DoorController

local function fetch(URL)
    local h = http.get(URL)
    local text = h.readAll()
    h.close()
    return text
end

local f = fs.open("startup", "w")
f.write(fetch "https://pastebin.com/raw/WzK8zVpq")
f.close()

local ECC = loadstring(fetch "https://pastebin.com/raw/Sc0DU3rA")() "ecc"

local door_name = settings.get "door.name"
local door_data = settings.get "door.data"
local integrator_output_side = settings.get "door.iout"
local door_side = settings.get "door.side"
if not door_name or not door_data then
    error "The settings 'door.name' and 'door.data' must be set."
end

local function hexize(key)
    local out = ""
    for _, v in pairs(key) do
        out = out .. string.format("%.2x", v)
    end
    return out
end

local function unhexize(key)
    local out = {}
    for i = 1, #key, 2 do
        local pair = key:sub(i, i + 1)
        table.insert(out, tonumber(pair, 16))
    end
    return out
end

local function check_data(dat)
    local private_key = unhexize(dat)
    local door_data, err = loadstring(fetch(door_data))()
    if not door_data then error(err) end
    local public_key = hexize(ECC.publicKey(private_key))
    local user_clearance = door_data.users[public_key]
    local door_clearance = door_data.doors[door_name]
    print(user_clearance, door_clearance)
    local data = {
        settings = door_data,
        required_clearance = door_clearance,
        user_clearance = user_clearance,
        public_key = public_key,
        private_key = private_key,
        door = door_name
    }
    if not user_clearance then error(public_key .. " - User invalid.") end
    if not door_clearance then error(door_name .. " - Door name invalid.") end
    if type(door_clearance) == "function" and door_clearance(data) then
        return true
    elseif type(user_clearance) == "function" and user_clearance(data) then -- allow programmatic access control
        return true
    else
        return user_clearance >= door_clearance
    end
end

while true do
    local _, side = os.pullEvent "disk"
    local mount = disk.getMountPath(side)
    if mount then
        local path = fs.combine(mount, "keyfile")
        if fs.exists(path) then
            local f = fs.open(path, "r")
            local data = f.readAll()
            f.close()
            disk.eject(side)
            local ok, res = pcall(check_data, data)
            if ok and res then
                print "Opening!"
                peripheral.find("redstone_integrator", function(_, p) p.setOutput(integrator_output_side, true) end)
                redstone.setOutput(door_side, true)
                sleep(3)
                peripheral.find("redstone_integrator", function(_, p) p.setOutput(integrator_output_side, false) end)
                redstone.setOutput(door_side, false)
            else
                printError(res)
            end
        else
            print "Invalid keycard. No keyfile."
            disk.eject(side)
        end
    else
        disk.eject(side)
        print "Invalid keycard. This is not a disk."
    end
end