/*
 * Copyright (C) 2013 Glyptodon LLC
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

/**
 * General set of UI elements and UI-related functions regarding
 * administration.
 */
var GuacAdmin = {

    "containers" : {
        "connection_list"         : document.getElementById("connection-list"),
        "user_list"               : document.getElementById("user-list"),
        "user_list_buttons"       : document.getElementById("user-list-buttons"),
    },

    "buttons" : {
        "back"                 : document.getElementById("back"),
        "logout"               : document.getElementById("logout"),
        "add_connection"       : document.getElementById("add-connection"),
        "add_connection_group" : document.getElementById("add-connection-group"),
        "add_user"             : document.getElementById("add-user")
    },

    "fields" : {
        "username"        : document.getElementById("username")
    },

    "cached_permissions" : null,
    "cached_protocols"   : null,
    "cached_root_group"  : null

};

/**
 * An arbitrary input field.
 * 
 * @constructor
 */
GuacAdmin.Field = function() {

    /**
     * Returns the DOM Element representing this field.
     * 
     * @return {Element} The DOM Element representing this field.
     */
    this.getElement = function() {};

    /**
     * Returns the value of this field.
     * 
     * @return {String} The value of this field.
     */
    this.getValue = function() {};

    /**
     * Sets the value of this field.
     * 
     * @param {String} value The value of this field.
     */
    this.setValue = function(value) {};

};

/**
 * Simple HTML input field.
 * 
 * @augments GuacAdmin.Field
 * @param {String} type The type of HTML field.
 */
GuacAdmin.Field._HTML_INPUT = function(type) {

    // Call parent constructor
    GuacAdmin.Field.apply(this);

    // Create backing element
    var element = GuacUI.createElement("input");
    element.setAttribute("type", type);

    this.getValue = function() {
        return element.value;
    };

    this.getElement = function() {
        return element;
    };

    this.setValue = function(value) {
        element.value = value;
    };

};

GuacAdmin.Field._HTML_INPUT.prototype = new GuacAdmin.Field();

/**
 * A basic text field.
 * 
 * @augments GuacAdmin.Field._HTML_INPUT
 */
GuacAdmin.Field.TEXT = function() {
    GuacAdmin.Field._HTML_INPUT.apply(this, ["text"]);
};

GuacAdmin.Field.TEXT.prototype = new GuacAdmin.Field._HTML_INPUT();

/**
 * A basic multiline text field.
 * 
 * @augments GuacAdmin.Field
 */
GuacAdmin.Field.MULTILINE = function() {

    // Call parent constructor
    GuacAdmin.Field.apply(this);

    // Create backing element
    var element = GuacUI.createElement("textarea");

    this.getValue = function() {
        return element.value;
    };

    this.getElement = function() {
        return element;
    };

    this.setValue = function(value) {
        element.value = value;
    };

};

GuacAdmin.Field.MULTILINE.prototype = new GuacAdmin.Field();

/**
 * A basic password field.
 * 
 * @augments GuacAdmin.Field._HTML_INPUT
 */
GuacAdmin.Field.PASSWORD = function() {
    GuacAdmin.Field._HTML_INPUT.apply(this, ["password"]);
};

GuacAdmin.Field.PASSWORD.prototype = new GuacAdmin.Field._HTML_INPUT();

/**
 * A basic numeric field, leveraging the new HTML5 field types.
 * 
 * @augments GuacAdmin.Field._HTML_INPUT
 */
GuacAdmin.Field.NUMERIC = function() {
    GuacAdmin.Field._HTML_INPUT.apply(this, ["number"]);
};

GuacAdmin.Field.NUMERIC.prototype = new GuacAdmin.Field._HTML_INPUT();

/**
 * Simple checkbox.
 * 
 * @augments GuacAdmin.Field
 */
GuacAdmin.Field.CHECKBOX = function(value) {

    // Call parent constructor
    GuacAdmin.Field.apply(this);

    // Create backing element
    var element = GuacUI.createElement("input");
    element.setAttribute("type", "checkbox");
    element.setAttribute("value", value);

    this.getValue = function() {
        if (element.checked)
            return value;
        else
            return "";
    };

    this.getElement = function() {
        return element;
    };

    this.setValue = function(new_value) {
        if (new_value == value)
            element.checked = true;
        else
            element.checked = false;
    };

};

GuacAdmin.Field.CHECKBOX.prototype = new GuacAdmin.Field();

/**
 * Enumerated field type.
 * 
 * @augments GuacAdmin.Field
 */
GuacAdmin.Field.ENUM = function(values) {

    // Call parent constructor
    GuacAdmin.Field.apply(this);

    // Create backing element
    var element = GuacUI.createElement("select");
    for (var i=0; i<values.length; i++) {
        var option = GuacUI.createChildElement(element, "option");
        option.textContent = values[i].title;
        option.value = values[i].value;
    }

    this.getValue = function() {
        return element.value;
    };

    this.getElement = function() {
        return element;
    };

    this.setValue = function(value) {
        element.value = value;
    };

};

GuacAdmin.Field.ENUM.prototype = new GuacAdmin.Field();

