local F = minetest.formspec_escape

cg.update_filter = function(player, context, filter)
	if (filter or "") == (context.cg_filter or "") then return end
	context.cg_page = 0
	context.cg_filter = filter
	cg.filter_items(player, filter)
end

local make_item_button = function(formspec, x, y, size, name)
	if name and name ~= "" then
		local groups, buttonText

		if name:sub(1, 6) == "group:" then
			groups = name:sub(7):split(",")
			buttonText = #groups > 1 and ("G " .. #groups) or "G"
			name = name:gsub(",", "/")
		end

		formspec[#formspec + 1] = string.format("item_image_button[%.2f,%.2f;%.2f,%.2f;%s;cgitem_%s;%s]",
				x, y, size, size,
				groups and (cg.group_stereotypes[groups[1]] or "") or name,
				name:match("^%S+"), -- Keep only the item name, not the quantity.
				buttonText or ""
			)

		if groups then
			formspec[#formspec + 1] = string.format("tooltip[cgitem_%s;%s]",
					name,
					#groups > 1 and
					F(cg.S("Any item in groups: @1", minetest.colorize("#72FF63", table.concat(groups, ", ")))) or
					F(cg.S("Any item in group: @1", minetest.colorize("#72FF63", groups[1])))
				)
		end
	else
		size = size * 0.8 + 0.2
		formspec[#formspec + 1] = string.format("image[%.2f,%.2f;%.2f,%.2f;gui_hb_bg.png]", x, y, size, size)
	end
end

local make_item_grid = function(formspec, player, context)
	local itemList = cg.get_item_list(player)
	context.cg_page = context.cg_page or 0

	formspec[#formspec + 1] = [[
			image_button[2.4,3.7;0.8,0.8;cg_plus_icon_search.png;cg_search;]
			image_button[3.1,3.7;0.8,0.8;cg_plus_icon_clear.png;cg_clear;]
			image_button[5.1,3.7;0.8,0.8;cg_plus_icon_prev.png;cg_prev;]
			image_button[7.1,3.7;0.8,0.8;cg_plus_icon_next.png;cg_next;]
		]]

	formspec[#formspec + 1] = string.format("label[0,0;%s]", F(cg.S("Crafting Guide")))

	formspec[#formspec + 1] = string.format("field[0.3,3.9;2.5,1;cg_filter;;%s]", F(context.cg_filter or ""))
	formspec[#formspec + 1] = "field_close_on_enter[cg_filter;false]"
	formspec[#formspec + 1] = string.format("label[6,3.8;%i / %i]", context.cg_page + 1, itemList.num_pages)

	local startIdx = context.cg_page * cg.PAGE_ITEMS + 1
	local item

	for itemIdx = 0, cg.PAGE_ITEMS - 1 do
		item = itemList.list[startIdx + itemIdx]

		if item then
			formspec[#formspec + 1] = string.format("item_image_button[%.2f,%.2f;1,1;%s;cgitem_%s;]",
					itemIdx % cg.PAGE_WIDTH,
					math.floor(itemIdx / cg.PAGE_WIDTH) + 0.5,
					item, item
				)
		end
	end
end

local make_craft_preview = function(formspec, player, context)
	formspec[#formspec + 1] = [[
			image_button[7.1,0.1;0.8,0.8;cg_plus_icon_prev.png;cg_craft_close;]
			image[0.1,0.1;0.8,0.8;gui_hb_bg.png]
		]]
	local item = context.cg_selected_item

	formspec[#formspec + 1] = string.format("item_image[0.1,0.1;0.8,0.8;%s]", item)
	formspec[#formspec + 1] = string.format("label[1,0;%s]",
			cg.crafts[item] and minetest.registered_items[item].description or item)

	local crafts = cg.crafts[item]

	if not crafts or #crafts == 0 then
		formspec[#formspec + 1] = string.format("label[1,0.5;%s]", F(cg.S("There are no recipes for this item.")))
		return
	end

	if #crafts > 1 then
		formspec[#formspec + 1] = [[
				image_button[1.85,3.7;0.8,0.8;cg_plus_icon_prev.png;cg_craft_prev;]
				image_button[3.85,3.7;0.8,0.8;cg_plus_icon_next.png;cg_craft_next;]
			]]
		formspec[#formspec + 1] = string.format("label[2.75,3.8;%i / %i]", context.cg_craft_page + 1, #crafts)
	end

	local craft = cg.parse_craft(crafts[context.cg_craft_page + 1])
	local template = cg.craft_types[craft.type] or {}

	if cg.autocrafting and template.uses_crafting_grid then
		formspec[#formspec + 1] = "image_button[0.1,3.7;0.8,0.8;cg_plus_icon_autocrafting.png;cg_auto_menu;]"
		formspec[#formspec + 1] = string.format("tooltip[cg_auto_menu;%s]", F(cg.S("Craft this recipe")))

		if context.cg_auto_menu then
			local num = 1
			local yPos = 3

			while true do
				num = math.min(num, context.cg_auto_max)
				formspec[#formspec + 1] = string.format("button[0.1,%.2f;0.8,0.8;cg_auto_%i;%i]", yPos, num, num)
				formspec[#formspec + 1] = string.format(
						"tooltip[cg_auto_%i;%s]",
						num,
						num == 1 and F(cg.S("Craft @1 item", num)) or F(cg.S("Craft @1 items", num))
					)

