-- Dinv inventory.lua
-- Copyright Duane Robertson (duane@duanerobertson.com), 2019
-- Distributed under the LGPLv2.1 (https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html)


local mod = dinv
local mod_name = 'dinv'


local sorted_items


local ADD_SCROLL_TO_DEFAULT_CHEST = true
local PROTECT_INVENTORY = false  -- Prevent ANY inventory loss.
local WORN_INV = 'worn'


local force_rep = {
	['wood'] = 'default:wood',
	['leaves'] = 'default:leaves',
	['stone'] = 'default:stone',
	['wool'] = 'wool:white',
}

-- This tables looks up groups that aren't already stored.
mod.group_rep = setmetatable({}, {
	__index = function(t, k)
		if not (t and k and type(k) == 'string' and type(t) == 'table') then
			return
		end

		local k = k:gsub('^group:', '')
		local r
		if force_rep[k] then
			r = force_rep[k]
		else
			for a, b in pairs(minetest.registered_items) do
				if b.groups and b.groups[k] then
					r = a
					break
				end
			end
		end

		if r then
			t[k] = r
			return t[k]
		else
			return
		end
	end
})
local group_rep = mod.group_rep



-- iterator over worn inventory
function mod.worn_items(player)
	if not player then
		return
	end

	local pinv = player:get_inventory()
	if not pinv then
		return
	end

	local flist = pinv:get_list(WORN_INV)
	return pairs(flist)
end
local worn_items = mod.worn_items



-- Formspec definitions are confusing.
mod.form_size = 'size[11.25,7.25]'
mod.main_inventory = 'list[current_player;main;2.25,3.5;8,4;'
mod.craft_inventory = 'list[current_player;craft;3.25,0;3,3;]'
mod.craft_preview = 'list[current_player;craftpreview;6.25,2;1,1;]'
mod.main_inventory_scroll_up = 'image_button[10.25,3.5;1,1;transparent_button.png;dinv_main_inventory_up;Up]'
mod.main_inventory_scroll_down = 'image_button[10.25,6.5;1,1;transparent_button.png;dinv_main_inventory_down;Down]'
mod.recipe_button = 'image_button[6.25,1;1,1;transparent_button.png;dinv_recipe_next;Next]'
mod.worn_items_inv = 'list[current_player;worn;0,3.5;2,4;]'
mod.empty_button = 'image_button[2.25,2;1,1;transparent_button.png;dinv_empty_craft;Empty]'
mod.fill_button = 'image_button[2.25,1;1,1;transparent_button.png;dinv_fill_craft;Fill]'

-- backguard compatibility for older default mod, game pre 5.1 release 
if not minetest.global_exists("default.chest") then
	default.chest = {}
	default.chest.get_chest_formspec = default.get_chest_formspec
	minetest.log("warning", "[dinv] using older chest api from default mod")
end

-- All this is necessary to add scroll buttons to chests.
if ADD_SCROLL_TO_DEFAULT_CHEST then
	function default.chest.get_chest_formspec(pos, player)
		local scroll_to = 8
		if player and player.get_player_name then
			local player_name = player:get_player_name()
			if mod.dat[player_name].scroll_main_to then
				scroll_to = mod.dat[player_name].scroll_main_to
			end
		end

		local spos = pos.x .. ',' .. pos.y .. ',' .. pos.z
		local formspec =
			'size[9,9]' ..
			'list[nodemeta:' .. spos .. ';main;0,0.3;8,4;]' ..
			'list[current_player;main;0,4.85;8,1;]' ..
			'list[current_player;main;0,6.08;8,3;' .. scroll_to .. ']' ..
			'listring[nodemeta:' .. spos .. ';main]' ..
			'listring[current_player;main]' ..
			 'image_button[8,6.08;1,1;transparent_button.png;dinv_chest_main_inventory_up;Up]' ..
			 'image_button[8,8.08;1,1;transparent_button.png;dinv_chest_main_inventory_down;Down]' ..
			default.get_hotbar_bg(0,4.85)
		return formspec
	end


