LiftCometChat.scala

package code.comet

import scala.xml.{NodeSeq, Text}
import net.liftweb._
import http._
import actor._
import http.js._
import JsCmds._
import JE._
import java.util.Date

object MessageStaus extends Enumeration {
  type MessageStaus = Value
  val Normal = Value("normal")
  val Add = Value("Add")
  val Delete = Value("Delete")
}

import MessageStaus._

case class ChatMessage(message: String, status: MessageStaus, timestamp: Date){
  
  def removeBtn = SHtml.ajaxButton("delete", () => { 
    NewChatServer ! ChatMessage(this.message,MessageStaus.Delete,this.timestamp)
    Noop
  })

    
  def toXhtml = {
    <li class={this.status.toString}>
      { this.toString }
      { this.removeBtn }
    </li>
  }
  
  override def equals(obj: Any) = obj match {
    case msg: ChatMessage => (this.message == msg.message && this.timestamp == msg.timestamp)
    case _ => false
  }
  
  override def toString = "(%s) %s, %s".format(status.toString, message, timestamp.toString) 
}

object NewChatServer extends LiftActor with ListenerManager {

  private var messages = List(ChatMessage("Welcome",MessageStaus.Normal, new Date()))

  def updateMessages = {
    messages = messages.map{ msg => msg match {
        case msg if msg.status == MessageStaus.Add => 
          ChatMessage(msg.message,MessageStaus.Normal,msg.timestamp)
        case msg: ChatMessage => msg
      }}
      .filter { msg => msg.status != MessageStaus.Delete }
  }

  def createUpdate = messages

  override def lowPriority = {
    case msg @ ChatMessage(_,MessageStaus.Delete,_) => {
      messages = messages.map{ message => 
        if (message == msg) {
          ChatMessage(msg.message,MessageStaus.Delete,msg.timestamp)
        } else {
          message
        }
      }
      updateListeners()
      updateMessages
    }
    case msg @ ChatMessage(_,_,_) => 
      messages ::= msg ; updateListeners(); updateMessages 
  }
}

class NewChat extends CometActor with CometListener {

  private var msgs: List[ChatMessage] = Nil

  def registerWith = NewChatServer

  override def lowPriority = {
    case m: List[ChatMessage] => msgs = m; reRender(true)
  }

  def render = {
    <div>
    <ul> { msgs.reverse.map( _.toXhtml ) } </ul>
    <lift:form>
    {
      SHtml.text("", s => NewChatServer ! ChatMessage(s,MessageStaus.Add, new Date))
    }
    <input type="submit" value="Chat"/>
    <script type="text/javascript">
    {
      Call("update")
    }
    </script>
    </lift:form>
    </div>
  }
}