creative = {}


minetest.register_privilege("creative", {
	description = "Allow player to use creative inventory",
	give_to_singleplayer = false,
	give_to_admin = false
})


local creative_mode_cache = minetest.settings:get_bool("creative_mode")

function creative.is_enabled_for(name)
	return creative_mode_cache or
			minetest.check_player_privs(name, {creative = true})
end


local player_inventory = {}
local inventory_cache = {}


local function init_creative_cache(items)

	inventory_cache[items] = {}

	local i_cache = inventory_cache[items]

	for name, def in pairs(items) do

		if def.groups.not_in_creative_inventory ~= 1 and
				def.description and def.description ~= "" then
			i_cache[name] = def
		end
	end

	table.sort(i_cache)

	return i_cache
end


function creative.init_creative_inventory(player)

	local player_name = player:get_player_name()

	player_inventory[player_name] = {
		size = 0,
		filter = "",
		start_i = 0
	}

	minetest.create_detached_inventory("creative_" .. player_name, {

		allow_move = function(inv, from_list, from_index, to_list, to_index, count, player2)

			local name = player2 and player2:get_player_name() or ""

			if not creative.is_enabled_for(name) or
					to_list == "main" then
				return 0
			end

			return count
		end,

		allow_put = function(inv, listname, index, stack, player2)
			return 0
		end,

		allow_take = function(inv, listname, index, stack, player2)

			local name = player2 and player2:get_player_name() or ""

			if not creative.is_enabled_for(name) then
				return 0
			end

			return -1
		end,

		on_move = function(inv, from_list, from_index, to_list, to_index, count, player2)
		end,

		on_take = function(inv, listname, index, stack, player2)

			if stack and stack:get_count() > 0 then
				minetest.log("action", player_name .. " takes " .. stack:get_name().. " from creative inventory")
			end
		end,
	}, player_name)

	return player_inventory[player_name]
end


function creative.update_creative_inventory(player_name, tab_content)

	local creative_list = {}

	local inv = player_inventory[player_name] or
			creative.init_creative_inventory(minetest.get_player_by_name(player_name))

	local player_inv = minetest.get_inventory({
		type = "detached",
		name = "creative_" .. player_name
	})

	local items = inventory_cache[tab_content] or
			init_creative_cache(tab_content)

	for name, def in pairs(items) do

		if def.name:find(inv.filter, 1, true) or
				def.description:lower():find(inv.filter, 1, true) then
			creative_list[#creative_list+1] = name
		end
	end

	table.sort(creative_list)
	player_inv:set_size("main", #creative_list)
	player_inv:set_list("main", creative_list)
	inv.size = #creative_list
end


-- Create the trash field
local trash = minetest.create_detached_inventory("creative_trash", {
	-- Allow the stack to be placed and remove it in on_put()
	-- This allows the creative inventory to restore the stack
	allow_put = function(inv, listname, index, stack, player)
		return stack:get_count()
	end,

	on_put = function(inv, listname)
		inv:set_list(listname, {})
	end,
})

trash:set_size("main", 1)

creative.formspec_add = ""


function creative.register_tab(name, title, inv_items)

	-- copy items table so that original isn't affected
	local items = table.copy(inv_items)

	-- remove item fluff and only keep name, description and groups
	for name, def in pairs(items) do
		items[name] = {
			name = name,
			description = def.description,
			groups = def.groups,
		}
	end

	-- formspec GUI related stuff from default
	local default_gui_bg = "bgcolor[#080808BB;true]"
	local default_gui_bg_img = "background[5,5;1,1;gui_formbg.png;true]"
	local default_gui_slots = "listcolors[#00000069;#5A5A5A;#141318;#30434C;#FFF]"
	local function default_get_hotbar_bg(x,y)
		local out = ""
		for i=0,7,1 do
			out = out .."image["..x+i..","..y..";1,1;gui_hb_bg.png]"
		end
		return out
	end

	-- register sfinv tab
	sfinv.register_page("creative:" .. name, {

		title = title,

		is_in_nav = function(self, player, context)
			return creative.is_enabled_for(player:get_player_name())
		end,

		get = function(self, player, context)

			local player_name = player:get_player_name()

			creative.update_creative_inventory(player_name, items)

			local inv = player_inventory[player_name]
			local start_i = inv.start_i or 0
			local pagenum = math.floor(start_i / (3*8) + 1)
			local pagemax = math.ceil(inv.size / (3*8))