	local original_chest_functions = {}
	for _, nd in pairs({ 'default:chest', 'default:chest_locked' }) do
		original_chest_functions[nd] = {}
		original_chest_functions[nd].on_rightclick = minetest.registered_items[nd].on_rightclick

		minetest.override_item(nd, {
			on_rightclick = function(pos, node, clicker, itemstack, pointed_thing)
				if clicker.get_player_name then
					local player_name = clicker:get_player_name()
					local dat = mod.dat[player_name]
					if dat then
						dat.chest_opened = pos
					end
				end

				original_chest_functions[nd].on_rightclick(pos, node, clicker, itemstack, pointed_thing)
			end
		})
	end


	minetest.register_on_player_receive_fields(function(player, formname, fields)
		if formname ~= 'default:chest' then
			return
		end

		if not (player and fields) then
			return
		end

		if not (
			fields['dinv_chest_main_inventory_up']
			or fields['dinv_chest_main_inventory_down']
		) then
			return
		end

		local player_name = player:get_player_name()

		local dat = mod.dat[player_name] or {}
		local pos = dat.chest_opened
		if not pos then
			return
		end

		local pinv = player:get_inventory()
		local main_inventory_size = pinv:get_size('main')

		if fields['dinv_chest_main_inventory_up'] then
			dat['scroll_main_to'] = math.max(8, (dat['scroll_main_to'] or 8) - 16)
			minetest.show_formspec(player_name, 'default:chest', default.chest.get_chest_formspec(pos, player))
		elseif fields['dinv_chest_main_inventory_down'] then
			dat['scroll_main_to'] = (dat['scroll_main_to'] or 8) + 16
			if dat['scroll_main_to'] >= main_inventory_size then
				dat['scroll_main_to'] = 8
			end
			minetest.show_formspec(player_name, 'default:chest', default.chest.get_chest_formspec(pos, player))
		end
	end)
end



function mod.damage_armor(player, damage)
	local wear = (damage + 1) * 100

	for k, v in worn_items(player) do
		local vs = v:get_name()
		local it = minetest.registered_items[vs]
		if it._dinv_armor then
			local ow = v:get_wear()
			v:add_wear(wear)
			player:get_inventory():set_stack(WORN_INV, k, v)
			if ow + wear > 65535 then
				mod.set_armor(player)
				mod.set_armor_textures(player)
			end
		end
	end
end


function mod.empty_craft(player)
	local pinv = player:get_inventory()
	local craft_size = pinv:get_size('craft')

	for i = 1, craft_size do
		local st = pinv:get_stack('craft', i)
		if pinv:room_for_item('main', st) then
			pinv:add_item('main', st)
			pinv:set_stack('craft', i, nil)
		else
			return
		end
	end

	return true
end


function mod.empty_trash(player)
	local pos

	if player and player.get_player_name then
		local player_name = player:get_player_name()
		if mod.dat[player_name].trash_opened then
			pos = mod.dat[player_name].trash_opened
		end
	end

	if not pos then
		return
	end

	local meta = minetest.get_meta(pos)
	if not meta then
		return
	end

	local inv = meta:get_inventory()
	if not inv then
		return
	end

	local size = inv:get_size('main')
	for i = 1, size do
		--local st = inv:get_stack('main', i)
		inv:set_stack('main', i, nil)
	end
end


function mod.get_all_craft_recipes(craft_item)
	local recipes = {}
	for k, v in pairs(minetest.get_all_craft_recipes(craft_item) or {}) do
		if v.type ~= 'cooking' then
			table.insert(recipes, v)
		end
	end

	if #recipes < 1 then
		return
	end

	return recipes
end


-- Calculate how big the main inventory should be.
function mod.get_main_size_by_bags(player)
	local isize = 32

	for k, v in worn_items(player) do
		local vs = v:get_name()
		local it = minetest.registered_items[vs]
		if it._dinv_storage_size then
			isize = isize + it._dinv_storage_size
		end
	end

	return isize
end


function mod.get_trashcan_formspec(pos, player)
	local scroll_to = 0
	if player and player.get_player_name then
		local player_name = player:get_player_name()
		if mod.dat[player_name].scroll_main_to then
			scroll_to = mod.dat[player_name].scroll_main_to
		end
	end

