receiver

local COMMAND_PROTOCOL = "controller.command"
local REQUEST_PROTOCOL = "controller.request"
local RESPONSE_PROTOCOL = "controller.response"

local ERR_PROCESS_COMMAND = "\nError running command '%s';\n%s"

local DIRECTION_FUNCTIONS = {
    move = {
        turtle.up,
        turtle.forward,
        turtle.down,
        turtle.back,
        turtle.turnLeft,
        turtle.turnRight,
    },
    dig = {
        turtle.digUp,
        turtle.dig,
        turtle.digDown,
    },
    place = {
        turtle.placeUp,
        turtle.place,
        turtle.placeDown,
    },
    drop = {
        turtle.dropUp,
        turtle.drop,
        turtle.dropDown,
    },
    suck = {
        turtle.suckUp,
        turtle.suck,
        turtle.suckDown,
    },
    attack = {
        turtle.attackUp,
        turtle.attack,
        turtle.attackDown,
    },
}

---@type table<string, fun(...: rednet.transmittable): nil>
local COMMANDS = {
    -- run lua code
    loadstring = function(code)
        local func = loadstring(code)

        if func then
            func()
        end
    end,
    -- run a program
    program = function(name, args)
        shell.execute(name, args)
    end,

    -- move the turtle
    move = function(direction)
        DIRECTION_FUNCTIONS.move[tonumber(direction)]()
    end,
    -- dig a block
    dig = function(direction)
        DIRECTION_FUNCTIONS.dig[tonumber(direction)]()
    end,
    -- place a block
    place = function(direction, text)
        DIRECTION_FUNCTIONS.place[tonumber(direction)](text)
    end,
    -- select a slot
    select = function(slot)
        turtle.select(tonumber(slot))
    end,
    -- drop an item
    drop = function(direction, amount)
        DIRECTION_FUNCTIONS.drop[tonumber(direction)](amount)
    end,
    -- suck an item
    suck = function(direction, amount)
        DIRECTION_FUNCTIONS.suck[tonumber(direction)](amount)
    end,
    attack = function(direction, side)
        DIRECTION_FUNCTIONS.attack[tonumber(direction)](side)
    end,

    shutdown = os.shutdown,
    reboot = os.reboot,
}

local function awaitController()
    rednet.broadcast("connect", REQUEST_PROTOCOL)

    local id = rednet.receive(RESPONSE_PROTOCOL, 5)

    if not id then
        return awaitController()
    end

    return id
end

---@param command command|rednet.transmittable
local function processCommand(command)
    local key = command.key
    local func = COMMANDS[key]

    local success, err = pcall(func, unpack(command.arguments))

    if not success then
        printError(ERR_PROCESS_COMMAND:format(key, err))
    end
end

local function receiver()
    term.clear()
    term.setCursorPos(1, 1)

    peripheral.find("modem", rednet.open)

    print("Awaiting controller...")

    local activeControllerId = awaitController()

    print("Got controller.", activeControllerId)

    while true do
        local id, command = rednet.receive(COMMAND_PROTOCOL)

        if id == activeControllerId then
            processCommand(command)
        end
    end
end

receiver()