			return sfinv.make_formspec(player, context,
				"label[6.2,3.35;" .. minetest.colorize("#FFFF00", tostring(pagenum)) .. " / " .. tostring(pagemax) .. "]" ..
				[[
					image[4.06,3.4;0.8,0.8;creative_trash_icon.png]
					listcolors[#00000069;#5A5A5A;#141318;#30434C;#FFF]
					list[current_player;main;0,4.7;8,1;]
					list[current_player;main;0,5.85;8,3;8]
					list[detached:creative_trash;main;4,3.3;1,1;]
					listring[]
					button[5.4,3.2;0.8,0.9;creative_prev;<]
					button[7.25,3.2;0.8,0.9;creative_next;>]
					button[2.1,3.4;0.8,0.5;creative_search;?]
					button[2.75,3.4;0.8,0.5;creative_clear;X]
					tooltip[creative_search;Search]
					tooltip[creative_clear;Reset]
					listring[current_player;main]
					field_close_on_enter[creative_filter;false]
				]] ..
				"field[0.3,3.5;2.2,1;creative_filter;;" .. minetest.formspec_escape(inv.filter) .. "]" ..
				"listring[detached:creative_" .. player_name .. ";main]" ..
				"list[detached:creative_" .. player_name .. ";main;0,0;8,3;" .. tostring(start_i) .. "]" ..
				default_get_hotbar_bg(0,4.7) ..
				default_gui_bg .. default_gui_bg_img .. default_gui_slots
				.. creative.formspec_add, false)
		end,

		on_enter = function(self, player, context)

			local player_name = player:get_player_name()
			local inv = player_inventory[player_name]

			if inv then
				inv.start_i = 0
			end
		end,

		on_player_receive_fields = function(self, player, context, fields)

			local player_name = player:get_player_name()
			local inv = player_inventory[player_name]

			assert(inv)

			if fields.creative_clear then

				inv.start_i = 0
				inv.filter = ""
				creative.update_creative_inventory(player_name, items)
				sfinv.set_player_inventory_formspec(player, context)

			elseif fields.creative_search or
					fields.key_enter_field == "creative_filter" then

				inv.start_i = 0
				inv.filter = fields.creative_filter:lower()
				creative.update_creative_inventory(player_name, items)
				sfinv.set_player_inventory_formspec(player, context)

			elseif not fields.quit then

				local start_i = inv.start_i or 0

				if fields.creative_prev then

					start_i = start_i - 3*8

					if start_i < 0 then

						start_i = inv.size - (inv.size % (3*8))

						if inv.size == start_i then
							start_i = math.max(0, inv.size - (3*8))
						end
					end

				elseif fields.creative_next then

					start_i = start_i + 3*8

					if start_i >= inv.size then
						start_i = 0
					end
				end

				inv.start_i = start_i

				sfinv.set_player_inventory_formspec(player, context)
			end
		end
	})
end


-- Only add a single 'Creative' tab with search ability for all items
creative.register_tab("all", "Creative", minetest.registered_items)


-- Set player homepage to 'Creative' tab if game mode or priv set
local old_homepage_name = sfinv.get_homepage_name

function sfinv.get_homepage_name(player)

	if creative.is_enabled_for(player:get_player_name()) then
		return "creative:all"
	else
		return old_homepage_name(player)
	end
end


if creative_mode_cache then
	-- Dig time is modified according to difference (leveldiff) between tool
	-- 'maxlevel' and node 'level'. Digtime is divided by the larger of
	-- leveldiff and 1.
	-- To speed up digging in creative, hand 'maxlevel' and 'digtime' have been
	-- increased such that nodes of differing levels have an insignificant
	-- effect on digtime.
	local digtime = 42
	local caps = {times = {digtime, digtime, digtime}, uses = 0, maxlevel = 256}

	minetest.register_item(":", {
		type = "none",
		wield_image = "wieldhand.png",
		wield_scale = {x = 1, y = 1, z = 2.5},
		range = 10,
		tool_capabilities = {
			full_punch_interval = 0.5,
			max_drop_level = 3,
			groupcaps = {
				crumbly = caps,
				cracky  = caps,
				snappy  = caps,
				choppy  = caps,
				oddly_breakable_by_hand = caps,
			},
			damage_groups = {fleshy = 10},
		}
	})
end


-- Unlimited node placement
minetest.register_on_placenode(function(pos, newnode, placer, oldnode, itemstack)
	if placer and placer:is_player() then
		return creative.is_enabled_for(placer:get_player_name())
	end
end)


-- Don't pick up if the item is already in the inventory
local old_handle_node_drops = minetest.handle_node_drops

function minetest.handle_node_drops(pos, drops, digger)

	if not digger or not digger:is_player() or
--			not creative.is_enabled_for(digger:get_player_name()) then
			not creative_mode_cache then
		return old_handle_node_drops(pos, drops, digger)
	end

	local inv = digger:get_inventory()

	if inv then

		for _, item in ipairs(drops) do

			if not inv:contains_item("main", item, true) then
				inv:add_item("main", item)
			end
		end
	end
end