using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Drawing;
using System.Xml;
using System.Xml.Serialization;
using System.Resources;
using System.IO;

namespace SpriteLibrary
{
    internal struct ImageStruct
    {
        internal Image TheImage;
        internal string ImageName;
    }

    /// <summary>
    /// Store Sprite information in a database.  You can preload your database with sprite definitions, and then
    /// create the sprites as needed.  This can drastically reduce the initial load time of a game or something.
    /// Though, what it really does is spread out the load time.  It still takes the same amount of time to
    /// load all the sprites, it just loads them on-demand.  Using a dictionary often hides any load time issues.
    /// </summary>
    public class SpriteDatabase
    {
        /// <summary>
        /// This is the list of SpriteInfo records that the database knows about.  You can create your own list,
        /// modify this list, or whatever.  The database has some reasonable functions for loading and saving a
        /// sprite database.
        /// </summary>
        public List<SpriteInfo> SpriteInfoList = new List<SpriteInfo>();
        List<ImageStruct> TheImages = new List<ImageStruct>();
        ResourceManager myResourceManager = null;
        string Filename = "";
        Size SnapGridSize = new Size(5, 5);

        /// <summary>
        /// The sprite database instantiation function.  The filename can either be a file on the computer or it
        /// can be the string name of a resource (the filename without the extension.  If your file is accessed
        /// by Properties.Resources.MySprites, the "filename" would be "MySprites")
        /// </summary>
        /// <param name="theResourceManager">The ResourceManager for your project.  Usually 
        /// Properties.Resources.ResourceManager</param>
        /// <param name="filename">Either a path and file (like: @"c:\users\me\Desktop\myfile.xml") or 
        /// the name of a resource (like: "myfile")</param>
        public SpriteDatabase(ResourceManager theResourceManager, string filename)
        {
            myResourceManager = theResourceManager;
            Filename = filename;
            Load();
        }

        internal void Load()
        {
            LoadSpriteInfo();
        }

        internal ResourceManager GetResourceManager()
        {
            return myResourceManager;
        }

        /// <summary>
        /// Tell the database to save the sprite definitions.  Use this while you are creating your game.
        /// When you are done, you will usually want to take your sprite definition file and add it to the
        /// resources of your game.  The resources cannot be saved to, so you cannot continue to add new sprites
        /// once you are loading and saving them from a resources file.  But, the resources file is included with
        /// the program when you build it.
        /// </summary>
        public void Save()
        {
            if(!DoesResourceExist(Filename))
            {
                //we will try to save it as a file
                try
                {
                    WriteToXmlFile<List<SpriteInfo>>(Filename, SpriteInfoList);
                }
                catch (Exception e)
                {
                    throw new Exception("SpriteDatabase failed to save: Filename:" + Filename +"\n" + "ERROR: " + e.ToString(), e);
                }
            }
        }

        public void SetSnapGridSize(Size GridSize)
        {
            if (GridSize.Width <= 0) return;
            if (GridSize.Height <= 0) return;
            if (GridSize.Width > 500) return;
            if (GridSize.Height > 500) return;
            SnapGridSize = GridSize;
        }

        //*******************************
        //****  Sprite Info Functions ***
        //*******************************
        #region SpriteInfo Functions
        void LoadSpriteInfo()
        {
            if (DoesResourceExist(Filename))
            {
                //This clears out the old list, as it gets replaced.
                SpriteInfoList = LoadObjectFromXmlFile<List<SpriteInfo>>(Filename, myResourceManager);
            }
            else
            {
                //try loading it from an actual filename
                if (File.Exists(Filename))
                    SpriteInfoList = ReadFromXmlFile<List<SpriteInfo>>(Filename);
            }
            //If neither works, we end up with an empty file.
            //If it fails, SpriteInfoList is null and things explode.
            if (SpriteInfoList == null)
                SpriteInfoList = new List<SpriteInfo>(); //make an empty one so things do not explode.
        }

        public List<string> SpriteNames()
        {
            List<string> theNames = new List<string>();
            foreach (SpriteInfo si in SpriteInfoList)
            {
                theNames.Add(si.SpriteName);
            }
            return theNames;
        }

        internal bool DoesResourceExist(string resourcename)
        {
            if (myResourceManager == null) return false;
            if (myResourceManager.GetObject(resourcename) != null)
                return true;
            return false;
        }

        public void OpenEditWindow(int FirstItemIndex=-1)
        {
            SpriteEntryForm SEF = new SpriteEntryForm(this, SpriteInfoList, SnapGridSize);
            SEF.ShowDialog();
            //Use the updated list returned from the form.
            SpriteInfoList.Clear();
            SpriteInfoList.AddRange(SEF.GetUpdatedList());
        }
        #endregion
        
