/*global define*/
define([
        '../Core/Credit',
        '../Core/defaultValue',
        '../Core/defined',
        '../Core/defineProperties',
        '../Core/DeveloperError',
        '../Core/MapboxApi',
        './UrlTemplateImageryProvider'
    ], function(
        Credit,
        defaultValue,
        defined,
        defineProperties,
        DeveloperError,
        MapboxApi,
        UrlTemplateImageryProvider) {
    'use strict';

    var trailingSlashRegex = /\/$/;
    var defaultCredit1 = new Credit('© Mapbox © OpenStreetMap', undefined, 'https://www.mapbox.com/about/maps/');
    var defaultCredit2 = [new Credit('Improve this map', undefined, 'https://www.mapbox.com/map-feedback/')];

    /**
     * Provides tiled imagery hosted by Mapbox.
     *
     * @alias MapboxImageryProvider
     * @constructor
     *
     * @param {Object} [options] Object with the following properties:
     * @param {String} [options.url='https://api.mapbox.com/v4/'] The Mapbox server url.
     * @param {String} options.mapId The Mapbox Map ID.
     * @param {String} [options.accessToken] The public access token for the imagery.
     * @param {String} [options.format='png'] The format of the image request.
     * @param {Object} [options.proxy] A proxy to use for requests. This object is expected to have a getURL function which returns the proxied URL.
     * @param {Ellipsoid} [options.ellipsoid] The ellipsoid.  If not specified, the WGS84 ellipsoid is used.
     * @param {Number} [options.minimumLevel=0] The minimum level-of-detail supported by the imagery provider.  Take care when specifying
     *                 this that the number of tiles at the minimum level is small, such as four or less.  A larger number is likely
     *                 to result in rendering problems.
     * @param {Number} [options.maximumLevel] The maximum level-of-detail supported by the imagery provider, or undefined if there is no limit.
     * @param {Rectangle} [options.rectangle=Rectangle.MAX_VALUE] The rectangle, in radians, covered by the image.
     * @param {Credit|String} [options.credit] A credit for the data source, which is displayed on the canvas.
     *
     *
     * @example
     * // Mapbox tile provider
     * var mapbox = new Cesium.MapboxImageryProvider({
     *     mapId: 'mapbox.streets',
     *     accessToken: 'thisIsMyAccessToken'
     * });
     *
     * @see {@link https://www.mapbox.com/developers/api/maps/#tiles}
     * @see {@link https://www.mapbox.com/developers/api/#access-tokens}
     */
    function MapboxImageryProvider(options) {
        options = defaultValue(options, defaultValue.EMPTY_OBJECT);
        var mapId = options.mapId;
        //>>includeStart('debug', pragmas.debug);
        if (!defined(mapId)) {
            throw new DeveloperError('options.mapId is required.');
        }
        //>>includeEnd('debug');

        var url = defaultValue(options.url, 'https://api.mapbox.com/v4/');
        this._url = url;
        this._mapId = mapId;
        this._accessToken = MapboxApi.getAccessToken(options.accessToken);
        this._accessTokenErrorCredit = MapboxApi.getErrorCredit(options.accessToken);
        var format = defaultValue(options.format, 'png');
        if (!/\./.test(format)) {
            format = '.' + format;
        }
        this._format = format;

        var templateUrl = url;
        if (!trailingSlashRegex.test(url)) {
            templateUrl += '/';
        }
        templateUrl += mapId + '/{z}/{x}/{y}' + this._format;
        if (defined(this._accessToken)) {
            templateUrl += '?access_token=' + this._accessToken;
        }

        if (defined(options.credit)) {
            var credit = options.credit;
            if (typeof credit === 'string') {
                credit = new Credit(credit);
            }
            defaultCredit1 = credit;
            defaultCredit2.length = 0;
        }

        this._imageryProvider = new UrlTemplateImageryProvider({
            url: templateUrl,
            proxy: options.proxy,
            credit: defaultCredit1,
            ellipsoid: options.ellipsoid,
            minimumLevel: options.minimumLevel,
            maximumLevel: options.maximumLevel,
            rectangle: options.rectangle
        });
    }

    defineProperties(MapboxImageryProvider.prototype, {
        /**
         * Gets the URL of the Mapbox server.
         * @memberof MapboxImageryProvider.prototype
         * @type {String}
         * @readonly
         */
        url : {
            get : function() {
                return this._url;
            }
        },

