local S = minetest.get_translator("teleports")
local F = minetest.formspec_escape

teleports = {}
teleports.teleports = {}
teleports.lastplayername =""
teleports.filename = minetest.get_worldpath() .. "/teleports.txt"

local TELEPORT_MAX_DIST = 260

function teleports:save()
	local datastring = minetest.serialize(self.teleports)
	if not datastring then
		return
	end
	local file, err = io.open(self.filename, "w")
	if err then
		return
	end
	file:write(datastring)
	file:close()
end
function teleports:load()
	local file, err = io.open(self.filename, "r")
	if err then
		self.teleports = {}
		return
	end
	self.teleports = minetest.deserialize(file:read("*all"))
	if type(self.teleports) ~= "table" then
		self.teleports = {}
	end
	file:close()
end
function teleports:find_nearby(pos, count)
	local nearby = {}
	for i = #teleports.teleports, 1, -1 do
		local EachTeleport = teleports.teleports[i]
		if not vector.equals(EachTeleport.pos, pos) and vector.distance(EachTeleport.pos, pos) < TELEPORT_MAX_DIST then
			table.insert(nearby, EachTeleport)
			if #nearby>count then
				break
			end
		end
	end
	return nearby
end
function teleports.animate(pos, playername)
	minetest.add_particlespawner({
		amount = 80,
		time = 5,
		minpos = {x=pos.x-1, y=pos.y, z=pos.z-1},
		maxpos = {x=pos.x+1, y=pos.y+3, z=pos.z+1},
		minvel = {x=0, y=-1, z=0},
		maxvel = {x=0, y=1, z=0},
		minacc = {x=0, y=-1, z=0},
		maxacc = {x=0, y=1, z=0},
		minexptime = 1,
		maxexptime = 1,
		minsize = 0.5,
		maxsize = 2,
		collisiondetection = false,
		vertical = true,
		texture = "default_diamond.png",
		playername = playername,
	})
	minetest.add_particlespawner({
		amount = 20,
		time = 5,
		minpos = {x=pos.x-1, y=pos.y, z=pos.z-1},
		maxpos = {x=pos.x+1, y=pos.y+3, z=pos.z+1},
		minvel = {x=0, y=-1, z=0},
		maxvel = {x=0, y=1, z=0},
		minacc = {x=0, y=-1, z=0},
		maxacc = {x=0, y=1, z=0},
		minexptime = 1,
		maxexptime = 1,
		minsize = 0.5,
		maxsize = 2,
		collisiondetection = false,
		vertical = true,
		texture = "default_diamond.png",
	})
end
function teleports.teleportate(parameters)
	local pos1,pos2,playername = parameters[1],parameters[2],parameters[3]

	local player = minetest.get_player_by_name(playername)
	if player and player:is_player() and playername~=teleports.lastplayername then
		local pos = player:getpos()
		if vector.distance(pos, {x=pos1.x,y=pos1.y+0.5,z=pos1.z}) < 0.52 then
			if math.random(1, 100) > 5 then
				teleports.lastplayername = playername
				player:setpos({x=pos2.x,y=pos2.y+0.5,z=pos2.z})
			else
				player:setpos({x=pos2.x-5+math.random(1, 10),y=pos2.y+3,z=pos2.z-5+math.random(1, 10)})
			end
		end
	end
end
function teleports.do_teleporting(pos1, pos2, playername)
	teleports.animate(pos1, playername)
	minetest.after(3.0, teleports.teleportate, {pos1, pos2, playername})
end
teleports.set_formspec = function(pos)
	local meta = minetest.get_meta(pos)
	local node = minetest.get_node(pos)

	local buttons = "";
	for i, EachTeleport in ipairs( teleports:find_nearby(pos, 5) ) do
		if EachTeleport["name"] then
			buttons = buttons.."button_exit[3,"..(i)..";4,0.5;tp"..i..";"..F(S("GO>@1",EachTeleport.name)).."]";
		else
			buttons = buttons.."button_exit[3,"..(i)..";4,0.5;tp"..i..";"..F(S("GO>@1,@2,@3",EachTeleport.pos.x,EachTeleport.pos.y,EachTeleport.pos.z)).."]";
		end

	end

	meta:set_string("formspec", "size[8,10;]"
		.."label[0,0;" .. F(S("Go to available teleports! Use mossy cobblestone as fuel!")) .. "]"
		.."list[current_name;price;0,1;1,1;]"

		..buttons

		.."button_exit[1,5;2,0.5;cancel;"..F(S("Cancel")).."]"
		.."list[current_player;main;0,6;8,4;]")
end
teleports.on_receive_fields = function(pos, formname, fields, player)
	local meta = minetest.env:get_meta(pos);
	local inv = meta:get_inventory();
	local price = {name="default:mossycobble", count=1, wear=0, metadata=""}
	if fields.tp1 or fields.tp2 or fields.tp3 or fields.tp4 or fields.tp5 or fields.tp6 then
		if inv:contains_item("price", price) then
			inv:remove_item("price", price);
			teleports.lastplayername = ""
			local available = teleports:find_nearby(pos, 5)
			if player ~= nil and player:is_player() then
				local playerpos = player:getpos()
				if fields.tp1 and #available>0 then
					teleports.do_teleporting(playerpos, available[1].pos, player:get_player_name())
				elseif fields.tp2 and #available>1 then
					teleports.do_teleporting(playerpos, available[2].pos, player:get_player_name())
				elseif fields.tp3 and #available>2 then
					teleports.do_teleporting(playerpos, available[3].pos, player:get_player_name())
				elseif fields.tp4 and #available>3 then
					teleports.do_teleporting(playerpos, available[4].pos, player:get_player_name())
				elseif fields.tp5 and #available>4 then
					teleports.do_teleporting(playerpos, available[5].pos, player:get_player_name())
				elseif fields.tp6 and #available>5 then
					teleports.do_teleporting(playerpos, available[6].pos, player:get_player_name())
				end
			end

