--Configuration values:
--Use these to customize this mod
local timeout_delay = 60

--DO NOT CHANGE:

local value_carryover = nil
local value_carryover2 = nil

local version = "0.1a"

local tpr_list = {}
local tphr_list = {}

--Teleport Request System

local function tpr_send(name, param)

	--Register variables

	local sender = name
	local receiver = param
	local value_carryover = param

	--Check for empty parameter
	if receiver == "" then
		minetest.chat_send_player(sender, "Usage: /tpr <Player name>")
		return
	end

	--If paremeter is valid, Send teleport message and set the table.

	if minetest.env:get_player_by_name(receiver) then
		minetest.chat_send_player(receiver, sender ..' is requesting to teleport to you. /tpy to accept.')
		minetest.chat_send_player(sender, 'Teleport request sent! It will time out in '.. timeout_delay ..' seconds.')

		--Write name values to list and clear old values.
		tpr_list[receiver] = nil
		tpr_list[receiver] = sender
		--Teleport timeout delay
		minetest.after(timeout_delay, reset_request)
	end
end

local function tphr_send(name, param)

	local sender2 = name
	local receiver2 = param
	local value_carryover2 = param

	--Check for empty parameter
	if receiver2 == "" then
		minetest.chat_send_player(sender2, "Usage: /tphr <Player name>")
		return
	end

	--If paremeter is valid, Send teleport message and set the table.
	if minetest.env:get_player_by_name(receiver2) then
		minetest.chat_send_player(receiver2, sender2 ..' is requesting that you teleport to them. /tpy to accept.')
		minetest.chat_send_player(sender2, 'Teleport request sent! It will time out in '.. timeout_delay ..' seconds.')

		--Write name values to list and clear old values.
		tphr_list[receiver2] = nil
		tphr_list[receiver2] = sender2
		--Teleport timeout delay
		minetest.after(timeout_delay, reset_request2)
	end
end


--Reset after configured delay.

function reset_request(name)
	if tpr_list[value_carryover] ~= nil then
		tpr_list[value_carryover] = nil
	end
end

function reset_request2(name)
	if tphr_list[value_carryover2] ~= nil then
		tphr_list[value_carryover2] = nil
	end
end

function tpr_deny(name)
	sender = tpr_list[value_carryover]
	if tpr_list[value_carryover] ~= nil then
		tpr_list[value_carryover] = nil
		minetest.chat_send_player(sender, 'Teleport request denied.')
	end
	sender2 = tphr_list[value_carryover2]
	if tphr_list[value_carryover2] ~= nil then
		tphr_list[value_carryover2] = nil
		minetest.chat_send_player(sender2, 'Teleport request denied.')
	end
end

--Teleport Accept Systems

local function tpr_accept(name, param)

	local receiver = name

	--Check to prevent constant teleporting.
	if tpr_list[name] == nil and tphr_list[name] == nil then
		minetest.chat_send_player(name, "Usage: /tpy allows you to accept teleport requests sent to you by other players")
		return
	end

	--Teleport Accept system
	--Check to ensure name is valid, then send appropriate chat messages

	if tpr_list[name] then
		local sender = tpr_list[name]
		minetest.chat_send_player(tpr_list[receiver], "Request Accepted!")
		minetest.chat_send_player(receiver, sender..' is teleporting to you.')

		--Code here copied from Celeron-55's /teleport command. Thanks Celeron!

		local function find_free_position_near(pos)
			local tries = {
				{x=1,y=0,z=0},
				{x=-1,y=0,z=0},
				{x=0,y=0,z=1},
				{x=0,y=0,z=-1},
			}
			for _, d in ipairs(tries) do
				local p = {x = pos.x+d.x, y = pos.y+d.y, z = pos.z+d.z}
				local n = minetest.env:get_node(p)
				if not minetest.registered_nodes[n.name].walkable then
					return p, true
				end
			end
			return pos, false
		end

		--Get names from variables and set position. Then actually teleport the player.

		local requester = minetest.env:get_player_by_name(sender)
		local accepter = minetest.env:get_player_by_name(name)

		-- Could happen if either player disconnects; if so just abort
		if requester == nil or accepter == nil then
			return
		end

		local p = nil
		p = accepter:getpos()
		p = find_free_position_near(p)
		requester:setpos(p)

		-- Set name values to nil to prevent re-teleporting on the same request.
		tpr_list[name] = nil

		return
	end

	--Teleport Here accepting system

	if tphr_list[name] then
		local sender = tphr_list[name]
		minetest.chat_send_player(tphr_list[receiver], "Request Accepted!")
		minetest.chat_send_player(receiver, 'you are teleporting to '..sender..'.')

		--Code here copied from Celeron-55's /teleport command. Thanks Celeron!

		local function find_free_position_near(pos)
			local tries = {
				{x=1,y=0,z=0},
				{x=-1,y=0,z=0},
				{x=0,y=0,z=1},
				{x=0,y=0,z=-1},
			}
			for _, d in ipairs(tries) do
				local p = {x = pos.x+d.x, y = pos.y+d.y, z = pos.z+d.z}
				local n = minetest.env:get_node(p)
				if not minetest.registered_nodes[n.name].walkable then
					return p, true
				end
			end
			return pos, false
		end

		--Get names from variables and set position. Then actually teleport the player.

		local requester = minetest.env:get_player_by_name(sender)
		local accepter = minetest.env:get_player_by_name(name)

		-- Could happen if either player disconnects; if so just abort
		if requester == nil or accepter == nil then
			return
		end

		local p = nil
		p = requester:getpos()
		p = find_free_position_near(p)
		accepter:setpos(p)

		-- Set name values to nil to prevent re-teleporting on the same request.
		tphr_list[name] = nil

		return
	end
end

--Initalize Permissions.

minetest.register_privilege("tpr_admin", {
	description = "Permission to override teleport to other players. UNFINISHED",
	give_to_singleplayer = true
})

--Initalize Commands.

minetest.register_chatcommand("tpr", {
	description = "Request teleport to another player",
	params = "<playername> | leave playername empty to see help message",
	privs = {interact=true},
	func = tpr_send

})

minetest.register_chatcommand("tphr", {
	description = "Request teleport to another player",
	params = "<playername> | leave playername empty to see help message",
	privs = {interact=true},
	func = tphr_send

})

minetest.register_chatcommand("tpy", {
	description = "Accept teleport requests from another player",
	func = tpr_accept
})

minetest.register_chatcommand("tpn", {
	description = "Deny teleport requests from another player",
	func = tpr_deny
})

print ("[Teleport Request] Teleport Request v" .. version .. " Loaded.")