Fix VideoPlayer (#1088)

* fix player's macOS issue

* replace local file path with public URL

components/VideoPlayer/demo/src/jvmMain/kotlin/org/jetbrains/compose/videoplayer/demo/Main.kt

@@ -13,7 +13,11 @@ fun main() {
     ) {
         MaterialTheme {
             DesktopTheme {
-                VideoPlayer("/System/Library/Compositions/Yosemite.mov", 640, 480)
+                VideoPlayer(
+                    url = "http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4",
+                    width = 640,
+                    height = 480
+                )
             }
         }
     }

components/VideoPlayer/library/src/desktopMain/kotlin/org/jetbrains/compose/videoplayer/DesktopVideoPlayer.kt

@@ -1,22 +1,31 @@
 package org.jetbrains.compose.videoplayer
 
-import androidx.compose.desktop.SwingPanel
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.SideEffect
 import androidx.compose.runtime.remember
-import androidx.compose.runtime.rememberCompositionContext
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.awt.SwingPanel
 import androidx.compose.ui.graphics.Color
 import uk.co.caprica.vlcj.factory.discovery.NativeDiscovery
+import uk.co.caprica.vlcj.player.base.MediaPlayer
+import uk.co.caprica.vlcj.player.component.CallbackMediaPlayerComponent
 import uk.co.caprica.vlcj.player.component.EmbeddedMediaPlayerComponent
+import java.util.*
+
 
 @Composable
 internal actual fun VideoPlayerImpl(url: String, width: Int, height: Int) {
     println("Video player for $url")
     NativeDiscovery().discover()
-    // Doesn't work on macOS, see https://github.com/caprica/vlcj/issues/887 for suggestions.
+    val mediaPlayerComponent = remember {
-    val mediaPlayerComponent = remember { EmbeddedMediaPlayerComponent() }
+        // see https://github.com/caprica/vlcj/issues/887#issuecomment-503288294 for why we're using CallbackMediaPlayerComponent for macOS.
+        if (isMacOS()) {
+            CallbackMediaPlayerComponent()
+        } else {
+            EmbeddedMediaPlayerComponent()
+        }
+    }
     SideEffect {
         val ok = mediaPlayerComponent.mediaPlayer().media().play(url)
         println("play gave $ok")
@@ -29,3 +38,21 @@ internal actual fun VideoPlayerImpl(url: String, width: Int, height: Int) {
         }
     )
 }
+
+/**
+ * To return mediaPlayer from player components.
+ * The method names are same, but they don't share the same parent/interface.
+ * That's why need this method.
+ */
+private fun Any.mediaPlayer(): MediaPlayer {
+    return when (this) {
+        is CallbackMediaPlayerComponent -> mediaPlayer()
+        is EmbeddedMediaPlayerComponent -> mediaPlayer()
+        else -> throw IllegalArgumentException("You can only call mediaPlayer() on vlcj player component")
+    }
+}
+
+private fun isMacOS(): Boolean {
+    val os = System.getProperty("os.name", "generic").lowercase(Locale.ENGLISH)
+    return os.indexOf("mac") >= 0 || os.indexOf("darwin") >= 0
+}