using System;
using System.Collections;
using System.Collections.Generic;
using System.Web;
using System.Reflection;
using umbraco.BasePages;
using umbraco.BusinessLogic.Utils;
using umbraco.cms.businesslogic.web;
using umbraco.cms.businesslogic.workflow;
using umbraco.interfaces;

namespace umbraco.BusinessLogic.Actions
{
    /// <summary>
    /// Actions and Actionhandlers are a key concept to umbraco and a developer whom wish to apply
    /// businessrules whenever data is changed within umbraco, by implementing the IActionHandler
    /// interface it's possible to invoke methods (foreign to umbraco) - this can be used whenever
    /// there is a specific rule which needs to be applied to content.
    ///
    /// The Action class itself has responsibility for registering actions and actionhandlers,
    /// and contains methods which will be invoked whenever a change is made to ex. a document, media or member
    /// 
    /// An action/actionhandler will automatically be registered, using reflection 
    /// which is enabling thirdparty developers to extend the core functionality of
    /// umbraco without changing the codebase.
    /// </summary>
    public class Action
    {
        private static readonly List<IAction> _actions = new List<IAction>();
        private static readonly Dictionary<string, string> _actionJs = new Dictionary<string, string>();
        private static readonly List<IActionHandler> _actionHandlers = new List<IActionHandler>();
        private static readonly List<string> _actionJSReference = new List<string>();

        static Action()
        {
            RegisterIActions();
            RegisterIActionHandlers();
        }

        /// <summary>
        /// Stores all IActionHandlers that have been loaded into memory into a list
        /// </summary>
        private static void RegisterIActionHandlers()
        {
            if (_actionHandlers.Count > 0)
                return;

            List<Type> foundIActionHandlers = TypeFinder.FindClassesOfType<IActionHandler>(true);
            foreach (Type type in foundIActionHandlers)
            {
                IActionHandler typeInstance;
                typeInstance = Activator.CreateInstance(type) as IActionHandler;
                if (typeInstance != null)
                    _actionHandlers.Add(typeInstance);
            }
        }

        /// <summary>
        /// Stores all IActions that have been loaded into memory into a list
        /// </summary>
        private static void RegisterIActions()
        {
            if (_actions.Count > 0)
                return;

            List<Type> foundIActions = TypeFinder.FindClassesOfType<IAction>(true);
            foreach (Type type in foundIActions)
            {
                IAction typeInstance;
                PropertyInfo instance = type.GetProperty("Instance", BindingFlags.Public | BindingFlags.Static);
                //if the singletone initializer is not found, try simply creating an instance of the IAction if it supports public constructors
                if (instance == null)
                    typeInstance = Activator.CreateInstance(type) as IAction;
                else
                    typeInstance = instance.GetValue(null, null) as IAction;

                if (typeInstance != null)
                {
                    if (!string.IsNullOrEmpty(typeInstance.JsSource))
                        _actionJSReference.Add(typeInstance.JsSource);
                    _actions.Add(typeInstance);
                }

            }
        }

        /// <summary>
        /// Whenever an action is performed upon a document/media/member, this method is executed, ensuring that 
        /// all registered handlers will have an oppotunity to handle the action.
        /// </summary>
        /// <param name="d">The document being operated on</param>
        /// <param name="action">The action triggered</param>
        public static void RunActionHandlers(Document d, IAction action)
        {
            foreach (IActionHandler ia in _actionHandlers)
            {
                try
                {
                    foreach (IAction a in ia.ReturnActions())
                    {
                        if (a.Alias == action.Alias)
                        {
                            // Uncommented for auto publish support
                            // System.Web.HttpContext.Current.Trace.Write("BusinessLogic.Action.RunActionHandlers", "Running " + ia.HandlerName() + " (matching action: " + a.Alias + ")");
                            ia.Execute(d, action);
                        }
                    }
                }
                catch (Exception iaExp)
                {
                    Log.Add(LogTypes.Error, User.GetUser(0), -1, string.Format("Error loading actionhandler '{0}': {1}",
                        ia.HandlerName(), iaExp));
                }
            }

