rcrf-wifi/ground-station.py

#!/usr/bin/env python

import asyncio
from websockets.server import serve

ADMIN_ID = "1234"

BOAT_STATE_INCTRL = 2
BOAT_STATE_AVAILABLE = 1
BOAT_STATE_LOCKED = 0
BOAT_STATE_TERMINATED = -1

Boats = []
Clients = []

async def echo_boats(client):
    """echo list of all not locked boats to client"""
    data = "boats:"
    for boat in Boats:
        if boat['state'] != BOAT_STATE_LOCKED and boat['state'] != BOAT_STATE_TERMINATED:
            data += str(boat['id']) + ";" + str(boat['name']) + ";"
            if boat["state"] == BOAT_STATE_AVAILABLE:
                data += 'available:'
            elif boat["state"] == BOAT_STATE_INCTRL:
                data += 'inctrl:'
    await client['ws'].send(data)

async def echo_locked_boats(client):
    """echo list of all locked boats to client"""
    if client['id'] == ADMIN_ID:
        data = "lockedBoats:"
        for boat in Boats:
            if boat['state'] == BOAT_STATE_LOCKED:
                data += str(boat['id']) + ";" + str(boat['name']) + ";locked:"
        await client['ws'].send(data + '\n')

async def echo_clients(client):
    """echo list of all clients to client"""
    if client['id'] == ADMIN_ID:
        data = "clients:"
        for clie in Clients:
            data += str(clie['id']) + ";" + str(clie['boat']) + ";" + str(clie['state']) + ":"
        await client['ws'].send(data + '\n')

async def take_controll(client, boat):
    """let a client take controll a boat"""
    if client['boat'] is not None:
        client['boat']["state"] = BOAT_STATE_AVAILABLE
        client["boat"] = None
    for b in Boats:
        if b['id'] == boat and b['state'] != BOAT_STATE_TERMINATED:
            if b['state'] == BOAT_STATE_AVAILABLE:
                b["state"] = BOAT_STATE_INCTRL
                print("take controll: " + str(client["id"]) + " -> " + b["name"])
                client["boat"] = b
                await client['ws'].send("OK")
                return
            else:
                break
    await client['ws'].send("FAIL")

async def free_boat(boat):
    """make boat available for next client"""
    for client in Clients:
        if client["boat"]['id'] == boat:
            client["boat"] = None
            break
    for b in Boats:
        if b['id'] == boat and b['state'] != BOAT_STATE_TERMINATED:
            if boat['state'] == BOAT_STATE_INCTRL:
                boat["state"] = BOAT_STATE_AVAILABLE
            break

async def lock_boat(boat):
    """lock a boat so client can't take controll over it"""
    for client in Clients:
        if client["boat"]['id'] == boat:
            client["boat"] = None
            break
    for b in Boats:
        if b['id'] == boat and b['state'] != BOAT_STATE_TERMINATED:
            boat["state"] = BOAT_STATE_LOCKED
            break



async def on_message(message, client):
    """handel for client messages"""
    data = message.replace('\n', '').split(';')
    if data[0] != client["id"]:
        print("invalid id: " + str(data[0]) + " != " + str(client["id"]))
    else:
        if   data[1] == "boats":
            await echo_boats(client)
        elif data[1] == "ctrl":
            await take_controll(client, data[2])
        elif data[1] == "end":
            await take_controll(client, -1)
        elif data[1] == "free":
            if client["id"] == ADMIN_ID:
                await free_boat(data[2])
        elif data[1] == "lock":
            if client["id"] == ADMIN_ID:
                await lock_boat(data[2])
        elif data[1] == "locked":
            await echo_locked_boats(client)
        elif data[1] == "kick":
            print("kick")
        elif data[1] == "clients":
            await echo_clients(client)
        elif data[1] == "d":
            if client['boat'] is None:
                print("WARN: controll cmd (" + client['id'] + ") to None: " + data[2])
            else:
                print("INFO: controll cmd (" + client['id'] + ") to " + client['boat']['name'] + ": " + data[2])
                await client['boat']['ws'].send("d:" + data[2] + "\n")
        else:
            print("WARN: invalid command (" + client['id'] + "): '" + data[1] + "'")

async def new_client(clientId, ws):
    """handler for every new client connection"""
    client = { "id": clientId, "boat": None, "ws": ws, "state": "active" }
    print("new client connected: " + client['id'])
    for clie in Clients:
        if clie['id'] == client['id']:
            clie['state'] = 'terminated'
    Clients.append(client)
    if client['id'] == ADMIN_ID:
        await echo_boats(client)
        await echo_locked_boats(client)
        await echo_clients(client)
    return client

async def new_boat(boatId, name, ws):
    """handler for every new boat connection"""
    boat = { "id": boatId, "name": name, "ws": ws, "state": BOAT_STATE_AVAILABLE }
    print("new boat connected: " + boatId)
    for bo in Boats:
        if bo['id'] == boat['id']:
            bo['state'] = BOAT_STATE_TERMINATED
            await bo['ws'].close()
    Boats.append(boat)
    return boat

async def run(ws, path):
    """hadeler for every new websocket connection"""
    client = None
    async for message in ws:
        message = message.split(';')
        if len(message) == 3 and message[1] == "4675":
            client = await new_client(message[0], ws)
            if client is not None:
                async for message in ws:
                    if client['state'] == 'active':
                        await on_message(message, client)
                    else:
                        break
            break
        elif (len(message) == 3 and message[1] == "3440"):
            client = await new_boat(message[0], message[2], ws)
            if client is not None:
                async for message in ws:
                    print("boat" + client['id'] + " says " + message)
            break

async def main():
    """main"""
    async with serve(run, "0.0.0.0", 8080):
        await asyncio.Future()

asyncio.run(main())