from flask import request

def gen_poll(db):
    # Get the client position
    req = int(request.args.get('head',1))
    
    # Find the maximum message number.
    t = db.execute("SELECT max(id) FROM comments").fetchone()
    if t[0] is None:
        head = 1
    else:
        head = t[0] + 1

    # Find the minium
    start = max(1, req, head-10)

    # Fetch the messages.
    t = db.execute("SELECT * FROM comments " +
        		f"WHERE {start} <= id and id < {head} ORDER BY id")
    handles = []
    messages = []
    for row in t:
        handles += [ row[1] ]
        messages += [ row[2] ]

    return { "head": head, "messages": messages, "ids": handles }
    
def mk_poll(app):
    @app.route("/poll")
    def poll():
        from . import db
        return gen_poll(db.get_db())