import * as DomEvent from './DomEvent';
import * as Util from '../core/Util';
import * as Browser from '../core/Browser';

/*
 * Extends L.DomEvent to provide touch support for Internet Explorer and Windows-based devices.
 */


var POINTER_DOWN =   Browser.msPointer ? 'MSPointerDown'   : 'pointerdown';
var POINTER_MOVE =   Browser.msPointer ? 'MSPointerMove'   : 'pointermove';
var POINTER_UP =     Browser.msPointer ? 'MSPointerUp'     : 'pointerup';
var POINTER_CANCEL = Browser.msPointer ? 'MSPointerCancel' : 'pointercancel';
var TAG_WHITE_LIST = ['INPUT', 'SELECT', 'OPTION'];

var _pointers = {};
var _pointerDocListener = false;

// DomEvent.DoubleTap needs to know about this
export var _pointersCount = 0;

// Provides a touch events wrapper for (ms)pointer events.
// ref http://www.w3.org/TR/pointerevents/ https://www.w3.org/Bugs/Public/show_bug.cgi?id=22890

export function addPointerListener(obj, type, handler, id) {
	if (type === 'touchstart') {
		_addPointerStart(obj, handler, id);

	} else if (type === 'touchmove') {
		_addPointerMove(obj, handler, id);

	} else if (type === 'touchend') {
		_addPointerEnd(obj, handler, id);
	}

	return this;
}

export function removePointerListener(obj, type, id) {
	var handler = obj['_leaflet_' + type + id];

	if (type === 'touchstart') {
		obj.removeEventListener(POINTER_DOWN, handler, false);

	} else if (type === 'touchmove') {
		obj.removeEventListener(POINTER_MOVE, handler, false);

	} else if (type === 'touchend') {
		obj.removeEventListener(POINTER_UP, handler, false);
		obj.removeEventListener(POINTER_CANCEL, handler, false);
	}

	return this;
}

function _addPointerStart(obj, handler, id) {
	var onDown = Util.bind(function (e) {
		if (e.pointerType !== 'mouse' && e.MSPOINTER_TYPE_MOUSE && e.pointerType !== e.MSPOINTER_TYPE_MOUSE) {
			// In IE11, some touch events needs to fire for form controls, or
			// the controls will stop working. We keep a whitelist of tag names that
			// need these events. For other target tags, we prevent default on the event.
			if (TAG_WHITE_LIST.indexOf(e.target.tagName) < 0) {
				DomEvent.preventDefault(e);
			} else {
				return;
			}
		}

		_handlePointer(e, handler);
	});

	obj['_leaflet_touchstart' + id] = onDown;
	obj.addEventListener(POINTER_DOWN, onDown, false);

	// need to keep track of what pointers and how many are active to provide e.touches emulation
	if (!_pointerDocListener) {
		// we listen documentElement as any drags that end by moving the touch off the screen get fired there
		document.documentElement.addEventListener(POINTER_DOWN, _globalPointerDown, true);
		document.documentElement.addEventListener(POINTER_MOVE, _globalPointerMove, true);
		document.documentElement.addEventListener(POINTER_UP, _globalPointerUp, true);
		document.documentElement.addEventListener(POINTER_CANCEL, _globalPointerUp, true);

		_pointerDocListener = true;
	}
}

function _globalPointerDown(e) {
	_pointers[e.pointerId] = e;
	_pointersCount++;
}

function _globalPointerMove(e) {
	if (_pointers[e.pointerId]) {
		_pointers[e.pointerId] = e;
	}
}

function _globalPointerUp(e) {
	delete _pointers[e.pointerId];
	_pointersCount--;
}

function _handlePointer(e, handler) {
	e.touches = [];
	for (var i in _pointers) {
		e.touches.push(_pointers[i]);
	}
	e.changedTouches = [e];

	handler(e);
}

function _addPointerMove(obj, handler, id) {
	var onMove = function (e) {
		// don't fire touch moves when mouse isn't down
		if ((e.pointerType === e.MSPOINTER_TYPE_MOUSE || e.pointerType === 'mouse') && e.buttons === 0) { return; }

		_handlePointer(e, handler);
	};

	obj['_leaflet_touchmove' + id] = onMove;
	obj.addEventListener(POINTER_MOVE, onMove, false);
}

function _addPointerEnd(obj, handler, id) {
	var onUp = function (e) {
		_handlePointer(e, handler);
	};

	obj['_leaflet_touchend' + id] = onUp;
	obj.addEventListener(POINTER_UP, onUp, false);
	obj.addEventListener(POINTER_CANCEL, onUp, false);
}