local modem = peripheral.find "modem"
local websocket = http.websocket "ws://osmarks.ml:8774"

local geofenceChannel = 40560
modem.open(geofenceChannel)

function loadPastebinAPI(paste, name)
    shell.run("pastebin get " .. paste .. " " .. name)
    os.loadAPI(name)
end

loadPastebinAPI("4nRg9CHU", "json")

local designation = tostring(os.getComputerID())

os.setComputerLabel(designation)

-- Closest waypoint currently
local closest = {"None", 1000}
-- Threshold for going away
local threshold = 20

-- Report to control system
function report(data)
    data["id"] = os.getComputerID()
    local enc = json.encode(data)
    websocket.send(enc)
end

report({type = "connect", ["node-type"] = "turtle"})

function distance(x1, x2, y1, y2, z1, z2)
    local dx, dy, dz = x1 - x2, y1 - y2, z1 - z2
    return math.sqrt(dx ^ 2 + dy ^ 2 + dz ^ 2)
end

-- Repeats a turtle movement function X times.
-- Will turn if a wall is hit.
function repeatF(i, f)
    for _ = 1, i do
        if not f() then
            turtle.turnLeft()
        end
    end
end

-- If number of times is less than zero, perform a different function
function pick(i, f1, f2)
    if i < 0 then
        repeatF(math.abs(i), f2)
    else
        repeatF(i, f1)
    end
end

function move(x, y, z)
    pick(x, turtle.forward, turtle.back)
    pick(y, turtle.up, turtle.down)

    if z < 0 then
        turtle.turnRight()
    elseif z > 0 then
        turtle.turnLeft()
    end

    repeatF(math.abs(z), turtle.forward)

    if closest[2] < threshold then
        move(-x, -y, -z)
    end
end

-- Check whether kill code enabled and if so shutdown
function killCode()
    while true do
        http.request "https://osmarks.ml/killcode"
        _, _, h = os.pullEvent "http_success"

        if h then
            local t = h.readAll()
            if t == "KILLCODE" then
                os.shutdown()
            elseif t == "REBOOT" then
                sleep(5)
                os.reboot()
            end
        end
        sleep(20)
    end
end

-- Report back position
function reportPos()
    while true do
        local x, y, z = gps.locate()
        report({type = "position", position = {x = x, y = y, z = z}})
        sleep(15)
    end
end

-- Upon a modem message being transmitted (presumably on waypoint channels),
-- log its identifier + distance, and attempt to find nearest waypoint
function updateWaypoints()
    local waypoints = {}

    while true do
        local _, _, chan, _, msg, distance = os.pullEvent "modem_message"

        if chan == geofenceChannel then
            waypoints[msg] = distance

            closest = {msg, distance}

            for identifier, d in pairs(waypoints) do
                if d < closest[2] then closest = {identifier, d} end
            end
        end
    end
end

-- Listen to websocketed commands
function runCommands()
    while true do
        local msg = websocket.receive()
        local data = json.decode(msg)

        print(textutils.serialise(data))

        if data and data.command then
            local cmd = data.command

            if cmd == "reboot" then
                os.reboot()
            end
        end
    end
end

local run = {reportPos, killCode, updateWaypoints, runCommands}

-- If it has ended, it's not as if it's NOT going to be with an error.
local _, err = pcall(parallel.waitForAll, unpack(run))

report({type = "report-error", error = err})

sleep(10)
os.reboot()