/**
 * jlibgamma — Display server abstraction layer for gamma ramp and Java
 * Copyright © 2014  Mattias Andrée (maandree@member.fsf.org)
 * 
 * This library 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.
 * 
 * This library 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 this library.  If not, see <http://www.gnu.org/licenses/>.
 */
package libgamma;


/**
 * Partition state.
 * 
 * Probably the majority of display server only one partition
 * per site. However, X.org can, and traditional used to have
 * on multi-headed environments, multiple partitions per site.
 * In X.org partitions are called 'screens'. It is not to be
 * confused with monitor. A screen is a collection of monitors,
 * and the mapping from monitors to screens is a surjection.
 * On hardware-level adjustment methods, such as Direct
 * Rendering Manager, a partition is a graphics card.
 */
public class Partition
{
    /**
     * Type initialiser.
     */
    static
    {
	Libgamma.initialise();
    }
    
    
    
    /**
     * Constructor.
     * 
     * @param  site       The site this partition belongs to.
     * @param  partition  The index of the partition.
     */
    public Partition(Site site, int partition) throws LibgammaException
    {
	this.site = site;
	this.partition = partition;
	long[] r = libgamma_partition_create(site.address, partition);
	this.address = r[0];
	this.crtcs_available = (int)(r[1]);
	if (r[2] != 0)
	    throw new LibgammaException((int)(r[2]));
    }
    
    
    /**
     * The site this partition belongs to.
     */
    public final Site site;
    
    /**
     * The index of the partition.
     */
    public final int partition;
    
    /**
     * The number of CRTC:s that are available under this
     * partition. Note that the CRTC:s are not necessarily
     * online.
     */
    public final int crtcs_available;
    
    /**
     * The address of the native object.
     */
    final long address;
    
    
    /**
     * Release resources.
     */
    public void close()
    {
	libgamma_partition_free(this.address);
    }
    
    /**
     * Restore the gamma ramps all CRTC:s within the partition to the system settings.
     */
    public void restore() throws LibgammaException
    {
	int r = libgamma_partition_restore(this.address);
	if (r != 0)
	    throw new LibgammaException(r);
    }
    
    
    /**
     * {@inheritDoc}
     */
    public String toString()
    {
	return "<Partition: site = " + this.site.toString() + ", " +
	              "partition = " + Integer.toString(this.partition) + ", " +
	        "crtcs_available = " + Integer.toString(this.crtcs_available) + ">";
    }
    
    
    
    /**
     * Create a partition state.
     * 
     * @param   site       The site state for the site that the partition belongs to.
     * @param   partition  The index of the partition within the site.
     * @return             Element 0:  The value for {@link #address}.
     *                     Element 1:  The value for {@link #crtcs_available}
     *                     Element 2:  Error code, zero on success.
     */
    private static native long[] libgamma_partition_create(long site, int partition);
    
    /**
     * Release all resources held by a partition state
     * and free the partition state pointer.
     * 
     * @param  address  The partition state.
     */
    private static native void libgamma_partition_free(long address);
    
    /**
     * Restore the gamma ramps all CRTC:s within a partition to the system settings.
     * 
     * @param   address  The partition state.
     * @return           Zero on success, and error code on failure.
     */
    private static native int libgamma_partition_restore(long address);
    
}