--[[

  $Id: //depot/p19.1/p4-test/server/extensions/examples/login_motd/main.lua#6 $
  $DateTime: 2019/04/30 13:18:49 $
  $Author: jgibson $
  $Change: 1796591 $

]]--

-- Add the Extension's archive directory to the package search path
-- so we can require() our assets.
package.path = Helix.Core.Server.GetArchDirFileName( "?.lua" )

local utils = require "ExtUtils"

-- Keep some state about the initialization of the Extension so we
-- don't keep retrieving static data all the time.

local initDone = false

function init()
  if not initdone then
    initDone = 1
    utils.init()
  end
end

-- This Extension doesn't have any global configuration.

function GlobalConfigFields()
  return {}
end

-- Each instance of this Extension has three things it can be configured
-- with.  The table we return ends up in the form accessed via
-- 'p4 extension --configure extName --name extInstance'.

function InstanceConfigFields()
  return {
           -- This gets sent to the user prior to authentication.
           message = "The message displayed before login.",
            groups = [[Space-separated list of groups whose
members receive the message.  An empty
list means the message goes to everyone.]],
          serverID = "Server ID to limit the message to."
         }
end

-- Here, the Extension tells the server which events it needs to be
-- registered for.  The keys of the table are the same as the set
-- of available triggers.

function InstanceConfigEvents()
  return { command = "pre-user-login" }
end

-- Connect to the hosting server and see if the user running
-- the login is a member of a particular set of groups.

function isUserInGroups( user, groups )
  local p4 = P4.P4:new()
  p4.prog = utils.getID()

  -- This function automatically logs the P4USER specified in the
  -- Extension's global config into the server running the Extension.
  p4:autoconnect()
  p4:connect()

  local grData = p4:run( "groups", "-u", "-i", user )
  local gs = {}

  for i, dict in ipairs( grData ) do
    gs[ dict[ "group" ] ] = 1
  end

  for k, v in pairs( groups ) do
    if gs[ k ] ~= nil then
      return true
    end
  end
  return false
end

-- The Extension callbacks for events in the server mirror the names
-- of the keys in the InstanceConfigEvents() function above.  In this case
-- this is a 'command' event that gets run before a command begins
-- execution.

function Command()
  init()

  -- Get the instance configuration data needed for the Extension to
  -- behave the way it is configured.

  local  groups  = utils.iCfgData[ "groups"   ]
  local ngroups  = utils.iCfgData[ "ngroups"  ]
  local serverID = utils.iCfgData[ "serverID" ]
  local message  = utils.iCfgData[ "message"  ]

  if serverID ~= nil and Helix.Core.Server.GetVar( "serverid" ) ~= serverID then
    return true
  end

  -- Don't double-display the message - once from the replica and once from the master.
  if serverID == nil and Helix.Core.Server.GetVar( "serverservices" ) ~= "commit-server" then
    return true
  end

  local err, ret

  if ngroups > 0 then
    err, ret = pcall( function()
        return isUserInGroups( Helix.Core.Server.GetVar( "user" ), groups )
      end )
  end

  if err == false then
    Helix.Core.Server.SetClientMsg( utils.msgHeader() .. ret )
    return false
  end

  if ret == true or ngroups == 0 then
    Helix.Core.Server.SetClientMsg( utils.msgHeader() .. "\n\n" .. message )
  end

  return true
end