TheDarkProject/mods/HUD/mcl_inventory/init.lua

local S = minetest.get_translator(minetest.get_current_modname())
local F = minetest.formspec_escape

mcl_inventory = {}

--local mod_player = minetest.get_modpath("mcl_player")
--local mod_craftguide = minetest.get_modpath("mcl_craftguide")

-- Returns a single itemstack in the given inventory to the main inventory, or drop it when there's no space left
function return_item(itemstack, dropper, pos, inv)
	if dropper:is_player() then
		-- Return to main inventory
		if inv:room_for_item("main", itemstack) then
			inv:add_item("main", itemstack)
		else
			-- Drop item on the ground
			local v = dropper:get_look_dir()
			local p = {x=pos.x, y=pos.y+1.2, z=pos.z}
			p.x = p.x+(math.random(1,3)*0.2)
			p.z = p.z+(math.random(1,3)*0.2)
			local obj = minetest.add_item(p, itemstack)
			if obj then
				v.x = v.x*4
				v.y = v.y*4 + 2
				v.z = v.z*4
				obj:set_velocity(v)
				obj:get_luaentity()._insta_collect = false
			end
		end
	else
		-- Fallback for unexpected cases
		minetest.add_item(pos, itemstack)
	end
	return itemstack
end

-- Return items in the given inventory list (name) to the main inventory, or drop them if there is no space left
function return_fields(player, name)
	local inv = player:get_inventory()
	local list = inv:get_list(name)
	if not list then return end
	for i,stack in ipairs(list) do
		return_item(stack, player, player:get_pos(), inv)
		stack:clear()
		inv:set_stack(name, i, stack)
	end
end

local function set_inventory(player, armor_change_only)
	if minetest.is_creative_enabled(player:get_player_name()) then
		if armor_change_only then
			-- Stay on survival inventory plage if only the armor has been changed
			mcl_inventory.set_creative_formspec(player, 0, 0, nil, nil, "inv")
		else
			mcl_inventory.set_creative_formspec(player, 0, 1)
		end
		return
	end
	local inv = player:get_inventory()
	inv:set_width("craft", 2)
	inv:set_size("craft", 4)

	local armor_slots = {"helmet", "chestplate", "leggings", "boots"}
	local armor_slot_imgs = ""
	for a=1,4 do
		if inv:get_stack("armor", a+1):is_empty() then
			armor_slot_imgs = armor_slot_imgs .. "image[0,"..(a-1)..";1,1;mcl_inventory_empty_armor_slot_"..armor_slots[a]..".png]"
		end
	end

	if inv:get_stack("offhand", 1):is_empty() then
		armor_slot_imgs = armor_slot_imgs .. "image[3,2;1,1;mcl_inventory_empty_armor_slot_shield.png]"
	end

	local form = "size[9,8.75]" ..
		"background[-0.19,-0.25;9.41,9.49;crafting_formspec_bg.png]" ..
		mcl_player.get_player_formspec_model(player, 1.0, 0.0, 2.25, 4.5, "") ..

		-- Armor
		"list[current_player;armor;0,0;1,1;1]" ..
		"list[current_player;armor;0,1;1,1;2]" ..
		"list[current_player;armor;0,2;1,1;3]" ..
		"list[current_player;armor;0,3;1,1;4]" ..
		mcl_formspec.get_itemslot_bg(0,0,1,1) ..
		mcl_formspec.get_itemslot_bg(0,1,1,1) ..
		mcl_formspec.get_itemslot_bg(0,2,1,1) ..
		mcl_formspec.get_itemslot_bg(0,3,1,1) ..
		"list[current_player;offhand;3,2;1,1]" ..
		mcl_formspec.get_itemslot_bg(3,2,1,1) ..
		armor_slot_imgs ..

		-- Craft and inventory
		"label[0,4;"..F(minetest.colorize("#313131", S("Inventory"))) .. "]" ..
		"list[current_player;main;0,4.5;9,3;9]" ..
		"list[current_player;main;0,7.74;9,1;]" ..
		"label[4,0.5;"..F(minetest.colorize("#313131", S("Crafting"))) .. "]" ..
		"list[current_player;craft;4,1;2,2]" ..
		"list[current_player;craftpreview;7,1.5;1,1;]" ..
		mcl_formspec.get_itemslot_bg(0, 4.5, 9, 3) ..
		mcl_formspec.get_itemslot_bg(0, 7.74, 9, 1) ..
		mcl_formspec.get_itemslot_bg(4, 1,2, 2) ..
		mcl_formspec.get_itemslot_bg(7, 1.5, 1, 1) ..

		-- Crafting guide button
		"image_button[4.5,3;1,1;craftguide_book.png;__mcl_craftguide;]" ..
		"tooltip[__mcl_craftguide;"..F(S("Recipe book")) .. "]" ..

		-- Help button
		"image_button[8,3;1,1;doc_button_icon_lores.png;__mcl_doc;]" ..
		"tooltip[__mcl_doc;" .. F(S("Help")) .. "]"

	-- Skins button
	if minetest.global_exists("mcl_skins") then
		form = form ..
			"image_button[3,3;1,1;mcl_skins_button.png;__mcl_skins;]" ..
			"tooltip[__mcl_skins;" .. F(S("Select player skin")) .. "]"
	end

	form = form ..
		-- Achievements button
		"image_button[7,3;1,1;mcl_achievements_button.png;__mcl_achievements;]" ..
		"tooltip[__mcl_achievements;" .. F(S("Advancements")) .. "]" ..

