-- Ephemeral third-person visuals only. Main loads this once before runtime.
-- No ItemStacks, inventories, metadata, static data, attacks or file paths from input.
local C, H = core, hearth
local meshes = {
	["hearth:knife"] = "hearth_knife.obj",
	["hearth:axe"] = "hearth_axe.obj",
	["hearth:pick"] = "hearth_pick.obj",
	["hearth:spear"] = "hearth_spear.obj",
}
local records, pending = {}, nil
local entity_name = "hearth:held_visual"

local function live(record)
	local p, name = record.player, record.name
	return C.get_player_by_name(name) == p and H.sessions[name] == record.session
		and H.players[name] ~= nil and not record.session.waiting
		and p:get_pos() ~= nil and p:get_hp() > 0
		and p:get_wielded_item():get_name() == record.item
end
local function remove(record)
	-- Clear ownership BEFORE remove/on_deactivate; an old callback cannot clear
	-- a replacement belonging to a same-name reconnect or a different weapon.
	if records[record.name] == record then records[record.name] = nil end
	local object = record.object
	record.object = nil
	if object and object:get_pos() then object:remove() end
end
local function attached(record)
	local object = record.object
	if not object or not object:get_pos() then return false end
	local parent, bone, pos, rotation, forced = object:get_attach()
	return parent == record.player and bone == "Hand_Right" and pos
		and pos.x == 0 and pos.y == 0 and pos.z == 0 and rotation
		and rotation.x == 90 and rotation.y == 0 and rotation.z == 0 and forced == false
end

C.register_entity(entity_name, {
	initial_properties = {
		visual = "mesh", mesh = "hearth_knife.obj", textures = {"hearth_person.png"},
		-- The generated B3D and held OBJ both use model units (10 per node).
		visual_size = {x = 1, y = 1, z = 1}, is_visible = false,
		physical = false, collide_with_objects = false, pointable = false,
		collisionbox = {0, 0, 0, 0, 0, 0}, selectionbox = {0, 0, 0, 0, 0, 0},
		static_save = false, hp_max = 1, makes_footstep_sound = false,
	},
	on_activate = function(self, staticdata)
		-- Only synchronous creation by presentation_step may bind an entity.
		-- Restored/foreign/unowned entities disappear rather than becoming drops.
		local record = pending
		if staticdata ~= "" or not record or record.object or not live(record) then
			self.object:remove(); return
		end
		record.object, self._held_record = self.object, record
		self.object:set_armor_groups({immortal = 1})
	end,
	get_staticdata = function() return "" end,
	on_step = function(self)
		local record = self._held_record
		if not record then self.object:remove(); return end
		if records[record.name] ~= record or not live(record) or not attached(record) then remove(record) end
	end,
	on_deactivate = function(self)
		local record = self._held_record
		self._held_record = nil
		if record then
			if records[record.name] == record then records[record.name] = nil end
			record.object = nil
		end
	end,
	-- Cosmetic, non-pointable, immortal; even a direct punch has no gameplay effect.
	on_punch = function() return true end,
	on_rightclick = function() end,
})

function H.presentation_step(player)
	local name = player:get_player_name()
	local record, session = records[name], H.sessions[name]
	local item = player:get_wielded_item():get_name()
	local mesh = meshes[item]
	if record then
		if record.player == player and live(record) and attached(record) then return end
		-- A deferred call on an old PlayerRef must not destroy the live replacement.
		if record.player ~= player and C.get_player_by_name(name) ~= player then return end
		remove(record)
	end
	if not mesh or not session then return end
	record = {name = name, player = player, session = session, item = item}
	if not live(record) then return end
	records[name], pending = record, record
	local ok, object = pcall(C.add_entity, player:get_pos(), entity_name)
	pending = nil
	if not ok or not object or object ~= record.object or not object:get_pos() then
		remove(record); return
	end
	object:set_properties({mesh = mesh})
	-- forced_visible is the FIFTH argument: false hides this from its owner in
	-- first person, but permits third-person rendering. Never toggle is_visible
	-- from a guessed server-side camera mode (it would hide it for observers).
	object:set_attach(player, "Hand_Right", {x = 0, y = 0, z = 0}, {x = 90, y = 0, z = 0}, false)
	if not attached(record) then remove(record); return end
	object:set_properties({is_visible = true})
end
function H.presentation_cleanup(player)
	local record = records[player:get_player_name()]
	if record and record.player == player then remove(record) end
end
C.register_on_leaveplayer(H.presentation_cleanup)
C.register_on_dieplayer(H.presentation_cleanup)
C.register_on_shutdown(function()
	local snapshot = {}; for _, record in pairs(records) do snapshot[#snapshot + 1] = record end
	for _, record in ipairs(snapshot) do remove(record) end
end)

return H.presentation_step