/**
 * An arbitrary button.
 * 
 * @constructor
 * @param {String} title A human-readable title for the button.
 */
GuacAdmin.Button = function(title) {

    /**
     * A human-readable title describing this button.
     */
    this.title = title;

    // Button element
    var element = GuacUI.createElement("button");
    element.textContent = title;

    /**
     * Returns the DOM element associated with this button.
     */
    this.getElement = function() {
        return element;
    };

};

/**
 * An arbitrary list item with an icon and caption.
 */
GuacAdmin.ListItem = function(type, title) {

    // Create connection display elements
    var element = GuacUI.createElement("div",  "list-item");
    var caption = GuacUI.createChildElement(element, "div", "caption");
    var icon    = GuacUI.createChildElement(caption, "div",  "icon");
    var name    = GuacUI.createChildElement(caption, "span", "name");
    GuacUI.addClass(icon, type);

    // Set name
    name.textContent = title;

    /**
     * Returns the DOM element representing this connection.
     */
    this.getElement = function() {
        return element;
    };

};

/*
 * Set handler for logout
 */

GuacAdmin.buttons.logout.onclick = function() {
    window.location.href = "logout";
};

/*
 * Set handler for back button 
 */

GuacAdmin.buttons.back.onclick = function() {
    window.location.href = "index.xhtml";
};

/**
 * Returns whether the given object has at least one property.
 */
GuacAdmin.hasEntry = function(object) {
    for (var name in object)
        return true;
    return false;
};

/**
 * Given a Date, returns a formatted String.
 * 
 * @param {Date} date The date tor format.
 * @return {String} A formatted String.
 */
GuacAdmin.formatDate = function(date) {

    var month = date.getMonth() + 1;
    var day   = date.getDate();
    var year  = date.getFullYear();

    var hour   = date.getHours();
    var minute = date.getMinutes();
    var second = date.getSeconds();

    return      ("00" +  month).slice(-2)
        + "/" + ("00" +    day).slice(-2)
        + "/" + year
        + " " + ("00" +   hour).slice(-2)
        + ":" + ("00" + minute).slice(-2)
        + ":" + ("00" + second).slice(-2);

};

/**
 * Given a number of seconds, returns a String representing that length
 * of time in a human-readable format.
 * 
 * @param {Number} seconds The number of seconds.
 * @return {String} A human-readable description of the duration specified.
 */
GuacAdmin.formatSeconds = function(seconds) {

    function round(value) {
        return Math.round(value * 10) / 10;
    }

    if (seconds < 60)    return round(seconds)        + " seconds";
    if (seconds < 3600)  return round(seconds / 60)   + " minutes";
    if (seconds < 86400) return round(seconds / 3600) + " hours";
    return round(seconds / 86400) + " days";

};

/**
 * Currently-defined pager for users, if any.
 */
GuacAdmin.userPager = null;

/**
 * Adds the user with the given name to the displayed user list.
 */
GuacAdmin.addUser = function(name, parameters) {

    // Create user list item
    var item = new GuacAdmin.ListItem("user", name);
    var item_element = item.getElement();
    GuacAdmin.userPager.addElement(item_element);

    // When clicked, build and display property form
    item_element.onclick = function() {

        // Open user editor
        var user_dialog = new GuacAdmin.UserEditor(name, parameters);
        document.body.appendChild(user_dialog.getElement());

    };

};

/**
 * User edit dialog which allows editing of the user's password and connection
 * access level.
 * 
 * @param {String} name The name of the user to edit.
 * @param {String} parameters Any parameters to add to service requests for sake
 *                            of authentication.
 */
GuacAdmin.UserEditor = function(name, parameters) {

    /**
     * Dialog containing the user editor.
     */
    var dialog = new GuacUI.Dialog();

    // Get user permissions
    var user_perms = GuacamoleService.Permissions.list(name, parameters);

    // Permission deltas
    var added_perms   = new GuacamoleService.PermissionSet();
    var removed_perms = new GuacamoleService.PermissionSet();

    // Create form base elements
    var user_header = GuacUI.createChildElement(dialog.getHeader(), "h2");
    var form_element = GuacUI.createChildElement(dialog.getBody(), "div", "form");
    var sections = GuacUI.createChildElement(
        GuacUI.createChildElement(form_element, "div", "settings section"),
        "dl");

    var field_header = GuacUI.createChildElement(sections, "dt");
    var field_table  = GuacUI.createChildElement(
        GuacUI.createChildElement(sections, "dd"),
        "table", "fields section");

    user_header.textContent = name;
    field_header.textContent = "Properties:";

    // Add password field
    var password_field = GuacUI.createChildElement(
            GuacUI.createTabulatedContainer(field_table, "Password:"),
            "input");
    password_field.setAttribute("type",  "password");
    password_field.setAttribute("value", "password");
        
    // Add password re-entry field
    var reenter_password_field = GuacUI.createChildElement(
            GuacUI.createTabulatedContainer(field_table, "Re-enter Password:"),
            "input");
    reenter_password_field.setAttribute("type",  "password");
    reenter_password_field.setAttribute("value", "password");

