/*--------------------------------------------------------
 * Copyright (c) 2011, The Dojo Foundation
 * This software is distributed under the "Simplified BSD license",
 * the text of which is available at http://www.winktoolkit.org/licence.txt
 * or see the "license.txt" file for more details.
 *--------------------------------------------------------*/

/**
 * @fileOverview The wink feature detection provider.
 * 
 * @author Sylvain LALANDE
 */

define(['../../../_amd/core'], function()
{
	var features = {},
		properties = {},
		isFunc = wink.isFunction;
	
	
	/**
	 * @namespace Feature detection
	 * 
	 * @compatibility iOS2, iOS3, iOS4, iOS5, iOS6, Android 1.1, Android 1.5, Android 2.1, Android 2.2, Android 2.3, Android 3.0, Android 3.1, Android 4.0, Android 4.1.2, BlackBerry 6, BlackBerry 7, BB10, Bada 1.0, Windows Phone 7.5, Windows Phone 8
	 * 
	 * @see <a href="WINK_ROOT_URL/_base/_feat/test/test_feat.html" target="_blank">Test page</a>
	 */
	wink.has = has;
	
	wink.has.prefixes = [ "-webkit-", "-moz-", "-o-", "ms-", "-khtml-" ];
	wink.has.prefix = null;
	
	/**
	 * Test if the given feature is supported
	 * 
	 * @function
	 * @name wink.has#has
	 * 
	 * @param {string} feature The feature to test
	 * 
	 * @returns {boolean} True if the feature is supported false otherwise
	 * 
	 * @example
	 * 
	 * if ( wink.has('native-geolocation') )
	 * {
	 * 	...
	 * }
	 * 
	 * // Supported features:
	 * 
	 * native-geolocation, 
	 * native-device-orientation, 
	 * native-device-motion, 
	 * css-transform, 
	 * css-transition, 
	 * css-translate3d, 
	 * css-border-radius, 
	 * css-text-shadow, 
	 * css-box-shadow, 
	 * css-gradient, 
	 * css-perspective, 
	 * css-matrix, 
	 * css-matrix-stack-inversed, 
	 * css-position-fixed, 
	 * touchstart, 
	 * touchmove, 
	 * touchend, 
	 * touch, 
	 * gesturestart, 
	 * gesturechange, 
	 * transitionend, 
	 * gestureend, 
	 * gesture, 
	 * json-parse
	 * 
	 */
	function has(feature) {
		if (isFunc(features[feature])) {
			features[feature] = features[feature]();
		}
		return features[feature];
	}
	
	/**
	 * Inquires about the given feature
	 * 
	 * @function
	 * @param {string} feature The feature to inquire
	 * @param {function} assertSupported The function that investigates or the boolean value if known
	 * @param {boolean} now Allows to investigate now
	 */
	wink.has.inquire = inquire;
	function inquire(feature, assertSupported, now) {
		if (wink.isBoolean(features[feature])) {
			return;
		}
		var assert = assertSupported;
		if (now && isFunc(assertSupported)) {
			assert = assertSupported();
		}
		features[feature] = assert;
	}

	/**
	 * Inquires about a map of features
	 * 
	 * @function
	 * @param {object} map The map of features
	 * @param {boolean} now Allows to investigate now
	 */
	wink.has.inquireMap = inquireMap;
	function inquireMap(map, now) {
		if (!map || map.length == 0) {
			return;
		}
		for (var f in map) {
			inquire(f, map[f], now);
		}
	}
	
	/**
	 * Set a property associated to the feature detection
	 * 
	 * @function
	 * @param {string} key The property
	 * @param {string} value The value
	 */
	wink.has.setProp = setProp;
	function setProp(key, value) {
		properties[key] = value;
	}

	/**
	 * Defer the property recovery on a function or on a feature detection
	 * 
	 * @function
	 * @param {string} key The property
	 * @param {function} proc The defered process
	 */
	wink.has.deferProp = deferProp;
	function deferProp(key, proc) {
		if (isFunc(proc)) {
			setProp(key, proc);
		} else {
			setProp(key, function() {
				wink.has(proc);
			});
		}
	}
	
	/**
	 * Get a property associated to the feature detection
	 * 
	 * @function
	 * @param {string} key The property
	 */
	wink.has.prop = prop;
	function prop(key) {
		var v = properties[key];
		if (isFunc(v)) {
			v();
			v = properties[key];
			if (isFunc(v)) {
				v = key;
			}
		}
		return v || key;
	}
	
	/**
	 * Get all features
	 * 
	 * @returns {object} the features object
	 */
	wink.has.getFeatures = getFeatures;
	function getFeatures() {
		return features;
	}
	
	/**
	 * Get all properties
	 * 
	 * @returns {object} the properties object
	 */
	wink.has.getProperties = getProperties;
	function getProperties() {
		return properties;
	}
	
	return wink.has;
});