	local spos = pos.x .. ',' .. pos.y .. ',' .. pos.z
	local formspec = 'size[9,8]' ..
	'list[nodemeta:' .. spos .. ';main;0,0.3;8,2;]' ..
	'list[current_player;main;0,4;8,4;' .. scroll_to .. ']' ..
	'listring[]' ..
	 'image_button[3,2.5;2,1;transparent_button.png;dinv_trash_empty;Empty Trash]' ..
	 'image_button[8,4;1,1;transparent_button.png;dinv_trash_inventory_up;Up]' ..
	 'image_button[8,6;1,1;transparent_button.png;dinv_trash_inventory_down;Down]'

	return formspec
end


-- Any warmth over zero is sufficient at the moment.
function mod.get_warmth(player)
	if not player then
		return
	end

	local warmth = 0

	for k, v in worn_items(player) do
		local vs = v:get_name()
		local it = minetest.registered_items[vs]
		if it._dinv_warmth then
			warmth = warmth + it._dinv_warmth
		end
	end

	return warmth
end


-- Check if there are any stacks in the given inventory,
--  at the given positions. This is important to avoid losing
--  those items when a bag is removed.
function mod.items_at_range(inv, name, i, j)
	if not (inv and name and i and j) then
		return
	end

	local a = inv:get_list(name)
	if not a then
		return
	end

	for ind = i + 1, j do
		if a[ind] and a[ind]:get_name() ~= '' then
			return true
		end
	end
end


-- The main formspec...
function mod.make_inventory_spec_sfinv(this, player, context)
	if not player then
		return
	end

	local player_name = player:get_player_name()
	if not mod.dat[player_name] then
		mod.dat[player_name] = {}
	end
	local dat = mod.dat[player_name]
	local scroll_main_to = dat['scroll_main_to'] or 0

	local inventory = ''
	inventory = inventory .. mod.worn_items_inv
	inventory = inventory .. mod.empty_button
	inventory = inventory .. mod.fill_button
	inventory = inventory .. mod.main_inventory .. scroll_main_to .. ']'
	inventory = inventory .. mod.craft_inventory
	inventory = inventory .. 'listring[]'
	inventory = inventory .. mod.craft_preview
	inventory = inventory .. mod.main_inventory_scroll_up
	inventory = inventory .. mod.main_inventory_scroll_down
	inventory = inventory .. mod.recipe_grid(player)
	inventory = inventory .. mod.recipe_list(player)

	local size = 'size[11.25,7.25]'
	local show_inv = false
	return sfinv.make_formspec(player, context, inventory, show_inv, size)
end


-- Change one or more privileges. Set a privilege value
--  to 0, in the input table, to remove it.
-----------------------------------------------
-- Note that this can remove granted privileges.
-----------------------------------------------
function mod.modify_privs(player, p)
	local player_name = player:get_player_name()
	local privs = minetest.get_player_privs(player_name) or {}

	for k, v in pairs(p) do
		if v == 0 then
			privs[k] = nil
		else
			privs[k] = v
		end
	end

	minetest.set_player_privs(player_name, privs)
end


-- Quick table of all wearable items.
-----------------------------------------------------
-- Populating this after the game starts might cause
--  problems, so I do it twice, just in case.
-----------------------------------------------------
mod.wearable = { }
function mod.populate_wearable_table()
	for k, v in pairs(minetest.registered_items) do
		if v._dinv_armor or v._dinv_storage_size
		or v._dinv_on_wear or v._dinv_on_remove
		or v._dinv_while_worn then
			mod.wearable[k] = true
		end
	end
end
mod.populate_wearable_table()
minetest.after(0, function()
	mod.populate_wearable_table()
end)


function mod.receive_sfinv_fields(self, player, context, fields)
	if not (player and fields) then
		return
	end

	if not (
		fields['dinv_main_inventory_up']
		or fields['dinv_main_inventory_down']
		or fields['dinv_recipe_list']
		or fields['dinv_recipe_next']
		or fields['dinv_empty_craft']
		or fields['dinv_fill_craft']
	) then
		return
	end