    // Update password if changed
    var password_modified = false;
    password_field.onchange =
    reenter_password_field.onchange = function() {
        password_modified = true;
    };

    // If administrator, allow manipulation of admin permissions on users
    if (GuacAdmin.cached_permissions.administer) {

        var permission_header = GuacUI.createChildElement(sections, "dt");
        var permission_table  = GuacUI.createChildElement(
            GuacUI.createChildElement(sections, "dd"),
            "table", "permissions section");

        permission_header.textContent = "Permissions:";

        // Add system administration checkbox
        var is_admin = GuacUI.createChildElement(
                GuacUI.createTabulatedContainer(permission_table, "Administer system:"),
                "input");
        is_admin.setAttribute("type", "checkbox");
        is_admin.setAttribute("value", "administer");

        // Check if set
        if (user_perms.administer)
            is_admin.checked = true;

        // Add create user permission checkbox
        var create_users = GuacUI.createChildElement(
                GuacUI.createTabulatedContainer(permission_table, "Create new users:"),
                "input");
        create_users.setAttribute("type", "checkbox");
        create_users.setAttribute("value",  "create_user");

        // Check if set
        if (user_perms.create_user)
            create_users.checked = true;

        // Add create connection permission checkbox
        var create_connections = GuacUI.createChildElement(
                GuacUI.createTabulatedContainer(permission_table, "Create new connections:"),
                "input");
        create_connections.setAttribute("type", "checkbox");
        create_connections.setAttribute("value", "create_connection");

        // Check if set
        if (user_perms.create_connection)
            create_connections.checked = true;

        // Add create connection group permission checkbox
        var create_connection_groups = GuacUI.createChildElement(
                GuacUI.createTabulatedContainer(permission_table, "Create new connection groups:"),
                "input");
        create_connection_groups.setAttribute("type", "checkbox");
        create_connection_groups.setAttribute("value", "create_connection_group");

        // Check if set
        if (user_perms.create_connection_group)
            create_connection_groups.checked = true;

        // Update system permissions when changed
        is_admin.onclick =
        create_users.onclick =
        create_connections.onclick =
        create_connection_groups.onclick =
            function() {

                // Update permission deltas for ADDED permission
                if (this.checked) {
                    added_perms[this.value]   = true;
                    removed_perms[this.value] = false;
                }

                // Update permission deltas for REMOVED permission
                else {
                    added_perms[this.value]   = false;
                    removed_perms[this.value] = true;
                }

            };

    }

    // If administrable connections/groups exist, list them
    if (GuacAdmin.cached_permissions.administer
        || GuacAdmin.hasEntry(GuacAdmin.cached_permissions.administer_connection)
        || GuacAdmin.hasEntry(GuacAdmin.cached_permissions.administer_connection_group)) {

        // Add fields for per-connection checkboxes
        var connections_header = GuacUI.createChildElement(sections, "dt");
        connections_header.textContent = "Connections:";

        var connections_section = GuacUI.createChildElement(sections, "dd");

        // Construct group view for all readable connections
        var group_view = new GuacUI.GroupView(GuacAdmin.cached_root_group,
           GuacUI.GroupView.SHOW_CONNECTIONS | GuacUI.GroupView.MULTISELECT);
        connections_section.appendChild(group_view.getElement());

        // Update connection permissions when changed
        group_view.onconnectionchange = function(connection, selected) {

            var id = connection.id;

            // Update permission deltas for ADDED permission
            if (selected) {
                added_perms.read_connection[id] = true;
                if (removed_perms.read_connection[id])
                    delete removed_perms.read_connection[id];
            }

            // Update permission deltas for REMOVED permission
            else {
                removed_perms.read_connection[id] = true;
                if (added_perms.read_connection[id])
                    delete added_perms.read_connection[id];
            }

        };

        // Update group permissions when changed
        group_view.ongroupchange = function(group, selected) {

            var id = group.id;

            // Update permission deltas for ADDED permission
            if (selected) {
                added_perms.read_connection_group[id] = true;
                if (removed_perms.read_connection_group[id])
                    delete removed_perms.read_connection_group[id];
            }

            // Update permission deltas for REMOVED permission
            else {
                removed_perms.read_connection_group[id] = true;
                if (added_perms.read_connection_group[id])
                    delete added_perms.read_connection_group[id];
            }

        };

        // Set selectable and selected states based on current permissions
        for (var conn_id in group_view.connections) {

            // Pre-select connection if readable by chosen user
            if (conn_id in user_perms.read_connection)
                group_view.setConnectionValue(conn_id, true);

            // If we lack permissions to admin this connection, disable it
            if (!GuacAdmin.cached_permissions.administer &&
                    !(conn_id in GuacAdmin.cached_permissions.administer_connection))
                group_view.setConnectionEnabled(conn_id, false);

        }

        for (var group_id in group_view.groups) {

            // Pre-select connection if readable by chosen user
            if (group_id in user_perms.read_connection_group)
                group_view.setGroupValue(group_id, true);