        #region General Functions
        public Image GetImageFromName(string Name, bool UseSmartImages)
        {
            Image MyImage = null;
            if (UseSmartImages)
            {
                foreach (ImageStruct IS in TheImages)
                {
                    if (IS.ImageName.Equals(Name, StringComparison.InvariantCultureIgnoreCase))
                    {
                        MyImage = IS.TheImage;
                        break;
                    }
                }
            }
            if (MyImage == null)
            {
                ResourceManager rm = myResourceManager;
                MyImage = (Bitmap)rm.GetObject(Name);
                if (UseSmartImages)
                {
                    ImageStruct NewIS = new ImageStruct();
                    NewIS.ImageName = Name;
                    NewIS.TheImage = MyImage;
                    TheImages.Add(NewIS);
                }
            }
            return MyImage;
        }

        public Sprite SmartDuplicateSprite(SpriteController theController, string SpriteName, bool UseSmartImages = true)
        {
            Sprite DestSprite = theController.DuplicateSprite(SpriteName);
            if (DestSprite != null) return DestSprite;

            //If it does not exist, make it
            foreach (SpriteInfo SI in SpriteInfoList)
            {
                if (SI.SpriteName == SpriteName)
                {
                    SI.CreateSprite(theController, this);
                    return theController.DuplicateSprite(SpriteName);
                }
            }
            return null;
        }
        #endregion

        #region Generic XML Funcs

        /// <summary>
        /// Load in an XML serialized item from the specified ResourceManager.  You will usually make one of these by
        /// creating an object and using <see cref="SpriteDatabase.WriteToXmlFile">SpriteDatabase.WriteToXmlFile</see> to
        /// save it to a file on your desktop.  Then you can drag and drop that file into your project and then use this 
        /// LoadObjectFromXmlFile function.
        /// </summary>
        /// <typeparam name="T">The type of object to load.  It could be something as simple as an int, a class, or a list of classes.</typeparam>
        /// <param name="XMLResourceToLoad">The resource item to load.  If you would access it like: properties.resources.myFile,
        /// the correct value to put here would be "myFile"</param>
        /// <param name="MyManager">The resource manager.  Usually Properties.Resources.ResourceManager</param>
        /// <returns>An object of the value you specified.  Or null if it fails.</returns>
        public static T LoadObjectFromXmlFile<T>(string XMLResourceToLoad, ResourceManager MyManager) where T : new()
        {
            //Load in the sprite data
            XmlSerializer serializer = new XmlSerializer(typeof(T));

            // Retrieves String and Image resources.
            object titem = MyManager.GetObject(XMLResourceToLoad);
            byte[] item = (byte[])System.Text.Encoding.UTF8.GetBytes((string)titem);

            try
            {
                return (T)serializer.Deserialize(new MemoryStream(item));
            }
            finally
            {

            }
        }

        /// <summary>
        /// Writes the given object instance to an XML file.
        /// <para>Only Public properties and variables will be written to the file. These can be any type though, even other classes.</para>
        /// <para>If there are public properties/variables that you do not want written to the file, decorate them with the [XmlIgnore] attribute.</para>
        /// <para>Object type must have a parameterless constructor.</para>
        /// </summary>
        /// <typeparam name="T">The type of object being written to the file.</typeparam>
        /// <param name="filePath">The file path to write the object instance to.</param>
        /// <param name="objectToWrite">The object instance to write to the file.</param>
        internal static void WriteToXmlFile<T>(string filePath, T objectToWrite) where T : new()
        {
            TextWriter writer = null;
            try
            {
                var serializer = new XmlSerializer(typeof(T));
                writer = new StreamWriter(filePath);
                serializer.Serialize(writer, objectToWrite);
            }
            finally
            {
                if (writer != null)
                    writer.Close();
            }
        }

        /// <summary>
        /// Reads an object instance from an XML file.
        /// <para>Object type must have a parameterless constructor.</para>
        /// </summary>
        /// <typeparam name="T">The type of object to read from the file.</typeparam>
        /// <param name="filePath">The file path to read the object instance from.</param>
        /// <returns>Returns a new instance of the object read from the XML file.</returns>
        public static T ReadFromXmlFile<T>(string filePath) where T : new()
        {
            TextReader reader = null;
            try
            {
                var serializer = new XmlSerializer(typeof(T));
                reader = new StreamReader(filePath);
                return (T)serializer.Deserialize(reader);
            }
            finally
            {
                if (reader != null)
                    reader.Close();
            }
        }

        public static string WriteToXMLString<T>(T toSerialize)
        {
            XmlSerializer xmlSerializer = new XmlSerializer(toSerialize.GetType());

            using (StringWriter textWriter = new StringWriter())
            {
                xmlSerializer.Serialize(textWriter, toSerialize);
                return textWriter.ToString();
            }
        }
        public static T ReadFromXmlString<T>(string toDeserialize) where T : new()
        {
            XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));
            using (StringReader textReader = new StringReader(toDeserialize))
                return (T)xmlSerializer.Deserialize(textReader);
        }

        public static T CloneByXMLSerializing<T>(T ObjectToClone)
        {
            XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));
            string dest;
            using (StringWriter textWriter = new StringWriter())
            {
                xmlSerializer.Serialize(textWriter, ObjectToClone);
                dest = textWriter.ToString();
            }

            using (StringReader textReader = new StringReader(dest))
                return (T)xmlSerializer.Deserialize(textReader);
        }
        #endregion
    }

}