19 files changed, 613 insertions, 42 deletions
diff --git a/kennel/app.py b/kennel/app.py
new file mode 100644
index 0000000..98a0448
--- /dev/null
+++ b/kennel/app.py
@@ -0,0 +1,13 @@
+import structlog
+from fastapi import FastAPI
+from fastapi.templating import Jinja2Templates
+
+app = FastAPI(
+    servers = [
+        {"url": "https://kennel.hatecomputers.club", "description": "prod"}
+    ]
+)
+
+logger = structlog.get_logger()
+
+templates = Jinja2Templates(directory="templates")
diff --git a/kennel/config.py b/kennel/config.py
new file mode 100644
index 0000000..8cec699
--- /dev/null
+++ b/kennel/config.py
@@ -0,0 +1,20 @@
+from dotenv import load_dotenv
+import os
+
+load_dotenv()
+
+
+class Config:
+    SIMULATION_WIDTH = int(os.getenv("SIMULATION_WIDTH", 1000))
+    SIMULATION_HEIGHT = int(os.getenv("SIMULATION_HEIGHT", 1000))
+
+    HATECOMPUTERS_ENDPOINT = os.getenv(
+        "HATECOMPUTERS_ENDPOINT", "https://hatecomputers.club"
+    )
+
+    MIN_TIME_STEP = float(os.getenv("MIN_TIME_STEP", 0.05))
+
+    COOKIE_MAX_AGE = int(os.getenv("COOKIE_MAX_AGE", 60 * 60 * 24 * 7))  # 1 week
+
+
+config = Config()
diff --git a/kennel/engine/__init__.py b/kennel/engine/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/kennel/engine/__init__.py
diff --git a/kennel/engine/components/__init__.py b/kennel/engine/components/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/kennel/engine/components/__init__.py
diff --git a/kennel/engine/components/component.py b/kennel/engine/components/component.py
new file mode 100644
index 0000000..c8ef2d0
--- /dev/null
+++ b/kennel/engine/components/component.py
@@ -0,0 +1,16 @@
+from enum import Enum
+from abc import abstractmethod
+
+
+class ComponentType(str, Enum):
+    POSITION = "POSITION"
+    CONTROLLABLE = "CONTROLLABLE"
+
+
+class Component:
+    def __init__(self, component_type: ComponentType):
+        self.component_type = component_type
+
+    @abstractmethod
+    def dict(self) -> dict:
+        pass
diff --git a/kennel/engine/components/controllable.py b/kennel/engine/components/controllable.py
new file mode 100644
index 0000000..49b0557
--- /dev/null
+++ b/kennel/engine/components/controllable.py
@@ -0,0 +1,13 @@
+from .component import Component, ComponentType
+
+
+class Controllable(Component):
+    def __init__(self, by: str):
+        super().__init__(ComponentType.CONTROLLABLE)
+        self.by = by
+
+    def __repr__(self) -> str:
+        return f"Controllable(by={self.by})"
+
+    def dict(self) -> dict:
+        return {"by": self.by}
diff --git a/kennel/engine/components/position.py b/kennel/engine/components/position.py
new file mode 100644
index 0000000..2a4da4a
--- /dev/null
+++ b/kennel/engine/components/position.py
@@ -0,0 +1,14 @@
+from .component import Component, ComponentType
+
+
+class Position(Component):
+    def __init__(self, x: float, y: float):
+        super().__init__(ComponentType.POSITION)
+        self.x = x
+        self.y = y
+
+    def __repr__(self) -> str:
+        return f"Position(x={self.x}, y={self.y})"
+
+    def dict(self) -> dict:
+        return {"x": self.x, "y": self.y}
diff --git a/kennel/engine/entities/__init__.py b/kennel/engine/entities/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/kennel/engine/entities/__init__.py
diff --git a/kennel/engine/entities/cat.py b/kennel/engine/entities/cat.py
new file mode 100644
index 0000000..02fdb33
--- /dev/null
+++ b/kennel/engine/entities/cat.py
@@ -0,0 +1,33 @@
+#
+# # IDLE, FROLICKING, EEPY, ALERT, CHASING_CURSOR, CHASING_CAT, SCRATCHING, ITCHY
+# state_stochastic_matrix = [
+#     # IDLE
+#     [0.5, 0.1, 0.1, 0.1, 0.1, 0.05, 0.05, 0],
+#     # FROLICKING
+#     [0.1, 0.5, 0.1, 0.1, 0.1, 0.05, 0.05, 0],
