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--
--  gcsd
--
--  gcsd the generic command sequencer daemon can be used to serialize 
--  commands sent over various paralell communication channels to a
--  single command output. It can be seen as a multiplexer for any
--  kind of communication between a single resource and various clients
--  which want to submit commands to it or query information from it.
--  gcsd is written in C and Lua. The goal is to provide an easy to 
--  understand high level API based on Lua which can be used to
--  implement the business logic of the so formed multiplexer daemon.
--  
--
--  Copyright (C) 2009-2010 Markus Grueneis <gimpf@spreadspace.org>
--                          Christian Pointner <equinox@spreadspace.org>
--
--  This file is part of gcsd.
--
--  gcsd is free software: you can redistribute it and/or modify
--  it under the terms of the GNU General Public License as published by
--  the Free Software Foundation, either version 3 of the License, or
--  any later version.
--
--  gcsd is distributed in the hope that it will be useful,
--  but WITHOUT ANY WARRANTY; without even the implied warranty of
--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
--  GNU General Public License for more details.
--
--  You should have received a copy of the GNU General Public License
--  along with gcsd. If not, see <http://www.gnu.org/licenses/>.
--

-- tcp_connect module class
local tcp_connect = {}
tcp_connect.properties = { type=defines.INOUT_MODULE, name="tcp-connect", max_instances=-1 }
tcp_connect.next_id = 0

-- create new instance of tcp_connect module class
function tcp_connect:new(config, runtype)
   local inst = {}
   inst.class = self
   inst.config = config
   inst.config.runtype = runtype
   if(config.name == nil or config.name == "") then
      inst.name = self.properties.name .. self.next_id
      self.next_id = self.next_id + 1
   else
      inst.name = config.name
   end

   local handle, connected = tcp.client(config.addr, config.port, config.resolv_type, config.source)
   if(not handle) then
      return nil
   end
   inst.connected = connected

   handle.in_buffer = ""
   handle.out_buffer = ""
   function handle:read() 
      -- TODO: which size should we request??
      local buffer, err = tcp.recv(self.fd, 100)
      if(buffer == nil) then
         log.printf(log.ERROR, inst.name .. ": connection error: %s", err)
         return defines.KILL_MODULE -- TODO: reconnect
      end
      if(#buffer == 0) then
         log.printf(log.INFO, inst.name .. ": connection closed")
         return defines.KILL_MODULE -- TODO: reconnect
      end

      self.in_buffer = self.in_buffer .. buffer
      if(inst.config.runtype == defines.IN_MODULE) then
         self.in_buffer = command_table:dispatch(self.in_buffer)
      else
         self.in_buffer = response_table:dispatch(self.in_buffer)
      end

      return defines.OK
   end
   function handle:write()
      local len, err = tcp.send(self.fd, self.out_buffer)
      if(len == nil) then
         log.printf(log.ERROR, inst.name .. ": connection error: %s", err)
         ret = defines.KILL_MODULE -- TODO: reconnect
      else
         self.out_buffer = string.sub(self.out_buffer, len+1)
      end
      if(inst.config.runtype == defines.OUT_MODULE and self.out_buffer == "") then
         command_queue:command_sent()
      end
      return defines.OK
   end

   local client = {}
   client.module_instance = inst
   client.name = inst.name .. "#0"
   function client:process_response() end
   function client:process_timeout() end
   function client:get_read_handles() 
      return { handle }
   end
   function client:get_write_handles() 
      if(handle.out_buffer ~= "") then
         return { handle }
      else
         return {}
      end
   end
   function client:cleanup()
      rawio.close(handle.fd)
   end
   handle.client_instance = client

   local connect_handle = {}
   connect_handle.fd = handle.fd
   function connect_handle:read() return defines.OK end
   function connect_handle:write()
      local connected, err = tcp.connect(handle.fd)
      if(not connected) then
         return defines.KILL_MODULE
      end
      inst.connected = true
      client_list:register(client)
      return defines.OK
   end
   connect_handle.client_instance = client

   function inst:cleanup()
      client_list:unregister_by_module(self)
   end
   function inst:get_read_handles()
      return {}
   end
   function inst:get_write_handles()
      if(not inst.connected) then
         return { connect_handle }
      else
         return {}
      end
   end
   function inst:start_command(command)
      handle.out_buffer = command
   end
   setmetatable(inst, {})
   getmetatable(inst).__gc = function() inst:cleanup() end

   return inst
end

return tcp_connect