            // If we lack permissions to admin this connection, disable it
            if (!GuacAdmin.cached_permissions.administer &&
                    !(group_id in GuacAdmin.cached_permissions.administer_connection_group))
                group_view.setGroupEnabled(group_id, false);

        }

    }

    // Add save button
    var save_button = GuacUI.createChildElement(dialog.getFooter(), "button");
    save_button.textContent = "Save";
    save_button.onclick = function(e) {

        e.stopPropagation();

        try {

            // If password modified, use password given
            var password;
            if (password_modified) {

                // Get passwords
                password = password_field.value;
                var reentered_password = reenter_password_field.value;

                // Check that passwords match
                if (password != reentered_password)
                    throw new Error("Passwords do not match.");

            }

            // Otherwise, do not change password
            else
                password = null;

            // Save user
            GuacamoleService.Users.update(name, password, added_perms, removed_perms, parameters);
            dialog.getElement().parentNode.removeChild(dialog.getElement());
            GuacAdmin.reset();

        }
        catch (e) {
            alert(e.message);
        }

    };

    // Add cancel button
    var cancel_button = GuacUI.createChildElement(dialog.getFooter(), "button");
    cancel_button.textContent = "Cancel";
    cancel_button.onclick = function(e) {
        e.stopPropagation();
        dialog.getElement().parentNode.removeChild(dialog.getElement());
    };

    // Add delete button if permission available
    if (GuacAdmin.cached_permissions.administer ||
        name in GuacAdmin.cached_permissions.remove_user) {
        
        // Create button
        var delete_button = GuacUI.createChildElement(dialog.getFooter(), "button", "danger");
        delete_button.textContent = "Delete";
        
        // Remove selected user when clicked
        delete_button.onclick = function(e) {

            e.stopPropagation();

            // Delete user upon confirmation
            if (confirm("Are you sure you want to delete the user \""
                        + name + "\"?")) {

                // Attempt to delete user
                try {
                    GuacamoleService.Users.remove(name, parameters);
                    dialog.getElement().parentNode.removeChild(dialog.getElement());
                    GuacAdmin.reset();
                }

                // Alert on failure
                catch (e) {
                    alert(e.message);
                }

            }

        };

    }

    /**
     * Returns the DOM Element representing this dialog.
     * 
     * @return {Element} The DOM Element representing this dialog.
     */
    this.getElement = function() {
        return dialog.getElement();
    };

};

/**
 * Connection edit dialog which allows editing of the connection parameters.
 * 
 * @param {GuacamoleService.Connection} connection The connection to edit. This
 *                                                 must be a connection without
 *                                                 an id, if the connection is
 *                                                 to be created.
 * @param {String} parameters Any parameters to add to service requests for sake
 *                            of authentication.
 */
GuacAdmin.ConnectionEditor = function(connection, parameters) {

    /**
     * Dialog containing the user editor.
     */
    var dialog = new GuacUI.Dialog();

    var i;

    // Create form base elements
    var connection_header = GuacUI.createChildElement(dialog.getHeader(), "h2");
    var form_element = GuacUI.createChildElement(dialog.getBody(), "div", "form");

    var sections = GuacUI.createChildElement(
        GuacUI.createChildElement(form_element, "div", "settings section"),
        "dl");

    // Header section
    var header_table  = GuacUI.createChildElement(
        GuacUI.createChildElement(sections, "dt"),
        "table", "fields section");

    // Header parameter containers
    var name_container     = GuacUI.createTabulatedContainer(header_table, "Name:");
    var location_container = GuacUI.createTabulatedContainer(header_table, "Location:");
    var protocol_container = GuacUI.createTabulatedContainer(header_table, "Protocol:");

    var name_field     = GuacUI.createChildElement(name_container, "input");
    var location       = GuacUI.createChildElement(location_container, "div", "location");
    var protocol_field = GuacUI.createChildElement(protocol_container, "select");
    name_field.setAttribute("type", "text");

    var location_value = connection.parent;
    location.textContent = connection.parent.name;
    location.onclick = function() {

        // Show group selector
        var group_select = new GuacAdmin.ConnectionGroupSelect(GuacAdmin.cached_root_group);
        location_container.appendChild(group_select.getElement());

        // Pre-select current value
        group_select.select(location_value);

        // Update location when chosen
        group_select.onselect = function(group) {
            location_value = group;
            location.textContent = group.name;
        };

    };

    // Set header
    name_field.value =
    connection_header.textContent = connection.name;

    // Associative set of protocols
    var available_protocols = {};

    // All form fields by parameter name
    var fields = {};

    // Add protocols
    for (i=0; i<GuacAdmin.cached_protocols.length; i++) {

        // Get protocol and store in associative set
        var protocol = GuacAdmin.cached_protocols[i];
        available_protocols[protocol.name] = protocol;

        // List protocol in select
        var protocol_title = GuacUI.createChildElement(protocol_field, "option");
        protocol_title.textContent = protocol.title;
        protocol_title.value = protocol.name;

    }

    // Parameter section
    var field_table  = GuacUI.createChildElement(
        GuacUI.createChildElement(sections, "dd"),
        "table", "fields section");

