/*
 @licstart  The following is the entire license notice for the
 JavaScript code in this page.


 Copyright (C) 2013-2014  neko259

 The JavaScript code in this page is free software: you can
 redistribute it and/or modify it under the terms of the GNU
 General Public License (GNU GPL) as published by the Free Software
 Foundation, either version 3 of the License, or (at your option)
 any later version.  The code is distributed WITHOUT ANY WARRANTY;
 without even the implied warranty of MERCHANTABILITY or FITNESS
 FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.

 As additional permission under GNU GPL version 3 section 7, you
 may distribute non-source (e.g., minimized or compacted) forms of
 that code without the copy of the GNU GPL normally required by
 section 4, provided you include this license notice and a URL
 through which recipients can access the Corresponding Source.

 @licend  The above is the entire license notice
 for the JavaScript code in this page.
 */

var CLASS_POST = '.post'

var POST_ADDED = 0;
var POST_UPDATED = 1;

var JS_AUTOUPDATE_PERIOD = 20000;

var ALLOWED_FOR_PARTIAL_UPDATE = [
    'refmap',
    'post-info'
];

var ATTR_CLASS = 'class';
var ATTR_UID = 'data-uid';

var wsUser = '';

var unreadPosts = 0;
var documentOriginalTitle = '';

// Thread ID does not change, can be stored one time
var threadId = $('div.thread').children(CLASS_POST).first().attr('id');

/**
 * Connect to websocket server and subscribe to thread updates. On any update we
 * request a thread diff.
 *
 * @returns {boolean} true if connected, false otherwise
 */
function connectWebsocket() {
    var metapanel = $('.metapanel')[0];

    var wsHost = metapanel.getAttribute('data-ws-host');
    var wsPort = metapanel.getAttribute('data-ws-port');

    if (wsHost.length > 0 && wsPort.length > 0) {
        var centrifuge = new Centrifuge({
            "url": 'ws://' + wsHost + ':' + wsPort + "/connection/websocket",
            "project": metapanel.getAttribute('data-ws-project'),
            "user": wsUser,
            "timestamp": metapanel.getAttribute('data-ws-token-time'),
            "token": metapanel.getAttribute('data-ws-token'),
            "debug": false
        });

        centrifuge.on('error', function(error_message) {
            console.log("Error connecting to websocket server.");
            console.log(error_message);
            console.log("Using javascript update instead.");

            // If websockets don't work, enable JS update instead
            enableJsUpdate()
        });

        centrifuge.on('connect', function() {
            var channelName = 'thread:' + threadId;
            centrifuge.subscribe(channelName, function(message) {
                getThreadDiff();
            });

            // For the case we closed the browser and missed some updates
            getThreadDiff();
            $('#autoupdate').hide();
        });

        centrifuge.connect();

        return true;
    } else {
        return false;
    }
}

/**
 * Get diff of the posts from the current thread timestamp.
 * This is required if the browser was closed and some post updates were
 * missed.
 */
function getThreadDiff() {
    var all_posts = $('.post');

    var uids = '';
    var posts = all_posts;
    for (var i = 0; i < posts.length; i++) {
        uids += posts[i].getAttribute('data-uid') + ' ';
    }

    var data = {
        uids: uids,
        thread: threadId
    }

    var diffUrl = '/api/diff_thread/';

    $.post(diffUrl,
        data,
        function(data) {
            var updatedPosts = data.updated;
            var addedPostCount = 0;

            for (var i = 0; i < updatedPosts.length; i++) {
                var postText = updatedPosts[i];
                var post = $(postText);

                if (updatePost(post) == POST_ADDED) {
                    addedPostCount++;
                }
            }

            var hasMetaUpdates = updatedPosts.length > 0;
            if (hasMetaUpdates) {
                updateMetadataPanel();
            }

            if (addedPostCount > 0) {
                updateBumplimitProgress(addedPostCount);
            }

            if (updatedPosts.length > 0) {
                showNewPostsTitle(addedPostCount);
            }

