// Utility functions for parsing and handling shortcodes in Javascript.

// Ensure the global `wp` object exists.

window.wp = window.wp || {};

(function(){

	wp.shortcode = {

		// ### Find the next matching shortcode

		//

		// Given a shortcode `tag`, a block of `text`, and an optional starting

		// `index`, returns the next matching shortcode or `undefined`.

		//

		// Shortcodes are formatted as an object that contains the match

		// `content`, the matching `index`, and the parsed `shortcode` object.

		next: function( tag, text, index ) {

			var re = wp.shortcode.regexp( tag ),

				match, result;

			re.lastIndex = index || 0;

			match = re.exec( text );

			if ( ! match )

				return;

			// If we matched an escaped shortcode, try again.

			if ( match[1] === '[' && match[7] === ']' )

				return wp.shortcode.next( tag, text, re.lastIndex );

			result = {

				index:     match.index,

				content:   match[0],

				shortcode: wp.shortcode.fromMatch( match )

			};

			// If we matched a leading `[`, strip it from the match

			// and increment the index accordingly.

			if ( match[1] ) {

				result.match = result.match.slice( 1 );

				result.index++;

			}

			// If we matched a trailing `]`, strip it from the match.

			if ( match[7] )

				result.match = result.match.slice( 0, -1 );

			return result;

		},

		// ### Replace matching shortcodes in a block of text

		//

		// Accepts a shortcode `tag`, content `text` to scan, and a `callback`

		// to process the shortcode matches and return a replacement string.

		// Returns the `text` with all shortcodes replaced.

		//

		// Shortcode matches are objects that contain the shortcode `tag`,

		// a shortcode `attrs` object, the `content` between shortcode tags,

		// and a boolean flag to indicate if the match was a `single` tag.

		replace: function( tag, text, callback ) {

			return text.replace( wp.shortcode.regexp( tag ), function( match, left, tag, attrs, slash, content, closing, right, offset ) {

				// If both extra brackets exist, the shortcode has been

				// properly escaped.

				if ( left === '[' && right === ']' )

					return match;

				// Create the match object and pass it through the callback.

				var result = callback( wp.shortcode.fromMatch( arguments ) );

				// Make sure to return any of the extra brackets if they

				// weren't used to escape the shortcode.

				return result ? left + result + right : match;

			});

		},

		// ### Generate a string from shortcode parameters

		//

		// Creates a `wp.shortcode` instance and returns a string.

		//

		// Accepts the same `options` as the `wp.shortcode()` constructor,

		// containing a `tag` string, a string or object of `attrs`, a boolean

		// indicating whether to format the shortcode using a `single` tag, and a

		// `content` string.

		string: function( options ) {

			return new wp.shortcode( options ).string();

		},

		// ### Generate a RegExp to identify a shortcode

		//

		// The base regex is functionally equivalent to the one found in

		// `get_shortcode_regex()` in `wp-includes/shortcodes.php`.

		//

		// Capture groups:

		//

		// 1. An extra `[` to allow for escaping shortcodes with double `[[]]`

		// 2. The shortcode name

		// 3. The shortcode argument list

		// 4. The self closing `/`

		// 5. The content of a shortcode when it wraps some content.

		// 6. The closing tag.

		// 7. An extra `]` to allow for escaping shortcodes with double `[[]]`

		regexp: _.memoize( function( tag ) {

			return new RegExp( '\\[(\\[?)(' + tag + ')(?![\\w-])([^\\]\\/]*(?:\\/(?!\\])[^\\]\\/]*)*?)(?:(\\/)\\]|\\](?:([^\\[]*(?:\\[(?!\\/\\2\\])[^\\[]*)*)(\\[\\/\\2\\]))?)(\\]?)', 'g' );

		}),

		// ### Parse shortcode attributes

		//

		// Shortcodes accept many types of attributes. These can chiefly be

		// divided into named and numeric attributes:

		//

		// Named attributes are assigned on a key/value basis, while numeric

		// attributes are treated as an array.

		//

		// Named attributes can be formatted as either `name="value"`,

		// `name='value'`, or `name=value`. Numeric attributes can be formatted

		// as `"value"` or just `value`.

		attrs: _.memoize( function( text ) {

			var named   = {},

				numeric = [],

				pattern, match;

			// This regular expression is reused from `shortcode_parse_atts()`

			// in `wp-includes/shortcodes.php`.

			//

			// Capture groups:

			//

			// 1. An attribute name, that corresponds to...

			// 2. a value in double quotes.

			// 3. An attribute name, that corresponds to...

			// 4. a value in single quotes.

			// 5. An attribute name, that corresponds to...

			// 6. an unquoted value.

			// 7. A numeric attribute in double quotes.

