local component = require("component")
local event = require("event")
local emerald = require("emerald")
local fs = require("filesystem")
local ser = require("serialization")
local term = require("term")

local data = component.data
local permdata = {}

-- LOG FUNCTION --
local function log(f, m)
  print(f..": "..m)
end

-- READ FUNCTION -- (Read the permissions file)
local function read()
  if fs.exists("/home/.sectec.data") then
    local file = io.open(".sectec.data")
    local stream = file:read()
    file:close()
    return ser.unserialize(stream)
  else
    log("ERR", "No config file.")
    return false
  end
end

-- WRITE FUNCTION -- (Write in the permissions file)
local function write()
  local file = io.open(".sectec.data", "w")
  file:write(ser.serialize(permdata))
  file:close()
end

permdata = read()
local prikey = data.deserializeKey(permdata.keys.pri, "ec-private")
local pubkey = data.deserializeKey(permdata.keys.pub, "ec-public")

-- ADMIN FUNCTIONS --
local function admin(user)
  log("ADMIN", user.name.." FROM "..user.alias)
  if user.cmd == "addusr" then
    permdata[user.who] = {}
    emerald.send(user.alias, data.ecdsa(data.md5(user.who), prikey))
    log("ADDUSR", user.who)
  elseif user.cmd == "delusr" then
    permdata[user.who] = nil
    emerald.send(user.alias, "DELUSR")
    log("DELUSR", user.who)
  elseif user.cmd == "addperm" then
    if permdata[user.who] then
      permdata[user.who][user.what] = true
      emerald.send(user.alias, "ADDPERM")
      log("ADDPERM", user.what.." TO "..user.who)
    end
  elseif user.cmd == "delperm" then
    if permdata[user.who] then
      permdata[user.who][user.what] = nil
      emerald.send(user.alias, "DELPERM")
      log("DELPERM", user.what.." TO "..user.who)
    end
  elseif user.cmd == "gethash" then
    emerald.send(user.alias, data.ecdsa(data.md5(user.who), prikey))
    log("GETHASH", user.who)
  end
  write()
end

term.clear()

emerald.connect()

while true do
  local _, flag, mess = event.pull("emerald")
  if flag == "MSG" then -- If emerald pushes a message
    local user = ser.unserialize(mess)
    if user.name == "keys" then
      log("ERR", "ABORT")
    elseif data.ecdsa(data.md5(user.name), pubkey, user.hash) then -- If the security hash is correct
      if permdata[user.name][user.perm] then -- Check the permission for the user
        if user.perm == "ADMIN" then
          admin(user)
        else
          emerald.send(user.alias, "GRANTED")
          log("GRANTED", user.name.." FROM "..user.alias)
        end
      else
        emerald.send(user.alias, "DENIED")
        log("DENIED", user.name.." FROM "..user.alias)
      end
    else
      emerald.send(user.alias, "SPOOF")
      log("SPOOF", user.name.." FROM "..user.alias)
    end
  else
    log(flag, mess)
  end
end