            // TODO Process removed posts if any
            $('.metapanel').attr('data-last-update', data.last_update);
        },
        'json'
    )
}

/**
 * Add or update the post on html page.
 */
function updatePost(postHtml) {
    // This needs to be set on start because the page is scrolled after posts
    // are added or updated
    var bottom = isPageBottom();

    var post = $(postHtml);

    var threadBlock = $('div.thread');

    var postId = post.attr('id');

    // If the post already exists, replace it. Otherwise add as a new one.
    var existingPosts = threadBlock.children('.post[id=' + postId + ']');

    var type;

    if (existingPosts.size() > 0) {
        replacePartial(existingPosts.first(), post, false);
        post = existingPosts.first();

        type = POST_UPDATED;
    } else {
        post.appendTo(threadBlock);

        if (bottom) {
            scrollToBottom();
        }

        type = POST_ADDED;
    }

    processNewPost(post);

    return type;
}

/**
 * Initiate a blinking animation on a node to show it was updated.
 */
function blink(node) {
    var blinkCount = 2;

    var nodeToAnimate = node;
    for (var i = 0; i < blinkCount; i++) {
        nodeToAnimate = nodeToAnimate.fadeTo('fast', 0.5).fadeTo('fast', 1.0);
    }
}

function isPageBottom() {
    var scroll = $(window).scrollTop() / ($(document).height()
        - $(window).height());

    return scroll == 1
}

function enableJsUpdate() {
    setInterval(getThreadDiff, JS_AUTOUPDATE_PERIOD);
    return true;
}

function initAutoupdate() {
    if (location.protocol === 'https:') {
        return enableJsUpdate();
    } else {
        if (connectWebsocket()) {
            return true;
        } else {
            return enableJsUpdate();
        }
    }
}

function getReplyCount() {
    return $('.thread').children(CLASS_POST).length
}

function getImageCount() {
    return $('.thread').find('img').length
}

/**
 * Update post count, images count and last update time in the metadata
 * panel.
 */
function updateMetadataPanel() {
    var replyCountField = $('#reply-count');
    var imageCountField = $('#image-count');

    var replyCount = getReplyCount();
    replyCountField.text(replyCount);
    var imageCount = getImageCount();
    imageCountField.text(imageCount);

    var lastUpdate = $('.post:last').children('.post-info').first()
        .children('.pub_time').first().html();
    if (lastUpdate !== '') {
        var lastUpdateField = $('#last-update');
        lastUpdateField.html(lastUpdate);
        blink(lastUpdateField);
    }

    blink(replyCountField);
    blink(imageCountField);

    $('#message-count-text').text(ngettext('message', 'messages', replyCount));
    $('#image-count-text').text(ngettext('image', 'images', imageCount));
}

/**
 * Update bumplimit progress bar
 */
function updateBumplimitProgress(postDelta) {
    var progressBar = $('#bumplimit_progress');
    if (progressBar) {
        var postsToLimitElement = $('#left_to_limit');

        var oldPostsToLimit = parseInt(postsToLimitElement.text());
        var postCount = getReplyCount();
        var bumplimit = postCount - postDelta + oldPostsToLimit;

        var newPostsToLimit = bumplimit - postCount;
        if (newPostsToLimit <= 0) {
            $('.bar-bg').remove();
        } else {
            postsToLimitElement.text(newPostsToLimit);
            progressBar.width((100 - postCount / bumplimit * 100.0) + '%');
        }
    }
}

