Replace jsCommunicator calls with new promise class

(benefits): allows for more concise passing of JSON back to the js side

android/app/src/main/java/io/freetubeapp/freetube/helpers/Promise.kt

@@ -0,0 +1,71 @@
+package io.freetubeapp.freetube.helpers
+
+import io.freetubeapp.freetube.javascript.AsyncJSCommunicator
+import java.util.UUID.randomUUID
+import java.util.concurrent.ThreadPoolExecutor
+
+class Promise<T, G> {
+  private val successListeners: MutableList<(T) -> Unit> = mutableListOf()
+  private var successResult: T? = null
+  private val errorListeners: MutableList<(G) -> Unit> = mutableListOf()
+  private var errorResult: G? = null
+  private val id = "${randomUUID()}"
+
+  constructor(executor: ThreadPoolExecutor, runnable: ((T) -> Unit, (G) -> Unit) -> Unit) {
+    executor.run {
+      runnable.invoke({
+        result ->
+        notifySuccess(result)
+      }, {
+        result ->
+        notifyError(result)
+      })
+    }
+  }
+
+  fun addJsCommunicator(communicator: AsyncJSCommunicator) : String {
+    then {
+      communicator.resolve(id, "$it")
+    }
+    catch {
+      communicator.reject(id, "$it")
+    }
+    return id
+  }
+
+  fun notifySuccess(result: T) {
+    successResult = result
+    successListeners.forEach {
+      listener ->
+      listener.invoke(result)
+    }
+  }
+
+  fun notifyError(result: G) {
+    errorResult = result
+    errorListeners.forEach {
+      listener ->
+      listener.invoke(result)
+    }
+  }
+
+  fun then(listener: (T) -> Unit): Promise<T, G> {
+    if (successResult != null) {
+      // assume success result won't be unset
+      listener(successResult!!)
+    } else {
+      successListeners.add(listener)
+    }
+    return this
+  }
+
+  fun catch(listener: (G) -> Unit): Promise<T, G> {
+    if (errorResult != null) {
+      // assume success result won't be unset
+      listener(errorResult!!)
+    } else {
+      errorListeners.add(listener)
+    }
+    return this
+  }
+}

android/app/src/main/java/io/freetubeapp/freetube/javascript/FreeTubeJavaScriptInterface.kt

@@ -26,6 +26,8 @@ import androidx.documentfile.provider.DocumentFile
 import io.freetubeapp.freetube.MainActivity
 import io.freetubeapp.freetube.MediaControlsReceiver
 import io.freetubeapp.freetube.R
+import io.freetubeapp.freetube.helpers.Promise
+import org.json.JSONObject
 import java.io.File
 import java.io.FileInputStream
 import java.net.URL
@@ -375,24 +377,25 @@ class FreeTubeJavaScriptInterface {
    */
   @JavascriptInterface
   fun readFile(basedir: String, filename: String): String {
-    val promise = jsCommunicator.jsPromise()
-    context.threadPoolExecutor.execute {
+    val promise = Promise(context.threadPoolExecutor, {
+      resolve,
+      reject ->
       try {
         if (basedir.startsWith("content://")) {
           val stream = context.contentResolver.openInputStream(Uri.parse(basedir))
           val content = String(stream!!.readBytes())
           stream!!.close()
-          jsCommunicator.resolve(promise, content)
+          resolve(content)
         } else {
           val path = getDirectory(basedir)
           val file = File(path, filename)
-          jsCommunicator.resolve(promise, FileInputStream(file).bufferedReader().use { it.readText() })
+          resolve(FileInputStream(file).bufferedReader().use { it.readText() })
         }
       } catch (ex: Exception) {
-        jsCommunicator.reject(promise, ex.stackTraceToString())
+        reject(ex.stackTraceToString())
       }
-    }
-    return promise
+    })
+    return promise.addJsCommunicator(jsCommunicator)
   }
 
   /**