/**
 * Dynamic form plugin
 * @author Nazar Lazorko
 * @requires $ jQuery 1.7.2+
 * @requires _ Underscore 1.4.2+
 */
(function ($) {
    "use strict";

    /**
     * @example
     * $(form).dynamicForm({
     *   relations: [
     *     {
     *       node: '',                        // {jQuery|HTMLElement|String} jQuery element or selector that match main selected element
     *       group: undefined,                // [{jQuery|HTMLElement|String}] optional jQuery element or selector that match entire checkbox or radio group
     *       event: '',                       // {String} jQuery event name
     *       rules: [
     *         {
     *           value: '',               // {String|Function} expected value or callback that checks value
     *           nodes: []                // [{jQuery|HTMLElement|String}, ...] list of related noted
     *           autoRebuildNodes: false, // {Boolean} determines the need to rebuild nodes before each activation/deactivation
     *           subRelations: [],        // [{Relation}, ...] optional list of sub relations
     *           activateFn: undefined,   // {Function} optional
     *           deactivateFn: undefined, // {Function} optional
     *         }
     *         // ...
     *       ]
     *     }
     *     // ...
     *   ]
     * });
     * @param {Object} options
     * @param {Array.<Relation|Object>} options.relations
     */
    $.fn.dynamicForm = function (options) {
        return new DynamicForm(this, options);
    };

    var DynamicForm = function () {
        this.init.apply(this, arguments);
    };

    DynamicForm.prototype = {
        /**
         * @param {jQuery} plugin
         * @param {Object} options
         * @param {Array.<Relation|Object>} options.relations
         * @return {*}
         */
        init: function (plugin, options) {
            this.plugin = plugin;
            this.options = options;
            /** @type {Array.<Relation>} */
            this.relations = [];

            this.setRelations(options.relations);
            this.refresh();
            return this;
        },

        setRelations: function (relations) {
            var relation, i, length;
            for (i = 0, length = relations.length; i < length; ++i) {
                relation = relations[i];
                relation.plugin = this.plugin;
                this.relations.push((relation instanceof Relation) ? relation : new Relation(relation));
            }
            return this;
        },

        refresh: function () {
            var relations = this.relations, i, length;
            for (i = 0, length = relations.length; i < length; ++i) {
                relations[i].eventHandler();
            }
            return this;
        }
    };

    /**
     *
     * @param {Object} options
     * @param {jQuery} options.plugin
     * @param {jQuery|HTMLElement|String} options.node
     * @param {jQuery|HTMLElement|String} [options.group]
     * @param {String} options.event
     * @param {Array.<Rule|Object>} options.rules
     * @return {Relation}
     * @constructor
     */
    var Relation = function (options) {
        /** @type {jQuery} */
        this.plugin = options.plugin;

        /** @type {jQuery} */
        this.node = (options.node instanceof jQuery) ? options.node : this.plugin.find(options.node);
        /** @type {jQuery} */
        this.group = (null == options.group)
            ? this.node
            : ((options.group instanceof jQuery) ? options.group : this.plugin.find(options.group));
        this.defaultValue = this.node.val();

        /** @type {String} */
        this.event = String(options.event);

        /** @type {Array.<Rule>} */
        this.rules = [];
        this.setRules(options.rules);

        this.group.on(this.event, _.bind(this.onEvent, this, this));

        return this;
    };
    Relation.prototype = {
        setRules: function (rules) {
            var rule, i, length;
            for (i = 0, length = rules.length; i < length; ++i) {
                rule = rules[i];
                rule.plugin = this.plugin;
                this.rules.push((rule instanceof Rule) ? rule : new Rule(rule));
            }
            return this;
        },

        reset: function () {
            var node = this.node;
            if (null !== this.defaultValue) {
                node.val(this.defaultValue);
            } else {
                if (node.is(':checkbox, :radio')) {
                    node.removeAttr('checked');
                } else {
                    node.val('');
                }
            }
            node.change();
            return this;
        },

        /**
         * @param {Object} relation
         * @param {jQuery.Event} e
         */
        onEvent: function (relation, e) {
            this.eventHandler($(e.currentTarget));
            return true;
        },

        /**
         * @param {jQuery} [target]
         * @return {*}
         */
        eventHandler: function (target) {
            target = target || this.node;
            var rules = this.getMatchedRules(this.rules, target);
            if (rules && rules.length) {
                this.deactivateRules(_.difference(this.rules, rules));
                this.activateRules(rules);
            } else {
                this.deactivateRules(this.rules);
            }
            return this;
        },

