tags.py

tags = [
        {"p": 1, "fav":False},
        {"p": 2, "fav":False},
        {"p": 5, "fav":False},
        {"p": 5.5, "fav":True},
        {"p": 5.6, "fav":True},
        {"p": 6, "fav":False},
        ]

# after changing position in frontend, we applying this function to update tags positions in db:
def change_db_pos_after_moving_tag(tags, curr_pos, tag):
    if not tag["fav"]:
        tag["pos"] = curr_pos
    else:
        # if fav tag, then check neighbours:
        tag_idx = tags.index(tag)

        # take neighbours
        lo_bo = tag_idx -1 if tag_idx >0 else 0
        hi_bo = tag_idx +1 if tag_idx < len(tags) -2 else len(tags) - 1

        # put private fav tag in the middle between neighbours but in float numbers space
        tag["pos"] = (tags[lo_bo]["pos"] + tags[hi_bo]["pos"])/2.0

        tags[tag_idx] = tag