local component = require("component")
local event = require("event")
local term = require("term")
local thread = require("thread")

local modem = component.modem

-- Constants
local PORT = 1
local PING = "ping"
local PONG = "pong"

local devices = {}

-- Open port if needed
if modem.isOpen(PORT) == false then
  modem.open(PORT)
  print("PORT '" .. PORT .. "' opened successfully!")
end

-- Read whole file
local function readAll(file)
    local f = assert(io.open(file, "r"))

    local content = f:read("*all")
    f:close()
    return content
end

-- Quit our program
local function quit()
  os.exit(1)
end

-- Remove the first element of a table
local function reorderParameters(parameters)
  local reordered = {}
  for k, param in pairs(parameters) do
    if k > 1 then
      reordered[k-1] = param
    end
  end

  return reordered
end

-- Send network message to all registered devices
local function sendToDevices(...)
  for _, device in pairs(devices) do
    modem.broadcast(PORT, ...)
  end
end

-- Commands
local commands = {
  -- Find all IoT devices
  discover = function()
    devices = {}

    local collectThread = thread.create(function()
      print("Discover Internet of Things...")
      modem.broadcast(PORT, PING)
      while true do
        local _, _, remoteAddress, _, _, payload = event.pull("modem_message")
        if payload == PONG then
          table.insert(devices, remoteAddress)
        end
      end
    end)

    -- Wait some seconds and kill the thread
    collectThread:join(2)
    collectThread:kill()
    print(#devices .. " devices found!")
  end,
  -- Load program from filesystem and execute on all devices
  executefile = function(filename)
    if not filename then
      print("Usage:")
      print("executeFile <filename>")
      return false
    end
    local program = readAll(filename)

    if program == nil then
      print("File not found!")
      return false
    end

    print("Execute '" .. filename .. "' on " .. #devices .. " devices...")
    sendToDevices(tostring(program))
  end,
  clear = function()
    term.clear()
  end
}
-- Find devices on startup
commands.discover()

-- Terminal history for up and down navigation
local history = {}

--  Main loop
while term.isAvailable() do
  -- Prefix input field
  io.write("\27[33mcommand> \27[37m")

  -- Read input
  local input = term.read(history)
  if not input then quit() end

  -- Push input to history
  table.insert(history, input)

  -- Get command parameters
  local parameters = {}
  for param in input:gmatch("%S+") do
    table.insert(parameters, param)
  end

  -- Define our command
  local command = parameters[1]

  -- Remove command from parameters
  parameters = reorderParameters(parameters)

  -- Check whether the command does not exist or should be called
  if commands[command] == nil then
    print("Command not found!")
  else
    pcall(commands[command], table.unpack(parameters))
  end
end