        /**
         * Gets a value indicating whether or not the provider is ready for use.
         * @memberof MapboxImageryProvider.prototype
         * @type {Boolean}
         * @readonly
         */
        ready : {
            get : function() {
                return this._imageryProvider.ready;
            }
        },

        /**
         * Gets a promise that resolves to true when the provider is ready for use.
         * @memberof MapboxImageryProvider.prototype
         * @type {Promise.<Boolean>}
         * @readonly
         */
        readyPromise : {
            get : function() {
                return this._imageryProvider.readyPromise;
            }
        },

        /**
         * Gets the rectangle, in radians, of the imagery provided by the instance.  This function should
         * not be called before {@link MapboxImageryProvider#ready} returns true.
         * @memberof MapboxImageryProvider.prototype
         * @type {Rectangle}
         * @readonly
         */
        rectangle: {
            get : function() {
                return this._imageryProvider.rectangle;
            }
        },

        /**
         * Gets the width of each tile, in pixels.  This function should
         * not be called before {@link MapboxImageryProvider#ready} returns true.
         * @memberof MapboxImageryProvider.prototype
         * @type {Number}
         * @readonly
         */
        tileWidth : {
            get : function() {
                return this._imageryProvider.tileWidth;
            }
        },

        /**
         * Gets the height of each tile, in pixels.  This function should
         * not be called before {@link MapboxImageryProvider#ready} returns true.
         * @memberof MapboxImageryProvider.prototype
         * @type {Number}
         * @readonly
         */
        tileHeight : {
            get : function() {
                return this._imageryProvider.tileHeight;
            }
        },

        /**
         * Gets the maximum level-of-detail that can be requested.  This function should
         * not be called before {@link MapboxImageryProvider#ready} returns true.
         * @memberof MapboxImageryProvider.prototype
         * @type {Number}
         * @readonly
         */
        maximumLevel : {
            get : function() {
                return this._imageryProvider.maximumLevel;
            }
        },

        /**
         * Gets the minimum level-of-detail that can be requested.  This function should
         * not be called before {@link MapboxImageryProvider#ready} returns true. Generally,
         * a minimum level should only be used when the rectangle of the imagery is small
         * enough that the number of tiles at the minimum level is small.  An imagery
         * provider with more than a few tiles at the minimum level will lead to
         * rendering problems.
         * @memberof MapboxImageryProvider.prototype
         * @type {Number}
         * @readonly
         */
        minimumLevel : {
            get : function() {
                return this._imageryProvider.minimumLevel;
            }
        },

        /**
         * Gets the tiling scheme used by the provider.  This function should
         * not be called before {@link MapboxImageryProvider#ready} returns true.
         * @memberof MapboxImageryProvider.prototype
         * @type {TilingScheme}
         * @readonly
         */
        tilingScheme : {
            get : function() {
                return this._imageryProvider.tilingScheme;
            }
        },

        /**
         * Gets the tile discard policy.  If not undefined, the discard policy is responsible
         * for filtering out "missing" tiles via its shouldDiscardImage function.  If this function
         * returns undefined, no tiles are filtered.  This function should
         * not be called before {@link MapboxImageryProvider#ready} returns true.
         * @memberof MapboxImageryProvider.prototype
         * @type {TileDiscardPolicy}
         * @readonly
         */
        tileDiscardPolicy : {
            get : function() {
                return this._imageryProvider.tileDiscardPolicy;
            }
        },

        /**
         * Gets an event that is raised when the imagery provider encounters an asynchronous error..  By subscribing
         * to the event, you will be notified of the error and can potentially recover from it.  Event listeners
         * are passed an instance of {@link TileProviderError}.
         * @memberof MapboxImageryProvider.prototype
         * @type {Event}
         * @readonly
         */
        errorEvent : {
            get : function() {
                return this._imageryProvider.errorEvent;
            }
        },