/**
 * Show 'new posts' text in the title if the document is not visible to a user
 */
function showNewPostsTitle(newPostCount) {
    if (document.hidden) {
        if (documentOriginalTitle === '') {
            documentOriginalTitle = document.title;
        }
        unreadPosts = unreadPosts + newPostCount;

        var newTitle = '* ';
        if (unreadPosts > 0) {
            newTitle += '[' + unreadPosts + '] ';
        }
        newTitle += documentOriginalTitle;

        document.title = newTitle;

        document.addEventListener('visibilitychange', function() {
            if (documentOriginalTitle !== '') {
                document.title = documentOriginalTitle;
                documentOriginalTitle = '';
                unreadPosts = 0;
            }

            document.removeEventListener('visibilitychange', null);
        });
    }
}

/**
 * Clear all entered values in the form fields
 */
function resetForm(form) {
    form.find('input:text, input:password, input:file, select, textarea').val('');
    form.find('input:radio, input:checkbox')
             .removeAttr('checked').removeAttr('selected');
    $('.file_wrap').find('.file-thumb').remove();
    $('#preview-text').hide();
}

/**
 * When the form is posted, this method will be run as a callback
 */
function updateOnPost(response, statusText, xhr, form) {
    var json = $.parseJSON(response);
    var status = json.status;

    showAsErrors(form, '');

    if (status === 'ok') {
        resetFormPosition();
        resetForm(form);
        getThreadDiff();
        scrollToBottom();
    } else {
        var errors = json.errors;
        for (var i = 0; i < errors.length; i++) {
            var fieldErrors = errors[i];

            var error = fieldErrors.errors;

            showAsErrors(form, error);
        }
    }
}

/**
 * Show text in the errors row of the form.
 * @param form
 * @param text
 */
function showAsErrors(form, text) {
    form.children('.form-errors').remove();

    if (text.length > 0) {
        var errorList = $('<div class="form-errors">' + text + '<div>');
        errorList.appendTo(form);
    }
}

/**
 * Run js methods that are usually run on the document, on the new post
 */
function processNewPost(post) {
    addRefLinkPreview(post[0]);
    highlightCode(post);
    blink(post);
}

function replacePartial(oldNode, newNode, recursive) {
    if (!equalNodes(oldNode, newNode)) {
        // Update parent node attributes
        updateNodeAttr(oldNode, newNode, ATTR_CLASS);
        updateNodeAttr(oldNode, newNode, ATTR_UID);

        // Replace children
        var children = oldNode.children();
        if (children.length == 0) {
            oldNode.replaceWith(newNode);
        } else {
            var newChildren = newNode.children();
            newChildren.each(function(i) {
                var newChild = newChildren.eq(i);
                var newChildClass = newChild.attr(ATTR_CLASS);

                // Update only certain allowed blocks (e.g. not images)
                if (ALLOWED_FOR_PARTIAL_UPDATE.indexOf(newChildClass) > -1) {
                    var oldChild = oldNode.children('.' + newChildClass);

                    if (oldChild.length == 0) {
                        oldNode.append(newChild);
                    } else {
                        if (!equalNodes(oldChild, newChild)) {
                            if (recursive) {
                                replacePartial(oldChild, newChild, false);
                            } else {
                                oldChild.replaceWith(newChild);
                            }
                        }
                    }
                }
            });
        }
    }
}

/**
 * Compare nodes by content
 */
function equalNodes(node1, node2) {
    return node1[0].outerHTML == node2[0].outerHTML;
}

/**
 * Update attribute of a node if it has changed
 */
function updateNodeAttr(oldNode, newNode, attrName) {
    var oldAttr = oldNode.attr(attrName);
    var newAttr = newNode.attr(attrName);
    if (oldAttr != newAttr) {
        oldNode.attr(attrName, newAttr);
    }
}

$(document).ready(function(){
    if (initAutoupdate()) {
        // Post form data over AJAX
        var threadId = $('div.thread').children('.post').first().attr('id');

        var form = $('#form');

        if (form.length > 0) {
            var options = {
                beforeSubmit: function(arr, $form, options) {
                    showAsErrors($('#form'), gettext('Sending message...'));
                },
                success: updateOnPost,
                error: function() {
                    showAsErrors($('#form'), gettext('Server error!'));
                },
                url: '/api/add_post/' + threadId + '/'
            };

            form.ajaxForm(options);

            resetForm(form);
        }
    }
});