--
--  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/>.
--

local defines = require("defines")

-- stdio module class
local stdio = {}
stdio.properties = { type=defines.INOUT_MODULE, name="stdio", max_instances=1 }

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

   local in_handle = {}
   in_handle.fd = 0
   rawio.setnonblock(in_handle.fd)
   in_handle.client_instance = nil
   in_handle.in_buffer = ""
   function in_handle:getfd() return self.fd end
   function in_handle:read() 
      -- TODO: which size should we request??
      local buffer, err = rawio.read(0, 100)
      if(buffer == nil) then
         log.printf(log.ERROR, inst.name .. ": connection error: %s", err)
         return defines.KILL_MODULE_CLASS
      end

      self.in_buffer = self.in_buffer .. buffer
      self.in_buffer = dispatch_table:dispatch(self.in_buffer)

      -- TODO: part of expected response handling
      command_queue:command_completed()

      return defines.OK
   end
   function in_handle:write() end

   local out_handle = {}
   out_handle.fd = 1
   rawio.setnonblock(out_handle.fd)
   out_handle.client_instance = nil
   out_handle.out_buffer = ""
   function out_handle:getfd() return self.fd end
   function out_handle:read() end
   function out_handle:write()
      local len, err = rawio.write(1, self.out_buffer)
      if(len == nil) then
         log.printf(log.ERROR, inst.name .. ": connection error: %s", err)
         ret = defines.KILL_MODULE_CLASS
      else
         self.out_buffer = string.sub(self.out_buffer, len+1)
      end
      if(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 { in_handle }
   end
   function client:get_write_handles() 
      if(out_handle.out_buffer ~= "") then
         return { out_handle }
      else
         return {}
      end
   end
   function client:cleanup() end
   in_handle.client_instance = client
   out_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()
      return {}
   end
   function inst:start_command(command)
      out_handle.out_buffer = command
   end
   setmetatable(inst, {})
   getmetatable(inst).__gc = function() inst:cleanup() end

   client_list:register(client)
   return inst
end

return stdio