-- MPD INTERATION

-- TODO password support

-- library

require 'socket'

-- public

local settings = {

	hostname     = "localhost",

	password     = nil,

	port         = 6600,

}

mpd = { }

-- separator allows split output into records, that are started by any of present in separator keys

-- returns table of field (lowercase) - value records

-- command status is returned in STATUS field

-- on unexpected errors returns just false, dropping any available data

function mpd.receive_message ( tcp, separator )

	local ret  = {}

	local line = tcp:receive ( '*l' )

	while line and not ( line:match ( '^OK' ) or line:match ( '^ACK' ) ) do

		local key, val = line:match ( '^(.-):%s*(.*)$' )

		if key then

			if separator then

				key = key:lower ()

				if separator[key] then

					table.insert ( ret, {} )

				end

				ret[#ret][key]   = val

			else

				ret[key:lower()] = val

			end

		end

		line = tcp:receive ( '*l' )

	end

	if not line then

		return false -- an error occured, ret, most likely, does not contains exact and complete info...

	else

		ret.STATUS = line:match ( '^%S+' )

		return ret

	end

end

-- use: mpd.call_command { 'status' }

--      mpd.call_command { 'lsinfo misc', list = { file = true, directory = true } }

--      mpd.call_command { 'next', noret = true }

--      mpd.call_command { 'status', 'currentsong' }

-- on one command returns just results of that command, on multi - array of results

-- on errors returns nil

-- noret can terminate socket too early, thus, do not use it with lists of commands

function mpd.call_command ( opts )

	local tcp = socket.tcp ()

	if not tcp then

		print ( 'mpd: cannot get master tcp object' )

		return nil

	elseif not tcp:connect ( settings.hostname, settings.port ) then

		tcp:close ()

		print ( 'mpd: cannot connect to server' )

		return nil

	end

	local ret = {}

	if not opts.noret then

		ret = mpd.receive_message ( tcp )

		if not ret then

			tcp:close ()

			print ( 'mpd: error getting greeting from server' )

			return nil

		elseif ret.STATUS ~= 'OK' then

			print ( 'mpd: server ack\'s in greeting' )

		end

	end

	for num, command in ipairs ( opts ) do

		if not tcp:send ( command .. "\n" ) then

			tcp:close ()

			print ( 'mpd: error sending command ' .. command )

			return nil

		end

		if not opts.noret then

			ret[num] = mpd.receive_message ( tcp, opts.list )

			if not ret[num] then

				print ( 'mpd: error getting result' )

			end

			if ret[num]['STATUS'] ~= 'OK' then

				print ( 'mpd: server acks our command ' .. command )

			end

		end

	end

	tcp:close ()

	if #ret > 1 then

		return ret

	else

		return ret[1]

	end

end

-- vim: se ts=4: --