From d90e7305d342378cb2526238d9d974a6b9272359 Mon Sep 17 00:00:00 2001
From: Xen0Xys <red57101@gmail.com>
Date: Tue, 30 Apr 2024 11:20:40 +0200
Subject: [PATCH] :art: Improve target and fov control flow using new Lock
 object

---
 js/imports.js              |  2 +-
 js/models/event_handler.js | 31 +++++++------------------------
 js/models/lock.js          | 27 +++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 25 deletions(-)
 create mode 100644 js/models/lock.js

diff --git a/js/imports.js b/js/imports.js
index d5274429..27c2fa99 100644
--- a/js/imports.js
+++ b/js/imports.js
@@ -1,3 +1,3 @@
-import A from "https://esm.sh/aladin-lite@3.3.3-beta";
+import A from "https://esm.sh/aladin-lite@3.4.0-beta";
 
 export default A;
diff --git a/js/models/event_handler.js b/js/models/event_handler.js
index df62997e..cee4f9e7 100644
--- a/js/models/event_handler.js
+++ b/js/models/event_handler.js
@@ -1,4 +1,5 @@
 import MessageHandler from "./message_handler";
+import Lock from "./lock";
 
 export default class EventHandler {
   /**
@@ -30,16 +31,12 @@ export default class EventHandler {
     // is also necessary for the field of view.
 
     /* Target control */
-    let targetJs = false;
-    let targetPy = false;
+    let targetLock = new Lock();
 
     // Event triggered when the user moves the map in Aladin Lite
     this.aladin.on("positionChanged", () => {
-      if (targetPy) {
-        targetPy = false;
-        return;
-      }
-      targetJs = true;
+      if (targetLock.unlock()) return;
+      targetLock.lock();
       const raDec = this.aladin.getRaDec();
       this.model.set("_target", `${raDec[0]} ${raDec[1]}`);
       this.model.set("shared_target", `${raDec[0]} ${raDec[1]}`);
@@ -48,26 +45,17 @@ export default class EventHandler {
 
     // Event triggered when the target is changed from the Python side using jslink
     this.model.on("change:shared_target", () => {
-      if (targetJs) {
-        targetJs = false;
-        return;
-      }
-      targetPy = true;
       const target = this.model.get("shared_target");
       const [ra, dec] = target.split(" ");
       this.aladin.gotoRaDec(ra, dec);
     });
 
     /* Field of View control */
-    let fovJs = false;
-    let fovPy = false;
+    let fovLock = new Lock();
 
     this.aladin.on("zoomChanged", (fov) => {
-      if (fovPy) {
-        fovPy = false;
-        return;
-      }
-      fovJs = true;
+      if (fovLock.unlock()) return;
+      fovLock.lock();
       // fov MUST be cast into float in order to be sent to the model
       this.model.set("_fov", parseFloat(fov.toFixed(5)));
       this.model.set("shared_fov", parseFloat(fov.toFixed(5)));
@@ -75,11 +63,6 @@ export default class EventHandler {
     });
 
     this.model.on("change:shared_fov", () => {
-      if (fovJs) {
-        fovJs = false;
-        return;
-      }
-      fovPy = true;
       let fov = this.model.get("shared_fov");
       this.aladin.setFoV(fov);
     });
diff --git a/js/models/lock.js b/js/models/lock.js
new file mode 100644
index 00000000..c70b51b6
--- /dev/null
+++ b/js/models/lock.js
@@ -0,0 +1,27 @@
+export default class Lock {
+  state = false;
+
+  /**
+   * Locks the object
+   * @returns {boolean} True if the object was locked, false otherwise
+   */
+  unlock() {
+    if (this.state) {
+      this.state = false;
+      return true;
+    }
+    return false;
+  }
+
+  /**
+   * Unlocks the object
+   * @returns {boolean} True if the object was unlocked, false otherwise
+   */
+  lock() {
+    if (!this.state) {
+      this.state = true;
+      return true;
+    }
+    return false;
+  }
+}