using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Xml;



namespace TextAdventures.Quest

{

    internal partial class GameSaver

    {

        private class ObjectsSaver : IElementsSaver

        {

            #region IElementsSaver Members



            public ElementType AppliesTo

            {

                get { return ElementType.Object; }

            }



            public void Save(GameXmlWriter writer, WorldModel worldModel)

            {

                ObjectSaver elementSaver = new ObjectSaver();

                elementSaver.GameSaver = GameSaver;



                IEnumerable<Element> allObjects = worldModel.Elements.GetElements(ElementType.Object).OrderBy(o => o.MetaFields[MetaFieldDefinitions.SortIndex]);



                foreach (Element e in allObjects.Where(e => e.Parent == null && GameSaver.CanSave(e)))

                {

                    SaveObjectAndChildren(writer, allObjects, e, elementSaver);

                }

            }



            public GameSaver GameSaver { get; set; }



            #endregion



            private void SaveObjectAndChildren(GameXmlWriter writer, IEnumerable<Element> allObjects, Element e, ObjectSaver saver)

            {

                saver.StartSave(writer, e);

                IEnumerable<Element> orderedChildren = from child in allObjects

                                                       where child.Parent == e

                                                       orderby child.MetaFields[MetaFieldDefinitions.SortIndex]

                                                       select child;



                foreach (Element child in orderedChildren)

                {

                    SaveObjectAndChildren(writer, allObjects, child, saver);

                }



                saver.EndSave(writer, e);

            }

        }



        private class ObjectSaver : ElementSaverBase

        {

            private Dictionary<ObjectType, IObjectSaver> m_savers = new Dictionary<ObjectType, IObjectSaver>();



            public ObjectSaver()

            {

                AddIgnoreField("type");

                AddIgnoreField("parent");

            }



            protected override void Initialise()

            {

                // Use Reflection to create instances of all IObjectSavers

                foreach (Type t in TextAdventures.Utility.Classes.GetImplementations(System.Reflection.Assembly.GetExecutingAssembly(),

                    typeof(IObjectSaver)))

                {

                    AddSaver((IObjectSaver)Activator.CreateInstance(t));

                }

            }



            private void AddSaver(IObjectSaver saver)

            {

                saver.ObjectSaver = this;

                m_savers.Add(saver.AppliesTo, saver);

            }



            #region IElementSaver Members



            public override ElementType AppliesTo

            {

                get { return ElementType.Object; }

            }



            public override void Save(GameXmlWriter writer, Element e)

            {

                IObjectSaver saver;

                if (GetSaver(writer, e, out saver))

                {

                    saver.StartSave(writer, e);

                    saver.EndSave(writer, e);

                }

            }



            #endregion



            private bool GetSaver(GameXmlWriter writer, Element e, out IObjectSaver saver)

            {

                if (!m_savers.TryGetValue(e.Type, out saver))

                {

                    throw new Exception("ERROR: No ObjectSaver for type " + e.Type.ToString());

                }

                return true;

            }



            public void StartSave(GameXmlWriter writer, Element e)

            {

                IObjectSaver saver;

                if (GetSaver(writer, e, out saver))

                {

                    saver.StartSave(writer, e);

                }

            }



            public void EndSave(GameXmlWriter writer, Element e)

            {

                IObjectSaver saver;

                if (GetSaver(writer, e, out saver))

                {

                    saver.EndSave(writer, e);

                }

            }



            protected override bool CanSaveAttribute(string attribute, Element e)

            {

                if (!base.CanSaveAttribute(attribute, e)) return false;

                return m_savers[e.Type].CanSaveAttribute(attribute);

            }



            protected override bool CanSaveTypeName(GameXmlWriter writer, string type, Element e)

            {

                if (!base.CanSaveTypeName(writer, type, e)) return false;

                if (e.Type == ObjectType.Command && e.Fields[FieldDefinitions.IsVerb] && type == "defaultverb") return false;

                return true;

            }



            private interface IObjectSaver

            {

                ObjectType AppliesTo { get; }

                void StartSave(GameXmlWriter writer, Element e);

                void EndSave(GameXmlWriter writer, Element e);

                ObjectSaver ObjectSaver { set; }

                bool CanSaveAttribute(string attribute);

            }



            private abstract class ObjectSaverBase : IObjectSaver

            {

                private List<string> m_ignoreAttributes = new List<string>();



                protected void AddIgnoreField(string field)

                {

                    m_ignoreAttributes.Add(field);