	local pinv = player:get_inventory()
	local main_inventory_size = pinv:get_size('main')

	if fields and fields['dinv_main_inventory_up'] then
		mod.scroll_main(player, -16, main_inventory_size)
	elseif fields and fields['dinv_main_inventory_down'] then
		mod.scroll_main(player, 16, main_inventory_size)
	elseif fields and fields['dinv_recipe_list'] then
		mod.show_recipe(player, fields['dinv_recipe_list'])
	elseif fields and fields['dinv_recipe_next'] then
		mod.switch_recipe(player, 1)
	elseif fields and fields['dinv_empty_craft'] then
		mod.empty_craft(player)
	elseif fields and fields['dinv_fill_craft'] then
		mod.recipe_fill(player)
	end
end


function mod.recipe_fill(player)
	local player_name = player:get_player_name()
	local dat = mod.dat[player_name]
	local craft_item_number = dat['craft_item_number']
	local recipe_number = dat['recipe_number'] or 1

	if not craft_item_number then
		return
	end

	local craft_item = sorted_items[craft_item_number]
	if not craft_item then
		return
	end

	local recipes = mod.get_all_craft_recipes(craft_item)
	if not recipes then
		return
	end

	local pinv = player:get_inventory()
	local main_size = pinv:get_size('main')

	if recipe_number > #recipes then
		recipe_number = 1
		dat['recipe_number'] = recipe_number
	end
	local recipe = recipes[recipe_number]

	local w = recipe.width or 3
	if w == 0 or w > 3 then
		w = 3
	end

	local items = {}
	local totals = {}
	local g_s = {}
	local i = 0
	for y = 0, 2 do
		for x = 1, w do
			i = i + 1

			local item, group
			if recipe.type == 'normal' then
				item = recipe.items[(y * w) + x]
			end

			if item then
				items[i] = item
				totals[item] = (totals[item] or 0) + 1
			end
		end
	end

	local avail = {}
	local groups = {}
	local stack_max = {}
	local only_one
	local max = 999999
	for k, v in pairs(totals) do
		if k:find('^group:') then
			local group = k:gsub('^group:', '')
			for i = 1, main_size do
				local st = pinv:get_stack('main', i)
				local name = st:get_name()
				--[[
				print(name)
				if name == 'bones:bones' then
					pinv:set_stack('main', i, nil)
				end
				--]]
				local it = minetest.registered_items[name]
				if not it then
					--print(mod_name..': Cannot find item: ' .. name)
					return
				end
				if it.groups and it.groups[group] then
					local ct = st:get_count()
					avail[k] = (avail[k] or 0) + ct
					groups[k] = (groups[k] or {})
					groups[k][name] = (groups[k][name] or 0) + ct
					stack_max[name] = it.stack_max or 99
				end
			end

			local gmax
			for l, w in pairs(groups[k] or {}) do
				if not gmax then
					gmax = w / v
				end
				gmax = math.min(math.max(gmax, w / v), stack_max[l])
			end
			if gmax then
				max = math.min(max, gmax)
			end
		else
			for i = 1, main_size do
				local st = pinv:get_stack('main', i)
				local name = st:get_name()
				if k == name then
					avail[k] = (avail[k] or 0) + st:get_count()
					local it = minetest.registered_items[k]
					if not it then
						--print(mod_name..': Cannot find item: ' .. name)
						return
					end
					stack_max[name] = it.stack_max or 99
					if stack_max[name] < 2 then
						only_one = true
					end
				end
			end
			if max and avail[k] and stack_max[k] then
				max = math.min(math.min(max, avail[k] / v), stack_max[k])
			end
		end
	end

	for k, v in pairs(totals) do
		if not (avail[k] and avail[k] >= v) then
			--print(mod_name..': Cannot find ' .. k .. ' in inventory.')
			return
		end
	end

	if only_one then
		max = 1
	else
		max = math.floor(max)
	end

	if max < 1 then
		return
	end

	if not mod.empty_craft(player) then
		--print(mod_name..': Cannot empty craft inventory')
		return
	end

	for k, v in pairs(items) do
		if v:find('^group:') then
			for l in pairs(groups[v]) do
				local w = groups[v][l]
				if w >= max then
					local st = pinv:remove_item('main', l .. ' ' .. max)
					groups[v][l] = groups[v][l] - st:get_count()
					pinv:set_stack('craft', k, st)
					break
				end
			end
		else
			local st = pinv:remove_item('main', v .. ' ' .. max)
			pinv:set_stack('craft', k, st)
		end
	end
end