    // History header
    var history_header = GuacUI.createChildElement(sections, "dt");
    history_header.textContent = "Usage History:";

    // If history present, display as table
    if (connection.history.length > 0) {

        // History section
        var history_section = GuacUI.createChildElement(sections, "dd");
        var history_table  = GuacUI.createChildElement(history_section,
            "table", "history section");

        var history_table_header = GuacUI.createChildElement(
            history_table, "tr");

        GuacUI.createChildElement(history_table_header, "th").textContent =
            "Username";

        GuacUI.createChildElement(history_table_header, "th").textContent =
            "Start Time";

        GuacUI.createChildElement(history_table_header, "th").textContent =
            "Duration";

        // Paginated body of history
        var history_buttons = GuacUI.createChildElement(history_section, "div",
            "list-pager-buttons");
        var history_body = GuacUI.createChildElement(history_table, "tbody");
        var history_pager = new GuacUI.Pager(history_body);

        // Add history
        for (i=0; i<connection.history.length; i++) {

            // Get record
            var record = connection.history[i];

            // Create record elements
            var row = GuacUI.createElement("tr");
            var user = GuacUI.createChildElement(row, "td", "username");
            var start = GuacUI.createChildElement(row, "td", "start");
            var duration = GuacUI.createChildElement(row, "td", "duration");

            // Display record
            user.textContent = record.username;
            start.textContent = GuacAdmin.formatDate(record.start);
            if (record.duration !== null)
                duration.textContent = GuacAdmin.formatSeconds(record.duration);
            else
                duration.textContent = "Active now";

            // Add record to pager
            history_pager.addElement(row);

        }

        // Init pager
        history_pager.setPage(0);

        // Add pager if more than one page
        if (history_pager.last_page !== 0)
            history_buttons.appendChild(history_pager.getElement());

    }
    else
        GuacUI.createChildElement(
            GuacUI.createChildElement(sections, "dd"), "p").textContent =
                "This connection has not yet been used.";

    // Display fields for the given protocol name 
    function setFields(protocol_name) {

        // Clear fields
        field_table.innerHTML = "";

        // Get protocol
        var protocol = available_protocols[protocol_name];

        // For each parameter
        for (var i=0; i<protocol.parameters.length; i++) {

            // Get parameter
            var parameter = protocol.parameters[i];
            var name = parameter.name;

            // Create corresponding field
            var field;
            switch (parameter.type) {

                // Text field
                case GuacamoleService.Protocol.Parameter.TEXT:
                    field = new GuacAdmin.Field.TEXT();
                    break;

                // Password field
                case GuacamoleService.Protocol.Parameter.PASSWORD:
                    field = new GuacAdmin.Field.PASSWORD();
                    break;

                // Numeric field
                case GuacamoleService.Protocol.Parameter.NUMERIC:
                    field = new GuacAdmin.Field.NUMERIC();
                    break;

                // Checkbox
                case GuacamoleService.Protocol.Parameter.BOOLEAN:
                    field = new GuacAdmin.Field.CHECKBOX(parameter.value);
                    break;

                // Select field
                case GuacamoleService.Protocol.Parameter.ENUM:
                    field = new GuacAdmin.Field.ENUM(parameter.options);
                    break;

                // Multiline text field
                case GuacamoleService.Protocol.Parameter.MULTILINE:
                    field = new GuacAdmin.Field.MULTILINE();
                    break;

                default:
                    continue;

            }

            // Create container for field
            var container = 
                GuacUI.createTabulatedContainer(field_table, parameter.title + ":");

            // Set initial value, if available
            if (connection.parameters[name])
                field.setValue(connection.parameters[name]);

            // Add field
            container.appendChild(field.getElement());
            fields[name] = field;

        } // end foreach parameter

    }

    // Set initially selected protocol
    if (connection.protocol) protocol_field.value = connection.protocol;
    setFields(protocol_field.value);

    protocol_field.onchange = protocol_field.onclick = function() {
        setFields(this.value);
    };

    // Add save button
    var save_button = GuacUI.createChildElement(dialog.getFooter(), "button");
    save_button.textContent = "Save";
    save_button.onclick = function(e) {

        e.stopPropagation();

        try {

            // Build connection
            var updated_connection = new GuacamoleService.Connection(
                protocol_field.value,
                connection.id,
                name_field.value
            );

            // Populate parameters
            for (var name in fields) {
                var field = fields[name];
                if (field)
                    updated_connection.parameters[name] = field.getValue();
            }

            // Update connection if it exists
            if (connection.id) {
                GuacamoleService.Connections.update(updated_connection, parameters);
                if (location_value.id !== connection.parent.id)
                    GuacamoleService.Connections.move(updated_connection, location_value, parameters);
            }

            // Otherwise, create
            else {
                updated_connection.parent = location_value;
                GuacamoleService.Connections.create(updated_connection, parameters);
            }

            // Hide dialog and reset UI
            dialog.getElement().parentNode.removeChild(dialog.getElement());
            GuacAdmin.reset();

        }
        catch (e) {
            alert(e.message);
        }

    };

