using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using System;
using Barotrauma.IO;
using System.Linq;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace Barotrauma
{
    public partial class Sprite
    {
        private class TextureRefCounter
        {
            public Texture2D Texture;
            public int RefCount;
        }

        private readonly static Dictionary<Identifier, TextureRefCounter> textureRefCounts = new Dictionary<Identifier, TextureRefCounter>();
        
        private bool cannotBeLoaded;

        protected volatile bool loadingAsync = false;
        
        protected Texture2D texture { get; private set; }
        public Texture2D Texture
        {
            get
            {
                EnsureLazyLoaded();
                return texture;
            }
        }

        private string disposeStackTrace;
        
        public bool Loaded
        {
            get { return texture != null && !cannotBeLoaded; }
        }

        public Sprite(Sprite other) : this(other.texture, other.sourceRect, other.offset, other.rotation, other.FilePath.Value)
        {
            Compress = other.Compress;
            size = other.size;
            effects = other.effects;
        }

        public Sprite(Texture2D texture, Rectangle? sourceRectangle, Vector2? newOffset, float newRotation = 0.0f, string path = null)
        {
            this.texture = texture;
            sourceRect = sourceRectangle ?? new Rectangle(0, 0, texture.Width, texture.Height);
            offset = newOffset ?? Vector2.Zero;
            size = new Vector2(sourceRect.Width, sourceRect.Height);
            origin = Vector2.Zero;
            effects = SpriteEffects.None;
            rotation = newRotation;
            FilePath = ContentPath.FromRaw(path);
            AddToList(this);
            if (!string.IsNullOrEmpty(path))
            {
                Identifier fullPath = Path.GetFullPath(path).CleanUpPathCrossPlatform(correctFilenameCase: false).ToIdentifier();
                lock (list)
                {
                    if (!textureRefCounts.TryAdd(fullPath, new TextureRefCounter { RefCount = 1, Texture = texture }))
                    {
                        textureRefCounts[fullPath].RefCount++;
                    }
                }
            }
        }

        partial void LoadTexture(ref Vector4 sourceVector, ref bool shouldReturn)
        {
            texture = LoadTexture(FilePath.Value, Compress);

            if (texture == null)
            {
                shouldReturn = true;
                return;
            }

            if (sourceVector.Z == 0.0f) sourceVector.Z = texture.Width;
            if (sourceVector.W == 0.0f) sourceVector.W = texture.Height;
        }

        public async Task LazyLoadAsync()
        {
            await Task.Yield();
            if (!LazyLoad || texture != null || cannotBeLoaded || loadingAsync) { return; }
            EnsureLazyLoaded(isAsync: true);
        }

        public void EnsureLazyLoaded(bool isAsync = false)
        {
            if (!LazyLoad || texture != null || cannotBeLoaded || loadingAsync) { return; }
            loadingAsync = isAsync;

            Vector4 sourceVector = Vector4.Zero;
            bool temp2 = false;
            int maxLoadRetries = File.Exists(FilePath) ? 3 : 0;
            for (int i = 0; i <= maxLoadRetries; i++)
            {
                try
                {
                    LoadTexture(ref sourceVector, ref temp2);
                }
                catch (System.IO.IOException)
                {
                    if (i == maxLoadRetries || !File.Exists(FilePath)) { throw; }
                    DebugConsole.NewMessage("Loading sprite \"" + FilePath + "\" failed, retrying in 250 ms...");
                    System.Threading.Thread.Sleep(500);
                }
            }

            if (sourceRect.Width == 0 && sourceRect.Height == 0)
            {
                sourceRect = new Rectangle((int)sourceVector.X, (int)sourceVector.Y, (int)sourceVector.Z, (int)sourceVector.W);
                size = SourceElement.GetAttributeVector2("size", Vector2.One);
                size.X *= sourceRect.Width;
                size.Y *= sourceRect.Height;
                RelativeOrigin = SourceElement.GetAttributeVector2("origin", new Vector2(0.5f, 0.5f));
            }
            if (texture == null)
            {
                cannotBeLoaded = true;
            }
        }

        public void ReloadTexture()
        {
            var oldTexture = texture;
            texture.Dispose();
            texture = TextureLoader.FromFile(FilePath.Value, Compress);
            Identifier pathKey = FullPath.ToIdentifier();
            if (textureRefCounts.ContainsKey(pathKey))
            {
                textureRefCounts[pathKey].Texture = texture;
            }
            foreach (Sprite sprite in LoadedSprites)
            {
                if (sprite.texture == oldTexture)
                {
                    sprite.texture = texture;
                }
            }
        }

