/**
 * jQuery json-viewer
 * @author: Alexandre Bodelot <alexandre.bodelot@gmail.com>
 */
(function ($) {

    /**
     * Check if arg is either an array with at least 1 element, or a dict with at least 1 key
     * @return boolean
     */
    function isCollapsable(arg) {
        return arg instanceof Object && Object.keys(arg).length > 0;
    }

    /**
     * Check if a string represents a valid url
     * @return boolean
     */
    function isUrl(string) {
        var regexp = /^(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?/;
        return regexp.test(string);
    }

    /**
     * Transform a json object into html representation
     * @return string
     */
    function json2html(json, options) {
        var html = '';
        if (typeof json === 'string') {
            /* Escape tags */
            json = json.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
            if (isUrl(json))
                html += '<a href="' + json + '" class="json-string">' + json + '</a>';
            else
                html += '<span class="json-string">"' + json + '"</span>';
        } else if (typeof json === 'number') {
            html += '<span class="json-literal">' + json + '</span>';
        } else if (typeof json === 'boolean') {
            html += '<span class="json-literal">' + json + '</span>';
        } else if (json === null) {
            html += '<span class="json-literal">null</span>';
        } else if (json instanceof Array) {
            if (json.length > 0) {
                html += '[<ol class="json-array">';
                for (var i = 0; i < json.length; ++i) {
                    html += '<li>';
                    /* Add toggle button if item is collapsable */
                    if (isCollapsable(json[i])) {
                        html += '<a href class="json-toggle"></a>';
                    }
                    html += json2html(json[i], options);
                    /* Add comma if item is not last */
                    if (i < json.length - 1) {
                        html += ',';
                    }
                    html += '</li>';
                }
                html += '</ol>]';
            } else {
                html += '[]';
            }
        } else if (typeof json === 'object') {
            var key_count = Object.keys(json).length;
            if (key_count > 0) {
                html += '{<ul class="json-dict">';
                for (var key in json) {
                    if (json.hasOwnProperty(key)) {
                        html += '<li>';
                        var keyRepr = options.withQuotes ?
                            '<span class="json-string">"' + key + '"</span>' : key;
                        /* Add toggle button if item is collapsable */
                        if (isCollapsable(json[key])) {
                            html += '<a href class="json-toggle">' + keyRepr + '</a>';
                        } else {
                            html += keyRepr;
                        }
                        html += ': ' + json2html(json[key], options);
                        /* Add comma if item is not last */
                        if (--key_count > 0)
                            html += ',';
                        html += '</li>';
                    }
                }
                html += '</ul>}';
            } else {
                html += '{}';
            }
        }
        return html;
    }

    /**
     * jQuery plugin method
     * @param json: a javascript object
     * @param options: an optional options hash
     */
    $.fn.jsonViewer = function (json, options) {
        options = options || {};

        /* jQuery chaining */
        return this.each(function () {

            /* Transform to HTML */
            var html = json2html(json, options);
            if (isCollapsable(json))
                html = '<a href class="json-toggle"></a>' + html;

            /* Insert HTML in target DOM element */
            $(this).html(html);

            /* Bind click on toggle buttons */
            $(this).off('click');
            $(this).on('click', 'a.json-toggle', function () {
                var target = $(this).toggleClass('collapsed').siblings('ul.json-dict, ol.json-array');
                target.toggle();
                if (target.is(':visible')) {
                    target.siblings('.json-placeholder').remove();
                } else {
                    var count = target.children('li').length;
                    var placeholder = count + (count > 1 ? ' items' : ' item');
                    target.after('<a href class="json-placeholder">' + placeholder + '</a>');
                }
                return false;
            });

            /* Simulate click on toggle button when placeholder is clicked */
            $(this).on('click', 'a.json-placeholder', function () {
                $(this).siblings('a.json-toggle').click();
                return false;
            });

            if (options.collapsed == true) {
                /* Trigger click to collapse all nodes */
                $(this).find('a.json-toggle').click();
            }
        });
    };
})(jQuery);