				if num < context.cg_auto_max then
					num = num * 10
					yPos = yPos - 0.7
				else
					break
				end
			end
		end
	end

	formspec[#formspec + 1] = string.format("label[5,0.5;%s]", template.description or "")
	formspec[#formspec + 1] = string.format("label[5,1;%s]", craft.infotext or "")
	formspec[#formspec + 1] = string.format("image[4.75,1.5;1,1;%s]",
			template.arrow_icon or "cg_plus_arrow.png")

	local slotSize = math.min(3 / math.max(craft.grid_size.x, craft.grid_size.y), 1)
	local xOffset = 4.75 - craft.grid_size.x * slotSize
	local yOffset = 2 - craft.grid_size.y * slotSize * 0.5

	for idx = 1, craft.grid_size.x * craft.grid_size.y do
		make_item_button(formspec,
				(idx - 1) % craft.grid_size.x * slotSize + xOffset,
				math.floor((idx - 1) / craft.grid_size.y) * slotSize + yOffset,
				slotSize,
				craft.items[idx]
			)
	end

	make_item_button(formspec, 5.75, 1.5, 1, craft.output)
end

sfinv.register_page("cg_plus:crafting_guide", {
	title = "Crafting Guide",
	get = function(self, player, context)
		local formspec = {[[
				image[0,4.75;1,1;gui_hb_bg.png]
				image[1,4.75;1,1;gui_hb_bg.png]
				image[2,4.75;1,1;gui_hb_bg.png]
				image[3,4.75;1,1;gui_hb_bg.png]
				image[4,4.75;1,1;gui_hb_bg.png]
				image[5,4.75;1,1;gui_hb_bg.png]
				image[6,4.75;1,1;gui_hb_bg.png]
				image[7,4.75;1,1;gui_hb_bg.png]
			]]}

		if context.cg_selected_item then
			make_craft_preview(formspec, player, context)
		else
			make_item_grid(formspec, player, context)
		end

		return sfinv.make_formspec(player, context, table.concat(formspec), true)
	end,

	on_player_receive_fields = function(self, player, context, fields)
		if fields.cg_craft_close then
			context.cg_selected_item = nil
			context.cg_craft_page = nil
			context.cg_auto_menu = false
		elseif fields.cg_prev and context.cg_page then
			context.cg_page = context.cg_page - 1
		elseif fields.cg_next and context.cg_page then
			context.cg_page = context.cg_page + 1
		elseif fields.cg_craft_prev and context.cg_craft_page then
			context.cg_craft_page = context.cg_craft_page - 1
			context.cg_auto_menu = false
		elseif fields.cg_craft_next and context.cg_craft_page then
			context.cg_craft_page = context.cg_craft_page + 1
			context.cg_auto_menu = false
		elseif fields.cg_search or fields.key_enter_field == "cg_filter" then
			cg.update_filter(player, context, fields.cg_filter)
		elseif fields.cg_clear then
			cg.update_filter(player, context, "")
		elseif fields.cg_auto_menu and cg.autocrafting then
			if not context.cg_auto_menu then
				-- Make sure the craft is valid, in case the client is sending fake formspec fields.
				local crafts = cg.crafts[context.cg_selected_item] or {}
				local craft = crafts[context.cg_craft_page + 1]

				if craft and cg.craft_types[craft.type] and cg.craft_types[craft.type].uses_crafting_grid then
					context.cg_auto_menu = true
					context.cg_auto_max = cg.auto_get_craftable(player, craft)
				end
			else
				context.cg_auto_menu = false
			end
		else
			for field, _ in pairs(fields) do
				if field:sub(1, 7) == "cgitem_" then
					local item = string.sub(field, 8)

					if item:sub(1, 6) == "group:" then
						if cg.group_search then
							cg.update_filter(player, context, item:gsub("/", ","))
							context.cg_selected_item = nil
							context.cg_auto_menu = false
						elseif cg.group_stereotypes[item:sub(7)] then
							context.cg_selected_item = cg.group_stereotypes[item:sub(7)]
							context.cg_craft_page = 0
							context.cg_auto_menu = false
						end
					elseif item ~= context.cg_selected_item then
						context.cg_selected_item = item
						context.cg_craft_page = 0
						context.cg_auto_menu = false
					end

					break
				elseif field:sub(1, 8) == "cg_auto_" and cg.autocrafting and context.cg_auto_menu then
					-- No need to sanity check, we already did that when showing the autocrafting menu.
					local num = tonumber(field:sub(9))

					if num > 0 and num <= context.cg_auto_max then
						cg.auto_craft(player, cg.crafts[context.cg_selected_item][context.cg_craft_page + 1], num)
						sfinv.set_page(player, "sfinv:crafting")
					end

					context.cg_auto_menu = false
					break
				end
			end
		end

		-- Wrap around when the player presses the next button on the last page, or the previous button on the first.
		if context.cg_page then
			context.cg_page = context.cg_page % math.max(cg.get_item_list(player).num_pages, 1)
		end

		if context.cg_craft_page then
			context.cg_craft_page = context.cg_craft_page % math.max(#(cg.crafts[context.cg_selected_item] or {}), 1)
		end

		-- Update the formspec.
		sfinv.set_player_inventory_formspec(player, context)
	end,
})