var noop = function () {};

var exports = {};

exports.make_zjquery = function () {

    var elems = {};

    function new_elem(selector) {
        var html = 'never-been-set';
        var text = 'never-been-set';
        var value;
        var shown = false;
        var focused = false;
        var children = new Dict();
        var my_parent;
        var properties = new Dict();
        var attrs = new Dict();
        var classes = new Dict();
        var on_functions = new Dict();

        function generic_event(event_name, arg) {
            if (typeof(arg) === 'function') {
                on_functions.set(event_name, arg);
            } else {
                var handler = on_functions.get(event_name);
                assert(handler);
                handler(arg);
            }
        }

        var self = {
            add_child: function (child_selector, child_elem) {
                child_elem.set_parent(self);
                children.set(child_selector, child_elem);
            },
            addClass: function (class_name) {
                classes.set(class_name, true);
                return self.wrapper;
            },
            attr: function (name, val) {
                if (val === undefined) {
                    return attrs.get(name);
                }
                attrs.set(name, val);
                return self.wrapper;
            },
            blur: function () {
                focused = false;
                return self.wrapper;
            },
            click: function (arg) {
                generic_event('click', arg);
                return self.wrapper;
            },
            css: noop,
            data: noop,
            debug: function () {
                return {
                    value: value,
                    shown: shown,
                    selector: selector,
                };
            },
            empty: noop,
            expectOne: function () {
                // silently do nothing
                return self.wrapper;
            },
            fadeTo: noop,
            find: function (child_selector) {
                var child = children.get(child_selector);
                if (child) {
                    return child;
                }

                throw Error("Cannot find " + child_selector + " in " + selector);
            },
            focus: function () {
                focused = true;
                return self.wrapper;
            },
            get: function (idx) {
                // We have some legacy code that does $('foo').get(0).
                assert.equal(idx, 0);
                return selector;
            },
            hasClass: function (class_name) {
                return classes.has(class_name);
            },
            height: noop,
            hide: function () {
                shown = false;
                return self.wrapper;
            },
            html: function (arg) {
                if (arg !== undefined) {
                    html = arg;
                    return self.wrapper;
                }
                return html;
            },
            is_focused: function () {
                // is_focused is not a jQuery thing; this is
                // for our testing
                return focused;
            },
            keydown: function (arg) {
                generic_event('keydown', arg);
                return self.wrapper;
            },
            keyup: function (arg) {
                generic_event('keyup', arg);
                return self.wrapper;
            },
            on: function (name, f) {
                var funcs = on_functions.setdefault(name, []);
                funcs.push(f);
                return self.wrapper;
            },
            parent: function () {
                return my_parent;
            },
            prop: function (name, val) {
                if (val === undefined) {
                    return properties.get(name);
                }
                properties.set(name, val);
                return self.wrapper;
            },
            removeAttr: function (name) {
                attrs.del(name);
                return self.wrapper;
            },
            remove_child: function (child_selector) {
                children.del(child_selector);
            },
            removeClass: function (class_name) {
                classes.del(class_name);
                return self.wrapper;
            },
            remove: function () {
                if (my_parent) {
                    my_parent.remove_child(selector);
                }
                return self.wrapper;
            },
            removeData: noop,
            select: function (arg) {
                generic_event('select', arg);
                return self.wrapper;
            },
            show: function () {
                shown = true;
                return self.wrapper;
            },
            set_parent: function (parent_elem) {
                my_parent = parent_elem;
            },
            stop: function () {
                return self.wrapper;
            },
            text: function (arg) {
                if (arg !== undefined) {
                    text = arg;
                    return self.wrapper;
                }
                return text;
            },
            trigger: function (ev) {
                var funcs = on_functions.get(ev.name) || [];
                _.each(funcs, function (f) {
                    f(ev.data);
                });
                return self.wrapper;
            },
            val: function () {
                if (arguments.length === 0) {
                    return value || '';
                }
                value = arguments[0];
                return self.wrapper;
            },
            visible: function () {
                return shown;
            },
        };

        if (selector[0] === '<') {
            self.html(selector);
        }

        return self;
    }

    function jquery_array(elem) {
        var result = [elem];

        for (var attr in elem) {
            if (Object.prototype.hasOwnProperty.call(elem, attr)) {
                result[attr] = elem[attr];
            }
        }
        elem.wrapper = result;

        return result;
    }

    var zjquery = function (arg) {
        if (typeof arg === "function") {
            // If somebody is passing us a function, we emulate
            // jQuery's behavior of running this function after
            // page load time.  But there are no pages to load,
            // so we just call it right away.
            arg();
            return;
        } else if (typeof arg === "object") {
            // If somebody is passing us an element, we return
            // the element itself if it's been created with
            // zjquery.
            // This may happen in cases like $(this).
            if (arg.debug) {
                var this_selector = arg.debug().selector;
                if (elems[this_selector]) {
                    return arg;
                }
            }
        }

        var selector = arg;
        if (elems[selector] === undefined) {
            var elem = new_elem(selector);
            elems[selector] = jquery_array(elem);
        }
        return elems[selector];
    };


    zjquery.stub_selector = function (selector, stub) {
        elems[selector] = stub;
    };

    zjquery.trim = function (s) { return s; };

    zjquery.state = function () {
        // useful for debugging
        var res =  _.map(elems, function (v) {
            return v.debug();
        });

        res = _.map(res, function (v) {
            return [v.selector, v.value, v.shown];
        });

        res.sort();

        return res;
    };

    zjquery.Event = function (name, data) {
        return {
            name: name,
            data: data,
        };
    };

    zjquery.extend = function (content, container) {
        return _.extend(content, container);
    };

    return zjquery;
};

module.exports = exports;