package flare.animate.interpolate
{
    /**
     * Interpolator for <code>Date</code> values.
     */
    public class DateInterpolator extends Interpolator
    {
        private var _start:Number;
        private var _end:Number;
        private var _d:Date;
        
        /**
         * Creates a new DateInterpolator.
         * @param target the object whose property is being interpolated
         * @param property the property to interpolate
         * @param start the starting date value to interpolate from
         * @param end the target date value to interpolate to
         */
        public function DateInterpolator(target:Object, property:String,
                                         start:Object, end:Object)
        {
            super(target, property, start, end);
        }
        
        /**
         * Initializes this interpolator.
         * @param start the starting value of the interpolation
         * @param end the target value of the interpolation
         */
        protected override function init(start:Object, end:Object) : void
        {
            _d = new Date();
            _start = (start as Date).time;
            _end = (end as Date).time - _start;
        }
        
        /**
         * Calculate and set an interpolated property value.
         * @param f the interpolation fraction (typically between 0 and 1)
         */
        public override function interpolate(f:Number) : void
        {
            _d.time = _start + f * _end;
            _prop.setValue(_target, _d);
        }
        
    } // end of class DateInterpolator
}