Laravel 5 raw query to query builder

I have bellow raw mysql query, what i want to do is to change this to query builder. need help.

SET @groupIds = '11,14';
SET @eventIds = '13,5';
SET @friendIds = '1000022';
SET @userFollowings = '1000001';


SELECT sn_posts.*
FROM sn_posts
WHERE 
sn_posts.deleted_at is null AND 
(
    sn_posts.user_id = '1000042' OR (
        (
            IF(@groupIds is not null AND @groupIds <> '',FIND_IN_SET(sn_posts.postable_id,@groupIds),0)
            OR IF(@eventIds is not null AND @eventIds <> '',FIND_IN_SET(sn_posts.postable_id,@eventIds),0)
            OR IF(sn_posts.privacy_level = 0, (
                IF(@friendIds is not null AND @friendIds <> '', FIND_IN_SET(sn_posts.`user_id`,@friendIds),0)
                OR IF(@userFollowings is not null AND @userFollowings <> '',FIND_IN_SET(sn_posts.`user_id`,@userFollowings),0)
                ), 
                IF(@friendIds is not null AND @friendIds <> '', FIND_IN_SET(sn_posts.user_id,@friendIds),0)
            )
        )
        AND IF(sn_posts.`parent_id` IS NOT NULL,(
            SELECT parent.id FROM sn_posts AS parent
            WHERE parent.id = sn_posts.`parent_id` AND IF(parent.privacy_level = 0,1,IF(@friendIds is not null AND @friendIds <> '', FIND_IN_SET(parent.`user_id`,@friendIds),0))
            ),1)
    )
)

ORDER BY sn_posts.created_at desc
LIMIT 21,10

I have php variables instead of those mysql variables. Because of need for result as collection, i need a way to get the result as collection.

via Chebli Mohamed