--	page.lua
--	Part of FusionPBX
--	Copyright (C) 2010-2022 Mark J Crane <markjcrane@fusionpbx.com>
--	All rights reserved.
--
--	Redistribution and use in source and binary forms, with or without
--	modification, are permitted provided that the following conditions are met:
--
--	1. Redistributions of source code must retain the above copyright notice,
--	   this list of conditions and the following disclaimer.
--
--	2. Redistributions in binary form must reproduce the above copyright
--	   notice, this list of conditions and the following disclaimer in the
--	   documentation and/or other materials provided with the distribution.
--
--	THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
--	INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
--	AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
--	AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
--	OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
--	SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
--	INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
--	CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
--	ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
--	POSSIBILITY OF SUCH DAMAGE.

--set default settings
	pin_number = "";
	max_tries = "3";
	digit_timeout = "3000";

--define the trim function
	require "resources.functions.trim";

--define the explode function
	require "resources.functions.explode";

--define the split function
	require "resources.functions.split";

--iterator over numbers.
	local function each_number(value)
		local begin_value, end_value = split_first(value, "-", true)
		if (not end_value) or (begin_value == end_value) then
			return function()
				local result = begin_value
				begin_value = nil
				return result
			end
		end

		if string.find(begin_value, "^0") then
			assert(#begin_value == #end_value, "number in range with leading `0` should have same length")
		end

		local number_length = ("." .. tostring(#begin_value))
		begin_value, end_value = tonumber(begin_value), tonumber(end_value)
		assert(begin_value and end_value and (begin_value <= end_value), "Invalid range: " .. value)

		return function()
			value, begin_value = begin_value, begin_value + 1
			if value > end_value then return end
			return string.format("%" .. number_length .. "d", value)
		end
	end

--make sure the session is ready
	if ( session:ready() ) then
		--answer the call
			session:answer();

		--get the dialplan variables and set them as local variables
			destination_number = session:getVariable("destination_number");
			pin_number = session:getVariable("pin_number");
			domain_name = session:getVariable("domain_name");
			sounds_dir = session:getVariable("sounds_dir");
			destinations = session:getVariable("destinations");
			rtp_secure_media = session:getVariable("rtp_secure_media");
			if (destinations == nil) then
				destinations = session:getVariable("extension_list");
			end
			destination_table = explode(",",destinations);
			caller_id_name = session:getVariable("caller_id_name");
			caller_id_number = session:getVariable("caller_id_number");
			sip_from_user = session:getVariable("sip_from_user");
			mute = session:getVariable("mute");

		--determine whether to check if the destination is available
			check_destination_status = session:getVariable("check_destination_status");
			if (not check_destination_status) then check_destination_status = 'false'; end

		--set the type of auto answer
			auto_answer = session:getVariable("auto_answer");
			if (not auto_answer) then auto_answer = 'call_info'; end
			if (auto_answer == 'call_info') then
				auto_answer = "sip_h_Call-Info=<sip:"..domain_name..">;answer-after=0";
			end
			if (auto_answer == 'sip_auto_answer') then
				auto_answer = "sip_auto_answer=true";
			end

		--set sip header Alert-Info
			alert_info = session:getVariable("alert_info");
			if (not alert_info) then alert_info = 'ring_answer'; end
			if (alert_info == 'auto_answer') then
				alert_info = "sip_h_Alert-Info='Auto Answer'";
			elseif (alert_info == 'ring_answer') then
				alert_info = "sip_h_Alert-Info='Ring Answer'";
			else
				alert_info = "sip_h_Alert-Info='"..alert_info.."'";
			end

		--set the sounds path for the language, dialect and voice
			default_language = session:getVariable("default_language");
			default_dialect = session:getVariable("default_dialect");
			default_voice = session:getVariable("default_voice");
			if (not default_language) then default_language = 'en'; end
			if (not default_dialect) then default_dialect = 'us'; end
			if (not default_voice) then default_voice = 'callie'; end

		--set rtp_secure_media to an empty string if not provided.
			if (rtp_secure_media == nil) then
				rtp_secure_media = 'false';
			end

		--define the conference name
			local conference_profile = "page";
			local conference_name = "page-"..destination_number.."@"..domain_name;
			local conference_bridge = conference_name.."@"..conference_profile;