        /**
         * Returns array of rules that match specified value
         * @param {Array.<Rule>} rules
         * @param {jQuery} target
         * @return {Array}
         */
        getMatchedRules: function (rules, target) {
            var result = [], match, i, length, targetValue = target.val(), ruleValue;
            for (i = 0, length = rules.length; i < length; ++i) {
                ruleValue = rules[i].value;
                if (this.match(ruleValue, target)) {
                    result.push(rules[i]);
                }
            }
            return result;
        },

      /**
       * Test if element value match with rule value
       * @param ruleValue
       * @param target
       */
        match: function (ruleValue, target) {
          switch ($.type(ruleValue)) {
            case 'function':
              return ruleValue.call(target, target.val());
            case 'array':
              return ruleValue.indexOf(target.val()) != -1;
            default:
              return (target.val() == ruleValue);
          }
        },

        /**
         * @param {Array.<Rule>} rules Non matched rules
         * @return {*}
         */
        deactivateRules: function (rules) {
            var i, length;
            for (i = 0, length = rules.length; i < length; ++i) {
                rules[i].deactivate();
            }
            return this;
        },

        /**
         * @param {Array.<Rule>} rules Matched rules
         * @return {*}
         */
        activateRules: function (rules) {
            var i, length;
            for (i = 0, length = rules.length; i < length; ++i) {
                rules[i].activate();
            }
            return this;
        }

    };

    /**
     * @param {Object} options
     * @param {jQuery} options.plugin
     * @param {String} options.value
     * @param {Array.<jQuery|HTMLElement|String>} [options.nodes]
     * @param {Boolean} [options.autoRebuildNodes=false]
     * @param {Array.<Relation>} [options.subRelations]
     * @param {Function} [options.activateFn]
     * @param {Function} [options.deactivateFn]
     * @constructor
     */
    var Rule = function (options) {
        /** @type {jQuery} */
        this.plugin = options.plugin;

        /** @type {String}|{Array} */
        this.value = options.value;

        /** @type {Array.<jQuery|HTMLElement|String>} */
        this.rawNodes = options.nodes;

        /** @type {jQuery} */
        this.nodes = undefined;
        this.rebuildNodes();

        /** @type {Boolean} */
        this.autoRebuildNodes = !!options.autoRebuildNodes || false;

        /** @type {Array.<Relation>} */
        this.subRelations = (options.subRelations) ? options.subRelations : undefined;

        /** @type {Function} optional */
        this.activateFn = options.activateFn;

        /** @type {Function} optional */
        this.deactivateFn = options.deactivateFn;

        return this;
    };
    Rule.prototype = {
        rebuildNodes: function () {
            this.nodes = (this.rawNodes) ? this.mergeNodes(this.rawNodes) : undefined;
            return this;
        },

        activate: function () {
            if (this.autoRebuildNodes) {
                this.rebuildNodes();
            }
            if (null == this.activateFn || false !== this.activateFn.call(this)) {
                if (this.nodes) {
                    this.nodes.show();
                }
                if (this.subRelations) {
                    for (var i = 0, length = this.subRelations.length; i < length; ++i) {
                        this.subRelations[i].reset();
                    }
                }
            }
            return this;
        },

        deactivate: function () {
            if (this.autoRebuildNodes) {
                this.rebuildNodes();
            }
            if (null == this.deactivateFn || false !== this.deactivateFn.call(this)) {
                if (this.nodes) {
                    this.nodes.hide();
                }
                if (this.subRelations) {
                    for (var i = 0, length = this.subRelations.length; i < length; ++i) {
                        this.subRelations[i].reset();
                    }
                }
            }
            return this;
        },

        /**
         *
         * @param {Array} list [{jQuery|HTMLElement|String}, ...]
         * @return {jQuery}
         */
        mergeNodes: function (list) {
            list = ('array' === $.type(list)) ? list : [list];
            var result = [], i, c, item;
            for (i = 0, c = list.length; i < c; ++i) {
                item = (list[i] instanceof jQuery) ? list[i] : this.plugin.find(list[i]);
                result = result.concat(item.get());
            }
            return $(result);
        }
    };

    $.fn.dynamicForm.Relation = Relation;
    $.fn.dynamicForm.Rule = Rule;

})(jQuery);