/*
    Digg Sidebar - Shows Digg stories in the Firefox sidebar in real time.
    Copyright (C) 2008  Abhinav Sarkar <abhinav dot sarkar at gmail dot com>

    This file is a part of Digg Sidebar.

    Digg Sidebar is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    Digg Sidebar is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with Digg Sidebar.  If not, see <http://www.gnu.org/licenses/>.

*/

var DiggSidebar = {
    homepageURL: "http://code.google.com/p/digg-sidebar/",
    prefs: Application.extensions.get("diggsidebar@abhinavsarkar.net").prefs,
    storyListRefreshEventTopic: "extension-diggsidebar-abhinavsarkar-net-storylist-refresh",
    endpoint: {
        container: null,
        topic: null,
        category: "all"
    },
    updateInterval: 1000,
    updateIntervalDecay: 0,
    lastUpdateAt: new Date().getTime(),
    shownStoriesCount: 30,
    categories: ['All', 'Popular', 'Upcoming', 'Hot', 'Top'],
    timerId: null,
    storyIds: [],
    refreshing: false,
    stories: [],
    expandedStory: null,

    fetchData: function(url, handler) {
        DiggSidebar.indicateActivity();

        var request = new XMLHttpRequest();
        request.onerror = DiggSidebar.errorHandler;
        request.onload = handler;
        request.open("GET", url, true);
        request.send(null);
    },

    errorHandler: function(e) {
        /*if (DiggSidebar.UI.notificationBox.allNotifications.length > 0)
            DiggSidebar.UI.notificationBox.removeAllNotifications(true);*/
        DiggSidebar.UI.notificationBox.appendNotification(
            "Unable to access Digg",
            "dsAccessFailNotification",
            null,
            "PRIORITY_CRITICAL_HIGH",
            [{callback:DiggSidebar.getStories, label: "Retry", accessKey: "R"}]
        );
        DiggSidebar.refreshing = false;
        DiggSidebar.indicateInactivity();
    },

    populateMenu: function(e) {
        var XHR = e.target;
        var data = DiggSidebar.Utils.decodeJson(XHR.responseText);
        var containers = data.containers;

        containers.forEach(function (container) {
            var cmenu = document.createElement('menu');
            cmenu.setAttribute('id', container.short_name + 'Menu');
            cmenu.setAttribute('label', container.name);
            cmenu.setAttribute('accesskey', container.name.charAt(0));

            var cmenupopup = document.createElement('menupopup');
            cmenupopup.setAttribute('id', container.short_name + 'Popup');

            DiggSidebar.categories.forEach(
                function (category) {
                    var cmenuitem = document.createElement('menuitem');
                    cmenuitem.setAttribute('label', category);
                    cmenuitem.setAttribute('value', '/container/' + container.short_name + '/' + category.toLowerCase());
                    cmenuitem.setAttribute('accesskey', category.charAt(0));
                    cmenuitem.setAttribute('oncommand', "DiggSidebar.setEndPoint(this.value)");
                    cmenupopup.appendChild(cmenuitem);
                }
            );
            cmenupopup.appendChild(document.createElement('menuseparator'));
            var topics = container.topics;
            topics.forEach(function (topic) {
                var tmenu = document.createElement('menu');
                tmenu.setAttribute('id', topic.short_name + 'Menu');
                tmenu.setAttribute('label', topic.name);
                tmenu.setAttribute('accesskey', topic.name.charAt(0));

                var tmenupopup = document.createElement('menupopup');
                tmenupopup.setAttribute('id', topic.short_name + 'Popup');

                DiggSidebar.categories.forEach(
                    function (category) {
                        var tmenuitem = document.createElement('menuitem');
                        tmenuitem.setAttribute('label', category);
                        tmenuitem.setAttribute('value', '/topic/' + topic.short_name + '/' + category.toLowerCase());
                        tmenuitem.setAttribute('accesskey', category.charAt(0));
                        tmenuitem.setAttribute('oncommand', "DiggSidebar.setEndPoint(this.value)");
                        tmenupopup.appendChild(tmenuitem);
                    }
                );
                tmenu.appendChild(tmenupopup);
                cmenupopup.appendChild(tmenu);
            });
            cmenu.appendChild(cmenupopup);
            DiggSidebar.UI.storiesPopup.appendChild(cmenu);
        });
    },

    populateStoryList: function() {
        var newStoryIds = new Array();

        var jp = new JPath(DiggSidebar.stories);
        var filteredStories = jp.$(function(story){
            return (story.$("category").json == DiggSidebar.endpoint.category) ;
        }).json;
        jp = new JPath(filteredStories);
        if (DiggSidebar.endpoint.topic)
            filteredStories = jp.$(function(story){
                return (story.$("topic/short_name").json == DiggSidebar.endpoint.topic);
            }).json;
        if (DiggSidebar.endpoint.container)
            filteredStories = jp.$(function(story){
                return story.$("container/short_name").json == DiggSidebar.endpoint.container;
            }).json;

        if (filteredStories.length > 0)
            DiggSidebar.Utils.removeAllChildren(DiggSidebar.UI.storyListBox);