		--set the caller id
			if (caller_id_name) then
				--caller id name provided do nothing
			else
				effective_caller_id_name = session:getVariable("effective_caller_id_name");
				caller_id_name = effective_caller_id_name;
			end

			if (caller_id_number) then
				--caller id number provided do nothing
			else
				effective_caller_id_number = session:getVariable("effective_caller_id_number");
				caller_id_number = effective_caller_id_number;
			end

		--set conference flags
			if (mute == "true") then
				flags = "flags{mute}";
			else
				flags = "flags{}";
			end

		--if the pin number is provided then require it
			if (pin_number) then
				--sleep
					session:sleep(500);

				--get the user pin number
					min_digits = 2;
					max_digits = 20;
					digits = session:playAndGetDigits(min_digits, max_digits, max_tries, digit_timeout, "#", "phrase:voicemail_enter_pass:#", "", "\\d+");

				--validate the user pin number
					pin_number_table = explode(",",pin_number);
					for index,pin_number in pairs(pin_number_table) do
						if (digits == pin_number) then
							--set the variable to true
								auth = true;
							--set the authorized pin number that was used
								session:setVariable("pin_number", pin_number);
							--end the loop
								break;
						end
					end

				--if not authorized play a message and then hangup
					if (not auth) then
						session:streamFile("phrase:voicemail_fail_auth:#");
						session:hangup("NORMAL_CLEARING");
						return;
					end
			end

		--log the destinations
			freeswitch.consoleLog("NOTICE", "[page] destinations "..destinations.." available\n");

		--create the api object
			api = freeswitch.API();

		--get the channels
			if (check_destination_status == 'true') then
				cmd_string = "show channels";
				channel_result = api:executeString(cmd_string);
			end

		--originate the calls
			destination_count = 0;

			for index,value in pairs(destination_table) do
				for destination in each_number(value) do

					--get the destination required for number-alias
					destination = api:execute("user_data", destination .. "@" .. domain_name .. " attr id");

					--prevent calling the user that initiated the page
					if (sip_from_user ~= destination) then
						if (check_destination_status == 'true') then
							--detect if the destination is available or busy
							destination_status = 'available';
							channel_array = explode("\n", channel_result);
							for index,row in pairs(channel_array) do
								if string.find(row, destination..'@'..domain_name, nil, true) then
									destination_status = 'busy';
									break;
								end
							end

							--if available then page then originate the call with auto answer
							if (destination_status == 'available') then
								freeswitch.consoleLog("NOTICE", "[page] destination "..destination.." available\n");
								if destination == sip_from_user then
									--this destination is the caller that initated the page
								else
									--originate the call
									cmd_string = "bgapi originate {"..auto_answer..","..alert_info..",hangup_after_bridge=false,rtp_secure_media="..rtp_secure_media..",origination_caller_id_name='"..caller_id_name.."',origination_caller_id_number="..caller_id_number.."}user/"..destination.."@"..domain_name.." conference:"..conference_bridge.."+"..flags.." inline";
									api:executeString(cmd_string);
									destination_count = destination_count + 1;
								end
							end
						else
							--endpoint determines what to do with the call when the destination is active
							freeswitch.consoleLog("NOTICE", "[page] endpoint determines what to do if the it has an active call.\n");
							if destination == sip_from_user then
								--this destination is the caller that initated the page
							else
								--originate the call
								cmd_string = "bgapi originate {"..auto_answer..","..alert_info..",hangup_after_bridge=false,rtp_secure_media="..rtp_secure_media..",origination_caller_id_name='"..caller_id_name.."',origination_caller_id_number="..caller_id_number.."}user/"..destination.."@"..domain_name.." conference:"..conference_bridge.."+"..flags.." inline";
								api:executeString(cmd_string);
								destination_count = destination_count + 1;
							end
						end
					end
				end
			end

		--send main call to the conference room
			if (destination_count > 0) then
				if (session:getVariable("moderator") == "true") then
					moderator_flag = ",moderator";
				else
					moderator_flag = "";
				end
				session:execute("conference", conference_bridge.."+flags{endconf,mintwo"..moderator_flag.."}");
			else
				session:execute("playback", "tone_stream://%(500,500,480,620);loops=3");
			end

	end