    // Add cancel button
    var cancel_button = GuacUI.createChildElement(dialog.getFooter(), "button");
    cancel_button.textContent = "Cancel";
    cancel_button.onclick = function(e) {
        e.stopPropagation();
        dialog.getElement().parentNode.removeChild(dialog.getElement());
    };

    // Add delete button if permission available
    if (GuacAdmin.cached_permissions.administer ||
        connection.id in GuacAdmin.cached_permissions.remove_connection) {
        
        // Create button
        var delete_button = GuacUI.createChildElement(dialog.getFooter(), "button", "danger");
        delete_button.textContent = "Delete";
        
        // Remove selected connection when clicked
        delete_button.onclick = function(e) {

            e.stopPropagation();

            // Delete connection upon confirmation
            if (confirm("Are you sure you want to delete the connection \""
                        + connection.name + "\"?")) {

                // Attempt to delete connection
                try {
                    GuacamoleService.Connections.remove(connection.id, parameters);
                    dialog.getElement().parentNode.removeChild(dialog.getElement());
                    GuacAdmin.reset();
                }

                // Alert on failure
                catch (e) {
                    alert(e.message);
                }

            }

        };

    }

    /**
     * Returns the DOM Element representing this dialog.
     * 
     * @return {Element} The DOM Element representing this dialog.
     */
    this.getElement = function() {
        return dialog.getElement();
    };

};

/**
 * Connection group edit dialog which allows editing of the group parameters.
 * 
 * @param {GuacamoleService.ConnectionGroup} group The group to edit. This must
 *                                                 be a group without an ID for
 *                                                 group creation.
 * @param {String} parameters Any parameters to add to service requests for sake
 *                            of authentication.
 */
GuacAdmin.ConnectionGroupEditor = function(group, parameters) {

    /**
     * Dialog containing the user editor.
     */
    var dialog = new GuacUI.Dialog();

    var i;

    // Create form base elements
    var group_header = GuacUI.createChildElement(dialog.getHeader(), "h2");
    var form_element = GuacUI.createChildElement(dialog.getBody(), "div", "form");

    var sections = GuacUI.createChildElement(
        GuacUI.createChildElement(form_element, "div", "settings section"),
        "dl");

    // Header section
    var header_table  = GuacUI.createChildElement(
        GuacUI.createChildElement(sections, "dt"),
        "table", "fields section");

    // Header parameter containers
    var name_container     = GuacUI.createTabulatedContainer(header_table, "Name:");
    var location_container = GuacUI.createTabulatedContainer(header_table, "Location:");
    var type_container     = GuacUI.createTabulatedContainer(header_table, "Type:");

    var name_field = GuacUI.createChildElement(name_container, "input");
    var location   = GuacUI.createChildElement(location_container, "div", "location");
    var type_field = GuacUI.createChildElement(type_container, "select");
    name_field.setAttribute("type", "text");

    var location_value = group.parent;
    location.textContent = group.parent.name;
    location.onclick = function() {

        // Show group selector
        var group_select = new GuacAdmin.ConnectionGroupSelect(GuacAdmin.cached_root_group);
        location_container.appendChild(group_select.getElement());

        // Pre-select current value
        group_select.select(location_value);

        // Update location when chosen
        group_select.onselect = function(selected_group) {

            // Prevent selecting a situation that would produce a cycle
            var current = selected_group;
            while (current !== null) {
                
                if (current.id === group.id) {
                    alert("Cannot move a group into a subgroup of itself.");
                    return;
                }
                
                current = current.parent;
            }

            location_value = selected_group;
            location.textContent = selected_group.name;
        };

    };

    // Set title
    name_field.value =
    group_header.textContent = group.name;

    // Organizational type
    var org_type = GuacUI.createChildElement(type_field, "option");
    org_type.textContent = "Organizational";
    org_type.value = "organizational";

    // Balancing type
    var bal_type = GuacUI.createChildElement(type_field, "option");
    bal_type.textContent = "Balancing";
    bal_type.value = "balancing";

    // Read type from group
    if (group.type === GuacamoleService.ConnectionGroup.Type.ORGANIZATIONAL)
        type_field.value = "organizational";
    else if (group.type === GuacamoleService.ConnectionGroup.Type.BALANCING)
        type_field.value = "balancing";

    // Add save button
    var save_button = GuacUI.createChildElement(dialog.getFooter(), "button");
    save_button.textContent = "Save";
    save_button.onclick = function(e) {

        e.stopPropagation();

        try {

            // Parse type
            var type;
            if (type_field.value === "organizational")
                type = GuacamoleService.ConnectionGroup.Type.ORGANIZATIONAL;
            else if (type_field.value === "balancing")
                type = GuacamoleService.ConnectionGroup.Type.BALANCING;

            // Build group 
            var updated_group = new GuacamoleService.ConnectionGroup(
                type,
                group.id,
                name_field.value
            );

            // Update group if provided
            if (group.id) {
                GuacamoleService.ConnectionGroups.update(updated_group, parameters);
                if (location_value.id !== group.parent.id)
                    GuacamoleService.ConnectionGroups.move(updated_group, location_value, parameters);
            }

