rednet.open("right")

local f= fs.open("users","r")
local users = textutils.unserialize(f.readAll())
f.close()

f = fs.open("perms","r")
local perms = textutils.unserialize(f.readAll())
f.close()

local clients = {}

function getDir(file)
  return string.gsub(file,fs.getName(file)+"%/","")
end

function fix(file)
  if file:sub(1,1) == "/" then
    file = file:sub(2)
  end
  return file
end

function getPerms(file)
  if perms[fix(getDir(file))] then
    if perms[fix(file)] then
      return perms[fix(file)]
    else
      return perms[fix(getDir(file))]
    end
  else
    return {write="all",read="all"}
  end
end

function hasRead(file, user)
  local perms = getPerms(file).read
  if perms == "anon" then
    return true
  elseif perms == "logged_in" then
    return user~=nil
  elseif type(perms) == string
    for k,v in pairs(perms) do
      if user == v then return true end
    end
    return false
  end
end

function hasWrite(file, user)
  local perms = getPerms(file).write
  if perms == "anon" then
    return true
  elseif perms == "logged_in" then
    return user~=nil
  elseif type(perms) == string
    for k,v in pairs(perms) do
      if user == v then return true end
    end
    return false
  end
end

function put(id,data)
  local filename ,contents = string.gmatch(data,"^(.-):(.+)$")()

  if not hasWrite(clients[id].user) then
    print("User " .. clients[id].user .. " tried to write forbidden file " ..filename)
    return false
  else
    local f = fs.open(filename,"w")
    f.write(contents)
    f.close()
    return true
  end
end

function get(id,data)
  local filename = data

  if not hasRead(clients[id].user) then
    print("User " .. clients[id].user .. " tried to read forbidden file ".. filename)
  else
    local f = fs.open(filename,"r")
    rednet.send(id,"DATA " .. f.readAll())
    f.close()
  end
end

function auth(id,data)
  local u , pass = string.gmatch(data,"^(.-):(.+)$")()

  if pass == users[u] then
    print(u .. " connected with id ".. id)
    clients[id] = {user=u}
    return true
  else
    print("Attempt to log into " .. u .. " failed!")
    return false
  end
end

function host()
  while true do
    local clientID,msg = rednet.receive()
    print(clientID," ",msg)
    if msg:sub(1,7) == "CONNECT" then
      if auth(clientID,msg:sub(9)) then
        rednet.send(clientID,"ACCEPT")
      else
        rednet.send(clientID,"DENY")
      end
    elseif msg:sub(1,3) == "GET" then
      get(clientID,msg:sub(5))
    elseif msg:sub(1,3) == "PUT" then
      put(clientID,msg:sub(5))
    elseif msg:sub(1,4) == "QUIT" then
      clients[clientID] = nil
    end
  end
end

host()

rednet.close("right")