/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.gecko.gfx;

import android.graphics.SurfaceTexture;
import android.os.Build;
import android.util.Log;
import android.util.LongSparseArray;
import androidx.annotation.RequiresApi;
import java.util.LinkedList;
import java.util.concurrent.atomic.AtomicInteger;
import org.mozilla.gecko.GeckoAppShell;
import org.mozilla.gecko.annotation.WrapForJNI;
import org.mozilla.gecko.mozglue.JNIObject;

/* package */ final class GeckoSurfaceTexture extends SurfaceTexture {
  private static final String LOGTAG = "GeckoSurfaceTexture";
  private static final int MAX_SURFACE_TEXTURES = 200;
  private static final LongSparseArray<GeckoSurfaceTexture> sSurfaceTextures =
      new LongSparseArray<GeckoSurfaceTexture>();

  private static LongSparseArray<LinkedList<GeckoSurfaceTexture>> sUnusedTextures =
      new LongSparseArray<LinkedList<GeckoSurfaceTexture>>();

  private long mHandle;
  private boolean mIsSingleBuffer;

  private long mAttachedContext;
  private int mTexName;

  private GeckoSurfaceTexture.Callbacks mListener;
  private AtomicInteger mUseCount;
  private boolean mFinalized;

  private long mUpstream;
  private NativeGLBlitHelper mBlitter;

  private GeckoSurfaceTexture(final long handle) {
    super(0);
    init(handle, false);
  }

  @RequiresApi(api = Build.VERSION_CODES.KITKAT)
  private GeckoSurfaceTexture(final long handle, final boolean singleBufferMode) {
    super(0, singleBufferMode);
    init(handle, singleBufferMode);
  }

  @Override
  protected void finalize() throws Throwable {
    // We only want finalize() to be called once
    if (mFinalized) {
      return;
    }

    mFinalized = true;
    super.finalize();
  }

  private void init(final long handle, final boolean singleBufferMode) {
    mHandle = handle;
    mIsSingleBuffer = singleBufferMode;
    mUseCount = new AtomicInteger(1);

    // Start off detached
    detachFromGLContext();
  }

  @WrapForJNI
  public long getHandle() {
    return mHandle;
  }

  @WrapForJNI
  public int getTexName() {
    return mTexName;
  }

  @WrapForJNI(exceptionMode = "nsresult")
  public synchronized void attachToGLContext(final long context, final int texName) {
    if (context == mAttachedContext && texName == mTexName) {
      return;
    }

    attachToGLContext(texName);

    mAttachedContext = context;
    mTexName = texName;
  }

  @Override
  @WrapForJNI(exceptionMode = "nsresult")
  public synchronized void detachFromGLContext() {
    super.detachFromGLContext();

    mAttachedContext = mTexName = 0;
  }

  @WrapForJNI
  public synchronized boolean isAttachedToGLContext(final long context) {
    return mAttachedContext == context;
  }

  @WrapForJNI
  public boolean isSingleBuffer() {
    return mIsSingleBuffer;
  }

  @Override
  @WrapForJNI
  public synchronized void updateTexImage() {
    try {
      if (mUpstream != 0) {
        SurfaceAllocator.sync(mUpstream);
      }
      super.updateTexImage();
      if (mListener != null) {
        mListener.onUpdateTexImage();
      }
    } catch (final Exception e) {
      Log.w(LOGTAG, "updateTexImage() failed", e);
    }
  }

  @Override
  public synchronized void release() {
    mUpstream = 0;
    if (mBlitter != null) {
      mBlitter.close();
    }
    try {
      super.release();
      synchronized (sSurfaceTextures) {
        sSurfaceTextures.remove(mHandle);
      }
    } catch (final Exception e) {
      Log.w(LOGTAG, "release() failed", e);
    }
  }

  @Override
  @WrapForJNI
  public synchronized void releaseTexImage() {
    if (!mIsSingleBuffer) {
      return;
    }

    try {
      super.releaseTexImage();
      if (mListener != null) {
        mListener.onReleaseTexImage();
      }
    } catch (final Exception e) {
      Log.w(LOGTAG, "releaseTexImage() failed", e);
    }
  }

  public synchronized void setListener(final GeckoSurfaceTexture.Callbacks listener) {
    mListener = listener;
  }

  @WrapForJNI
  public static boolean isSingleBufferSupported() {
    return Build.VERSION.SDK_INT >= 19;
  }

  @WrapForJNI
  public synchronized void incrementUse() {
    mUseCount.incrementAndGet();
  }

