/**
 * Remote Scripting Library
 * Copyright 2005 modernmethod, inc
 * Under the open source BSD license
 * http://www.modernmethod.com/sajax/
 */

/*jscs:disable requireCamelCaseOrUpperCaseIdentifiers */
/*global alert */
( function ( mw ) {

	/**
	 * if sajax_debug_mode is true, this function outputs given the message into
	 * the element with id = sajax_debug; if no such element exists in the document,
	 * it is injected.
	 */
	function debug( text ) {
		if ( !window.sajax_debug_mode ) {
			return false;
		}

		var b, m,
			e = document.getElementById( 'sajax_debug' );

		if ( !e ) {
			e = document.createElement( 'p' );
			e.className = 'sajax_debug';
			e.id = 'sajax_debug';

			b = document.getElementsByTagName( 'body' )[0];

			if ( b.firstChild ) {
				b.insertBefore( e, b.firstChild );
			} else {
				b.appendChild( e );
			}
		}

		m = document.createElement( 'div' );
		m.appendChild( document.createTextNode( text ) );

		e.appendChild( m );

		return true;
	}

	/**
	 * Compatibility wrapper for creating a new XMLHttpRequest object.
	 */
	function createXhr() {
		debug( 'sajax_init_object() called..' );
		var a;
		try {
			// Try the new style before ActiveX so we don't
			// unnecessarily trigger warnings in IE 7 when
			// set to prompt about ActiveX usage
			a = new XMLHttpRequest();
		} catch ( xhrE ) {
			try {
				a = new window.ActiveXObject( 'Msxml2.XMLHTTP' );
			} catch ( msXmlE ) {
				try {
					a = new window.ActiveXObject( 'Microsoft.XMLHTTP' );
				} catch ( msXhrE ) {
					a = null;
				}
			}
		}
		if ( !a ) {
			debug( 'Could not create connection object.' );
		}

		return a;
	}

	/**
	 * Perform an AJAX call to MediaWiki. Calls are handled by AjaxDispatcher.php
	 *   func_name - the name of the function to call. Must be registered in $wgAjaxExportList
	 *   args - an array of arguments to that function
	 *   target - the target that will handle the result of the call. If this is a function,
	 *            if will be called with the XMLHttpRequest as a parameter; if it's an input
	 *            element, its value will be set to the resultText; if it's another type of
	 *            element, its innerHTML will be set to the resultText.
	 *
	 * Example:
	 *    sajax_do_call( 'doFoo', [1, 2, 3], document.getElementById( 'showFoo' ) );
	 *
	 * This will call the doFoo function via MediaWiki's AjaxDispatcher, with
	 * (1, 2, 3) as the parameter list, and will show the result in the element
	 * with id = showFoo
	 */
	function doAjaxRequest( func_name, args, target ) {
		var i, x, uri, post_data;
		uri = mw.util.wikiScript() + '?action=ajax';
		if ( window.sajax_request_type === 'GET' ) {
			if ( uri.indexOf( '?' ) === -1 ) {
				uri = uri + '?rs=' + encodeURIComponent( func_name );
			} else {
				uri = uri + '&rs=' + encodeURIComponent( func_name );
			}
			for ( i = 0; i < args.length; i++ ) {
				uri = uri + '&rsargs[]=' + encodeURIComponent( args[i] );
			}
			// uri = uri + '&rsrnd=' + new Date().getTime();
			post_data = null;
		} else {
			post_data = 'rs=' + encodeURIComponent( func_name );
			for ( i = 0; i < args.length; i++ ) {
				post_data = post_data + '&rsargs[]=' + encodeURIComponent( args[i] );
			}
		}
		x = createXhr();
		if ( !x ) {
			alert( 'AJAX not supported' );
			return false;
		}

		try {
			x.open( window.sajax_request_type, uri, true );
		} catch ( e ) {
			if ( location.hostname === 'localhost' ) {
				alert( 'Your browser blocks XMLHttpRequest to "localhost", try using a real hostname for development/testing.' );
			}
			throw e;
		}
		if ( window.sajax_request_type === 'POST' ) {
			x.setRequestHeader( 'Method', 'POST ' + uri + ' HTTP/1.1' );
			x.setRequestHeader( 'Content-Type', 'application/x-www-form-urlencoded' );
		}
		x.setRequestHeader( 'Pragma', 'cache=yes' );
		x.setRequestHeader( 'Cache-Control', 'no-transform' );
		x.onreadystatechange = function () {
			if ( x.readyState !== 4 ) {
				return;
			}

			debug( 'received (' + x.status + ' ' + x.statusText + ') ' + x.responseText );

			// if ( x.status != 200 )
			//   alert( 'Error: ' + x.status + ' ' + x.statusText + ': ' + x.responseText );
			// else

			if ( typeof target === 'function' ) {
				target( x );
			} else if ( typeof target === 'object' ) {
				if ( target.tagName === 'INPUT' ) {
					if ( x.status === 200 ) {
						target.value = x.responseText;
					}
					// else alert( 'Error: ' + x.status + ' ' + x.statusText + ' (' + x.responseText + ')' );
				} else {
					if ( x.status === 200 ) {
						target.innerHTML = x.responseText;
					} else {
						target.innerHTML = '<div class="error">Error: ' + x.status +
							' ' + x.statusText + ' (' + x.responseText + ')</div>';
					}
				}
			} else {
				alert( 'Bad target for sajax_do_call: not a function or object: ' + target );
			}
		};

		debug( func_name + ' uri = ' + uri + ' / post = ' + post_data );
		x.send( post_data );
		debug( func_name + ' waiting..' );

		return true;
	}

	/**
	 * @return {boolean} Whether the browser supports AJAX
	 */
	function wfSupportsAjax() {
		var request = createXhr(),
			supportsAjax = request ? true : false;

		request = undefined;
		return supportsAjax;
	}

	// Expose + Mark as deprecated
	var deprecationNotice = 'Sajax is deprecated, use jQuery.ajax or mediawiki.api instead.';

	// Variables
	mw.log.deprecate( window, 'sajax_debug_mode', false, deprecationNotice );
	mw.log.deprecate( window, 'sajax_request_type', 'GET', deprecationNotice );
	// Methods
	mw.log.deprecate( window, 'sajax_debug', debug, deprecationNotice );
	mw.log.deprecate( window, 'sajax_init_object', createXhr, deprecationNotice );
	mw.log.deprecate( window, 'sajax_do_call', doAjaxRequest, deprecationNotice );
	mw.log.deprecate( window, 'wfSupportsAjax', wfSupportsAjax, deprecationNotice );

}( mediaWiki ) );