		-- For shortcuts
		"listring[current_player;main]" ..
		"listring[current_player;armor]" ..
		"listring[current_player;main]" ..
		"listring[current_player;craft]" ..
		"listring[current_player;main]"

	player:set_inventory_formspec(form)
end

-- Drop items in craft grid and reset inventory on closing
minetest.register_on_player_receive_fields(function(player, formname, fields)
	if fields.quit then
		return_fields(player,"craft")
		return_fields(player,"enchanting_lapis")
		return_fields(player,"enchanting_item")
		if not minetest.is_creative_enabled(player:get_player_name()) and (formname == "" or formname == "main") then
			set_inventory(player)
		end
	end
end)

if not minetest.is_creative_enabled("") then
	function mcl_inventory.update_inventory_formspec(player)
		set_inventory(player)
	end
end

-- Drop crafting grid items on leaving
minetest.register_on_leaveplayer(function(player)
	return_fields(player, "craft")
	return_fields(player, "enchanting_lapis")
	return_fields(player, "enchanting_item")
end)

minetest.register_on_joinplayer(function(player)
	--init inventory
	local inv = player:get_inventory()
	inv:set_width("main", 9)
	inv:set_size("main", 36)
	inv:set_size("offhand", 1)

	--set hotbar size
	player:hud_set_hotbar_itemcount(9)
	--add hotbar images
	player:hud_set_hotbar_image("mcl_inventory_hotbar.png")
	player:hud_set_hotbar_selected_image("mcl_inventory_hotbar_selected.png")

	local old_update_player = mcl_armor.update_player
	function mcl_armor.update_player(player, info)
		old_update_player(player, info)
		set_inventory(player, true)
	end

	-- In Creative Mode, the initial inventory setup is handled in creative.lua
	if not minetest.is_creative_enabled(player:get_player_name()) then
		set_inventory(player)
	end

	--[[ Make sure the crafting grid is empty. Why? Because the player might have
	items remaining in the crafting grid from the previous join; this is likely
	when the server has been shutdown and the server didn't clean up the player
	inventories. ]]
	return_fields(player, "craft")
	return_fields(player, "enchanting_item")
	return_fields(player, "enchanting_lapis")
end)

dofile(minetest.get_modpath(minetest.get_current_modname()).."/creative.lua")

mcl_player.register_on_visual_change(mcl_inventory.update_inventory_formspec)

local mt_is_creative_enabled = minetest.is_creative_enabled

function minetest.is_creative_enabled(name)
	if mt_is_creative_enabled(name) then return true end
	if not name then return false end
	local p = minetest.get_player_by_name(name)
	if p then
		return p:get_meta():get_string("gamemode") == "creative"
	end
	return false
end

--Insta "digging" nodes in gamemode-creative
minetest.register_on_punchnode(function(pos, node, puncher, pointed_thing)
	if not puncher or not puncher:is_player() then return end
	local name = puncher:get_player_name()
	if not minetest.is_creative_enabled(name) then return end
	if pointed_thing.type ~= "node" then return end
	local def = minetest.registered_nodes[node.name]
	if def then
		minetest.node_dig(pos,node,puncher)
		return true
	end
end)

--Don't subtract from inv when placing in gamemode-creative
minetest.register_on_placenode(function(pos, newnode, placer, oldnode, itemstack, pointed_thing)
	if placer and placer:is_player() and minetest.is_creative_enabled(placer:get_player_name()) then return true end
end)

local function in_table(n,h)
	for k,v in pairs(h) do
		if v == n then return true end
	end
	return false
end

local gamemodes = {
	"survival",
	"creative"
}

function mcl_inventory.player_set_gamemode(p,g)
	local m = p:get_meta()
	m:set_string("gamemode",g)
	if g == "survival" then
		 mcl_experience.setup_hud(p)
		 mcl_experience.update(p)
	elseif g == "creative" then
		 mcl_experience.remove_hud(p)
	end
	set_inventory(p)
end

minetest.register_chatcommand("gamemode",{
	params = S("[<gamemode>] [<player>]"),
	description = S("Change gamemode (survival/creative) for yourself or player"),
	privs = { server = true },
	func = function(n,param)
		-- Full input validation ( just for @erlehmann <3 )
		local p
		local args = param:split(" ")
		if args[2] ~= nil then
			p = minetest.get_player_by_name(args[2])
			n = args[2]
		else
			p = minetest.get_player_by_name(n)
		end
		if not p then
			return false, S("Player not online")
		end
		if args[1] ~= nil and not in_table(args[1],gamemodes) then
			return false, S("Gamemode " .. args[1] .. " does not exist.")
		elseif args[1] ~= nil then
			mcl_inventory.player_set_gamemode(p,args[1])
		end

		--Result message - show effective game mode
		local gm = p:get_meta():get_string("gamemode")
		if gm == "" then gm = gamemodes[1] end
		return true, S("Gamemode for player ")..n..S(": "..gm)
	end
})