ComfyFactorio/maps/fish_defender_v1/bouncy_shells.lua

local radius = 9
local math_random = math.random

local ammo_to_projectile_translation = {
    ['shotgun-shell'] = 'shotgun-pellet',
    ['piercing-shotgun-shell'] = 'piercing-shotgun-pellet'
}

local function create_projectile(surface, position, target, name)
    surface.create_entity(
        {
            name = name,
            position = position,
            source = position,
            target = target,
            max_range = 16,
            speed = 0.3
        }
    )
end

local function bounce(surface, position, ammo)
    if math_random(1, 3) ~= 1 then
        return
    end
    local valid_entities = {}
    for _, e in pairs(surface.find_entities_filtered({area = {{position.x - radius, position.y - radius}, {position.x + radius, position.y + radius}}})) do
        if e.health then
            if e.force.name ~= 'player' then
                --local distance_from_center = math_sqrt((e.position.x - position.x) ^ 2 + (e.position.y - position.y) ^ 2)
                --if distance_from_center <= radius then
                valid_entities[#valid_entities + 1] = e
            --end
            end
        end
    end

    if not valid_entities[1] then
        return
    end

    for _ = 1, math_random(3, 6), 1 do
        create_projectile(surface, position, valid_entities[math_random(1, #valid_entities)].position, ammo)
    end
end

local function bouncy_shells(event)
    if event.damage_type.name ~= 'physical' then
        return false
    end
    local player = event.cause
    if player.shooting_state.state == defines.shooting.not_shooting then
        return false
    end
    local selected_weapon = player.get_inventory(defines.inventory.character_guns)[player.selected_gun_index]
    if selected_weapon.name ~= 'combat-shotgun' and selected_weapon.name ~= 'shotgun' then
        return false
    end

    local selected_ammo = player.get_inventory(defines.inventory.character_ammo)[player.selected_gun_index]
    if not selected_ammo then
        return
    end
    if not ammo_to_projectile_translation[selected_ammo.name] then
        return
    end

    bounce(player.surface, event.entity.position, ammo_to_projectile_translation[selected_ammo.name])
end

return bouncy_shells