using System;
using System.Runtime.InteropServices;


namespace Avahi
{

    public enum EntryGroupState {
        Uncommited,
        Registering,
        Established,
        Collision
    }

    internal delegate void EntryGroupCallback (IntPtr group, EntryGroupState state, IntPtr userdata);
    public delegate void EntryGroupStateHandler (object o, EntryGroupState state);
    
    public class EntryGroup : IDisposable
    {
        private Client client;
        private IntPtr handle;
        
        [DllImport ("avahi-client")]
        private static extern IntPtr avahi_entry_group_new (IntPtr client, EntryGroupCallback cb, IntPtr userdata);

        [DllImport ("avahi-client")]
        private static extern void avahi_entry_group_commit (IntPtr group);

        [DllImport ("avahi-client")]
        private static extern void avahi_entry_group_reset (IntPtr group);

        [DllImport ("avahi-client")]
        private static extern EntryGroupState avahi_entry_group_get_state (IntPtr group);

        [DllImport ("avahi-client")]
        private static extern bool avahi_entry_group_is_empty (IntPtr group);

        [DllImport ("avahi-client")]
        private static extern void avahi_entry_group_add_service_strlst (IntPtr group, int iface, Protocol proto,
                                                                         IntPtr name, IntPtr type, IntPtr domain,
                                                                         IntPtr host, UInt16 port, IntPtr strlst);
        
        [DllImport ("avahi-client")]
        private static extern void avahi_entry_group_free (IntPtr group);

        [DllImport ("avahi-common")]
        private static extern IntPtr avahi_string_list_new (IntPtr txt);

        [DllImport ("avahi-common")]
        private static extern void avahi_string_list_add (IntPtr list, IntPtr txt);

        [DllImport ("avahi-common")]
        private static extern void avahi_string_list_free (IntPtr list);

        public event EntryGroupStateHandler StateChanged;
        
        public EntryGroupState State
        {
            get { return avahi_entry_group_get_state (handle); }
        }

        public bool IsEmpty
        {
            get { return avahi_entry_group_is_empty (handle); }
        }
        
        public EntryGroup (Client client)
        {
            this.client = client;
            handle = avahi_entry_group_new (client.Handle, OnEntryGroupCallback, IntPtr.Zero);
            client.CheckError ();
        }

        ~EntryGroup ()
        {
            Dispose ();
        }

        public void Dispose ()
        {
            if (handle != IntPtr.Zero) {
                avahi_entry_group_free (handle);
                handle = IntPtr.Zero;
            }
        }

        public void Commit ()
        {
            avahi_entry_group_commit (handle);
            client.CheckError ();
        }

        public void Reset ()
        {
            avahi_entry_group_reset (handle);
            client.CheckError ();
        }

        public void AddService (string name, string type, string domain,
                                UInt16 port, string[] txt)
        {
            AddService (-1, Protocol.Unspecified, name, type, domain, null, port, txt);
        }

        public void AddService (int iface, Protocol proto, string name, string type, string domain,
                                string host, UInt16 port, string[] txt)
        {
            IntPtr list = avahi_string_list_new (IntPtr.Zero);

            if (txt != null) {
                foreach (string item in txt) {
                    IntPtr itemPtr = Utility.StringToPtr (item);
                    avahi_string_list_add (list, itemPtr);
                    Utility.Free (itemPtr);
                }
            }

            IntPtr namePtr = Utility.StringToPtr (name);
            IntPtr typePtr = Utility.StringToPtr (type);
            IntPtr domainPtr = Utility.StringToPtr (domain);
            IntPtr hostPtr = Utility.StringToPtr (host);
            avahi_entry_group_add_service_strlst (handle, iface, proto, namePtr, typePtr, domainPtr,
                                                  hostPtr, port, list);
            avahi_string_list_free (list);

            client.CheckError ();
            
            Console.WriteLine ("Added service: {0}, {1}, {2}, {3}, {4}", name, type, domain, host, port);
        }

        private void OnEntryGroupCallback (IntPtr group, EntryGroupState state, IntPtr userdata)
        {
            if (StateChanged != null)
                StateChanged (this, state);
        }
    }
}