main.py

from typing import List

from fastapi import FastAPI, WebSocket, WebSocketDisconnect
from fastapi.responses import HTMLResponse

from pydantic import BaseModel

app = FastAPI()


class Coordinate(BaseModel):
    latitude: float = 0
    longitude: float = 0


class ConnectionManager:
    def __init__(self):
        self.active_connections: List[WebSocket] = []
        self.client_ids: list[int] = []
        self.markers: dict = {}

    async def connect(self, websocket: WebSocket):
        await websocket.accept()
        self.active_connections.append(websocket)

    def disconnect(self, websocket: WebSocket):
        self.active_connections.remove(websocket)

    async def broadcast(self, client_id: int, coordinate: str):
        self.client_ids.append(client_id)
        self.markers[client_id] = {
            "coordinate": coordinate,
            "marker_size": self.client_ids.index(client_id) + 40,
        }

        for connection in self.active_connections:
            await connection.send_json({
                "message": f"user {client_id}'s location: {coordinate}",
                "markers": self.markers
            })


manager = ConnectionManager()


@app.get("/")
async def get():
    with open("viewer.html", "r", encoding='utf-8') as f:
        html = f.read()
    return HTMLResponse(html)


@app.websocket("/ws/{client_id}")
async def websocket_endpoint(websocket: WebSocket, client_id: int):
    await manager.connect(websocket)
    try:
        while True:
            text = await websocket.receive_text()
            await manager.broadcast(client_id, text)

    except WebSocketDisconnect:
        manager.disconnect(websocket)
        del manager.markers[client_id]