-- Minetest: builtin/item.lua (override falling entity with new features)

local builtin_shared = ...

-- override falling nodes to add damage

local function add_fall_damage(node, damage)

	if core.registered_nodes[node] then

		local group = core.registered_nodes[node].groups

		group.falling_node_damage = damage

		core.override_item(node, {groups = group})
	else
		print (node .. " not found to add fall_damage to")
	end
end

add_fall_damage("default:sand", 2)
add_fall_damage("default:desert_sand", 2)
add_fall_damage("default:silver_sand", 2)
add_fall_damage("caverealms:coal_dust", 3)
add_fall_damage("tnt:tnt_burning", 4)


--
-- Falling stuff
--

local node_fall_hurt = minetest.setting_getbool("node_fall_hurt") ~= false
local delay = 0.25

local function fall_hurt_check(self, pos, dtime)

	if not node_fall_hurt then return end

	if self.hurt_timer > 0 then
		self.hurt_timer = self.hurt_timer - (dtime * delay)
	else
		-- Get damage level from falling_node_damage group
		local damage = core.registered_nodes[self.node.name] and
			core.registered_nodes[self.node.name].groups.falling_node_damage

		if damage then

			local all_objects = minetest.get_objects_inside_radius(pos, 0.7)

			for _,obj in ipairs(all_objects) do

				local name = obj:get_luaentity() and
					obj:get_luaentity().name or ""

				if name ~= "__builtin:item"
						and name ~= "__builtin:falling_node" then

					obj:punch(obj, 4.0, {
						full_punch_interval = 4.0,
						damage_groups = {fleshy = damage}})
					self.hurt_timer = 0.2
				end
			end
		end
	end
end


core.register_entity(":__builtin:falling_node", {
	initial_properties = {
		visual = "wielditem",
		visual_size = {x = 0.667, y = 0.667},
		textures = {},
		physical = true,
		is_visible = false,
		collide_with_objects = false,
		collisionbox = {-0.5, -0.5, -0.5, 0.5, 0.5, 0.5},
	},

	node = {},
	meta = {},

	set_node = function(self, node, meta)

		self.node = node
		self.meta = meta or {}
		self.hurt_timer = 0

		self.object:set_properties({
			is_visible = true,
			textures = {node.name},
		})
	end,

	get_staticdata = function(self)

		local ds = {node = self.node, meta = self.meta}

		return core.serialize(ds)
	end,

	on_activate = function(self, staticdata)

		self.object:set_armor_groups({immortal = 1})

		local ds = core.deserialize(staticdata)

		if ds and ds.node then

			self:set_node(ds.node, ds.meta)

		elseif ds then

			self:set_node(ds)

		elseif staticdata ~= "" then

			self:set_node({name = staticdata})
		end
	end,

	on_step = function(self, dtime)

		self.timer = (self.timer or 0) + dtime

		if self.timer < delay then
			return
		end

		self.timer = 0

		-- Set gravity
		local acceleration = self.object:getacceleration()

		if not vector.equals(acceleration, {x = 0, y = -10, z = 0}) then
			self.object:setacceleration({x = 0, y = -10, z = 0})
		end

		-- Turn to actual node when colliding with ground, or continue to move
		local pos = self.object:get_pos()

		-- Position of bottom center point
		local below_pos = {x = pos.x, y = pos.y - 0.7, z = pos.z}

		-- Check for player/mobs below falling node and hurt them >:D
		fall_hurt_check(self, below_pos, dtime)

		-- Avoid bugs caused by an unloaded node below
		local below_node = core.get_node_or_nil(below_pos)

		-- Delete on contact with ignore at world edges
		if below_node and below_node.name == "ignore" then

			self.object:remove()

			return
		end

		local below_nodef = below_node and
				core.registered_nodes[below_node.name]

		-- Is below node walkable, or liquid that node floats on?
		if below_node and
				(not below_nodef or below_nodef.walkable or
				(core.get_item_group(self.node.name, "float") ~= 0 and
				below_nodef.liquidtype ~= "none")) then

			-- Is it a level node we can add to?
			if below_nodef and below_nodef.leveled and
					below_node.name == self.node.name then

				local addlevel = self.node.level

				if not addlevel or addlevel <= 0 then
					addlevel = below_nodef.leveled
				end

				if core.add_node_level(below_pos, addlevel) == 0 then

					self.object:remove()

					return
				end

			-- Remove node below if buildable_to and not liquid?
			elseif below_nodef and below_nodef.buildable_to and
					(core.get_item_group(self.node.name, "float") == 0 or
					below_nodef.liquidtype == "none") then

				core.remove_node(below_pos)

				return
			end

			-- Get falling node position and see what's there
--			local np = {x = below_pos.x, y = below_pos.y + 1, z = below_pos.z}
			local np = self.object:get_pos()
			local nod = core.get_node(np)
			local nodef = core.registered_nodes[nod.name]
			local unbreak = nodef and
					core.get_item_group(nod.name, "unbreakable") ~= 0

			-- If not air or liquid or has unbreakable group set,
			-- remove node and replace with it's drops
			if nod.name ~= "air" and not unbreak and
					(not nodef or nodef.liquidtype == "none") then

				core.remove_node(np)

				if nodef.buildable_to == false then

					-- Add dropped items
					local drops = core.get_node_drops(nod, "")

					for _, dropped_item in pairs(drops) do
						core.add_item(np, dropped_item)
					end
				end

				-- Run script hook
				for _, callback in pairs(core.registered_on_dignodes) do
					callback(np, nod)
				end
			end

			-- Create node and remove entity
			local def = core.registered_nodes[self.node.name]

			if def then

				-- If the node below has unbreakable group set
				-- then move the Y position up 1
				if unbreak then
					np.y = np.y + 1
				end

				core.add_node(np, self.node)

				if self.meta then

					local meta = core.get_meta(np)

					meta:from_table(self.meta)
				end

				if def.sounds and def.sounds.place and def.sounds.place.name then
					core.sound_play(def.sounds.place, {pos = np})
				end
			end

			self.object:remove()

			core.check_for_falling(np)

			return
		end

		local vel = self.object:getvelocity()

		if vector.equals(vel, {x = 0, y = 0, z = 0}) then

			local npos = self.object:get_pos()

			self.object:setpos(vector.round(npos))
		end
	end
})