        filteredStories.forEach(function (story, index) {
            if (index < DiggSidebar.shownStoriesCount) {
                var now = new Date();
                if (story.promote_date != null)
                    var then = new Date(story.promote_date*1000);
                else
                    var then = new Date(story.submit_date*1000);
                var diff = Math.max(now - then, 0)

                var hr = Math.floor(diff/(1000*3600));
                var min = Math.floor(diff/(1000*60)) - 60*hr;

                var relativeTime = ((hr > 0) && (min > 0)) ?
                    (hr + " hr " + min + " mins ago") :
                    ((hr == 0) && (min > 0)) ?
                    (min + " mins ago") :
                    ((hr == 0) && (min == 0)) ?
                    "just now" : "";

                var li = DiggSidebar.UI.storyListBox.appendChild(document.createElement('richlistitem'));
                li.id = "story_" + story.id;
                var attributes = {
                    title: story.title,
                    date: relativeTime,
                    status: story.status,
                    container: story.container.name,
                    topic: story.topic.name,
                    username: story.user.name,
                    userlink: "http://digg.com/users/" + story.user.name,
                    diggs: story.diggs,
                    comments: story.comments,
                    desc: story.description,
                    link: story.link,
                    href:  story.href
                }
                for (var attr in attributes)
                    li.setAttribute(attr, attributes[attr]);

                li.read = story.read;
                if (story.id == DiggSidebar.expandedStory)
                    li.showDescription();
            }
            if (DiggSidebar.storyIds.indexOf(story.id) == -1) newStoryIds.push(story.id);
        });
        DiggSidebar.storyIds = DiggSidebar.storyIds.concat(newStoryIds);
    },

    showDescription: function(storyId) {
        var jp = new JPath(DiggSidebar.stories);
        var story = jp.query('//[id == ' + storyId + ']')[0];
        story.read = true;
        DiggSidebar.expandedStory = parseInt(storyId);

        var listitems = DiggSidebar.UI.storyListBox.children;
        for (var i=0; i<listitems.length; i++)
            listitems[i].hideDescription();

        document.getElementById('story_'+ story.id).showDescription();
    },

    getStories: function() {
        if (!DiggSidebar.refreshing) {
            DiggSidebar.refreshing = true;
            var ep = DiggSidebar.prefs.get("endpoint").value || '';

            DiggSidebar.fetchData("http://services.digg.com/stories" + ep.replace(/\/all/g, '') +
                "?count=30" + "&type=json" +
                "&appkey=" + encodeURIComponent(DiggSidebar.homepageURL),
                function(e) {
                    DiggSidebar.UI.endPointDesc.value = "digg" + ep;

                    var stories = DiggSidebar.Utils.decodeJson(e.target.responseText).stories;
                    var newStories = stories.filter(
                        function(story) {
                            return !(DiggSidebar.storyIds.indexOf(story.id) != -1);
                        });
                    newStories.forEach(function(story) {
                        story.category = DiggSidebar.endpoint.category;
                        story.read = false;
                    });
                    DiggSidebar.stories = newStories.concat(DiggSidebar.stories);
                    var observerService = Components.classes["@mozilla.org/observer-service;1"]
                        .getService(Components.interfaces.nsIObserverService);
                    observerService.notifyObservers(null, DiggSidebar.storyListRefreshEventTopic, null);

                    DiggSidebar.refreshing = false;
                    DiggSidebar.setUpdateInterval(stories);

                    window.clearTimeout(DiggSidebar.timerId);
                    var timeout = DiggSidebar.calculateTimeout();
                    DiggSidebar.timerId = window.setTimeout(DiggSidebar.getStories, timeout);

                    DiggSidebar.indicateInactivity();
                });
        } else {
            window.setTimeout(DiggSidebar.getStories, 1000);
        }
    },

    createMenu: function() {
        DiggSidebar.fetchData("http://services.digg.com/containers" + "?type=json" +
            "&appkey=" + encodeURIComponent(DiggSidebar.homepageURL),
            DiggSidebar.populateMenu);
    },

    setUpdateInterval: function(stories) {
        //Adaptive update interval code START
        if (stories.length == 0) return;
        var sum = 0;
        var weights = [4, 3, 2, 1]
        var date = (stories[0].promote_date != null) ? 'promote_date' : 'submit_date';
        stories.sort(function (a, b) {
            if (a[date] > b[date]) return -1;
            else if (a[date] < b[date]) return 1;
            return 0;
        });
        for (var i=0; i<Math.min(4, stories.length-1); i++) {
            var diff = stories[i][date] - stories[i+1][date];
            sum += weights[i]*diff;
        }
        var newUpdateInterval = Math.round(
            sum*1000/weights
            .splice(0,Math.min(4, stories.length-1))
            .reduce(function(a, b){return a + b;})
        );

        if (newUpdateInterval > 0) {
            var previousUpdateInterval = DiggSidebar.updateInterval;
            DiggSidebar.updateInterval = newUpdateInterval;