+#     # EEPY
+#     [0.1, 0.1, 0.5, 0.1, 0.1, 0.05, 0.05, 0],
+#     # ALERT
+#     [0.1, 0.1, 0.1, 0.5, 0.1, 0.05, 0.05, 0],
+#     # CHASING_CURSOR
+#     [0.1, 0.1, 0.1, 0.1, 0.5, 0.05, 0.05, 0],
+#     # CHASING_CAT
+#     [0.1, 0.1, 0.1, 0.1, 0.1, 0.5, 0.05, 0],
+#     # SCRATCHING
+#     [0.1, 0.1, 0.1, 0.1, 0.1, 0.05, 0.5, 0],
+#     # ITCHY
+#     [0, 0, 0, 0, 0, 0, 0, 1],
+# ]
+#
+#
+# class CatState(Enum):
+#     IDLE = 0
+#     FROLICKING = 1
+#     EEPY = 2
+#     ALERT = 3
+#     CHASING_CURSOR = 4
+#     CHASING_CAT = 5
+#     SCRATCHING = 6
+#     ITCHY = 7
+#
+#
diff --git a/kennel/engine/entities/entity.py b/kennel/engine/entities/entity.py
new file mode 100644
index 0000000..0ca8666
--- /dev/null
+++ b/kennel/engine/entities/entity.py
@@ -0,0 +1,60 @@
+from enum import Enum
+from kennel.engine.components.component import Component, ComponentType
+from typing import List, Optional
+
+
+class EntityType(str, Enum):
+    LASER = "LASER"
+
+
+class Entity:
+    def __init__(
+        self, entity_type: EntityType, id: str, component_list: List[Component]
+    ):
+        self.entity_type = entity_type
+        self.id = id
+        self.components = {}
+        for component in component_list:
+            self.add_component(component)
+
+    def get_component(self, component_type: ComponentType) -> Optional[Component]:
+        return self.components[component_type]
+
+    def add_component(self, component: Component) -> None:
+        self.components[component.component_type] = component
+
+
+class EntityManager:
+    def __init__(self):
+        self.entities = {}
+        self.component_entities = {}
+
+    def update(self) -> None:
+        self.component_entities = {}
+        for entity in self.entities.values():
+            for component in entity.components.values():
+                if component.component_type not in self.component_entities:
+                    self.component_entities[component.component_type] = set()
+                self.component_entities[component.component_type].add(entity)
+
+    def get_entities_with_component(
+        self, component_type: ComponentType
+    ) -> List[Entity]:
+        return self.component_entities.get(component_type, [])
+
+    def add_entity(self, entity: Entity) -> None:
+        self.entities[entity.id] = entity
+        for component in entity.components.values():
+            if component.component_type not in self.component_entities:
+                self.component_entities[component.component_type] = set()
+            self.component_entities[component.component_type].add(entity)
+
+    def remove_entity(self, entity_id: str) -> None:
+        if entity_id in self.entities:
+            entity = self.entities[entity_id]
+            for component in entity.components.values():
+                if component.component_type in self.component_entities:
+                    self.component_entities[component.component_type].remove(entity)
+
+    def get_entity(self, entity_id: str) -> Optional[Entity]:
+        return self.entities.get(entity_id)
diff --git a/kennel/engine/entities/laser.py b/kennel/engine/entities/laser.py
new file mode 100644
index 0000000..ead72a6
--- /dev/null
+++ b/kennel/engine/entities/laser.py
@@ -0,0 +1,13 @@
+from .entity import Entity, EntityType
+from kennel.engine.components.position import Position
+from kennel.engine.components.controllable import Controllable
+
+
+class Laser(Entity):
+    def __init__(self, id: str, controllable_by: str):
+        components = [
+            Position(0, 0),
+            Controllable(controllable_by),
+        ]
+
+        super().__init__(EntityType.LASER, id, components)
