var pm_list = (function () {

var exports = {};

var private_messages_open = false;

// This module manages the "Private Messages" section in the upper
// left corner of the app.  This was split out from stream_list.js.
//
// TODO: We want to manage our own unread counts, but that logic is
//       still in stream_list.js.

// This is a copy of a similar method in stream_list.js, but
// we don't want to de-dup this, we want to simplify it.
function iterate_to_find(selector, name_to_find, context) {
    var lowercase_name = name_to_find.toLowerCase();
    var found = _.find($(selector, context), function (elem) {
        return $(elem).attr('data-name').toLowerCase() === lowercase_name;
    });
    return found ? $(found) : $();
}

function get_filter_li() {
    return iterate_to_find("#global_filters > li", "private");
}

exports.get_private_message_filter_li = function (conversation) {
    var pm_li = get_filter_li();
    return iterate_to_find(".expanded_private_messages li.expanded_private_message",
        conversation, pm_li);
};

function remove_expanded_private_messages() {
    popovers.hide_topic_sidebar_popover();
    $("ul.expanded_private_messages").remove();
    resize.resize_stream_filters_container();
}

exports.reset_to_unnarrowed = function () {
    private_messages_open = false;
    $("ul.filters li").removeClass('active-filter active-sub-filter');
    remove_expanded_private_messages();
};

exports._build_private_messages_list = function (active_conversation, max_private_messages) {

    var private_messages = message_store.recent_private_messages || [];
    var display_messages = [];
    var hiding_messages = false;

    _.each(private_messages, function (private_message_obj, idx) {
        var recipients_string = private_message_obj.display_reply_to;
        var replies_to = private_message_obj.reply_to;
        var num_unread = unread.num_unread_for_person(private_message_obj.reply_to);

        var always_visible = (idx < max_private_messages) || (num_unread > 0)
            || (replies_to === active_conversation);

        if (!always_visible) {
            hiding_messages = true;
        }

        var display_message = {
            recipients: recipients_string,
            reply_to: replies_to,
            unread: num_unread,
            is_zero: num_unread === 0,
            zoom_out_hide: !always_visible,
            url: narrow.pm_with_uri(private_message_obj.reply_to)
        };
        display_messages.push(display_message);
    });

    var recipients_dom = templates.render('sidebar_private_message_list',
                                  {messages: display_messages,
                                   want_show_more_messages_links: hiding_messages});
    return recipients_dom;
};

exports.rebuild_recent = function (active_conversation) {
    remove_expanded_private_messages();
    if (private_messages_open)
    {
        var max_private_messages = 5;
        var private_li = get_filter_li();
        var private_messages_dom = exports._build_private_messages_list(active_conversation,
            max_private_messages);
        private_li.append(private_messages_dom);
    }
    if (active_conversation) {
        exports.get_private_message_filter_li(active_conversation).addClass('active-sub-filter');
    }

    resize.resize_stream_filters_container();
};

exports.update_private_messages = function () {
    exports._build_private_messages_list();

    if (! narrow.active()) {
        return;
    }

    var is_pm_filter = _.contains(narrow.filter().operands('is'), "private");
    var conversation = narrow.filter().operands('pm-with');
    if (conversation.length === 1) {
        exports.rebuild_recent(conversation[0]);
    } else if (conversation.length !== 0) {
        // TODO: This should be the reply-to of the thread.
        exports.rebuild_recent("");
    } else if (is_pm_filter) {
        exports.rebuild_recent("");
    }
};

exports.set_click_handlers = function () {
    $('#global_filters').on('click', '.show-more-private-messages', function (e) {
        popovers.hide_all();
        $(".expanded_private_messages").expectOne().removeClass("zoom-out").addClass("zoom-in");
        $(".expanded_private_messages li.expanded_private_message").each(function () {
            $(this).show();
        });

        e.preventDefault();
        e.stopPropagation();
    });
};

exports.expand = function (op_pm) {
    private_messages_open = true;
    if (op_pm.length === 1) {
        $("#user_presences li[data-email='" + op_pm[0] + "']").addClass('active-filter');
        exports.rebuild_recent(op_pm[0]);
    } else if (op_pm.length !== 0) {
        // TODO: Should pass the reply-to of the thread
        exports.rebuild_recent("");
    } else {
        $("#global_filters li[data-name='private']").addClass('active-filter zoom-out');
        exports.rebuild_recent("");
    }
};


return exports;
}());
if (typeof module !== 'undefined') {
    module.exports = pm_list;
}