using Gee;

namespace Xmpp {

public string random_uuid() {
    uint32 b1 = Random.next_int();
    uint16 b2 = (uint16)Random.next_int();
    uint16 b3 = (uint16)(Random.next_int() | 0x4000u) & ~0xb000u;
    uint16 b4 = (uint16)(Random.next_int() | 0x8000u) & ~0x4000u;
    uint16 b5_1 = (uint16)Random.next_int();
    uint32 b5_2 = Random.next_int();
    return "%08x-%04x-%04x-%04x-%04x%08x".printf(b1, b2, b3, b4, b5_1, b5_2);
}

public abstract class StanzaListener<T> : Object {
    public abstract string action_group { get; }
    public abstract string[] after_actions { get; }

    public abstract async void run(XmppStream stream, T stanza);
}

public class StanzaListenerHolder<T> : Object {
    private ArrayList<StanzaListener<T>> listeners = new ArrayList<StanzaListener<T>>();

    public new void connect(StanzaListener<T> listener) {
        listeners.add(listener);
        resort_list();
    }

    public new void disconnect(StanzaListener<T> listener) {
        listeners.remove(listener);
        resort_list();
    }

    public async void run(XmppStream stream, T stanza) {
        foreach (StanzaListener<T> l in listeners) {
            yield l.run(stream, stanza);
        }
    }

    private bool set_contains_action(Gee.List<StanzaListener<T>> s, string[] actions) {
        foreach (StanzaListener<T> l in s) {
            if (l.action_group in actions) {
                return true;
            }
        }
        return false;
    }

    private void resort_list() {
        ArrayList<StanzaListener<T>> new_list = new ArrayList<StanzaListener<T>>();
        ArrayList<StanzaListener<T>> remaining = new ArrayList<StanzaListener<T>>();
        remaining.add_all(listeners);
        while (remaining.size > 0) {
            bool changed = false;
            Gee.Iterator<StanzaListener<T>> iter = remaining.iterator();
            while (iter.has_next()) {
                if (!iter.valid) {
                    iter.next();
                }
                StanzaListener<T> l = iter.get();
                if (!set_contains_action(remaining, l.after_actions)) {
                    new_list.add(l);
                    iter.remove();
                    changed = true;
                }
            }
            if (!changed) error("Can't sort listeners");
        }
        listeners = new_list;
    }
}

}