From 03670958a5eab132a4f1a6ae5ae58b88f55bfe2f Mon Sep 17 00:00:00 2001
From: =?utf8?q?Tomas=20Wenstr=C3=B6m?= <tomas.wenstrom@gmail.com>
Date: Tue, 21 Mar 2017 22:59:29 +0100
Subject: [PATCH] Added a device listener

---
 config.properties                           |  1 -
 src/kaka/cakelight/Configuration.java       |  2 --
 src/kaka/cakelight/FrameGrabber.java        |  4 +--
 src/kaka/cakelight/VideoDeviceListener.java | 50 +++++++++++++++++++++++++++++
 src/kaka/cakelight/VideoMode.java           | 28 ++++++++++++----
 5 files changed, 73 insertions(+), 12 deletions(-)
 create mode 100644 src/kaka/cakelight/VideoDeviceListener.java

diff --git a/config.properties b/config.properties
index cb1d685..ad972c2 100644
--- a/config.properties
+++ b/config.properties
@@ -1,6 +1,5 @@
 # default settings
 
-video.device=/dev/video2
 video.width=720
 video.height=576
 video.bpp=2
diff --git a/src/kaka/cakelight/Configuration.java b/src/kaka/cakelight/Configuration.java
index 30308e2..0d7bf5b 100644
--- a/src/kaka/cakelight/Configuration.java
+++ b/src/kaka/cakelight/Configuration.java
@@ -56,14 +56,12 @@ public class Configuration {
     }
 
     public class VideoConfiguration {
-        public String device;
         public int width;
         public int height;
         public int bpp;
         public CropConfiguration crop;
 
         private VideoConfiguration(Properties prop) {
-            device = get(prop, "video.device", "/dev/video0");
             width = Integer.parseInt(get(prop, "video.width", "720"));
             height = Integer.parseInt(get(prop, "video.height", "576"));
             bpp = Integer.parseInt(get(prop, "video.bpp", "2"));
diff --git a/src/kaka/cakelight/FrameGrabber.java b/src/kaka/cakelight/FrameGrabber.java
index 8fbb16f..92fd50a 100644
--- a/src/kaka/cakelight/FrameGrabber.java
+++ b/src/kaka/cakelight/FrameGrabber.java
@@ -14,10 +14,10 @@ public class FrameGrabber implements Closeable {
     private FrameGrabber() {
     }
 
-    public static FrameGrabber from(Configuration config) {
+    public static FrameGrabber from(File videoDevice, Configuration config) {
         FrameGrabber fg = new FrameGrabber();
         fg.config = config;
-        fg.file = new File(config.video.device);
+        fg.file = videoDevice;
         fg.bytesPerFrame = config.video.width * config.video.height * config.video.bpp;
         fg.prepare();
         return fg;
diff --git a/src/kaka/cakelight/VideoDeviceListener.java b/src/kaka/cakelight/VideoDeviceListener.java
new file mode 100644
index 0000000..23c0b02
--- /dev/null
+++ b/src/kaka/cakelight/VideoDeviceListener.java
@@ -0,0 +1,50 @@
+package kaka.cakelight;
+
+import java.io.File;
+import java.util.Optional;
+import java.util.function.Consumer;
+
+import static kaka.cakelight.Main.log;
+
+public class VideoDeviceListener {
+    private Thread thread;
+    private Consumer<Optional<File>> changeConsumer;
+    private File lastDevice = null;
+
+    public void startListening() {
+	thread = new Thread() {
+	    public void run() {
+		try {
+		    while (!isInterrupted()) {
+			Optional<File> device = findVideoDevice();
+			if (!device.equals(Optional.ofNullable(lastDevice))) {
+			    log("Video device change: %s", device.map(File::getAbsolutePath).orElse("none"));
+			    changeConsumer.accept(device);
+			    lastDevice = device.orElseGet(() -> null);
+			}
+			Thread.sleep(1000);
+		    }
+		} catch (InterruptedException e) {
+		}
+	    }
+	};
+	thread.start();
+    }
+
+    public void stopListening() {
+        thread.interrupt();
+    }
+
+    private Optional<File> findVideoDevice() {
+	File[] files = new File("/dev").listFiles((dir, name) -> name.matches("video[0-9]+"));
+	if (files == null || files.length == 0) {
+	    return Optional.empty();
+	} else {
+	    return Optional.of(files[0]);
+	}
+    }
+
+    public void onVideoDeviceChange(Consumer<Optional<File>> consumer) {
+	changeConsumer = consumer;
+    }
+}
diff --git a/src/kaka/cakelight/VideoMode.java b/src/kaka/cakelight/VideoMode.java
index 53cf09b..e0dc386 100644
--- a/src/kaka/cakelight/VideoMode.java
+++ b/src/kaka/cakelight/VideoMode.java
@@ -1,33 +1,38 @@
 package kaka.cakelight;
 
+import java.io.File;
 import java.io.IOException;
 import java.util.Optional;
 import java.util.function.Consumer;
 
-import static kaka.cakelight.Main.log;
-import static kaka.cakelight.Main.timeIt;
-
-public class VideoMode implements Mode {
+public class VideoMode implements Mode, Consumer<Optional<File>> {
     private Configuration config;
     private Thread thread;
     private Consumer<Frame> frameConsumer;
+    private VideoDeviceListener deviceListener;
+
+    public VideoMode() {
+        deviceListener = new VideoDeviceListener();
+        deviceListener.onVideoDeviceChange(this);
+    }
 
     @Override
     public void enter(Configuration config) {
         this.config = config;
-        startGrabberThread();
+        deviceListener.startListening();
     }
 
     @Override
     public void exit() {
         thread.interrupt();
+        deviceListener.stopListening();
     }
 
-    private void startGrabberThread() {
+    private void startGrabberThread(File videoDevice) {
         assert frameConsumer != null;
         thread = new Thread() {
             public void run() {
-                try (FrameGrabber grabber = FrameGrabber.from(config)) {
+                try (FrameGrabber grabber = FrameGrabber.from(videoDevice, config)) {
                     while (!isInterrupted()) {
 //                        Optional<Frame> frame = grabber.grabFrame();
                         grabber.grabFrame().ifPresent(frameConsumer);
@@ -46,4 +51,13 @@ public class VideoMode implements Mode {
     public void onFrame(Consumer<Frame> consumer) {
         frameConsumer = consumer;
     }
+
+    @Override
+    public void accept(Optional<File> videoDevice) {
+        // Should only happen when this mode is active!
+        if (thread != null) {
+            thread.interrupt();
+        }
+        videoDevice.ifPresent(this::startGrabberThread);
+    }
 }
-- 
2.11.0