                }



                #region IObjectSaver Members



                public abstract ObjectType AppliesTo { get; }



                public abstract void StartSave(GameXmlWriter writer, Element e);

                public abstract void EndSave(GameXmlWriter writer, Element e);



                public ObjectSaver ObjectSaver

                {

                    get;

                    set;

                }



                public bool CanSaveAttribute(string attribute)

                {

                    if (m_ignoreAttributes.Contains(attribute)) return false;

                    return true;

                }



                #endregion

            }



            private class ObjectElementSaver : ObjectSaverBase

            {

                #region IObjectSaver Members



                public override ObjectType AppliesTo

                {

                    get { return ObjectType.Object; }

                }



                public override void StartSave(GameXmlWriter writer, Element e)

                {

                    writer.WriteStartElement("object");

                    writer.WriteAttributeString("name", e.Name);

                    ObjectSaver.SaveFields(writer, e);

                }



                public override void EndSave(GameXmlWriter writer, Element e)

                {

                    writer.WriteEndElement();

                }



                #endregion

            }



            private class GameElementSaver : ObjectSaverBase

            {

                public GameElementSaver()

                {

                    AddIgnoreField("gamename");

                }



                #region IObjectSaver Members



                public override ObjectType AppliesTo

                {

                    get { return ObjectType.Game; }

                }



                public override void StartSave(GameXmlWriter writer, Element e)

                {

                    writer.WriteStartElement("game");

                    writer.WriteAttributeString("name", e.Fields.GetString("gamename"));

                    ObjectSaver.SaveFields(writer, e);

                }



                public override void EndSave(GameXmlWriter writer, Element e)

                {

                    writer.WriteEndElement();

                }



                #endregion

            }



            private class CommandSaver : ObjectSaverBase

            {

                public CommandSaver()

                {

                    AddIgnoreField("isverb");

                    AddIgnoreField("anonymous");

                }



                #region IObjectSaver Members



                public override ObjectType AppliesTo

                {

                    get { return ObjectType.Command; }

                }



                public override void StartSave(GameXmlWriter writer, Element e)

                {

                    if (e.Fields[FieldDefinitions.IsVerb])

                    {

                        writer.WriteStartElement("verb");

                    }

                    else

                    {

                        writer.WriteStartElement("command");

                    }

                    if (writer.Mode == SaveMode.SavedGame || !e.Fields[FieldDefinitions.Anonymous])

                    {

                        writer.WriteAttributeString("name", e.Name);

                    }

                    ObjectSaver.SaveFields(writer, e);

                }



                public override void EndSave(GameXmlWriter writer, Element e)

                {

                    writer.WriteEndElement();

                }



                #endregion

            }



            private class ExitElementSaver : ObjectSaverBase

            {

                public ExitElementSaver()

                {

                    AddIgnoreField("to");

                    AddIgnoreField("alias");

                    AddIgnoreField("anonymous");

                }



                public override ObjectType AppliesTo

                {

                    get { return ObjectType.Exit; }

                }



                public override void StartSave(GameXmlWriter writer, Element e)

                {

                    writer.WriteStartElement("exit");

                    if (writer.Mode == SaveMode.SavedGame || !e.Fields[FieldDefinitions.Anonymous])

                    {

                        writer.WriteAttributeString("name", e.Name);

                    }

                    if (!string.IsNullOrEmpty(e.Fields[FieldDefinitions.Alias]))

                    {

                        writer.WriteAttributeString("alias", e.Fields[FieldDefinitions.Alias]);

                    }

                    if (e.Fields[FieldDefinitions.To] != null)

                    {

                        writer.WriteAttributeString("to", e.Fields[FieldDefinitions.To].Name);

                    }

                    ObjectSaver.SaveFields(writer, e);

                }



                public override void EndSave(GameXmlWriter writer, Element e)

                {

                    writer.WriteEndElement();

                }

            }



            private class TurnScriptElementSaver : ObjectSaverBase

            {

                public TurnScriptElementSaver()

                {

                    AddIgnoreField("anonymous");

                }



                public override ObjectType AppliesTo

                {

                    get { return ObjectType.TurnScript; }

                }



                public override void StartSave(GameXmlWriter writer, Element e)

                {

                    writer.WriteStartElement("turnscript");

                    if (writer.Mode == SaveMode.SavedGame || !e.Fields[FieldDefinitions.Anonymous])

                    {

                        writer.WriteAttributeString("name", e.Name);

                    }

                    ObjectSaver.SaveFields(writer, e);

                }



                public override void EndSave(GameXmlWriter writer, Element e)

                {

                    writer.WriteEndElement();

                }

            }



        }

    }

}