define(function (require) {

    var echarts = require('echarts');

    function BMapCoordSys(bmap, api) {
        this._bmap = bmap;
        this.dimensions = ['lng', 'lat'];
        this._mapOffset = [0, 0];

        this._api = api;
    }

    BMapCoordSys.prototype.dimensions = ['lng', 'lat'];

    BMapCoordSys.prototype.setMapOffset = function (mapOffset) {
        this._mapOffset = mapOffset;
    };

    BMapCoordSys.prototype.getBMap = function () {
        return this._bmap;
    };

    BMapCoordSys.prototype.dataToPoint = function (data) {
        var point = new BMap.Point(data[0], data[1]);
        // TODO pointToOverlayPixel is toooooooo slow, cache the transform
        var px = this._bmap.pointToOverlayPixel(point);
        var mapOffset = this._mapOffset;
        return [px.x - mapOffset[0], px.y - mapOffset[1]];
    };

    BMapCoordSys.prototype.pointToData = function (pt) {
        var mapOffset = this._mapOffset;
        var pt = this._bmap.overlayPixelToPoint({
            x: pt[0] + mapOffset[0],
            y: pt[1] + mapOffset[1]
        });
        return [pt.lng, pt.lat];
    };

    BMapCoordSys.prototype.getViewRect = function () {
        var api = this._api;
        return new echarts.graphic.BoundingRect(0, 0, api.getWidth(), api.getHeight());
    };

    BMapCoordSys.prototype.getRoamTransform = function () {
        return echarts.matrix.create();
    };

    var Overlay;

    // For deciding which dimensions to use when creating list data
    BMapCoordSys.dimensions = BMapCoordSys.prototype.dimensions;

    function createOverlayCtor() {
        function Overlay(root) {
            this._root = root;
        }

        Overlay.prototype = new BMap.Overlay();
        /**
         * 初始化
         *
         * @param {BMap.Map} map
         * @override
         */
        Overlay.prototype.initialize = function (map) {
            map.getPanes().labelPane.appendChild(this._root);
            return this._root;
        };
        /**
         * @override
         */
        Overlay.prototype.draw = function () {};

        return Overlay;
    }

    BMapCoordSys.create = function (ecModel, api) {
        var bmapCoordSys;
        var root = api.getDom();

        // TODO Dispose
        ecModel.eachComponent('bmap', function (bmapModel) {
            var viewportRoot = api.getZr().painter.getViewportRoot();
            if (typeof BMap === 'undefined') {
                throw new Error('BMap api is not loaded');
            }
            Overlay = Overlay || createOverlayCtor();
            if (bmapCoordSys) {
                throw new Error('Only one bmap component can exist');
            }
            if (!bmapModel.__bmap) {
                // Not support IE8
                var bmapRoot = root.querySelector('.ec-extension-bmap');
                if (bmapRoot) {
                    // Reset viewport left and top, which will be changed
                    // in moving handler in BMapView
                    viewportRoot.style.left = '0px';
                    viewportRoot.style.top = '0px';
                    root.removeChild(bmapRoot);
                }
                bmapRoot = document.createElement('div');
                bmapRoot.style.cssText = 'width:100%;height:100%';
                // Not support IE8
                bmapRoot.classList.add('ec-extension-bmap');
                root.appendChild(bmapRoot);
                var bmap = bmapModel.__bmap = new BMap.Map(bmapRoot);

                var overlay = new Overlay(viewportRoot);
                bmap.addOverlay(overlay);
            }
            var bmap = bmapModel.__bmap;

            // Set bmap options
            // centerAndZoom before layout and render
            var center = bmapModel.get('center');
            var zoom = bmapModel.get('zoom');
            if (center && zoom) {
                var pt = new BMap.Point(center[0], center[1]);
                bmap.centerAndZoom(pt, zoom);
            }

            bmapCoordSys = new BMapCoordSys(bmap, api);
            bmapCoordSys.setMapOffset(bmapModel.__mapOffset || [0, 0]);
            bmapModel.coordinateSystem = bmapCoordSys;
        });

        ecModel.eachSeries(function (seriesModel) {
            if (seriesModel.get('coordinateSystem') === 'bmap') {
                seriesModel.coordinateSystem = bmapCoordSys;
            }
        });
    };

    return BMapCoordSys;
});