diff --git a/kennel/engine/game.py b/kennel/engine/game.py
new file mode 100644
index 0000000..2236306
--- /dev/null
+++ b/kennel/engine/game.py
@@ -0,0 +1,53 @@
+from kennel.engine.entities.entity import EntityManager
+from kennel.engine.systems.system import SystemManager
+from kennel.app import logger
+from typing import List, Optional
+import time
+import asyncio
+
+
+class Game:
+    def __init__(
+        self,
+        entity_manager: EntityManager,
+        system_manager: SystemManager,
+        min_time_step: float,
+    ):
+        self.entity_manager = entity_manager
+        self.system_manager = system_manager
+        self.min_time_step = min_time_step
+
+        self.last_time = time.time()
+        self.running = False
+
+    async def update(self, delta_time: float) -> None:
+        self.entity_manager.update()
+        await self.system_manager.update(self.entity_manager, delta_time)
+
+    async def run(self) -> None:
+        logger.info("Game started")
+        self.running = True
+        self.last_time = time.time()
+        steps_since_log = 0
+
+        while self.running:
+            current_time = time.time()
+            if (int(current_time) - int(self.last_time)) == 1 and int(
+                current_time
+            ) % 10 == 0:
+                logger.info(f"Game loop: {steps_since_log} steps since last log time")
+                steps_since_log = 0
+
+            delta_time = current_time - self.last_time
+            self.last_time = current_time
+
+            await self.update(delta_time)
+            await asyncio.sleep(
+                max(self.min_time_step - (time.time() - current_time), 0)
+            )
+
+            steps_since_log += 1
+
+    def stop(self) -> None:
+        self.running = False
+        logger.info("Game stopped")
diff --git a/kennel/engine/systems/__init__.py b/kennel/engine/systems/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/kennel/engine/systems/__init__.py
diff --git a/kennel/engine/systems/network.py b/kennel/engine/systems/network.py
new file mode 100644
index 0000000..7df8088
--- /dev/null
+++ b/kennel/engine/systems/network.py
@@ -0,0 +1,88 @@
+from enum import Enum
+from kennel.engine.entities.entity import EntityManager
+from .system import System, SystemType
+from abc import abstractmethod
+import asyncio
+
+
+class EventType(str, Enum):
+    ENTITY_BORN = "ENTITY_BORN"
+    ENTITY_POSITION_UPDATE = "ENTITY_POSITION_UPDATE"
+    ENTITY_DEATH = "ENTITY_DEATH"
+
+
+class Event:
+    def __init__(self, event_type: EventType, data: dict):
+        self.event_type = event_type
+        self.data = data
+
+    def __str__(self):
+        return f"Event({self.event_type}, {self.data})"
+
+    def dict(self):
+        return {"event_type": self.event_type, "data": self.data}
+
+    @staticmethod
+    def from_dict(data: dict):
+        return Event(EventType(data["event_type"]), data["data"])
+
+
+class Publishable:
+    @abstractmethod
+    async def publish(self, event: Event):
+        pass
+
+
+class ClientEventTransformer:
+    @abstractmethod
+    def apply(self, event: Event) -> Event:
+        pass
+
+
+class EventProcessor:
+    @abstractmethod
+    def accept(self, entity_manager: EntityManager, event: Event) -> None:
+        pass
+
+
+class NetworkSystem(System):
+    def __init__(
+        self,
+        event_processor: EventProcessor,
+        client_event_transformer: ClientEventTransformer,
+    ):
+        super().__init__(SystemType.NETWORK)
+        self.event_processor = event_processor
+        self.client_event_transformer = client_event_transformer
+
+        self.events = []
+        self.clients = {}
+
+    async def update(self, entity_manager: EntityManager, delta_time: float) -> None:
+        for event in self.events:
+            self.event_processor.accept(entity_manager, event)
+        client_events = [
+            self.client_event_transformer.apply(entity_manager, event)
+            for event in self.events
+        ]
+        await asyncio.gather(
+            *[
+                client.publish(event)
+                for client in self.clients.values()
+                for event in client_events
+            ]
+        )
+        self.events = []
+
+    def client_event(self, client_id: str, event: Event) -> None:
+        event.data["client_id"] = client_id
+        self.events.append(event)
+
+    def add_event(self, event: Event) -> None:
+        self.events.append(event)
+
+    def add_client(self, client_id: str, client: Publishable) -> None:
+        self.clients[client_id] = client
+
+    def remove_client(self, client_id: str) -> None:
+        del self.clients[client_id]
diff --git a/kennel/engine/systems/system.py b/kennel/engine/systems/system.py
new file mode 100644
index 0000000..0e51f3a
--- /dev/null
+++ b/kennel/engine/systems/system.py
@@ -0,0 +1,31 @@
+from enum import Enum
+from kennel.engine.entities.entity import EntityManager
+from abc import abstractmethod
+
+
+class SystemType(str, Enum):
+    NETWORK = "NETWORK"
+
+
+class System:
+    def __init__(self, system_type: SystemType):
+        self.system_type = system_type
+
+    @abstractmethod
+    async def update(self, entity_manager: EntityManager, delta_time: float):
+        pass
+
+
+class SystemManager:
+    def __init__(self):
+        self.systems = {}
+
+    def add_system(self, system: System) -> None:
+        self.systems[system.system_type] = system
+
+    def get_system(self, system_type: SystemType) -> System:
+        return self.systems.get(system_type)
+
+    async def update(self, entity_manager: EntityManager, delta_time: float) -> None:
+        for system in self.systems.values():
+            await system.update(entity_manager, delta_time)
diff --git a/kennel/kennel.py b/kennel/kennel.py
new file mode 100644
index 0000000..0b38261
--- /dev/null
+++ b/kennel/kennel.py
@@ -0,0 +1,81 @@
+from kennel.engine.game import Game
+from kennel.engine.components.component import ComponentType
+from kennel.engine.entities.entity import EntityManager, Entity
+from kennel.engine.entities.laser import Laser
+from kennel.engine.systems.system import SystemManager
+from kennel.engine.systems.network import (
+    NetworkSystem,
+    EventProcessor,
+    ClientEventTransformer,
+    Event,
+    EventType,
+)
+from kennel.config import config
+from .app import logger
+from typing import List
+import uuid
+
+entity_manager = EntityManager()
+system_manager = SystemManager()
+
+
+class KennelEventProcessor(EventProcessor):
+    def accept(self, entity_manager: EntityManager, event: Event) -> None:
+        if event.event_type == EventType.ENTITY_POSITION_UPDATE:
+            self._process_entity_position_update(entity_manager, event)
+
+    def _process_entity_position_update(
+        self, entity_manager: EntityManager, event: Event
+    ) -> None:
+        entity = entity_manager.get_entity(event.data["entity_id"])
+        if entity is None:
+            logger.error(f"Entity {event.data['entity_id']} does not exist")
+            return
+        if event.data["client_id"] is None:
+            logger.error("Client ID is required for position updates")
+            return
+        controllable = entity.get_component(ComponentType.CONTROLLABLE)
+        if controllable is None:
+            logger.error(f"Entity {entity} is not controllable")
+            return
+        if controllable.by != event.data["client_id"]:
