uniham/system/crush_nodes.lua

-- Register replacements for the hammer. Entry ID is the ID of the node to
-- replace and entry value is the ID of the node to replace with.
local replacements = {
    -- sefault stone crushing
    ['default:obsidian']          =  'default:stone',
    ['default:stone']             =  'default:cobble',
    ['default:cobble']            =  'default:gravel',
    ['default:gravel']            =  'default:sand',
    -- sandstone types to sand
    ['default:sandstone']         =  'default:sand',
    ['default:desert_sandstone']  =  'default:desert_cobble',
    ['default:desert_cobble']     =  'default:desert_sand',
    ['default:silver_sandstone']  =  'default:silver_sand',
}


-- Hammer use function
--
-- The function is called when using the hammer. It either converts the node to
-- its replacement or does nothing. When converting the modified (added wear)
-- itemstack is returned.
--
-- @param itemstack      The `itemstack` as per on_use definition
-- @param player         The `player` as per on_use definition
-- @param pointed_thing  The `pointed_thing` as per on_use definition
-- @see <https://dev.minetest.net/on_use#on_use>
-- @return itemstack|void
uniham.crush_nodes = function (itemstack, player, pointed_thing)
    if pointed_thing.type ~= 'node' then return end
    local node_pos = minetest.get_pointed_thing_position(pointed_thing)
    local node_name = minetest.get_node(node_pos).name
    local node_sounds = minetest.registered_nodes[node_name].sounds

    if not replacements[node_name] then
        minetest.sound_play(node_sounds.dug.name, {
            pos = node_pos,
            max_hear_distance = 8,
            gain = node_sounds.dug.gain,
        })
        return
    end

    local replacement = replacements[node_name]
    local replacement_sounds = minetest.registered_nodes[replacement].sounds
    local uses = minetest.registered_tools[itemstack:get_name()]._uniham.uses

    minetest.sound_play(replacement_sounds.dug.name, {
        pos = node_pos,
        max_hear_distance = 8,
        gain = replacement_sounds.dug.gain,
    })

    minetest.set_node(node_pos, { name = replacement })
    minetest.check_for_falling(node_pos)

    itemstack:add_wear(math.ceil(65535 / uses) + 1)
    return itemstack
end