/*
 * PhoneGap is available under *either* the terms of the modified BSD license *or* the
 * MIT License (2008). See http://opensource.org/licenses/alphabetical for full text.
 *
 * Copyright (c) 2005-2011, Nitobi Software Inc.
 * Copyright (c) 2011, Microsoft Corporation
 */

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Collections.Generic;
using WP7GapClassLib.PhoneGap.Commands;
using System.Reflection;
using System.Diagnostics;

namespace WP7GapClassLib.PhoneGap
{
    /// <summary>
    /// Provides functionality to create phone gap command by name.
    /// </summary>
    public static class CommandFactory
    {
        /// <summary>
        /// Represents predefined namespace name for custom plugins
        /// </summary>
        private static readonly string CustomPluginNamespacePrefix = "PhoneGap.Extension.Commands.";

        private static readonly string BaseCommandNamespacePrefix  = "WP7GapClassLib.PhoneGap.Commands.";

        /// <summary>
        /// Performance optimization allowing more faster create already known commands.
        /// </summary>

        private static Dictionary<string, Type> commandMap = new Dictionary<string, Type>();
 
        /// <summary>
        /// Creates command using command class name. Returns null for unknown commands.
        /// </summary>
        /// <param name="service">Command class name, for example Device or Notification</param>
        /// <returns>Command class instance or null</returns>
        public static BaseCommand CreateByServiceName(string service)
        {

            if (string.IsNullOrEmpty(service))
            {
                throw new ArgumentNullException("service", "service to create can't be null");
            }

            if (!commandMap.ContainsKey(service))
            {

                Type t = Type.GetType(BaseCommandNamespacePrefix + service);

                // custom plugin could be defined in own namespace and assembly
                if (t == null)
                {
                    string serviceFullName = service.Contains(".") ? service : CustomPluginNamespacePrefix + service;
                    
                    foreach (Assembly a in AppDomain.CurrentDomain.GetAssemblies())
                    {
                        // in this case service name represents full type name including namespace
                        t = a.GetType(serviceFullName);

                        if (t == null) // try the Commands Namespace
                        {
                            t = a.GetType(BaseCommandNamespacePrefix + service);
                        }

                        if (t != null)
                        {
                            break;
                        }
                    }

                }

                // unknown command, still didn't find it
                if (t == null)
                {
                    Debug.WriteLine("Unable to locate command :: " + service);
                    return null;
                }

                commandMap[service] = t;
            }

            return Activator.CreateInstance(commandMap[service]) as BaseCommand;
        }
    }
}