HaxeFlixel/flixel

package flixel;

import flixel.system.FlxBGSprite;
import flixel.util.FlxColor;
import flixel.util.FlxDestroyUtil;

/**
 * A `FlxSubState` can be opened inside of a `FlxState`.
 * By default, it also stops the parent state from updating,
 * making it convenient for pause screens or menus.
 * 
 * @see [FlxSubstate snippet](https://snippets.haxeflixel.com/states/flxsubstate/)
 * @see [Substate demo](https://haxeflixel.com/demos/SubState/)
 */
class FlxSubState extends FlxState
{
    /**
     * Callback method for state open/resume event.
     * @since 4.3.0
     */
    public var openCallback:Void->Void;

    /**
     * Callback method for state close event.
     */
    public var closeCallback:Void->Void;

    /**
     * Helper sprite object for non-flash targets. Draws the background.
     */
    @:noCompletion
    var _bgSprite:FlxBGSprite;

    /**
     * Helper var for `close()` so `closeSubState()` can be called on the parent.
     */
    @:allow(flixel.FlxState.resetSubState)
    var _parentState:FlxState;

    @:noCompletion
    var _bgColor:FlxColor;

    @:noCompletion
    @:allow(flixel.FlxState.resetSubState)
    var _created:Bool = false;

    /**
     * @param   bgColor   background color for this substate
     */
    public function new(bgColor = FlxColor.TRANSPARENT)
    {
        super();
        closeCallback = null;
        openCallback = null;

        if (FlxG.renderTile)
        {
            _bgSprite = new FlxBGSprite();
        }
        this.bgColor = bgColor;
    }

    override public function draw():Void
    {
        // Draw background
        if (FlxG.renderBlit)
        {
            for (camera in getCamerasLegacy())
            {
                camera.fill(bgColor);
            }
        }
        else // FlxG.renderTile
        {
            if (_bgSprite != null && _bgSprite.visible)
                _bgSprite.draw();
        }

        // Now draw all children
        super.draw();
    }

    override public function destroy():Void
    {
        super.destroy();
        closeCallback = null;
        openCallback = null;
        _parentState = null;
        _bgSprite = FlxDestroyUtil.destroy(_bgSprite);
    }

    /**
     * Closes this substate.
     */
    public function close():Void
    {
        if (_parentState != null && _parentState.subState == this)
            _parentState.closeSubState();
    }

    @:noCompletion
    override inline function get_bgColor():FlxColor
    {
        return _bgColor;
    }

    @:noCompletion
    override function set_bgColor(value:FlxColor):FlxColor
    {
        if (FlxG.renderTile && _bgSprite != null)
        {
            _bgSprite.alpha = value.alphaFloat;
            _bgSprite.visible = _bgSprite.alpha > 0;
            _bgSprite.color = value.rgb;
        }

        return _bgColor = value;
    }
}