            // Otherwise, create
            else {
                updated_group.parent = location_value;
                GuacamoleService.ConnectionGroups.create(updated_group, parameters);
            }

            dialog.getElement().parentNode.removeChild(dialog.getElement());
            GuacAdmin.reset();

        }
        catch (e) {
            alert(e.message);
        }

    };

    // Add cancel button
    var cancel_button = GuacUI.createChildElement(dialog.getFooter(), "button");
    cancel_button.textContent = "Cancel";
    cancel_button.onclick = function(e) {
        e.stopPropagation();
        dialog.getElement().parentNode.removeChild(dialog.getElement());
    };

    // Add delete button if permission available
    if (GuacAdmin.cached_permissions.administer ||
        group.id in GuacAdmin.cached_permissions.remove_connection_group) {
        
        // Create button
        var delete_button = GuacUI.createChildElement(dialog.getFooter(), "button", "danger");
        delete_button.textContent = "Delete";
        
        // Remove selected group when clicked
        delete_button.onclick = function(e) {

            e.stopPropagation();

            // Delete group upon confirmation
            if (confirm("Are you sure you want to delete the group \""
                        + group.name + "\"?")) {

                // Attempt to delete group 
                try {
                    GuacamoleService.ConnectionGroups.remove(group.id, parameters);
                    dialog.getElement().parentNode.removeChild(dialog.getElement());
                    GuacAdmin.reset();
                }

                // Alert on failure
                catch (e) {
                    alert(e.message);
                }

            }

        };

    }

    /**
     * Returns the DOM Element representing this dialog.
     * 
     * @return {Element} The DOM Element representing this dialog.
     */
    this.getElement = function() {
        return dialog.getElement();
    };

};

/**
 * Connection group dialog which allows selection of a single group.
 * 
 * @param {GuacamoleService.ConnectionGroup} group The group to view.
 */
GuacAdmin.ConnectionGroupSelect = function(group) {

    /**
     * Reference to this group selector.
     * @private
     */
    var group_select = this;

    // Add section with group view
    var container = GuacUI.createElement("div");
    var group_outside = GuacUI.createChildElement(container, "div", "overlay");
    var group_section = GuacUI.createChildElement(container, "div", "dropdown");

    var view = new GuacUI.GroupView(group, GuacUI.GroupView.SHOW_ROOT_GROUP,

        // Only show organizational groups or balancing groups we can administer
        function(group) {

            if (group.type === GuacamoleService.ConnectionGroup.Type.ORGANIZATIONAL)
                return true;

            return    GuacAdmin.cached_permissions.administer
                   || GuacAdmin.cached_permissions.administer_connection_group[group.id];

        });

    group_section.appendChild(view.getElement());

    // Hide when clicked outside
    group_outside.addEventListener("click", function(e) {
        e.stopPropagation();
        container.parentNode.removeChild(container);
    }, false);

    // Handle select
    view.ongroupclick = function(group) {

        // Fire event if defined
        if (group_select.onselect)
            group_select.onselect(group);

        // Hide dialog
        container.parentNode.removeChild(container);

    };

    /**
     * Fired when a group is selected.
     * 
     * @event
     * @param {GuacamoleService.ConnectionGroup} group The selected group.
     */
    this.onselect = null;

    /**
     * Returns the DOM Element representing this dialog.
     * 
     * @return {Element} The DOM Element representing this dialog.
     */
    this.getElement = function() {
        return container;
    };

    /**
     * Pre-selects the given group.
     * 
     * @param {GuacamoleService.ConnectionGroup} group The group to select.
     */
    this.select = function(group) {
        view.expand(group);
    };

};

GuacAdmin.reset = function() {

    // Get parameters from query string
    var parameters = window.location.search.substring(1);

    /*
     * Show admin elements if admin permissions available
     */

    // Query service for permissions, protocols, and connections
    GuacAdmin.cached_permissions = GuacamoleService.Permissions.list(null, parameters);
    GuacAdmin.cached_protocols   = GuacamoleService.Protocols.list(parameters);
    GuacAdmin.cached_root_group  = GuacamoleService.Connections.list(parameters);

    // Connection management
    if (GuacAdmin.cached_permissions.administer
        || GuacAdmin.cached_permissions.create_connection
        || GuacAdmin.hasEntry(GuacAdmin.cached_permissions.update_connection)
        || GuacAdmin.hasEntry(GuacAdmin.cached_permissions.remove_connection)
        || GuacAdmin.hasEntry(GuacAdmin.cached_permissions.administer_connection)
        || GuacAdmin.hasEntry(GuacAdmin.cached_permissions.update_connection_group)
        || GuacAdmin.hasEntry(GuacAdmin.cached_permissions.remove_connection_group)
        || GuacAdmin.hasEntry(GuacAdmin.cached_permissions.administer_connection_group))
            GuacUI.addClass(document.body, "manage-connections");
        else
            GuacUI.removeClass(document.body, "manage-connections");

