/* Communication module for Android terminals.  -*- c-file-style: "GNU" -*-

Copyright (C) 2023 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */

package org.gnu.emacs;

import java.io.IOException;
import java.util.List;
import java.util.ArrayList;

import android.graphics.Canvas;
import android.graphics.Bitmap;
import android.graphics.Point;

import android.view.View;

import android.annotation.TargetApi;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.res.AssetManager;
import android.os.Build;
import android.os.Looper;
import android.os.IBinder;
import android.os.Handler;

import android.util.Log;
import android.util.DisplayMetrics;

class Holder<T>
{
  T thing;
};

/* EmacsService is the service that starts the thread running Emacs
   and handles requests by that Emacs instance.  */

public class EmacsService extends Service
{
  public static final String TAG = "EmacsService";
  public static final int MAX_PENDING_REQUESTS = 256;
  public static volatile EmacsService SERVICE;

  private EmacsThread thread;
  private Handler handler;

  /* Display metrics used by font backends.  */
  public DisplayMetrics metrics;

  @Override
  public int
  onStartCommand (Intent intent, int flags, int startId)
  {
    return START_NOT_STICKY;
  }

  @Override
  public IBinder
  onBind (Intent intent)
  {
    return null;
  }

  @TargetApi (Build.VERSION_CODES.GINGERBREAD)
  String
  getLibraryDirectory ()
  {
    int apiLevel;
    Context context;

    context = getApplicationContext ();
    apiLevel = Build.VERSION.SDK_INT;

    if (apiLevel >= Build.VERSION_CODES.GINGERBREAD)
      return context.getApplicationInfo().nativeLibraryDir;
    else if (apiLevel >= Build.VERSION_CODES.DONUT)
      return context.getApplicationInfo().dataDir + "/lib";

    return "/data/data/" + context.getPackageName() + "/lib";
  }

  @Override
  public void
  onCreate ()
  {
    AssetManager manager;
    Context app_context;
    String filesDir, libDir;
    double pixelDensityX;
    double pixelDensityY;

    SERVICE = this;
    handler = new Handler (Looper.getMainLooper ());
    manager = getAssets ();
    app_context = getApplicationContext ();
    metrics = getResources ().getDisplayMetrics ();
    pixelDensityX = metrics.xdpi;
    pixelDensityY = metrics.ydpi;

    try
      {
	/* Configure Emacs with the asset manager and other necessary
	   parameters.  */
	filesDir = app_context.getFilesDir ().getCanonicalPath ();
	libDir = getLibraryDirectory ();

	Log.d (TAG, "Initializing Emacs, where filesDir = " + filesDir
	       + " and libDir = " + libDir);

	EmacsNative.setEmacsParams (manager, filesDir, libDir,
				    (float) pixelDensityX,
				    (float) pixelDensityY,
				    this);

	/* Start the thread that runs Emacs.  */
	thread = new EmacsThread (this);
	thread.start ();
      }
    catch (IOException exception)
      {
	EmacsNative.emacsAbort ();
	return;
      }
  }



  /* Functions from here on must only be called from the Emacs
     thread.  */

  void
  runOnUiThread (Runnable runnable)
  {
    handler.post (runnable);
  }

  EmacsView
  getEmacsView (final EmacsWindow window, final int visibility,
		final boolean isFocusedByDefault)
  {
    Runnable runnable;
    final Holder<EmacsView> view;

    view = new Holder<EmacsView> ();

    runnable = new Runnable () {
	public void
	run ()
	{
	  synchronized (this)
	    {
	      view.thing = new EmacsView (window);
	      view.thing.setVisibility (visibility);
	      view.thing.setFocusedByDefault (isFocusedByDefault);
	      notify ();
	    }
	}
      };

    synchronized (runnable)
      {
	runOnUiThread (runnable);

	try
	  {
	    runnable.wait ();
	  }
	catch (InterruptedException e)
	  {
	    EmacsNative.emacsAbort ();
	  }
      }

    return view.thing;
  }

  public void
  fillRectangle (EmacsDrawable drawable, EmacsGC gc,
		 int x, int y, int width, int height)
  {
    EmacsFillRectangle.perform (drawable, gc, x, y,
				width, height);
  }

  public void
  fillPolygon (EmacsDrawable drawable, EmacsGC gc,
	       Point points[])
  {
    EmacsFillPolygon.perform (drawable, gc, points);
  }

  public void
  drawRectangle (EmacsDrawable drawable, EmacsGC gc,
		 int x, int y, int width, int height)
  {
    EmacsDrawRectangle.perform (drawable, gc, x, y,
				width, height);
  }

  public void
  drawLine (EmacsDrawable drawable, EmacsGC gc,
	    int x, int y, int x2, int y2)
  {
    EmacsDrawLine.perform (drawable, gc, x, y,
			   x2, y2);
  }

  public void
  drawPoint (EmacsDrawable drawable, EmacsGC gc,
	     int x, int y)
  {
    EmacsDrawPoint.perform (drawable, gc, x, y);
  }

  public void
  copyArea (EmacsDrawable srcDrawable, EmacsDrawable dstDrawable,
	    EmacsGC gc,
	    int srcX, int srcY, int width, int height, int destX,
	    int destY)
  {
    EmacsCopyArea.perform (srcDrawable, gc, dstDrawable,
			   srcX, srcY, width, height, destX,
			   destY);
  }

  public void
  clearWindow (EmacsWindow window)
  {
    window.clearWindow ();
  }

  public void
  clearArea (EmacsWindow window, int x, int y, int width,
	     int height)
  {
    window.clearArea (x, y, width, height);
  }
};