/*
 * Extends L.Map to handle panning animations.
 */

L.Map.include({

	setView: function (center, zoom, options) {

		zoom = zoom === undefined ? this._zoom : this._limitZoom(zoom);
		center = this._limitCenter(L.latLng(center), zoom, this.options.maxBounds);
		options = options || {};

		if (this._panAnim) {
			this._panAnim.stop();
		}

		if (this._loaded && !options.reset && options !== true) {

			if (options.animate !== undefined) {
				options.zoom = L.extend({animate: options.animate}, options.zoom);
				options.pan = L.extend({animate: options.animate}, options.pan);
			}

			// try animating pan or zoom
			var animated = (this._zoom !== zoom) ?
				this._tryAnimatedZoom && this._tryAnimatedZoom(center, zoom, options.zoom) :
				this._tryAnimatedPan(center, options.pan);

			if (animated) {
				// prevent resize handler call, the view will refresh after animation anyway
				clearTimeout(this._sizeTimer);
				return this;
			}
		}

		// animation didn't start, just reset the map view
		this._resetView(center, zoom);

		return this;
	},

	panBy: function (offset, options) {
		offset = L.point(offset).round();
		options = options || {};

		if (!offset.x && !offset.y) {
			return this;
		}

		if (!this._panAnim) {
			this._panAnim = new L.PosAnimation();

			this._panAnim.on({
				'step': this._onPanTransitionStep,
				'end': this._onPanTransitionEnd
			}, this);
		}

		// don't fire movestart if animating inertia
		if (!options.noMoveStart) {
			this.fire('movestart');
		}

		// animate pan unless animate: false specified
		if (options.animate !== false) {
			L.DomUtil.addClass(this._mapPane, 'leaflet-pan-anim');

			var newPos = this._getMapPanePos().subtract(offset);
			this._panAnim.run(this._mapPane, newPos, options.duration || 0.25, options.easeLinearity);
		} else {
			this._rawPanBy(offset);
			this.fire('move').fire('moveend');
		}

		return this;
	},

	_onPanTransitionStep: function () {
		this.fire('move');
	},

	_onPanTransitionEnd: function () {
		L.DomUtil.removeClass(this._mapPane, 'leaflet-pan-anim');
		this.fire('moveend');
	},

	_tryAnimatedPan: function (center, options) {
		// difference between the new and current centers in pixels
		var offset = this._getCenterOffset(center)._floor();

		// don't animate too far unless animate: true specified in options
		if ((options && options.animate) !== true && !this.getSize().contains(offset)) { return false; }

		this.panBy(offset, options);

		return true;
	}
});