    // User management
    if (GuacAdmin.cached_permissions.administer
        || GuacAdmin.cached_permissions.create_user
        || GuacAdmin.hasEntry(GuacAdmin.cached_permissions.update_user)
        || GuacAdmin.hasEntry(GuacAdmin.cached_permissions.remove_user)
        || GuacAdmin.hasEntry(GuacAdmin.cached_permissions.administer_user))
            GuacUI.addClass(document.body, "manage-users");
        else
            GuacUI.removeClass(document.body, "manage-users");

    // Connection creation 
    if (GuacAdmin.cached_permissions.administer
        || GuacAdmin.cached_permissions.create_connection) {
        GuacUI.addClass(document.body, "add-connections");

        GuacAdmin.buttons.add_connection.onclick = function() {

            // Create stub base connection
            var connection = new GuacamoleService.Connection(null, null, "New Connection");
            connection.parent = GuacAdmin.cached_root_group;

            // Open connection creation dialog
            var connection_dialog = new GuacAdmin.ConnectionEditor(connection, parameters);
            document.body.appendChild(connection_dialog.getElement());

        };

    }

    // Connection group creation 
    if (GuacAdmin.cached_permissions.administer
        || GuacAdmin.cached_permissions.create_connection_group) {
        GuacUI.addClass(document.body, "add-connection-groups");

        GuacAdmin.buttons.add_connection_group.onclick = function() {

            // Create stub base group 
            var group = new GuacamoleService.ConnectionGroup(
                    GuacamoleService.ConnectionGroup.Type.ORGANIZATIONAL, null, "New Group");
            group.parent = GuacAdmin.cached_root_group;

            // Open group creation dialog
            var group_dialog = new GuacAdmin.ConnectionGroupEditor(group, parameters);
            document.body.appendChild(group_dialog.getElement());

        };

    }

    // User creation
    if (GuacAdmin.cached_permissions.administer
       || GuacAdmin.cached_permissions.create_user) {
        GuacUI.addClass(document.body, "add-users");

        GuacAdmin.buttons.add_user.onclick = function() {

            // Attempt to create user
            try {
                GuacamoleService.Users.create(GuacAdmin.fields.username.value, parameters);
                GuacAdmin.fields.username.value = "";
                GuacAdmin.reset();
            }

            // Alert on failure
            catch (e) {
                alert(e.message);
            }

        };

    }

    var i;

    /*
     * Add readable users.
     */

    // Get previous page, if any
    var user_previous_page = 0;
    if (GuacAdmin.userPager)
        user_previous_page = GuacAdmin.userPager.current_page;

    // Add new pager
    GuacAdmin.containers.user_list.innerHTML = "";
    GuacAdmin.userPager = new GuacUI.Pager(GuacAdmin.containers.user_list);

    // Add users to pager
    var usernames = GuacamoleService.Users.list(parameters);
    for (i=0; i<usernames.length; i++) {
        if (GuacAdmin.cached_permissions.administer
            || usernames[i] in GuacAdmin.cached_permissions.update_user)
            GuacAdmin.addUser(usernames[i], parameters);
    }

    // If more than one page, add navigation buttons
    GuacAdmin.containers.user_list_buttons.innerHTML = "";
    if (GuacAdmin.userPager.last_page != 0)
        GuacAdmin.containers.user_list_buttons.appendChild(GuacAdmin.userPager.getElement());

    // Set starting page
    GuacAdmin.userPager.setPage(Math.min(GuacAdmin.userPager.last_page,
            user_previous_page));

    /*
     * Add readable connections.
     */

    // Add new group view
    GuacAdmin.containers.connection_list.innerHTML = "";
    var group_view = new GuacUI.GroupView(GuacAdmin.cached_root_group, GuacUI.GroupView.SHOW_CONNECTIONS,
    
        // Show all organizational groups and balancing groups we have admin
        // for
        function(group) {

            if (group.type === GuacamoleService.ConnectionGroup.Type.ORGANIZATIONAL)
                return true;

            return    GuacAdmin.cached_permissions.administer
                   || GuacAdmin.cached_permissions.administer_connection_group[group.id];

        },

        // Only show connections we can update/administer
        function(connection) {
            return    GuacAdmin.cached_permissions.administer
                   || GuacAdmin.cached_permissions.update_connection[connection.id]
                   || GuacAdmin.cached_permissions.administer_connection[connection.id];
        });

    GuacAdmin.containers.connection_list.appendChild(group_view.getElement());

    // Show connection editor when connections are clicked
    group_view.onconnectionclick = function(connection) {
        var connection_dialog = new GuacAdmin.ConnectionEditor(connection, parameters);
        document.body.appendChild(connection_dialog.getElement());
    };

    // Show group editor when groups are clicked
    group_view.ongroupclick = function(group) {

        // Only show group editor if we can actually update/admin this group
        if (GuacAdmin.cached_permissions.administer
               || GuacAdmin.cached_permissions.update_connection_group[group.id]
               || GuacAdmin.cached_permissions.administer_connection_group[group.id]) {

            var group_dialog = new GuacAdmin.ConnectionGroupEditor(group, parameters);
            document.body.appendChild(group_dialog.getElement());

       }

    };

};

// Initial load
GuacAdmin.reset();