            // Run notification
            // Find current user
            User u;
            try
            {
                u = new UmbracoEnsuredPage().getUser();
            }
            catch
            {
                u = User.GetUser(0);
            }
            Notification.GetNotifications(d, u, action);
        }

        /// <summary>
        /// Jacascript for the contextmenu
        /// Suggestion: this method should be moved to the presentation layer.
        /// </summary>
        /// <param name="language"></param>
        /// <returns>String representation</returns>
        public string ReturnJavascript(string language)
        {
            return findActions(language);
        }

        /// <summary>
        /// Returns a list of JavaScript file paths.
        /// </summary>
        /// <returns></returns>
        public static List<string> GetJavaScriptFileReferences()
        {
            return _actionJSReference;
        }

        /// <summary>
        /// Javascript menuitems - tree contextmenu
        /// Umbraco console
        /// 
        /// Suggestion: this method should be moved to the presentation layer.
        /// </summary>
        /// <param name="language"></param>
        /// <returns></returns>
        private static string findActions(string language)
        {
            if (!_actionJs.ContainsKey(language))
            {
                string _actionJsList = "";

                foreach (IAction action in _actions)
                {
                    // Adding try/catch so this rutine doesn't fail if one of the actions fail
                    // Add to language JsList
                    try
                    {
                        // NH: Add support for css sprites
                        string icon = action.Icon;
                        if (!string.IsNullOrEmpty(icon) && icon.StartsWith("."))
                            icon = icon.Substring(1, icon.Length - 1);
                        else
                            icon = "images/" + icon;

                        _actionJsList += string.Format(",\n\tmenuItem(\"{0}\", \"{1}\", \"{2}\", \"{3}\")",
                            action.Letter, icon, ui.GetText("actions", action.Alias, language), action.JsFunctionName);
                    }
                    catch (Exception ee)
                    {
                        Log.Add(LogTypes.Error, -1, "Error registrering action to javascript: " + ee.ToString());
                    }
                }

                if (_actionJsList.Length > 0)
                    _actionJsList = _actionJsList.Substring(2, _actionJsList.Length - 2);

                _actionJsList = "\nvar menuMethods = new Array(\n" + _actionJsList + "\n)\n";
                _actionJs.Add(language, _actionJsList);
            }

            return _actionJs[language];

        }

        /// <summary>
        /// 
        /// </summary>
        /// <returns>An arraylist containing all javascript variables for the contextmenu in the tree</returns>
        public static ArrayList GetAll()
        {
            return new ArrayList(_actions);
        }

        /// <summary>
        /// This method will return a list of IAction's based on a string list. Each character in the list may represent
        /// an IAction. This will associate any found IActions based on the Letter property of the IAction with the character being referenced.
        /// </summary>
        /// <param name="actions"></param>
        /// <returns>returns a list of actions that have an associated letter found in the action string list</returns>
        public static List<IAction> FromString(string actions)
        {
            List<IAction> list = new List<IAction>();
            foreach (char c in actions.ToCharArray())
            {
                IAction action = _actions.Find(
                    delegate(IAction a)
                    {
                        return a.Letter == c;
                    }
                );
                if (action != null)
                    list.Add(action);
            }
            return list;
        }

        /// <summary>
        /// Returns the string representation of the actions that make up the actions collection
        /// </summary>
        /// <returns></returns>
        public static string ToString(List<IAction> actions)
        {
            string[] strMenu = Array.ConvertAll<IAction, string>(actions.ToArray(), delegate(IAction a) { return (a.Letter.ToString()); });
            return string.Join("", strMenu);
        }

        /// <summary>
        /// Returns a list of IActions that are permission assignable
        /// </summary>
        /// <returns></returns>
        public static List<IAction> GetPermissionAssignable()
        {
            return _actions.FindAll(
                delegate(IAction a)
                {
                    return (a.CanBePermissionAssigned);
                }
            );
        }
    }

    
}