DMDirc-Plugins/osd/src/main/java/com/dmdirc/addons/osd/OsdPolicy.java

/*
 * Copyright (c) 2006-2017 DMDirc Developers
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
 * documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
 * OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package com.dmdirc.addons.osd;

/**
 * Enumerates OSD Policies.
 */
public enum OsdPolicy {

    /** Spawn new windows below old ones. */
    DOWN("Place new windows below old ones", true) {

                @Override
                public int getYPosition(final OsdManager osdManager, final int startY) {
                    int y = startY;
                    for (OsdWindow window : osdManager.getWindowList()) {
                        if (window.isVisible()) {
                            y = Math.max(y, window.getY() + window.getHeight() + WINDOW_GAP);
                        }
                    }
                    return y;
                }
            },
    /** Spawn new windows above old ones. */
    UP("Place new windows above old ones", true) {

                @Override
                public int getYPosition(final OsdManager osdManager, final int startY) {
                    int y = startY;
                    for (OsdWindow window : osdManager.getWindowList()) {
                        if (window.isVisible()) {
                            y = Math.min(y, window.getY() - window.getHeight() - WINDOW_GAP);
                        }
                    }
                    return y;
                }
            },
    /** Close old OSD windows and display the new windows. */
    CLOSE("Close existing windows", false) {

                @Override
                public int getYPosition(final OsdManager osdManager, final int startY) {
                    osdManager.closeAll();
                    return startY;
                }
            },
    /** Place new windows on top of old windows. */
    ONTOP("Place new windows on top of existing windows", false) {

                @Override
                public int getYPosition(final OsdManager osdManager, final int startY) {
                    return startY;
                }
            };
    /** The spacing between the windows. */
    private static final int WINDOW_GAP = 5;
    /** Description of policy. */
    private final String description;
    /** Does policy need to change window location */
    private final boolean changesPosition;

    /**
     * Creates a new instance of OsdPolicies.
     *
     * @param description Description of the behaviour of the enum value
     */
    OsdPolicy(final String description, final boolean changesPosition) {
        this.description = description;
        this.changesPosition = changesPosition;
    }

    /**
     * Calculates the Y position for new windows according to this policy.
     * <p>
     * In order to ensure that windows are displayed at the correct position, the calling party MUST
     * ensure that the window list is not altered between this method's invocation and the time at
     * which the window is displayed. If the window list is altered, multiple windows may appear on
     * top of each other instead of stacking correctly, or there may be gaps in up/down policy
     * layouts.
     *
     * @param osdManager OSD Manager we are using
     * @param startY     Value of startY from the main config
     *
     * @return returns Y Value to use for new windows
     */
    public abstract int getYPosition(final OsdManager osdManager, final int startY);

    /**
     * See if this behaviour changes window position
     *
     * @return true or false depending on window behaviour
     */
    public boolean changesPosition() {
        return changesPosition;
    }

    /**
     * Return a description of what each policy does.
     *
     * @return Description of policies behaviour
     */
    public String getDescription() {
        return description;
    }

}