using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Windows;
using System.Windows.Media.Imaging;
using JD.Serialization;
using JD.WPF.Extensions;

namespace JD.SceneExplorer.Utils
{
    /// <summary>
    /// Manager allowing to get the editor icon associated to an actor tag. 
    /// </summary>
    public class EditorIconsManager
    {
        private static readonly EditorIconsManager m_instance;

        private string m_dataBranch;
        private BitmapImage m_allIconsMasterImage;
        private List<EditorIcon> m_allIcons;
        private bool m_initialized;

        static EditorIconsManager()
        {
            m_instance = new EditorIconsManager();
        }

        public EditorIconsManager()
        {
            m_dataBranch = null;
            m_allIconsMasterImage = null;
            m_initialized = false;
            m_allIcons = new List<EditorIcon>();
        }

        public static EditorIconsManager Instance { get { return m_instance; } }
        public bool Initialized { get { return m_initialized; } }
        public bool HasTags { get { return m_allIcons != null && m_allIcons.Count > 0; } }

        public bool Init(string dataBranch)
        {
            if (String.IsNullOrEmpty(dataBranch))
                return false;

            m_dataBranch = dataBranch;
            string pathToEditorIcons = m_dataBranch.TrimEnd('\\') + "\\EngineData\\editor\\icons\\tagIcons.tga";
            if (!File.Exists(pathToEditorIcons))
                return false;

            m_allIconsMasterImage = TargaImageExtensions.LoadTargaImageAsBitmapImage(pathToEditorIcons);
            if (m_allIconsMasterImage == null)
                return false;

            string pathToEditorIconsAtlas = m_dataBranch.TrimEnd('\\') + "\\EngineData\\editor\\icons\\tagIcons.atl";
            AtlasList allAtlas = new AtlasList(pathToEditorIconsAtlas);

            string pathToEditorIconsTagAssociation = m_dataBranch.TrimEnd('\\') + "\\EngineData\\editor\\icons\\tagIcons.tia";
            TagIconAssociation allTagIconAssociations = new TagIconAssociation(pathToEditorIconsTagAssociation);

            var allIconsEnum = from atlas in allAtlas.AllAtlas
                               from tagIconAssoc in allTagIconAssociations.AllTagIcons
                               where atlas.Index == tagIconAssoc.AtlasIndex
                               select new EditorIcon(atlas, tagIconAssoc, m_allIconsMasterImage);
            m_allIcons = allIconsEnum.ToList();

            m_initialized = true;
            return true;
        }

        public BitmapSource GetIconLocationFromTag(string tag)
        {
            if (!HasTags)
                return null;

            tag = tag.ToLower();
            EditorIcon icon = m_allIcons.FirstOrDefault(editorIcon => editorIcon.Tag == tag);
            if (icon != null)
                return icon.Image;
            return null;
        }

        public bool IsLowPriorityTag(string tag)
        {
            if (!HasTags)
                return false;

            tag = tag.ToLower();
            EditorIcon icon = m_allIcons.FirstOrDefault(editorIcon => editorIcon.Tag == tag);
            if (icon != null)
                return icon.LowPriority;
            return false;
        }

        public BitmapSource GetIconLocationFromTags(IEnumerable<string> tags)
        {
            BitmapSource imageLocation = null;
            BitmapSource lowPrioImageLocation = null;
            foreach (string tag in tags)
            {
                imageLocation = GetIconLocationFromTag(tag);
                if (imageLocation != null)
                {
                    if (IsLowPriorityTag(tag))
                    {
                        if(lowPrioImageLocation == null)
                            lowPrioImageLocation = imageLocation;
                    }
                    else
                    {
                        break;
                    }
                }
            }

            if (imageLocation != null)
                return imageLocation;
            else
                return lowPrioImageLocation;
        }

        private class EditorIcon
        {
            private readonly string m_tag;
            private readonly BitmapSource m_image;
            private readonly bool m_lowPriority;

            public EditorIcon(Atlas iconAtlas, TagIcon tagIcon, BitmapImage imageSource)
            {
                if (iconAtlas.Index != tagIcon.AtlasIndex)
                    throw new InvalidOperationException("Atlas index is not matching. ");

                m_tag = tagIcon.Tag.ToLower();
                m_lowPriority = tagIcon.LowPriority;

                Int32Rect imageSelection = new Int32Rect();
                imageSelection.X = (int) (imageSource.PixelWidth * iconAtlas.Uv[0].Uv.X);
                imageSelection.Y = (int) (imageSource.PixelHeight * iconAtlas.Uv[0].Uv.Y);
                imageSelection.Width = (int) (imageSource.PixelWidth * (iconAtlas.Uv[1].Uv.X - iconAtlas.Uv[0].Uv.X) );
                imageSelection.Height = (int) (imageSource.PixelHeight * (iconAtlas.Uv[1].Uv.Y - iconAtlas.Uv[0].Uv.Y) );

                m_image = new CroppedBitmap(imageSource, imageSelection);
            }

            public string Tag { get { return m_tag; } }

            /// <summary>
            /// Bitmap source used to display image.
            /// </summary>
            public BitmapSource Image { get { return m_image; } }

            public bool LowPriority { get { return m_lowPriority; } }
        }
    }
}