        partial void CalculateSourceRect()
        {
            sourceRect = new Rectangle(0, 0, texture.Width, texture.Height);
        }

        public static Texture2D LoadTexture(string file, bool compress = true)
        {
            if (string.IsNullOrWhiteSpace(file))
            {
                Texture2D t = null;
                CrossThread.RequestExecutionOnMainThread(() =>
                {
                    t = new Texture2D(GameMain.GraphicsDeviceManager.GraphicsDevice, 1, 1);
                });
                return t;
            }
            Identifier fullPath = Path.GetFullPath(file).CleanUpPathCrossPlatform(correctFilenameCase: false).ToIdentifier();
            lock (list)
            {
                if (textureRefCounts.ContainsKey(fullPath))
                {
                    textureRefCounts[fullPath].RefCount++;
                    return textureRefCounts[fullPath].Texture;
                }
            }

            if (File.Exists(file))
            {
                if (!ToolBox.IsProperFilenameCase(file))
                {
#if DEBUG
                    DebugConsole.ThrowError("Texture file \"" + file + "\" has incorrect case!");
#endif
                }

                Texture2D newTexture = TextureLoader.FromFile(file, compress);
                lock (list)
                {
                    if (!textureRefCounts.TryAdd(fullPath,
                            new TextureRefCounter { RefCount = 1, Texture = newTexture }))
                    {
                        CrossThread.RequestExecutionOnMainThread(() => newTexture.Dispose());
                        textureRefCounts[fullPath].RefCount++;
                        return textureRefCounts[fullPath].Texture;
                    }
                }
                return newTexture;
            }
            else
            {
                DebugConsole.ThrowError($"Sprite \"{file}\" not found!");
                DebugConsole.Log(Environment.StackTrace.CleanupStackTrace());
            }

            return null;
        }

        public void Draw(ISpriteBatch spriteBatch, Vector2 pos, float rotate = 0.0f, float scale = 1.0f, SpriteEffects spriteEffect = SpriteEffects.None)
        {
            this.Draw(spriteBatch, pos, Color.White, rotate, scale, spriteEffect);
        }

        public void Draw(ISpriteBatch spriteBatch, Vector2 pos, Color color, float rotate = 0.0f, float scale = 1.0f, SpriteEffects spriteEffect = SpriteEffects.None, float? depth = null)
        {
            this.Draw(spriteBatch, pos, color, this.origin, rotate, new Vector2(scale, scale), spriteEffect, depth);
        }

        public void Draw(ISpriteBatch spriteBatch, Vector2 pos, Color color, Vector2 origin, float rotate = 0.0f, float scale = 1.0f, SpriteEffects spriteEffect = SpriteEffects.None, float? depth = null)
        {
            this.Draw(spriteBatch, pos, color, origin, rotate, new Vector2(scale, scale), spriteEffect, depth);
        }

        public virtual void Draw(ISpriteBatch spriteBatch, Vector2 pos, Color color, Vector2 origin, float rotate, Vector2 scale, SpriteEffects spriteEffect = SpriteEffects.None, float? depth = null)
        {
            if (Texture == null) { return; }
            //DrawSilhouette(spriteBatch, pos, origin, rotate, scale, spriteEffect, depth);
            spriteBatch.Draw(texture, pos + offset, sourceRect, color, rotation + rotate, origin, scale, spriteEffect, depth ?? this.depth);
        }

        /// <summary>
        /// Creates a silhouette for the sprite (or outline if the sprite is rendered on top of it)
        /// </summary>
        public void DrawSilhouette(SpriteBatch spriteBatch, Vector2 pos, Vector2 origin, float rotate, Vector2 scale, SpriteEffects spriteEffect = SpriteEffects.None, float? depth = null)
        {
            if (Texture == null) { return; }
            for (int x = -1; x <= 1; x += 2)
            {
                for (int y = -1; y <= 1; y += 2)
                {
                    spriteBatch.Draw(texture, pos + offset + new Vector2(x, y), sourceRect, Color.Black, rotation + rotate, origin, scale, spriteEffect, (depth ?? this.depth) + 0.01f);
                }
            }
        }

        public void DrawTiled(ISpriteBatch spriteBatch, Vector2 position, Vector2 targetSize,
            Color? color = null, Vector2? startOffset = null, Vector2? textureScale = null, float? depth = null)
        {
            if (Texture == null) { return; }
            //Init optional values
            Vector2 drawOffset = startOffset ?? Vector2.Zero;
            Vector2 scale = textureScale ?? Vector2.One;
            Color drawColor = color ?? Color.White;

            bool flipHorizontal = (effects & SpriteEffects.FlipHorizontally) != 0;
            bool flipVertical = (effects & SpriteEffects.FlipVertically) != 0;

