sumo_with_spectate/items.lua

local stick_knockback = 30 --multiplier for how hard the stick hits
local stick_vault_reach = 3 -- how close to the pointed node must the player be to vault
local stick_vault_timeout = 1 -- int timer for how long the vault cannot be used after it is used
local allow_swap_distance = 4 -- if an opponent is within this distance, then if the player uses the pushstick with the shift key pressed, the players switch positions.


minetest.register_craftitem("sumo:pushstick", {
    description = "Push Stick",
    inventory_image = "default_stick.png",
    stack_max = 1,
    wield_scale = {x = 2, y = 2, z = 2},
    on_drop = function() end,

    on_use = function(itemstack, user, pointed_thing)
        local sound = 'swish'..math.random(1,4)
        minetest.sound_play(sound, {
            pos = user:get_pos(),
            max_hear_distance = 5,
            gain = 10.0,
        })

        if pointed_thing == nil then return end
        if pointed_thing.type == 'object' then
            if minetest.is_player(pointed_thing.ref) == true then

                local dir = user:get_look_dir()
                local keys = user:get_player_control()
                local swap = false
                local hitted_pos = pointed_thing.ref:get_pos()
                local hitter_pos = user:get_pos()
                if keys.sneak and vector.distance(hitted_pos,hitter_pos) < allow_swap_distance then
                    swap = true
                    user:move_to(hitted_pos, true)
                    pointed_thing.ref:move_to(hitter_pos, true)
                    pointed_thing.ref:add_player_velocity(vector.multiply({x = -dir.x, y = dir.y, z= -dir.z}, stick_knockback/2))
                else
                    pointed_thing.ref:add_player_velocity(vector.multiply(dir, stick_knockback))
                    if not swap then
                        local sound = 'thwack'..math.random(1,3)
                        minetest.sound_play(sound, {
                            pos = user:get_pos(),
                            max_hear_distance = 10,
                            gain = 10.0,
                        })
                        local sound = 'hurt'..math.random(1,2)
                        minetest.sound_play(sound, {
                            to_player = pointed_thing.ref:get_player_name(),
                            pos = user:get_pos(),
                            gain = 10.0,
                        })
                    end
                end

            end
        end
    end,

    on_place = function(itemstack, placer, pointed_thing)
        if pointed_thing == nil then return end
        if pointed_thing.type == 'node' then

            if vector.distance(pointed_thing.under, placer:get_pos()) < stick_vault_reach then
                local first_use = false
                local imeta = itemstack:get_meta()
                local old_time = imeta:get_int('old_time')
                local current_time = minetest.get_gametime()
                if old_time == 0 or old_time == nil then
                    first_use = true
                end
                if first_use or current_time > old_time + stick_vault_timeout then
                    local lookvect = placer:get_look_dir()
                    local pushvect = vector.normalize( {x=lookvect.x, z=lookvect.z, y= math.sqrt(1-(lookvect.y*lookvect.y))})
                    --gives a unit vector that is 90 deg offset in the vert direction
                    local force = 10 * vector.length(vector.normalize( {x=lookvect.x, z=lookvect.z, y= 0}))

                    placer:add_player_velocity(vector.multiply(pushvect, force))
                    --update the staff time for next check
                    local sound = 'jump'..math.random(1,2)
                    minetest.sound_play(sound, {
                        pos = placer:get_pos(),
                        max_hear_distance = 10,
                        gain = 10.0,
                    })

                    imeta:set_int('old_time', current_time)
                    return itemstack
                end
            end
        end
    end,

})