+            logger.error(
+                f"Entity {entity} is not controllable by client {event.data['client_id']}"
+            )
+            return
+        position = entity.get_component(ComponentType.POSITION)
+        if position is None:
+            logger.error(f"Entity {entity} has no position")
+            return
+        entity.add_component(position)
+
+
+class KennelClientEventTransformer(ClientEventTransformer):
+    def apply(self, entity_manager: EntityManager, event: Event) -> Event:
+        if event.event_type == EventType.ENTITY_BORN:
+            id = event.data["id"]
+            entity = entity_manager.get_entity(id)
+            if entity is None:
+                logger.error(f"Entity {id} does not exist")
+                return event
+            for component_type in entity.components:
+                if component_type == ComponentType.CONTROLLABLE:
+                    # Do not send controllable components to clients
+                    continue
+                component = entity.get_component(component_type)
+                if component is not None:
+                    event.data[component_type] = component.dict()
+
+        return event
+
+
+system_manager.add_system(
+    NetworkSystem(EventProcessor(), KennelClientEventTransformer())
+)
+
+kennel = Game(entity_manager, system_manager, config.MIN_TIME_STEP)
+
+
+def create_session_controllable_entities(session: str) -> List[Entity]:
+    laser = Laser(uuid.uuid4().hex, session)
+    return [laser]
diff --git a/kennel/kennelcats.py b/kennel/kennelcats.py
new file mode 100644
index 0000000..340b07e
--- /dev/null
+++ b/kennel/kennelcats.py
@@ -0,0 +1,45 @@
+from datetime import datetime
+from typing import List
+import requests
+
+
+class KennelCat:
+    def __init__(
+        self,
+        id: str,
+        user_id: str,
+        name: str,
+        link: str,
+        description: str,
+        spritesheet: str,
+        created_at: datetime,
+    ):
+        self.id = id
+        self.user_id = user_id
+        self.name = name
+        self.link = link
+        self.description = description
+        self.spritesheet = spritesheet
+        self.created_at = created_at
+
+    @staticmethod
+    def from_dict(dict: dict) -> "KennelCat":
+        return KennelCat(
+            id=dict["id"],
+            user_id=dict["user_id"],
+            name=dict["name"],
+            link=dict["link"],
+            description=dict["description"],
+            spritesheet=dict["spritesheet"],
+            created_at=datetime.fromisoformat(dict["created_at"]),
+        )
+
+
+class KennelCatService:
+    def __init__(self, endpoint: str):
+        self.endpoint = endpoint
+
+    def get_kennel(self) -> List[KennelCat]:
+        response = requests.get(f"{self.endpoint}/kennel")
+        response.raise_for_status()
+        return [KennelCat.from_dict(cat) for cat in response.json()]
diff --git a/kennel/main.py b/kennel/main.py
index 183fb64..122e40a 100644
--- a/kennel/main.py
+++ b/kennel/main.py
@@ -1,57 +1,118 @@
+from fastapi import (
+    FastAPI,
+    Request,
+    Response,
+    WebSocket,
+    WebSocketException,
+    status,
+    Cookie,
+    Depends,
+)
+from fastapi.staticfiles import StaticFiles
+from kennel.engine.systems.system import SystemType
+from kennel.engine.systems.network import Event, Publishable, EventType
+from typing import Annotated, Optional
+from .kennel import (
+    kennel,
+    system_manager,
+    entity_manager,
+    create_session_controllable_entities,
+)
+from .app import app, templates, logger
+from .kennelcats import KennelCatService
+from .middleware import logger_middleware
+from .config import config
+import asyncio
 import uuid
 