  @WrapForJNI
  public synchronized void decrementUse() {
    final int useCount = mUseCount.decrementAndGet();

    if (useCount == 0) {
      setListener(null);

      if (mAttachedContext == 0) {
        release();
        synchronized (sUnusedTextures) {
          sSurfaceTextures.remove(mHandle);
        }
        return;
      }

      synchronized (sUnusedTextures) {
        LinkedList<GeckoSurfaceTexture> list = sUnusedTextures.get(mAttachedContext);
        if (list == null) {
          list = new LinkedList<GeckoSurfaceTexture>();
          sUnusedTextures.put(mAttachedContext, list);
        }
        list.addFirst(this);
      }
    }
  }

  @WrapForJNI
  public static void destroyUnused(final long context) {
    final LinkedList<GeckoSurfaceTexture> list;
    synchronized (sUnusedTextures) {
      list = sUnusedTextures.get(context);
      sUnusedTextures.delete(context);
    }

    if (list == null) {
      return;
    }

    for (final GeckoSurfaceTexture tex : list) {
      try {
        if (tex.isSingleBuffer()) {
          tex.releaseTexImage();
        }

        tex.detachFromGLContext();
        tex.release();

        // We need to manually call finalize here, otherwise we can run out
        // of file descriptors if the GC doesn't kick in soon enough. Bug 1416015.
        try {
          tex.finalize();
        } catch (final Throwable t) {
          Log.e(LOGTAG, "Failed to finalize SurfaceTexture", t);
        }
      } catch (final Exception e) {
        Log.e(LOGTAG, "Failed to destroy SurfaceTexture", e);
      }
    }
  }

  public static GeckoSurfaceTexture acquire(final boolean singleBufferMode, final long handle) {
    if (singleBufferMode && !isSingleBufferSupported()) {
      throw new IllegalArgumentException("single buffer mode not supported on API version < 19");
    }

    // Attempting to create a SurfaceTexture from an isolated process on Android versions prior to
    // 8.0 results in an indefinite hang. See bug 1706656.
    if (GeckoAppShell.isIsolatedProcess() && Build.VERSION.SDK_INT < Build.VERSION_CODES.O) {
      return null;
    }

    synchronized (sSurfaceTextures) {
      // We want to limit the maximum number of SurfaceTextures at any one time.
      // This is because they use a large number of fds, and once the process' limit
      // is reached bad things happen. See bug 1421586.
      if (sSurfaceTextures.size() >= MAX_SURFACE_TEXTURES) {
        return null;
      }

      if (sSurfaceTextures.indexOfKey(handle) >= 0) {
        throw new IllegalArgumentException("Already have a GeckoSurfaceTexture with that handle");
      }

      final GeckoSurfaceTexture gst;
      if (isSingleBufferSupported()) {
        gst = new GeckoSurfaceTexture(handle, singleBufferMode);
      } else {
        gst = new GeckoSurfaceTexture(handle);
      }

      sSurfaceTextures.put(handle, gst);

      return gst;
    }
  }

  @WrapForJNI
  public static GeckoSurfaceTexture lookup(final long handle) {
    synchronized (sSurfaceTextures) {
      return sSurfaceTextures.get(handle);
    }
  }

  /* package */ synchronized void track(final long upstream) {
    mUpstream = upstream;
  }

  /* package */ synchronized void configureSnapshot(
      final GeckoSurface target, final int width, final int height) {
    mBlitter = NativeGLBlitHelper.create(mHandle, target, width, height);
  }

  /* package */ synchronized void takeSnapshot() {
    mBlitter.blit();
  }

  public interface Callbacks {
    void onUpdateTexImage();

    void onReleaseTexImage();
  }

  @WrapForJNI
  public static final class NativeGLBlitHelper extends JNIObject {
    public static NativeGLBlitHelper create(
        final long textureHandle,
        final GeckoSurface targetSurface,
        final int width,
        final int height) {
      final NativeGLBlitHelper helper = nativeCreate(textureHandle, targetSurface, width, height);
      helper.mTargetSurface = targetSurface; // Take ownership of surface.
      return helper;
    }

    public static native NativeGLBlitHelper nativeCreate(
        final long textureHandle,
        final GeckoSurface targetSurface,
        final int width,
        final int height);

    public native void blit();

    public void close() {
      disposeNative();
      if (mTargetSurface != null) {
        mTargetSurface.release();
        mTargetSurface = null;
      }
    }

    @Override
    protected native void disposeNative();

    private GeckoSurface mTargetSurface;
  }
}