
                self.sockets[client].remove(socket)