-- global
pova = {}

-- local
local pova_list = {}
local min, max = math.min, math.max

-- time each override loop runs, 0 to disable
local pova_loop = minetest.settings:get_bool("pova_loop") or 1.0

-- if enabled activate main loop that totals override list on timer
if pova_loop > 0 then

	local timer = 0

	minetest.register_globalstep(function(dtime)

		timer = timer + dtime

		if timer < pova_loop then
			return
		end

		timer = 0

		-- loop through players and apply overrides
		for _,player in ipairs(minetest.get_connected_players()) do
			pova.do_override(player)
		end
	end)
end


-- global functions
pova.add_override = function(name, item, def)

	-- nil check
	if not name or not item then return end

	-- priority defaults to 50 when not included
	def.priority = tonumber(def.priority) or 50

	-- if same item is assigned with lower priority then change ignored
	if pova_list[name][item]
	and pova_list[name][item].priority
	and pova_list[name][item].priority > def.priority then
		return
	end

	pova_list[name][item] = def
end

pova.get_override = function(name, item)
	return pova_list[name][item]
end

pova.del_override = function(name, item)
	pova_list[name][item] = nil
end

pova.do_override = function(player)

	local name = player:get_player_name()

	-- somehow player list is missing
	if not pova_list[name] then
		return
	end

	-- set base defaults
	local speed, jump, gravity = 1, 1, 1

	-- check for new defaults
	if pova_list[name]["default"] then
		speed = pova_list[name]["default"].speed or 1
		jump = pova_list[name]["default"].jump or 1
		gravity = pova_list[name]["default"].gravity or 1
	end

	-- loop through list of named overrides
	for id, var in pairs(pova_list[name]) do

		-- skip any custom names
		if var
		and id ~= "default"
		and id ~= "min"
		and id ~= "max"
		and id ~= "force" then

			-- add any additional changes
			speed = speed + (pova_list[name][id].speed or 0)
			jump = jump + (pova_list[name][id].jump or 0)
			gravity = gravity + (pova_list[name][id].gravity or 0)
		end
	end

	-- make sure total doesn't go below minimum values
	if pova_list[name]["min"] then
		speed = max(pova_list[name]["min"].speed or 0, speed)
		jump = max(pova_list[name]["min"].jump or 0, jump)
		gravity = max(pova_list[name]["min"].gravity or 0, gravity)
	end

	-- make sure total doesn't go above maximum values
	if pova_list[name]["max"] then
		speed = min(pova_list[name]["max"].speed or speed, speed)
		jump = min(pova_list[name]["max"].jump or jump, jump)
		gravity = min(pova_list[name]["max"].gravity or gravity, gravity)
	end

	-- force values (for things like sleeping in bed when speed is 0)
	if pova_list[name]["force"] then
		speed = pova_list[name]["force"].speed or speed
		jump = pova_list[name]["force"].jump or jump
		gravity = pova_list[name]["force"].gravity or gravity
	end

	-- for testing only
	if name == "singleplayer" then
		print ("speed: " .. speed .. " / jump: " .. jump .. " / gravity: " .. gravity)
	end

	-- set new overrides
	player:set_physics_override(speed, jump, gravity)
end


-- set player table on join
minetest.register_on_joinplayer(function(player)
	pova_list[ player:get_player_name() ] = {}
	pova.do_override(player)
end)

-- reset player table on respawn
minetest.register_on_respawnplayer(function(player)
	pova_list[ player:get_player_name() ] = {}
	pova.do_override(player)
end)

-- blank player table on leave
minetest.register_on_leaveplayer(function(player)
	pova_list[ player:get_player_name() ] = nil
end)


-- axe tool to showcase features
minetest.register_craftitem("pova:axe", {
	description = "Test Axe (left to apply, right to remove effects)",
	inventory_image = "default_tool_steelaxe.png",

	on_use = function(itemstack, user, pointed_thing)

		local name = user:get_player_name()

		-- set new defaults
		pova.add_override(name, "default", {speed = 2, jump = 3, gravity = 1})

		-- define changes that are added onto defaults
		pova.add_override(name, "test", {speed = 1, jump = -1, gravity = 0.5})

--= speed is now 3, jump is 2 and gravity is 1.5

		-- set new minimum for jump
		pova.add_override(name, "min", {jump = 3})

		-- add new maximum for speed
		pova.add_override(name, "max", {speed = 2})

		-- add force value for gravity
		pova.add_override(name, "force", {gravity = 1.2})

--= speed is now max 2, jump is min 3 and gravity forced to 1.2

		-- this wont get applied because priority is lower than 50
		pova.add_override(name, "force", {speed = 8, priority = 10})

		-- apply override
		pova.do_override(user)
	end,

	on_place = function(itemstack, user, pointed_thing)

		local name = user:get_player_name()

		-- remove changes
		pova.del_override(name, "min")
		pova.del_override(name, "max")
		pova.del_override(name, "force")
		pova.del_override(name, "test")
		pova.del_override(name, "default")

		-- apply override
		pova.do_override(user)
	end,
})