using System;
using System.Collections.Generic;
using JD.Kernel.Classes;
using JD.Kernel.Structs;
using JD.LogService;
using JD.TeaBoxAddinSystem.Addins.Attributes;
using JD.TeaBoxAddinSystem.Addins.Description;

namespace JD.TeaBoxAddinSystem.Addins.Internal
{
    /// <summary>
    /// A generic node.
    /// </summary>
    public abstract class Node
    {
        #region Inner Types

        private class DeserializationLoggingContext : LoggingContext
        {
            protected override void OnEventLogged(ItemEventArgs<LogEvent> e)
            {
                AddinManager.Log(e.Item);
                base.OnEventLogged(e);
            }
        }

        #endregion

        #region Constants

#if DEBUG
        private static Dictionary<string, object> m_standardAttributes = new Dictionary<string,object>();
#endif

        #endregion

        #region Variables

        // Set through Initialize        
        private Module m_module;
        private NodeType m_type;

        #endregion

        #region Constructor

        static Node()
        {
#if DEBUG
            m_standardAttributes.Add("id", null);
            m_standardAttributes.Add("insertbefore", null);
            m_standardAttributes.Add("insertafter", null);
#endif
        }

        /// <summary>
        /// Internal constructor to forbid inheritance by other assemblies.
        /// </summary>
        internal Node()
        {
        }

        #endregion

        #region Properties

        /// <summary>
        /// Gets the file location of the extension node.
        /// </summary>
        /// <returns></returns>
        public virtual FileLocation FileLocation
        {
            get
            {
                return m_module.FileLocation.GetValueOrDefault();
            }
        }

        /// <summary>
        /// Addin of this node.
        /// </summary>
        public Addin Addin
        {
            get
            {
                return m_module.Addin;
            }
        }

        /// <summary>
        /// Module of this node.
        /// </summary>
        public Module Module
        {
            get
            {
                return m_module;
            }
        }

        /// <summary>
        /// Type of this node.
        /// </summary>
        public NodeType Type
        {
            get
            {
                return m_type;
            }
        }

        #endregion

        #region Methods

        /// <summary>
        /// Reads the node from a <see cref="DeserializationContext"/>.
        /// </summary>
        /// <remarks>
        /// Consider using <see cref="NodeAttributeAttribute"/>s to deserialize automatically.
        /// </remarks>
        /// <param name="context">Context to deserialize from.</param>
        protected virtual void Read(DeserializationContext context)
        {
        }

        /// <summary>
        /// Watch out, do not call this method! Use Initialize of derived class.
        /// </summary>
        /// <param name="module"></param>
        /// <param name="description"></param>
        /// <param name="type"></param>
        /// <returns></returns>
        internal bool Initialize(Module module, NodeDescription description, NodeType type)
        {
            System.Diagnostics.Debug.Assert(module != null);

            m_module = module;
            m_type = type;

            if (description != null)
            {
                try
                {
                    if (!ReadDefault(description))
                    {
                        return false;
                    }

                    LoggingContext loggingContext = new DeserializationLoggingContext();
                    Read(new DeserializationContext(description, loggingContext));

                    if (loggingContext.Errors.Count > 0)
                    {
                        return false;
                    }
                }
                catch (Exception e)
                {
                    description.LogError("Unexpected error while deserializing node of type {0}: {1}", GetType().FullName, e.Message);
                    return false;
                }
            }

            return true;
        }

        private bool ReadDefault(NodeDescription description)
        {
            System.Diagnostics.Debug.Assert(description != null);
            System.Diagnostics.Debug.Assert(Type != null);
            System.Diagnostics.Debug.Assert(Type.Type != null);
            System.Diagnostics.Debug.Assert(Type.Descriptors != null);

            StringPropertyConverter deserializer = new StringPropertyConverter();
            deserializer.ErrorLogger = delegate(string errorMsg)
            {
                description.LogError(errorMsg);
            };

#if DEBUG
            deserializer.SuperfluousPropertiesProduceErrors = true;
            deserializer.SuperfluousPropertyLogger = delegate(string property)
            {
                if (!m_standardAttributes.ContainsKey(property.ToLowerInvariant()))
                {
                    AddinManager.Log(new Error(LogCategory.Warning, "Attribute '{0}' is an unknown attribute for extension node '{1}'", property, Type));
                }
            };
#endif

            deserializer.CustomConverter = delegate(System.Type targetType, string value, out object convertedValue)
            {
                object[] attributes = targetType.GetCustomAttributes(typeof(AddinConverterAttribute), true);
                if (attributes.Length > 0)
                {
                    convertedValue = ((AddinConverterAttribute)attributes[0]).Convert(targetType, value, this);
                    return true;
                }

                convertedValue = null;
                return false;
            };

            return deserializer.Deserialize(this, Type.Descriptors, description.Attributes);
        }

        internal static T CreateNode<T>(string nodeTypeName, NodeType type) where T : Node
        {
            System.Diagnostics.Debug.Assert(!string.IsNullOrEmpty(nodeTypeName));
            System.Diagnostics.Debug.Assert(type != null);            

            Type nodeType = type.Type;

            if (nodeType == null)
            {
                // Something went wrong
                return null;
            }

            T node = null;
            try
            {
                node = Activator.CreateInstance(nodeType) as T;
            }
            catch (System.MissingMethodException)
            {
                type.LogError("Cannot create {0} node of type {1} because it doesn't have a parameterless public constructor", nodeTypeName, nodeType.FullName);
                return null;
            }
            catch (System.Reflection.TargetInvocationException e)
            {
                type.LogError("Unexpected exception thrown while creating {0} node of type {1}: {2}", nodeTypeName, nodeType.FullName, e.InnerException.Message);
                return null;
            }
            catch (Exception e)
            {
                type.LogError("Unexpected error while creating {0} node of type {0}: {1}", nodeTypeName, nodeType.FullName, e.Message);
                return null;
            }

            if (node == null)
            {
                string correctName = nodeTypeName.ToUpper()[0] + nodeTypeName.Substring(1);
                type.LogError("{0} node type {1} must be a subclass of {2}", correctName, nodeType.FullName, typeof(T).Name);
                return null;
            }

            return node;
        }

        #endregion
    }
}