-- Return a 3 x 3 grid of images matching the selected recipe.
-- This appears over then actual craft grid, but won't interfere
--  with it.
function mod.recipe_grid(player)
	local player_name = player:get_player_name()
	local dat = mod.dat[player_name]
	local craft_item_number = dat['craft_item_number']
	local recipe_number = dat['recipe_number'] or 1

	if not craft_item_number then
		return ''
	end

	local craft_item = sorted_items[craft_item_number]
	if not craft_item then
		return ''
	end

	local recipes = mod.get_all_craft_recipes(craft_item)
	if not recipes then
		return ''
	end

	if recipe_number > #recipes then
		recipe_number = 1
		dat['recipe_number'] = recipe_number
	end
	local recipe = recipes[recipe_number]

	local inv = ''
	inv = inv .. 'container[3.25,0]'

	do
		local tooltip = craft_item
		inv = inv .. 'item_image[3,2;1,1;' .. craft_item .. ']'
		tooltip = minetest.registered_items[craft_item].description or tooltip
		inv = inv .. 'tooltip[3,2;0.8,0.8;' .. 'recipe: ' .. tooltip .. ']'
	end

	local w = recipe.width or 3
	if w == 0 or w > 3 then
		w = 3
	end

	local g_s = {}
	local i = 0
	for y = 0, 2 do
		for x = 1, w do
			i = i + 1
			local item, group
			if recipe.type == 'normal' then
				item = recipe.items[(y * w) + x]
			end
			local tooltip = item
			if item and item:find('^group') then
				--print(item)
				item = group_rep[item]
				if item then
					g_s[i] = true
				end
			elseif item then
				tooltip = minetest.registered_items[item].description or tooltip
			end
			if item then
				inv = inv .. 'item_image[' .. (x - 1) .. ',' .. (y) .. ';1,1;' .. item .. ']'
				inv = inv .. 'tooltip[' .. (x - 1) .. ',' .. (y) .. ';0.8,0.8;' .. 'recipe: ' .. tooltip .. ']'
			end
		end
	end

	for i = 1, 9 do
		if g_s[i] then
			local x = (i - 1) % w
			local y = math.floor((i - 1) / w)
			inv = inv .. 'image[' .. (x - 0) .. ',' .. (y) .. ';1,1;big_g.png]'
		end
	end
	inv = inv .. 'container_end[]'

	if #recipes > 1 then
		inv = inv .. mod.recipe_button
	end

	return inv
end


-- Return a listbox filled with items that can be crafted.
function mod.recipe_list(player)
	if not sorted_items then
		sorted_items = {}
		for k, v in pairs(minetest.registered_items) do
			if k and k ~= '' and mod.get_all_craft_recipes(k) then
				local recs = mod.get_all_craft_recipes(k)
				for a, b in pairs(recs) do
					if b.type ~= 'cooking' then
						table.insert(sorted_items, k)
						break
					end
				end
			end
		end
		table.sort(sorted_items)
	end

	local inv = ''
	inv = inv .. 'textlist[7.25,0;3.75,2.9;dinv_recipe_list;'
	local t
	for k, v in pairs(sorted_items) do
		if t then
			inv = inv .. ','
		end
		inv = inv .. v
		--print(v)
		t = true
	end
	inv = inv .. ';'
	return inv
end


