-- This file provides the actual flow and pathfinding logic that makes water
-- move through the pipes.
--
-- Contributed by mauvebic, 2013-01-03, with tweaks by Vanessa Ezekowitz
--

local finitewater = minetest.setting_getbool("liquid_finite")

local check4liquids = function(pos)
	local coords = {
		{x=pos.x,y=pos.y-1,z=pos.z},
		{x=pos.x,y=pos.y+1,z=pos.z},
		{x=pos.x-1,y=pos.y,z=pos.z},
		{x=pos.x+1,y=pos.y,z=pos.z},
		{x=pos.x,y=pos.y,z=pos.z-1},
		{x=pos.x,y=pos.y,z=pos.z+1},	}
	for i =1,6 do
		local name = minetest.get_node(coords[i]).name
		if string.find(name,"water") then
			if finitewater then minetest.remove_node(coords[i]) end
			return true
		end
	end
	return false
end

local check4inflows = function(pos,node)
	local coords = {
		{x=pos.x,y=pos.y-1,z=pos.z},
		{x=pos.x,y=pos.y+1,z=pos.z},
		{x=pos.x-1,y=pos.y,z=pos.z},
		{x=pos.x+1,y=pos.y,z=pos.z},
		{x=pos.x,y=pos.y,z=pos.z-1},
		{x=pos.x,y=pos.y,z=pos.z+1},	}
	local newnode = false
	local source = false
	for i =1,6 do
		if newnode then break end
		local name = minetest.get_node(coords[i]).name
		if (name == "pipeworks:pump_on" and check4liquids(coords[i])) or string.find(name,"_loaded") then
			if string.find(name,"_loaded") then
				local source = minetest.get_meta(coords[i]):get_string("source")
				if source == minetest.pos_to_string(pos) then break end
			end
			newnode = string.gsub(node.name,"empty","loaded")
			source = {x=coords[i].x,y=coords[i].y,z=coords[i].z}
		end
	end
	if newnode then 
		minetest.add_node(pos,{name=newnode, param2 = node.param2}) 
		minetest.get_meta(pos):set_string("source",minetest.pos_to_string(source))
	end
end

local checksources = function(pos,node)
	local sourcepos = minetest.string_to_pos(minetest.get_meta(pos):get_string("source"))
	if not sourcepos then return end
	local source = minetest.get_node(sourcepos).name
	local newnode = false
	if not ((source == "pipeworks:pump_on" and check4liquids(sourcepos)) or string.find(source,"_loaded") or source == "ignore" ) then
		newnode = string.gsub(node.name,"loaded","empty")
	end

	if newnode then 
		minetest.add_node(pos,{name=newnode, param2 = node.param2}) 
		minetest.get_meta(pos):set_string("source","")
	end
end

local spigot_check = function(pos, node)
	local belowname = minetest.get_node({x=pos.x,y=pos.y-1,z=pos.z}).name
	if belowname == "air" or belowname == "default:water_flowing" or belowname == "default:water_source" then 
		local spigotname = minetest.get_node(pos).name
		local fdir=node.param2
		local check = {
			{x=pos.x,y=pos.y,z=pos.z+1},
			{x=pos.x+1,y=pos.y,z=pos.z},
			{x=pos.x,y=pos.y,z=pos.z-1},
			{x=pos.x-1,y=pos.y,z=pos.z}
		}
		if string.find(minetest.get_node(check[fdir+1]).name, "_loaded") then
			if spigotname == "pipeworks:spigot" then
				minetest.add_node(pos,{name = "pipeworks:spigot_pouring", param2 = fdir})
				if finitewater or belowname ~= "default:water_source" then
					minetest.add_node({x=pos.x,y=pos.y-1,z=pos.z},{name = "default:water_source"})
				end
			end
		else
			if spigotname == "pipeworks:spigot_pouring" then
				minetest.add_node({x=pos.x,y=pos.y,z=pos.z},{name = "pipeworks:spigot", param2 = fdir})
				if belowname == "default:water_source" and not finitewater then
					minetest.remove_node({x=pos.x,y=pos.y-1,z=pos.z})
				end
			end
		end
	end
end

table.insert(pipes_empty_nodenames,"pipeworks:valve_on_empty")
table.insert(pipes_empty_nodenames,"pipeworks:valve_off_empty")
table.insert(pipes_empty_nodenames,"pipeworks:entry_panel_empty")
table.insert(pipes_empty_nodenames,"pipeworks:flow_sensor_empty")

table.insert(pipes_full_nodenames,"pipeworks:valve_on_loaded")
table.insert(pipes_full_nodenames,"pipeworks:entry_panel_loaded")
table.insert(pipes_full_nodenames,"pipeworks:flow_sensor_loaded")

minetest.register_abm({
	nodenames = pipes_empty_nodenames,
	interval = 1,
	chance = 1,
	action = function(pos, node, active_object_count, active_object_count_wider) check4inflows(pos,node) end
})

minetest.register_abm({
	nodenames = pipes_full_nodenames,
	interval = 1,
	chance = 1,
	action = function(pos, node, active_object_count, active_object_count_wider) checksources(pos,node) end
})

minetest.register_abm({
	nodenames = {"pipeworks:spigot","pipeworks:spigot_pouring"},
	interval = 1,
	chance = 1,
	action = function(pos, node, active_object_count, active_object_count_wider) 
		spigot_check(pos,node)
	end
})