upgrade_packs = {}
upgrade_packs.health_items = {}
upgrade_packs.breath_items = {}

local modpath = minetest.get_modpath("upgrade_packs")

dofile(modpath .. "/api.lua")
if minetest.get_modpath("unified_inventory") then
	dofile(modpath .. "/gui_unified_inventory.lua")
elseif minetest.get_modpath("sfinv") then
	dofile(modpath .. "/gui_sfinv.lua")
end

upgrade_packs.register_pack("upgrade_packs:hp_10", "health", {
	description = "+10 HP",
	strength = 10,
	image = "heart.png"
})

upgrade_packs.register_pack("upgrade_packs:breath_5", "breath", {
	description = "+5 Breath",
	strength = 5,
	image = "bubble.png"
})

-- Cache items which are interesting for this mod
minetest.after(0, function()
	local items = minetest.registered_items
	local health_items = {}
	local breath_items = {}

	for name, def in pairs(items) do
		local groups = def.groups or {}
		if groups.upgrade_health
				and groups.upgrade_health ~= 0 then
			health_items[name] = groups.upgrade_health
		end
		if groups.upgrade_breath
				and groups.upgrade_breath ~= 0 then
			breath_items[name] = groups.upgrade_breath
		end
	end
	upgrade_packs.health_items = health_items
	upgrade_packs.breath_items = breath_items
end)

minetest.register_on_joinplayer(function(player)
	local inv = player:get_inventory()
	inv:set_size("ugpacks", 4)
	upgrade_packs.update_player(player)
end)

minetest.register_on_item_eat(function(hp_change, replace_with_item, itemstack, user)
	print(dump(hp_change))
	if hp_change == 0 then
		return
	end
	-- Undo some of the wear when eating instead of dying
	upgrade_packs.add_wear(user, "health", hp_change * -10)
end)

minetest.register_on_player_hpchange(function(player, hp_change, reason)
	if hp_change >= 0 then
		return
	end
	if reason == "drown" then
		upgrade_packs.add_wear(player, "breath", 200)
	else
		upgrade_packs.add_wear(player, "health", hp_change * -10)
	end
end, false)

minetest.register_allow_player_inventory_action(function(player, action, inv, data)
	print(dump(data))
	if data.to_list ~= "ugpacks" then
		return -- Not interesting for this mod
	end
	local stack = inv:get_stack(data.from_list, data.from_index)

	if upgrade_packs.health_items[stack:get_name()] then
		return 1
	end
	if upgrade_packs.breath_items[stack:get_name()] then
		return 1
	end

	return 0
end)

minetest.register_on_player_inventory_action(function(player, action, inv, data)
	if data.to_list == "ugpacks" or data.from_list == "ugpacks" then
		upgrade_packs.update_player(player)
	end
end)