/* See LICENSE file for copyright and license details. */
package libgamma;


/**
 * Site state
 * <p>
 * On operating systems that integrate a graphical environment
 * there is usually just one site. However, one systems with
 * pluggable graphics, like Unix-like systems such as GNU/Linux
 * and the BSD:s, there can usually be any (feasible) number of
 * sites. In X.org parlance they are called displays.
 */
public class Site
{
	/**
	 * Type initialiser
	 */
	static
	{
		Libgamma.initialise();
	}


	/**
	 * Constructor
	 * 
	 * @param  method  The adjustmet method
	 * @param  site    The site identifier
	 */
	public Site(AdjustmentMethod method, String site) throws LibgammaException
	{
		this.method = method;
		this.site = site;
		long[] r = libgamma_site_create(method.value, site);
		this.address = r[0];
		this.partitions_available = (int)(r[1]);
		if (r[2] != 0)
			throw new LibgammaException((int)(r[2]));
	}


	/**
	 * This field specifies, for the methods if this library,
	 * which adjustment method (display server and protocol)
	 * is used to adjust the gamma ramps
	 */
	public final AdjustmentMethod method;

	/**
	 * The site identifier. It can either be {@code null} or
	 * a string. {@code null} indicates the default site. On
	 * systems like the Unix-like systems, where the graphics
	 * are pluggable, this is usually resolved by an environment
	 * variable, such as "DISPLAY" for X.org.
	 */
	public final String site;

	/**
	 * The number of partitions that is available on this site.
	 * 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 final int partitions_available;

	/**
	 * The address of the native object
	 */
	final long address;


	/**
	 * Release resources
	 */
	public void close()
	{
		libgamma_site_free(this.address);
	}

	/**
	 * Restore the gamma ramps all CRTC:s within the site to the system settings
	 */
	public void restore() throws LibgammaException
	{
		int r = libgamma_site_restore(this.address);
		if (r != 0)
			throw new LibgammaException(r);
	}


	/**
	 * {@inheritDoc}
	 */
	public String toString()
	{
		return "<Site: method = " + this.method.toString() + ", " +
		       "site = " + (this.site == null ? "(null)" : this.site) + ", " +
		       "partitions_available = " + Integer.toString(this.partitions_available) + ">";
	}

	/**
	 * Create a site state
	 * 
	 * @param   method  The adjustment method (display server and protocol)
	 * @param   site    The site identifier
	 * @return          Element 0: The value for {@link #address}<br>
	 *                  Element 1: The value for {@link #partitions_available}<br>
	 *                  Element 2: Error code, zero on success
	 */
	private static native long[] libgamma_site_create(int method, String site);

	/**
	 * Release all resources held by a site state
	 * and free the site state pointer
	 * 
	 * @param  address  The site state
	 */
	private static native void libgamma_site_free(long address);

	/**
	 * Restore the gamma ramps all CRTC:s within a site to the system settings
	 * 
	 * @param   address  The site state
	 * @return           Zero on success, and error code on failure
	 */
	private static native int libgamma_site_restore(long address);
}