        /**
         * Gets the credit to display when this imagery provider is active.  Typically this is used to credit
         * the source of the imagery. This function should
         * not be called before {@link MapboxImageryProvider#ready} returns true.
         * @memberof MapboxImageryProvider.prototype
         * @type {Credit}
         * @readonly
         */
        credit : {
            get : function() {
                return this._imageryProvider.credit;
            }
        },

        /**
         * Gets the proxy used by this provider.
         * @memberof MapboxImageryProvider.prototype
         * @type {Proxy}
         * @readonly
         */
        proxy : {
            get : function() {
                return this._imageryProvider.proxy;
            }
        },

        /**
         * Gets a value indicating whether or not the images provided by this imagery provider
         * include an alpha channel.  If this property is false, an alpha channel, if present, will
         * be ignored.  If this property is true, any images without an alpha channel will be treated
         * as if their alpha is 1.0 everywhere.  When this property is false, memory usage
         * and texture upload time are reduced.
         * @memberof MapboxImageryProvider.prototype
         * @type {Boolean}
         * @readonly
         */
        hasAlphaChannel : {
            get : function() {
                return this._imageryProvider.hasAlphaChannel;
            }
        }
    });

    /**
     * Gets the credits to be displayed when a given tile is displayed.
     *
     * @param {Number} x The tile X coordinate.
     * @param {Number} y The tile Y coordinate.
     * @param {Number} level The tile level;
     * @returns {Credit[]} The credits to be displayed when the tile is displayed.
     *
     * @exception {DeveloperError} <code>getTileCredits</code> must not be called before the imagery provider is ready.
     */
    MapboxImageryProvider.prototype.getTileCredits = function(x, y, level) {
        var credits = defaultCredit2.slice();
        if (defined(this._accessTokenErrorCredit)) {
            credits.push(this._accessTokenErrorCredit);
        }
        return credits;
    };

    /**
     * Requests the image for a given tile.  This function should
     * not be called before {@link MapboxImageryProvider#ready} returns true.
     *
     * @param {Number} x The tile X coordinate.
     * @param {Number} y The tile Y coordinate.
     * @param {Number} level The tile level.
     * @param {Number} [distance] The distance of the tile from the camera, used to prioritize requests.
     * @returns {Promise.<Image|Canvas>|undefined} A promise for the image that will resolve when the image is available, or
     *          undefined if there are too many active requests to the server, and the request
     *          should be retried later.  The resolved image may be either an
     *          Image or a Canvas DOM object.
     *
     * @exception {DeveloperError} <code>requestImage</code> must not be called before the imagery provider is ready.
     */
    MapboxImageryProvider.prototype.requestImage = function(x, y, level, distance) {
        return this._imageryProvider.requestImage(x, y, level, distance);
    };

    /**
     * Asynchronously determines what features, if any, are located at a given longitude and latitude within
     * a tile.  This function should not be called before {@link MapboxImageryProvider#ready} returns true.
     * This function is optional, so it may not exist on all ImageryProviders.
     *
     *
     * @param {Number} x The tile X coordinate.
     * @param {Number} y The tile Y coordinate.
     * @param {Number} level The tile level.
     * @param {Number} longitude The longitude at which to pick features.
     * @param {Number} latitude  The latitude at which to pick features.
     * @return {Promise.<ImageryLayerFeatureInfo[]>|undefined} A promise for the picked features that will resolve when the asynchronous
     *                   picking completes.  The resolved value is an array of {@link ImageryLayerFeatureInfo}
     *                   instances.  The array may be empty if no features are found at the given location.
     *                   It may also be undefined if picking is not supported.
     *
     * @exception {DeveloperError} <code>pickFeatures</code> must not be called before the imagery provider is ready.
     */
    MapboxImageryProvider.prototype.pickFeatures = function(x, y, level, longitude, latitude) {
        return this._imageryProvider.pickFeatures(x, y, level, longitude, latitude);
    };

    return MapboxImageryProvider;
});