-import structlog
-from fastapi import FastAPI, Request, Response
-from fastapi.staticfiles import StaticFiles
-from fastapi.templating import Jinja2Templates
+app.mount("/static", StaticFiles(directory="static"), name="static")
 
-app = FastAPI(
-    servers = [
-        {"url": "https://kennel.hatecomputers.club", "description": "prod"}
-    ]
-)
-logger = structlog.get_logger()
+loop = asyncio.get_event_loop()
 
 
-@app.middleware("http")
-async def logger_middleware(request: Request, call_next):
-    structlog.contextvars.clear_contextvars()
-    structlog.contextvars.bind_contextvars(
-        path=request.url.path,
-        method=request.method,
-        client_host=request.client.host,
-        request_id=str(uuid.uuid4()),
-    )
-    response = await call_next(request)
+@app.on_event("startup")
+async def startup_event():
+    logger.info("Starting Kennel...")
+    loop.create_task(kennel.run())
 
-    structlog.contextvars.bind_contextvars(
-        status_code=response.status_code,
-    )
 
-    # Exclude /healthcheck endpoint from producing logs
-    if request.url.path != "/healthcheck":
-        if 400 <= response.status_code < 500:
-            logger.warn("Client error")
-        elif response.status_code >= 500:
-            logger.error("Server error")
-        else:
-            logger.info("OK")
+@app.on_event("shutdown")
+async def shutdown_event():
+    logger.info("Stopping Kennel...")
+    kennel.stop()
+    loop.stop()
+    logger.info("Kennel stopped")
 
-    return response
 
-templates = Jinja2Templates(directory="templates")
+@app.get("/")
+async def index(request: Request):
+    return templates.TemplateResponse(request=request, name="index.html")
 
 
-@app.get("/healthcheck")
-async def healthcheck():
-    return Response("hello")
+@app.get("/assign")
+async def assign(
+    response: Response,
+    session: Annotated[Optional[str], Cookie()] = None,
+):
+    if session is None:
+        session = str(uuid.uuid4().hex)
+        response.set_cookie(key="session", value=session, max_age=config.COOKIE_MAX_AGE)
+    return {"session": session}
 
 
-@app.get("/")
-async def read_main(request: Request):
-    return templates.TemplateResponse(
-        request=request, name="index.html"
-    )
+async def get_cookie_or_token(
+    websocket: WebSocket,
+    session: Annotated[str | None, Cookie()] = None,
+):
+    if session is None:
+        raise WebSocketException(code=status.WS_1008_POLICY_VIOLATION)
+    return session
+
 
-app.mount("/static", StaticFiles(directory = "static"), name = "static")
+class WebSocketClient(Publishable):
+    def __init__(self, websocket: WebSocket):
+        self.websocket = websocket
 
+    async def publish(self, event: Event):
+        await self.websocket.send_json(event.dict())
+
+
+@app.websocket("/ws")
+async def websocket_endpoint(
+    websocket: WebSocket,
+    session: Annotated[str, Depends(get_cookie_or_token)],
+):
+    await websocket.accept()
+    logger.info(f"Websocket connection established for session {session}")
+
+    session_entities = create_session_controllable_entities(session)
+    try:
+        network_system = system_manager.get_system(SystemType.NETWORK)
+        if network_system is None:
+            raise "Network system not found"
+
+        for entity in session_entities:
+            logger.info(f"Adding entity {entity.id} for session {session}")
+            entity_manager.add_entity(entity)
+            network_system.add_event(Event(EventType.ENTITY_BORN, {"id": entity.id}))
+
+        network_system.add_client(session, WebSocketClient(websocket))
+        while True:
+            message = await websocket.receive_json()
+            network_system.client_event(session, Event.from_dict(message))
+    except Exception as e:
+        logger.error(f"WebSocket exception {e}")
+    finally:
+        logger.info("Websocket connection closed")
+        for entity in session_entities:
+            logger.info(f"Removing entity {entity.id} for session {session}")
+            entity_manager.remove_entity(entity.id)
+            network_system.add_event(Event(EventType.ENTITY_DEATH, {"id": entity.id}))
+
+        network_system.remove_client(session)
+        await websocket.close()
+
+
+@app.get("/healthcheck")
+async def healthcheck():
+    return Response("healthy")
diff --git a/kennel/middleware.py b/kennel/middleware.py
new file mode 100644
index 0000000..dddf63b
--- /dev/null
+++ b/kennel/middleware.py
@@ -0,0 +1,30 @@
+import uuid
+import structlog
+from fastapi import Request, Response
+from .app import app, logger
+
+@app.middleware("http")
+async def logger_middleware(request: Request, call_next):
+    structlog.contextvars.clear_contextvars()
+    structlog.contextvars.bind_contextvars(
+        path=request.url.path,
+        method=request.method,
+        client_host=request.client.host,
+        request_id=str(uuid.uuid4()),
+    )
+    response = await call_next(request)
+
+    structlog.contextvars.bind_contextvars(
+        status_code=response.status_code,
+    )
+
+    # Exclude /healthcheck endpoint from producing logs
+    if request.url.path != "/healthcheck":
+        if 400 <= response.status_code < 500:
+            logger.warn("Client error")
+        elif response.status_code >= 500:
+            logger.error("Server error")
+        else:
+            logger.info("OK")
+
+    return response