-- Recreate the inventory formspec when the player scrolls
--  up or down in the main inventory.
function mod.scroll_main(player, amount, max)
	if not (player and amount) then
		return
	end

	local player_name = player:get_player_name()
	if not player_name then
		return
	end

	local scroll = mod.dat[player_name].scroll_main_to or 0
	if scroll and scroll % 8 == 0 then
		scroll = (scroll + amount)
		if scroll > max - 1 or scroll < 0 then
			scroll = 0
		end
		mod.dat[player_name].scroll_main_to = scroll
		sfinv.set_player_inventory_formspec(player)
	end
end


function mod.scroll_trash(player, amount, max)
	if not (player and amount) then
		return
	end

	local player_name = player:get_player_name()
	if not player_name then
		return
	end

	local dat = mod.dat[player_name] or {}
	local pos = dat.trash_opened
	if not pos then
		return
	end

	local scroll = mod.dat[player_name].scroll_main_to or 0
	if scroll and scroll % 8 == 0 then
		scroll = (scroll + amount)
		if scroll > max - 1 or scroll < 0 then
			scroll = 0
		end
		mod.dat[player_name].scroll_main_to = scroll
		minetest.show_formspec(player_name, mod_name..':trashcan', mod.get_trashcan_formspec(pos, player))
	end
end


function mod.set_armor(player)
	if not player then
		return
	end

	local armor = 100

	for k, v in worn_items(player) do
		local vs = v:get_name()
		local it = minetest.registered_items[vs]
		if it._dinv_armor then
			armor = armor * it._dinv_armor
		end
	end

	local player_name = player:get_player_name()
	if player_name then
		minetest.chat_send_player(player_name, 'Your armor: ' .. armor)
	end

	local armor_g = player:get_armor_groups()
	if not (armor_g and armor_g.fleshy) then
		return
	end

	armor_g.fleshy = armor
	player:set_armor_groups(armor_g)
end


-----------------------------------------------
-- Todo: Handle different character textures.
-----------------------------------------------
function mod.set_armor_textures(player)
	local prop = player:get_properties()
	local textures = prop.textures
	--local tex = (textures and textures[1] or 'character.png')
	local tex = 'character.png'
	local pile = {}
	for k, v in worn_items(player) do
		local vs = v:get_name()
		local it = minetest.registered_items[vs]
		if it._dinv_location and it._dinv_texture then
			pile[it._dinv_location] = it._dinv_texture
		end
	end
	for _, loc in pairs({ 'body', 'feet', 'head', 'arm', 'back' }) do
		if pile[loc] then
			tex = tex .. '^' .. pile[loc]
		end
	end
	textures = { tex }
	if minetest.get_modpath("player_api") then
		player_api.set_textures(player, textures)
	else
		default.player_set_textures(player, textures)
	end
end


-- Set the size of the main inventory.
function mod.set_main_size_by_bags(player)
	if not player then
		return
	end

	local pinv = player:get_inventory()
	if not pinv then
		return
	end

	local prsize = pinv:get_size('main')
	local isize = mod.get_main_size_by_bags(player)

	if PROTECT_INVENTORY and isize < prsize then
		print(mod_name..': *** Preventing lost inventory from reducing bag sizes')
		isize = prsize
	end

	if not pinv:set_size('main', isize) then
		print(mod_name..': *** ERROR setting inventory size.')
	end

	return isize
end


-- Recreate the inventory formspec to show a recipe given
--  by the return value from the recipe list.
function mod.show_recipe(player, field)
	if not (player and field) then
		return
	end

	local player_name = player:get_player_name()
	if not player_name then
		return
	end

	local t = minetest.explode_textlist_event(field)
	if t.type == 'CHG' and t.index then
		mod.dat[player_name].craft_item_number = tonumber(t.index)
		mod.dat[player_name].recipe_number = 1

		sfinv.set_player_inventory_formspec(player)
	end
end


-- Recreate the inventory formspec to show a different recipe
--  for the current item (if it has more than one).
function mod.switch_recipe(player, amount)
	if not (player and amount) then
		return
	end

	local player_name = player:get_player_name()
	if not player_name then
		return
	end

