Ooui-tws-port/Ooui/EventTarget.cs

228 lines
7.0 KiB
C#

using System;
using System.Collections.Generic;
using System.Linq;
namespace Ooui
{
[Newtonsoft.Json.JsonConverter (typeof (EventTargetJsonConverter))]
public abstract class EventTarget
{
readonly List<Message> stateMessages = new List<Message> ();
readonly Dictionary<string, List<TargetEventHandler>> eventListeners =
new Dictionary<string, List<TargetEventHandler>> ();
public string Id { get; private set; } = GenerateId ();
public string TagName { get; private set; }
public event Action<Message> MessageSent;
public IReadOnlyList<Message> StateMessages {
get {
lock (stateMessages) {
return new List<Message> (stateMessages).AsReadOnly ();
}
}
}
protected EventTarget (string tagName)
{
TagName = tagName;
Send (new Message {
MessageType = MessageType.Create,
TargetId = Id,
Key = TagName,
});
}
public override string ToString() => $"<{TagName} id=\"{Id}\" />";
public virtual EventTarget GetElementById (string id)
{
if (id == Id) return this;
return null;
}
public void AddEventListener (string eventType, TargetEventHandler handler)
{
if (eventType == null) return;
if (handler == null) return;
var sendListen = false;
List<TargetEventHandler> handlers;
lock (eventListeners) {
if (!eventListeners.TryGetValue (eventType, out handlers)) {
handlers = new List<TargetEventHandler> ();
eventListeners[eventType] = handlers;
sendListen = true;
}
handlers.Add (handler);
}
if (sendListen)
Send (new Message {
MessageType = MessageType.Listen,
TargetId = Id,
Key = eventType,
});
}
public void RemoveEventListener (string eventType, TargetEventHandler handler)
{
if (eventType == null) return;
if (handler == null) return;
List<TargetEventHandler> handlers;
lock (eventListeners) {
if (eventListeners.TryGetValue (eventType, out handlers)) {
handlers.Remove (handler);
}
}
}
protected bool SetProperty<T> (ref T backingStore, T newValue, string attributeName, [System.Runtime.CompilerServices.CallerMemberName] string propertyName = "")
{
if (EqualityComparer<T>.Default.Equals (backingStore, newValue))
return false;
backingStore = newValue;
SendSet (attributeName, newValue);
OnPropertyChanged (propertyName);
return true;
}
protected virtual void OnPropertyChanged (string propertyName)
{
}
public const char IdPrefix = '\u2999';
static long idCounter = 0;
static string GenerateId ()
{
var id = System.Threading.Interlocked.Increment (ref idCounter);
return $"{IdPrefix}{id}";
}
public void Send (Message message)
{
if (message == null)
return;
if (message.TargetId == Id)
SaveStateMessageIfNeeded (message);
MessageSent?.Invoke (message);
}
protected void SendCall (string methodName, params object[] args)
{
Send (Message.Call (Id, methodName, args));
}
protected void SendSet (string attributeName, object value)
{
Send (new Message {
MessageType = MessageType.Set,
TargetId = Id,
Key = attributeName,
Value = value,
});
}
public void Receive (Message message)
{
if (message == null)
return;
SaveStateMessageIfNeeded (message);
TriggerEventFromMessage (message);
}
protected void AddStateMessage (Message message)
{
lock (stateMessages) stateMessages.Add (message);
}
protected void UpdateStateMessages (Action<List<Message>> updater)
{
lock (stateMessages) updater (stateMessages);
}
protected virtual bool SaveStateMessageIfNeeded (Message message)
{
if (message.TargetId != Id)
return false;
switch (message.MessageType) {
case MessageType.Create:
AddStateMessage (message);
break;
case MessageType.Set:
UpdateStateMessages (state => {
state.RemoveAll (x => x.MessageType == MessageType.Set && x.Key == message.Key);
state.Add (message);
});
break;
case MessageType.Listen:
AddStateMessage (message);
break;
}
return true;
}
protected virtual bool TriggerEventFromMessage (Message message)
{
if (message.TargetId != Id)
return false;
List<TargetEventHandler> handlers = null;
lock (eventListeners) {
List<TargetEventHandler> hs;
if (eventListeners.TryGetValue (message.Key, out hs)) {
handlers = new List<TargetEventHandler> (hs);
}
}
if (handlers != null) {
var args = new TargetEventArgs ();
if (message.Value is Newtonsoft.Json.Linq.JObject o) {
args.OffsetX = (double)o["offsetX"];
args.OffsetY = (double)o["offsetY"];
}
foreach (var h in handlers) {
h.Invoke (this, args);
}
}
return true;
}
}
class EventTargetJsonConverter : Newtonsoft.Json.JsonConverter
{
public override bool CanRead => false;
public override void WriteJson (Newtonsoft.Json.JsonWriter writer, object value, Newtonsoft.Json.JsonSerializer serializer)
{
writer.WriteValue (((EventTarget)value).Id);
}
public override object ReadJson (Newtonsoft.Json.JsonReader reader, Type objectType, object existingValue, Newtonsoft.Json.JsonSerializer serializer)
{
throw new NotSupportedException ();
}
public override bool CanConvert (Type objectType)
{
return typeof (EventTarget).IsAssignableFrom (objectType);
}
}
public delegate void TargetEventHandler (object sender, TargetEventArgs e);
public class TargetEventArgs : EventArgs
{
public double OffsetX { get; set; }
public double OffsetY { get; set; }
}
}