public class CoreConnector {
  static Eva.Term match_gui_init;
  static Eva.Term match_roster_update;
  static Eva.Term match_resource_entry;
  static Eva.Term match_avatar;
  static Eva.Term match_new_conversation;
  static Eva.Term match_chat_message;
  
  static construct {
    match_gui_init = Eva.parse("{gui_init,Terms}");
    match_roster_update = Eva.parse("{roster_update,JID,Name,Subscription,Groups,Resources,Avatar}");
    match_resource_entry = Eva.parse("{Name,{resource_entry,Priority,Show,Status}}");
    match_avatar = Eva.parse("{avatar,Data}");
    match_new_conversation = Eva.parse("{new_conversation,JID}");
    match_chat_message = Eva.parse("{chat_message,JID,Type,From,Body}");
  }
  
  Eva.PacketHandler con;
  
  public signal void update_contact(Contact contact);
  public signal void new_conversation(string jid);
  public signal void chat_message(string jid, string from, string type, string message);
  
  public void start() {
    con = new Eva.PacketHandler(new UnixInputStream(3, true), new UnixOutputStream(4, true), 4);
    con.received_term.connect(handle_term);
    con.start();
  }
  
  public void stop() {
    con.send(new Eva.Atom("stop"));
  }
  
  private static string from_utf8(Eva.Binary bin) {
    if(bin.len == 0)
      return "";
    
    string ret = ((string)bin.data).ndup(bin.len);
    warn_if_fail(ret.validate());
    return ret;
  }
  
  private void handle_term(Eva.Term term) {
    Gee.Map<string, Eva.Term> match;
    
    if((match = term.match(match_gui_init)) != null) {
      Eva.Cons terms = match["Terms"] as Eva.Cons;
      
      while(terms != null) {
        Eva.Tuple tuple = terms.head as Eva.Tuple;
        
        if(tuple != null && tuple.size > 0) {
          Eva.Atom key = tuple[0] as Eva.Atom;
          
          /*if(key != null) {
            switch(key.value) {
              // None yet
            }
            }*/
        }
        
        terms = terms.tail as Eva.Cons;
      }
    }
    else if((match = term.match(match_roster_update)) != null) {
      Eva.Binary jid_term = match["JID"] as Eva.Binary;
      if(jid_term == null) {
        warn_if_reached();
        return;
      }
      string jid = from_utf8(jid_term);
      
      Eva.Binary name_term = match["Name"] as Eva.Binary;
      string? name;
      if (name_term != null)
        name = from_utf8(name_term);
      else
        name = null;
      
      Contact contact = new Contact(jid, name);
      
      Eva.Atom subscription = match["Subscription"] as Eva.Atom;
      if(subscription != null) {
        switch(subscription.value) {
        case "none":
          contact.subscription = Contact.Subscription.NONE;
          break;
        case "to":
          contact.subscription = Contact.Subscription.TO;
          break;
        case "from":
          contact.subscription = Contact.Subscription.FROM;
          break;
        case "both":
          contact.subscription = Contact.Subscription.BOTH;
          break;
        default:
          stderr.printf("Unknown subscription: %s\r\n", subscription.value);
          break;
        }
      }
      
      Eva.Cons groups = match["Groups"] as Eva.Cons;
      while(groups != null) {
        Eva.Binary group_term = groups.head as Eva.Binary;
        
        if(group_term != null) {
          string group = from_utf8(group_term);
          contact.add_group(group);
        }
        
        groups = groups.tail as Eva.Cons;
      }
      
      Eva.Cons resources = match["Resources"] as Eva.Cons;
      while(resources != null) {
        Gee.Map<string, Eva.Term> r;
        
        if((r = resources.head.match(match_resource_entry)) != null) {
          Eva.Binary rname_term = r["Name"] as Eva.Binary;
          Eva.Numeric prio_term = r["Priority"] as Eva.Numeric;
          Eva.Atom show_term = r["Show"] as Eva.Atom;
          Eva.Binary status_term = r["Status"] as Eva.Binary;
          
          if(rname_term != null && prio_term != null && show_term != null) {
            string rname = from_utf8(rname_term);
            int prio = prio_term.int_value;
            
            Contact.Show show = Contact.Show.UNDEFINED;
            switch(show_term.value) {
            case "online":
              show = Contact.Show.ONLINE;
              break;
            case "away":
              show = Contact.Show.AWAY;
              break;
            case "chat":
              show = Contact.Show.CHAT;
              break;
            case "dnd":
              show = Contact.Show.DND;
              break;
            case "xa":
              show = Contact.Show.XA;
              break;
            }
            
            string? status = null;
            if(status_term != null) {
              status = from_utf8(status_term);
              if(status == "")
                status = null;
            }
            
            contact.update_resource(rname, new Contact.Resource(prio, show, status));
          }
        }
        
        resources = resources.tail as Eva.Cons;
      }
      
      Gee.Map<string, Eva.Term> avatar = match["Avatar"].match(match_avatar);
      if(avatar != null) {
        Eva.Binary avatarData = avatar["Data"] as Eva.Binary;
        
        if(avatarData != null) {
          InputStream avatarStream = new MemoryInputStream.from_data(avatarData.data, avatarData.len, null);
          try {
            contact.avatar = new Gdk.Pixbuf.from_stream_at_scale(avatarStream, 32, 32, true, null);
            avatarStream.close(null);
          } catch(Error e) {
            warn_if_reached();
          }
        }
      }
      update_contact(contact);
    }
    else if((match = term.match(match_new_conversation)) != null) {
      Eva.Binary jid_term = match["JID"] as Eva.Binary;
      if(jid_term == null) {
        warn_if_reached();
        return;
      }
      string jid = from_utf8(jid_term);
      
      new_conversation(jid);
    }
    else if((match = term.match(match_chat_message)) != null) {
      Eva.Binary jid_term = match["JID"] as Eva.Binary;
      if(jid_term == null) {
        warn_if_reached();
        return;
      }
      string jid = from_utf8(jid_term);
      
      Eva.Atom type_term = match["Type"] as Eva.Atom;
      if(type_term == null) {
        warn_if_reached();
        return;
      }
      string type = type_term.value;
      
      Eva.Binary from_term = match["From"] as Eva.Binary;
      if(from_term == null) {
        warn_if_reached();
        return;
      }
      string from = from_utf8(from_term);
      
      Eva.Binary body_term = match["Body"] as Eva.Binary;
      if(body_term == null) {
        warn_if_reached();
        return;
      }
      string body = from_utf8(body_term);
      
      chat_message(jid, type, from, body);
    }
    else {
      stdout.printf("Received unhandled term: %s\n", term.to_string());
    }
  }
    
  public void start_conversation(string jid) {
    char[] jid_utf8 = jid.to_utf8();
    con.send(Eva.parse("{start_conversation,~w}", new Eva.Binary(jid_utf8)));
  }
  
  public void send_message(string jid, string type, string message) {
    char[] jid_utf8 = jid.to_utf8();
    char[] message_utf8 = message.to_utf8();
    con.send(Eva.parse("{send_message,~w,~a,~w}", new Eva.Binary(jid_utf8), type, new Eva.Binary(message_utf8)));
  }
}