			// 8. An unquoted numeric attribute.

			pattern = /(\w+)\s*=\s*"([^"]*)"(?:\s|$)|(\w+)\s*=\s*\'([^\']*)\'(?:\s|$)|(\w+)\s*=\s*([^\s\'"]+)(?:\s|$)|"([^"]*)"(?:\s|$)|(\S+)(?:\s|$)/g;

			// Map zero-width spaces to actual spaces.

			text = text.replace( /[\u00a0\u200b]/g, ' ' );

			// Match and normalize attributes.

			while ( (match = pattern.exec( text )) ) {

				if ( match[1] ) {

					named[ match[1].toLowerCase() ] = match[2];

				} else if ( match[3] ) {

					named[ match[3].toLowerCase() ] = match[4];

				} else if ( match[5] ) {

					named[ match[5].toLowerCase() ] = match[6];

				} else if ( match[7] ) {

					numeric.push( match[7] );

				} else if ( match[8] ) {

					numeric.push( match[8] );

				}

			}

			return {

				named:   named,

				numeric: numeric

			};

		}),

		// ### Generate a Shortcode Object from a RegExp match

		// Accepts a `match` object from calling `regexp.exec()` on a `RegExp`

		// generated by `wp.shortcode.regexp()`. `match` can also be set to the

		// `arguments` from a callback passed to `regexp.replace()`.

		fromMatch: function( match ) {

			var type;

			if ( match[4] )

				type = 'self-closing';

			else if ( match[6] )

				type = 'closed';

			else

				type = 'single';

			return new wp.shortcode({

				tag:     match[2],

				attrs:   match[3],

				type:    type,

				content: match[5]

			});

		}

	};

	// Shortcode Objects

	// -----------------

	//

	// Shortcode objects are generated automatically when using the main

	// `wp.shortcode` methods: `next()`, `replace()`, and `string()`.

	//

	// To access a raw representation of a shortcode, pass an `options` object,

	// containing a `tag` string, a string or object of `attrs`, a string

	// indicating the `type` of the shortcode ('single', 'self-closing', or

	// 'closed'), and a `content` string.

	wp.shortcode = _.extend( function( options ) {

		_.extend( this, _.pick( options || {}, 'tag', 'attrs', 'type', 'content' ) );

		var attrs = this.attrs;

		// Ensure we have a correctly formatted `attrs` object.

		this.attrs = {

			named:   {},

			numeric: []

		};

		if ( ! attrs )

			return;

		// Parse a string of attributes.

		if ( _.isString( attrs ) ) {

			this.attrs = wp.shortcode.attrs( attrs );

		// Identify a correctly formatted `attrs` object.

		} else if ( _.isEqual( _.keys( attrs ), [ 'named', 'numeric' ] ) ) {

			this.attrs = attrs;

		// Handle a flat object of attributes.

		} else {

			_.each( options.attrs, function( value, key ) {

				this.set( key, value );

			}, this );

		}

	}, wp.shortcode );

	_.extend( wp.shortcode.prototype, {

		// ### Get a shortcode attribute

		//

		// Automatically detects whether `attr` is named or numeric and routes

		// it accordingly.

		get: function( attr ) {

			return this.attrs[ _.isNumber( attr ) ? 'numeric' : 'named' ][ attr ];

		},

		// ### Set a shortcode attribute

		//

		// Automatically detects whether `attr` is named or numeric and routes

		// it accordingly.

		set: function( attr, value ) {

			this.attrs[ _.isNumber( attr ) ? 'numeric' : 'named' ][ attr ] = value;

			return this;

		},

		// ### Transform the shortcode match into a string

		string: function() {

			var text    = '[' + this.tag;

			_.each( this.attrs.numeric, function( value ) {

				if ( /\s/.test( value ) )

					text += ' "' + value + '"';

				else

					text += ' ' + value;

			});

			_.each( this.attrs.named, function( value, name ) {

				text += ' ' + name + '="' + value + '"';

			});

			// If the tag is marked as `single` or `self-closing`, close the

			// tag and ignore any additional content.

			if ( 'single' === this.type )

				return text + ']';

			else if ( 'self-closing' === this.type )

				return text + ' /]';

			// Complete the opening tag.

			text += ']';

			if ( this.content )

				text += this.content;

			// Add the closing tag.

			return text + '[/' + this.tag + ']';

		}

	});

}());

// HTML utility functions

// ----------------------

//

// Experimental. These functions may change or be removed in the future.

(function(){

	wp.html = _.extend( wp.html || {}, {

		// ### Parse HTML attributes.

		//

		// Converts `content` to a set of parsed HTML attributes.

		// Utilizes `wp.shortcode.attrs( content )`, which is a valid superset of

		// the HTML attribute specification. Reformats the attributes into an

		// object that contains the `attrs` with `key:value` mapping, and a record

		// of the attributes that were entered using `empty` attribute syntax (i.e.

		// with no value).

		attrs: function( content ) {

			var result, attrs;

			// If `content` ends in a slash, strip it.

			if ( '/' === content[ content.length - 1 ] )

				content = content.slice( 0, -1 );

			result = wp.shortcode.attrs( content );

			attrs  = result.named;

			_.each( result.numeric, function( key ) {

				if ( /\s/.test( key ) )

					return;

				attrs[ key ] = '';

			});

			return attrs;

		},

		// ### Convert an HTML-representation of an object to a string.

		string: function( options ) {

			var text = '<' + options.tag,

				content = options.content || '';

			_.each( options.attrs, function( value, attr ) {

				text += ' ' + attr;

				// Use empty attribute notation where possible.

				if ( '' === value )

					return;

				// Convert boolean values to strings.

				if ( _.isBoolean( value ) )

					value = value ? 'true' : 'false';

				text += '="' + value + '"';

			});

			// Return the result if it is a self-closing tag.

			if ( options.single )

				return text + ' />';

			// Complete the opening tag.

			text += '>';

			// If `content` is an object, recursively call this function.

			text += _.isObject( content ) ? wp.html.string( content ) : content;

			return text + '</' + options.tag + '>';

		}

	});

}());