			teleports.set_formspec(pos)
		end
	end
end
teleports.allow_metadata_inventory_put = function(pos, listname, index, stack, player)
	if listname=="price" and stack:get_name()=="default:mossycobble" then
		return 99
	else
		return 0
	end
end
teleports.allow_metadata_inventory_take = function(pos, listname, index, stack, player)
	return 0
end

teleports:load()


minetest.register_node("teleports:teleport", {
	description = S("Teleport"),
	drawtype = "glasslike",
	tiles = {"teleports_teleport_top.png"},
	is_ground_content = false,
	light_source = LIGHT_MAX,
	groups = {cracky=1, level=3},
	drop = 'default:diamond',
	sounds = default.node_sound_stone_defaults(),
	after_place_node = function(pos, placer)
		if placer and placer:is_player() then
			local meta = minetest.env:get_meta(pos)
			local inv = meta:get_inventory()
			inv:set_size("price", 1)
			local initialcharge = {name="default:mossycobble", count=30, wear=0, metadata=""}
			inv:add_item("price", initialcharge)
			teleports.set_formspec(pos)
			local sign_pos = minetest.find_node_near(pos, 1, "default:sign_wall_wood")
			if sign_pos then
				local sign_meta = minetest.env:get_meta(sign_pos)
				local sign_text = sign_meta:get_string("text")
				local secret_name = sign_text:sub(0, 16)
				table.insert(teleports.teleports, {pos=vector.round(pos), name=secret_name})
			else
				table.insert(teleports.teleports, {pos=vector.round(pos)})
			end
			teleports:save()
		end
	end,
	on_destruct = function(pos)
		for i, EachTeleport in ipairs(teleports.teleports) do
			if vector.equals(EachTeleport.pos, pos) then
				table.remove(teleports.teleports, i)
				teleports:save()
			end
		end
	end,
	on_receive_fields = teleports.on_receive_fields,
	allow_metadata_inventory_put = teleports.allow_metadata_inventory_put,
	allow_metadata_inventory_take = teleports.allow_metadata_inventory_take,
})


minetest.override_item("default:diamondblock", {
	on_place = function(itemstack, placer, pointed_thing)
		local stack = ItemStack("default:diamondblock")
		local pos = pointed_thing.above
		if
			minetest.get_node({x=pos.x+1,y=pos.y,z=pos.z}).name=="default:diamondblock" and
			minetest.get_node({x=pos.x+1,y=pos.y,z=pos.z+1}).name=="default:diamondblock" and
			minetest.get_node({x=pos.x+1,y=pos.y,z=pos.z-1}).name=="default:diamondblock" and
			minetest.get_node({x=pos.x-1,y=pos.y,z=pos.z}).name=="default:diamondblock" and
			minetest.get_node({x=pos.x-1,y=pos.y,z=pos.z+1}).name=="default:diamondblock" and
			minetest.get_node({x=pos.x-1,y=pos.y,z=pos.z-1}).name=="default:diamondblock" and
			minetest.get_node({x=pos.x,y=pos.y,z=pos.z+1}).name=="default:diamondblock" and
			minetest.get_node({x=pos.x,y=pos.y,z=pos.z-1}).name=="default:diamondblock"
		then
			stack = ItemStack("teleports:teleport")
		end
		local ret = minetest.item_place(stack, placer, pointed_thing)
		if ret==nil then
			return itemstack
		else
			return ItemStack("default:diamondblock "..itemstack:get_count()-(1-ret:get_count()))
		end
	end,
})

minetest.register_abm({
	nodenames = {"teleports:teleport"},
	interval = 3,
	chance = 1,
	action = function(pos)
		local objectsnear=minetest.get_objects_inside_radius({x=pos.x,y=pos.y+0.5,z=pos.z}, 0.52);
		if #objectsnear>0 then
			local player = objectsnear[1];
			-- check only first two objekts then give up
			if #objectsnear>1 and not player:is_player() then
				player = objectsnear[2];
			end
			if player:is_player() and player:get_player_name()~=teleports.lastplayername then
				local positions = teleports:find_nearby(pos, 10)
				if #positions>0 then
					local key = math.random(1, #positions)
					local dir, dirmag;
					local view = player:get_look_dir();
					local dist, distmin; distmin = 99;
					for i=1,#positions do -- find teleport closest to where player is looking
						dir = {x=positions[i].pos.x-pos.x,y=positions[i].pos.y-pos.y,z=positions[i].pos.z-pos.z};
						dirmag = math.sqrt(dir.x*dir.x+dir.y*dir.y+dir.z*dir.z); if dirmag == 0 then dirmag = 1 end
						dir.x=dir.x/dirmag;dir.y=dir.y/dirmag;dir.z=dir.z/dirmag;
						dir.x = view.x-dir.x;dir.y = view.y-dir.y;dir.z = view.z-dir.z;
						dist = math.sqrt(dir.x*dir.x+dir.y*dir.y+dir.z*dir.z);
						if dist<distmin then distmin = dist; key = i end
					end

					local pos2 = positions[key].pos
					teleports.do_teleporting(pos, pos2, player:get_player_name())
				end
			else
				teleports.lastplayername = ""
			end
		end
	end,
})