	local dat = mod.dat[player_name]
	if not dat.recipe_number then
		dat.recipe_number = 1
	end
	dat.recipe_number = dat.recipe_number + amount
	if dat.recipe_number < 1 then
		dat.recipe_number = 1
	end

	sfinv.set_player_inventory_formspec(player)
end


function mod.trashcan_can_dig(pos,player)
	local meta = minetest.get_meta(pos);
	local inv = meta:get_inventory()
	return inv:is_empty('main')
end


function mod.trashcan_construct(pos)
	local meta = minetest.get_meta(pos)
	meta:set_string('infotext', 'Trashcan')
	local inv = meta:get_inventory()
	inv:set_size('main', 8*2)
end


function mod.trashcan_rightclick(pos, node, player, itemstack, pointed_thing)
	local player_name
	if player and player.get_player_name then
		player_name = player:get_player_name()
	end

	if not player_name then
		return
	end

	local dat = mod.dat[player_name]
	if dat then
		dat.trash_opened = pos
	end

	minetest.show_formspec(player_name, mod_name..':trashcan', mod.get_trashcan_formspec(pos, player))
end


-- Return true if there's an item at that body location.
function mod.wearing_on_location(player, loc)
	for k, v in worn_items(player) do
		local vs = v:get_name()
		local it = minetest.registered_items[vs]
		if it._dinv_location == loc then
			return true
		end
	end
end



-- Check for BAD THINGS if a player moves/adds/removes this item.
minetest.register_allow_player_inventory_action(function(player, action, inventory, inventory_info)
	if not (player and action and inventory and inventory_info) then
		return
	end

	if not (inventory_info.from_list == WORN_INV or inventory_info.to_list == WORN_INV or inventory_info.listname == WORN_INV) then
		return
	end

	local item_from, item_from_s
	if action == 'move' and inventory_info.from_list then
		item_from = inventory:get_stack(inventory_info.from_list, inventory_info.from_index)
	else
		item_from = inventory_info.stack
	end

	if item_from and item_from.get_name then
		item_from_s = item_from:get_name()
	end

	local item_to, item_to_s
	if action == 'move' and inventory_info.to_list then
		item_to = inventory:get_stack(inventory_info.to_list, inventory_info.to_index)
	end
	if item_to and item_to.get_name then
		item_to_s = item_to:get_name()
	end

	if action == 'move' then
		if not mod.wearable[item_from_s] then
			if inventory_info.to_list == WORN_INV then
				return 0
			else
				return
			end
		end

		if item_to_s and item_to_s ~= '' then
			return 0
		end

		if inventory_info.to_list == inventory_info.from_list then
			return
		end

		local item_from_it = minetest.registered_items[item_from_s]
		if item_from_it._dinv_location and inventory_info.to_list == WORN_INV
		and mod.wearing_on_location(player, item_from_it._dinv_location) then
			return 0
		end

		if item_from_it._dinv_storage_size then
			local prsize = mod.get_main_size_by_bags(player)
			local isize = prsize
			if inventory_info.to_list == WORN_INV then
				isize = isize + item_from_it._dinv_storage_size
			elseif inventory_info.from_list == WORN_INV then
				isize = isize - item_from_it._dinv_storage_size
			end

			if isize < prsize and mod.items_at_range(inventory, 'main', isize, prsize) then
				return 0
			elseif inventory_info.to_index > isize then
				return 0
			end
		end
	elseif action == 'take' and mod.wearable[item_from_s] then
		return 0
	elseif action == 'put' then
		return 0
	end
end)


-- Damage items that can only be worn for a limited time.
local last_wear_check = 0
minetest.register_globalstep(function(dtime)
	local time = minetest.get_gametime()
	if type(time) ~= 'number' then
		return
	end

	if time - last_wear_check < 5 then
		return
	end

	local players = minetest.get_connected_players()

	for i = 1, #players do
		local player = players[i]

		for k, v in worn_items(player) do
			local vs = v:get_name()
			local it = minetest.registered_items[vs]
			if it._dinv_wears_out then
				local ow = v:get_wear()
				local wear = it._dinv_wears_out
				v:add_wear(wear)
				player:get_inventory():set_stack(WORN_INV, k, v)
				if ow + wear > 65535 then
					if it._dinv_on_remove then
						it._dinv_on_remove(player)
					end
					--[[
					mod.set_armor(player)
					mod.set_armor_textures(player)
					--]]
				end