            if (previousUpdateInterval == newUpdateInterval)
                DiggSidebar.updateIntervalDecay += 1;
            else
                DiggSidebar.updateIntervalDecay = 0;
        }
        //Adaptive update interval code END
    },

    calculateTimeout: function() {
        return Math.round(DiggSidebar.updateInterval*(Math.pow(1.5, DiggSidebar.updateIntervalDecay)))
    },

    setEndPoint: function(ep) {
        DiggSidebar.prefs.get("endpoint").value = ep;
        DiggSidebar.endpoint = DiggSidebar.getEndpointParts(ep);
        window.clearTimeout(DiggSidebar.timerId);
        DiggSidebar.getStories();
    },

    getEndpointParts: function(ep) {
        var tmp = {
            topic: null,
            container: null,
            category: "all"
        };
        var parts = ep.split("/");
        if (parts.length == 2)
            tmp.category = parts[1];
        else if (parts.length == 4) {
            tmp[parts[1]] = parts[2];
            tmp.category = parts[3];
        }
        return tmp;
    },

    indicateActivity: function() {
        DiggSidebar.UI.indicator.src = "chrome://global/skin/icons/loading_16.png";
        with (DiggSidebar.UI.indicator.parentNode) {
            disabled = true;
            setAttribute('tooltiptext', "Refreshing");
            onmouseover = null;
        }
    },

    indicateInactivity: function() {
        DiggSidebar.UI.indicator.src = "chrome://global/skin/icons/notloading_16.png";
        with (DiggSidebar.UI.indicator.parentNode) {
            disabled = false;
            onmouseover = function() {
                var autoRefreshTime = Math.round(
                    (DiggSidebar.lastUpdateAt + DiggSidebar.calculateTimeout() - new Date().getTime())/1000
                );
                autoRefreshTime = (autoRefreshTime > 3600) ?
                                        Math.round(autoRefreshTime/3600) + " hours":
                                        (autoRefreshTime > 60) ?
                                            Math.round(autoRefreshTime/60) + " minutes":
                                            autoRefreshTime + " seconds";
                setAttribute('tooltiptext', "Click to refresh now.\n" +
                    "Autorefreshing in " + autoRefreshTime);
            }
        }
        DiggSidebar.lastUpdateAt = new Date().getTime();
    },

    initialize: function(){
        DiggSidebar.endpoint = DiggSidebar.getEndpointParts(DiggSidebar.prefs.get("endpoint").value);
        var $ = function(id) {return document.getElementById(id)};

        DiggSidebar.UI = {};
        DiggSidebar.UI.notificationBox = $('dsNotificationBox');
        DiggSidebar.UI.indicator = $('dsBusyIndicator');
        DiggSidebar.UI.storiesPopup = $('dsStoriesPopup');
        DiggSidebar.UI.storyListBox = $('dsStoryListBox');
        DiggSidebar.UI.endPointDesc = $('dsEndPointDesc');

        DiggSidebar.storyListObserver = new DiggSidebar.StoryListObserver();
        DiggSidebar.createMenu();
        DiggSidebar.getStories();
    },

    destroy: function(){
        DiggSidebar.storyListObserver.unregister();
    }
};

DiggSidebar.Utils = {
    url: function(spec) {
        var ios = Components.classes["@mozilla.org/network/io-service;1"]
                    .getService(Components.interfaces.nsIIOService);
        return ios.newURI(spec, null, null);
    },

    openUrlInTab: function(url) {
        Application.activeWindow.open(DiggSidebar.Utils.url(url));
    },

    decodeJson: function(string) {
        var json = Components.classes["@mozilla.org/dom/json;1"]
            .createInstance(Components.interfaces.nsIJSON);
        return json.decode(string);
    },

    removeAllChildren: function(node) {
        while (node.firstChild)
            node.removeChild(node.firstChild);
    }
}

DiggSidebar.StoryListObserver = function() {
   this.registered = false;
   this.register();
}

DiggSidebar.StoryListObserver.prototype = {
    observe: function(subject, topic, data) {
        if (topic == window.DiggSidebar.storyListRefreshEventTopic) {
            window.DiggSidebar.populateStoryList();
        }
    },

    register: function() {
        if (this.registered == false) {
            var observerService = Components.classes["@mozilla.org/observer-service;1"]
                .getService(Components.interfaces.nsIObserverService);
            observerService.addObserver(this, DiggSidebar.storyListRefreshEventTopic, false);
            this.registered = true;
        }
    },

    unregister: function() {
        if (this.registered == true) {
            var observerService = Components.classes["@mozilla.org/observer-service;1"]
                .getService(Components.interfaces.nsIObserverService);
            observerService.removeObserver(this, DiggSidebar.storyListRefreshEventTopic);
            this.registered = false;
        }
    }
}

/*DONE
 v0.2
 added kdb navigation
 Added progressmeter
 added error notification
 added accesskeys
 added new story notification

 v0.2.1
 adaptive polling interval
 promote_date
 pause/play

 v0.5
 new ui

 v0.7
 moved to JSON data format
 moved HTML template to XBL
 refactored JavaScript/Using FUEL
 implemented caching and notifier-observer
 new UI
 added toolbar button
 put license
*/