local api = blockgame.crafting

local stack_recipes = {}

function api.register_stack_recipe (top_node, bottom_node, result, consumes_top)
	local consumes_top = consumes_top
	if consumes_top == nil then consumes_top = true end

	stack_recipes[top_node] = stack_recipes[top_node] or {}

	local def = {
		["type"] = "stack_two_nodes",
		index_key = top_node,
		top_node = top_node,
		bottom_node = bottom_node,
		result = result,
		consumes_top = consumes_top,
	}

	table.insert(stack_recipes[top_node], def)
	table.insert(api.registered_recipes, def)
end

function api.handle_stack_recipe (recipe, pos, top_node)
	if top_node.name ~= recipe.top_node then return false end

	local down = vector.add(pos, vector.new(0, -1, 0))
	local below = minetest.get_node(down)
	if below.name ~= recipe.bottom_node then return false end

	minetest.remove_node(pos)
	minetest.set_node(down, recipe.result)

	return true
end

function api.handle_placement (pos, new_node, placer, old_node, itemstack, pointed_thing)
	if stack_recipes[new_node.name] == nil then return false end

	for _, recipe in pairs(stack_recipes[new_node.name]) do
		local result = api.handle_stack_recipe(recipe, pos, new_node)
		if result then return not recipe.consumes_top end
	end

	return false
end

blockgame.register_on_placenode(function (...)
	return blockgame.crafting.handle_placement(...)
end)