--[[
	drua-tg
	Based on JuanPotato's lua-tg (https://github.com/juanpotato/lua-tg),
	modified to work more naturally from an API bot.

	Usage:
		drua = require('drua-tg')
		drua.IP = 'localhost' -- 'localhost' is default
		drua.PORT = 4567 -- 4567 is default
		drua.message(chat_id, text)

The MIT License (MIT)

Copyright (c) 2015-2016 Juan Potato

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
]]

local SOCKET = require('socket')

local comtab = {
	add = { 'chat_add_user %s %s', 'channel_invite %s %s' },
	kick = { 'chat_del_user %s %s', 'channel_kick %s %s' },
	rename = { 'rename_chat %s "%s"', 'rename_channel %s "%s"' },
	link = { 'export_chat_link %s', 'export_channel_link %s' },
	photo_set = { 'chat_set_photo %s %s', 'channel_set_photo %s %s' },
	photo_get = { [0] = 'load_user_photo %s', 'load_chat_photo %s', 'load_channel_photo %s' },
	info = { [0] = 'user_info %s', 'chat_info %s', 'channel_info %s' }
}

local format_target = function(target)
	target = tonumber(target)
	if target < -1000000000000 then
		target = 'channel#' .. math.abs(target) - 1000000000000
		return target, 2
	elseif target < 0 then
		target = 'chat#' .. math.abs(target)
		return target, 1
	else
		target = 'user#' .. target
		return target, 0
	end
end

local escape = function(text)
	text = text:gsub('\\', '\\\\')
	text = text:gsub('\n', '\\n')
	text = text:gsub('\t', '\\t')
	text = text:gsub('"', '\\"')
	return text
end

local drua = {
	IP = 'localhost',
	PORT = 4567
}

drua.send = function(command, do_receive)
	local s = SOCKET.connect(drua.IP, drua.PORT)
	assert(s, '\nUnable to connect to tg session.')
	s:send(command..'\n')
	local output
	if do_receive then
		output = string.match(s:receive('*l'), 'ANSWER (%d+)')
		output = s:receive(tonumber(output)):gsub('\n$', '')
	end
	s:close()
	return output
end

drua.message = function(target, text)
	target = format_target(target)
	text = escape(text)
	local command = 'msg %s "%s"'
	command = command:format(target, text)
	return drua.send(command)
end

drua.send_photo = function(target, photo)
	target = format_target(target)
	local command = 'send_photo %s %s'
	command = command:format(target, photo)
	return drua.send(command)
end

drua.add_user = function(chat, target)
	local a
	chat, a = format_target(chat)
	target = format_target(target)
	local command = comtab.add[a]:format(chat, target)
	return drua.send(command)
end

drua.kick_user = function(chat, target)
	-- Get the group info so tg will recognize the target.
	drua.get_info(chat)
	local a
	chat, a = format_target(chat)
	target = format_target(target)
	local command = comtab.kick[a]:format(chat, target)
	return drua.send(command)
end

drua.rename_chat = function(chat, name)
	local a
	chat, a = format_target(chat)
	local command = comtab.rename[a]:format(chat, name)
	return drua.send(command)
end

drua.export_link = function(chat)
	local a
	chat, a = format_target(chat)
	local command = comtab.link[a]:format(chat)
	return drua.send(command, true)
end

drua.get_photo = function(chat)
	local a
	chat, a = format_target(chat)
	local command = comtab.photo_get[a]:format(chat)
	local output = drua.send(command, true)
	if output:match('FAIL') then
		return false
	else
		return output:match('Saved to (.+)')
	end
end

drua.set_photo = function(chat, photo)
	local a
	chat, a = format_target(chat)
	local command = comtab.photo_set[a]:format(chat, photo)
	return drua.send(command)
end

drua.get_info = function(target)
	local a
	target, a = format_target(target)
	local command = comtab.info[a]:format(target)
	return drua.send(command, true)
end

drua.channel_set_admin = function(chat, user, rank)
	chat = format_target(chat)
	user = format_target(user)
	local command = 'channel_set_admin %s %s %s'
	command = command:format(chat, user, rank)
	return drua.send(command)
end

drua.channel_set_about = function(chat, text)
	chat = format_target(chat)
	text = escape(text)
	local command = 'channel_set_about %s "%s"'
	command = command:format(chat, text)
	return drua.send(command)
end

drua.block = function(user)
	return drua.send('block_user user#' .. user)
end

drua.unblock = function(user)
	return drua.send('unblock_user user#' .. user)
end

return drua