				if it._dinv_while_worn then
					it._dinv_while_worn(player)
				end
			end
		end
	end

	last_wear_check = minetest.get_gametime()
end)


minetest.register_on_joinplayer(function(player)
	local player_name = player:get_player_name()
	--[[
	if not mod.dat[player_name] then
		mod.dat[player_name] = {}
	end
	--]]

	local pinv = player:get_inventory()
	pinv:set_size(WORN_INV, 8)
	mod.set_main_size_by_bags(player)
	mod.set_armor(player)
	mod.set_armor_textures(player)
end)


--sfinv.register_page(mod_name..':inventory', {
sfinv.override_page('sfinv:crafting', {
	title = 'Inventory',
	get = mod.make_inventory_spec_sfinv,
	on_player_receive_fields = mod.receive_sfinv_fields,
})


-- Handle inventory moves (change armor, etc.).
minetest.register_on_player_inventory_action(function(player, action, inventory, inventory_info)
	if not (player and action and inventory and inventory_info) then
		return
	end

	if not (inventory_info.from_list == WORN_INV or inventory_info.to_list == WORN_INV or inventory_info.listname == WORN_INV) then
		return
	end

	local item
	if action == 'move' then
		if not (inventory_info.to_list and inventory_info.to_index) then
			return
		end

		item = inventory:get_stack(inventory_info.to_list, inventory_info.to_index)
	else
		item = inventory_info.stack
	end

	if not item then
		return
	end

	local item_s = item:get_name()
	if not mod.wearable[item_s] then
		return
	end

	mod.set_main_size_by_bags(player)
	mod.set_armor(player)
	mod.set_armor_textures(player)

	local it = minetest.registered_items[item_s]
	if inventory_info.to_list == inventory_info.from_list then
		-- nop
	elseif it._dinv_on_wear and inventory_info.to_list == WORN_INV then
		it._dinv_on_wear(player)
	elseif it._dinv_on_remove and inventory_info.from_list == WORN_INV then
		it._dinv_on_remove(player)
	end
end)


-- Get input from the trash formspec buttons.
minetest.register_on_player_receive_fields(function(player, formname, fields)
	if formname ~= mod_name..':trashcan' then
		return
	end

	if not (player and fields) then
		return
	end

	if not (
		fields['dinv_trash_inventory_up']
		or fields['dinv_trash_inventory_down']
		or fields['dinv_trash_empty']
	) then
		return
	end

	local pinv = player:get_inventory()
	local main_inventory_size = pinv:get_size('main')

	if fields and fields['dinv_trash_inventory_up'] then
		mod.scroll_trash(player, -16, main_inventory_size)
	elseif fields and fields['dinv_trash_inventory_down'] then
		mod.scroll_trash(player, 16, main_inventory_size)
	elseif fields and fields['dinv_trash_empty'] then
		mod.empty_trash(player)
	end
end)


-- Every time the player gets punched, armor is damaged,
--  even if no damage is done to the player.
minetest.register_on_punchplayer(function(player, hitter, time_from_last_punch, tool_capabilities, dir, damage)
	mod.damage_armor(player, damage)
end)


if not minetest.get_modpath('bones') then
	print(mod_name..': Player gear will suffer when the player dies.')

	minetest.register_on_dieplayer(function(player, reason)
		if not player then
			return
		end

		local pinv = player:get_inventory()
		if not pinv then
			return
		end

		local wear = 20000
		local main_size = pinv:get_size('main')
		for i = 1, main_size do
			local st = pinv:get_stack('main', i)
			local name = st:get_name()

			if minetest.registered_tools[name] then
				local ow = st:get_wear()
				st:add_wear(wear)
				pinv:set_stack('main', i, st)
			end
		end

		mod.damage_armor(player, 199)
		mod.set_armor(player)
		mod.set_armor_textures(player)
	end)
end