            //wrap the drawOffset inside the sourceRect
            drawOffset.X = (drawOffset.X / scale.X) % sourceRect.Width;
            drawOffset.Y = (drawOffset.Y / scale.Y) % sourceRect.Height;

            Vector2 flippedDrawOffset = Vector2.Zero;
            if (flipHorizontal)
            {
                float diff = targetSize.X % (sourceRect.Width * scale.X);
                flippedDrawOffset.X = (sourceRect.Width * scale.X - diff) / scale.X;
                flippedDrawOffset.X =
                    MathUtils.NearlyEqual(flippedDrawOffset.X, MathF.Round(flippedDrawOffset.X)) ?
                    MathF.Round(flippedDrawOffset.X) : flippedDrawOffset.X;
            }
            if (flipVertical)
            {
                float diff = targetSize.Y % (sourceRect.Height * scale.Y);
                flippedDrawOffset.Y = (sourceRect.Height * scale.Y - diff) / scale.Y;
                flippedDrawOffset.Y =
                    MathUtils.NearlyEqual(flippedDrawOffset.Y, MathF.Round(flippedDrawOffset.Y)) ?
                    MathF.Round(flippedDrawOffset.Y) : flippedDrawOffset.Y;
            }
            drawOffset += flippedDrawOffset;

            //how many times the texture needs to be drawn on the x-axis
            int xTiles = (int)Math.Ceiling((targetSize.X + drawOffset.X * scale.X) / (sourceRect.Width * scale.X));
            //how many times the texture needs to be drawn on the y-axis
            int yTiles = (int)Math.Ceiling((targetSize.Y + drawOffset.Y * scale.Y) / (sourceRect.Height * scale.Y));

            //where the current tile is being drawn;
            Vector2 currDrawPosition = position - drawOffset;
            //which part of the texture we are currently drawing
            Rectangle texPerspective = sourceRect;

            
            for (int x = 0; x < xTiles; x++)
            {
                texPerspective.X = sourceRect.X;
                texPerspective.Width = sourceRect.Width;
                texPerspective.Height = sourceRect.Height;

                //offset to the left, draw a partial slice
                if (currDrawPosition.X < position.X)
                {
                    float diff = (position.X - currDrawPosition.X);
                    currDrawPosition.X += diff;
                    texPerspective.Width -= (int)diff;
                    if (!flipHorizontal)
                    {
                        texPerspective.X += (int)diff;
                    }
                    if (!flipVertical)
                    {
                        texPerspective.Y += (int)diff;
                    }
                }
                //drawing an offset flipped sprite, need to draw an extra slice to the left side
                if (currDrawPosition.X > position.X && x == 0)
                {
                    if (flipHorizontal)
                    {
                        int sliceWidth = (int)((currDrawPosition.X - position.X) * scale.X);

                        Vector2 slicePos = currDrawPosition;
                        slicePos.X = position.X;
                        Rectangle sliceRect = texPerspective;
                        sliceRect.X = SourceRect.X;
                        sliceRect.Width = (int)(sliceWidth / scale.X);
                        
                        if (flipVertical)
                        {
                            slicePos.Y += flippedDrawOffset.Y;
                        }
                        
                        spriteBatch.Draw(texture, slicePos, sliceRect, drawColor, rotation, Vector2.Zero, scale, effects, depth ?? this.depth);                        
                        currDrawPosition.X = slicePos.X + sliceWidth;
                    }
                }
                //make sure the rightmost tiles don't go over the right side
                if (x == xTiles - 1)
                {
                    int diff = (int)(((currDrawPosition.X + texPerspective.Width * scale.X) - (position.X + targetSize.X)) / scale.X);
                    texPerspective.Width -= diff;
                    if (flipHorizontal)
                    {
                        texPerspective.X += diff;
                    }
                }
                
                currDrawPosition.Y = position.Y - drawOffset.Y;

                for (int y = 0; y < yTiles; y++)
                {
                    texPerspective.Y = sourceRect.Y;
                    texPerspective.Height = sourceRect.Height;

                    //offset above the top, draw a partial slice
                    if (currDrawPosition.Y < position.Y)
                    {
                        float diff = (position.Y - currDrawPosition.Y);
                        currDrawPosition.Y += diff;
                        texPerspective.Height -= (int)diff;
                        if (!flipVertical)
                        {
                            texPerspective.Y += (int)diff;
                        }
                    }

                    //drawing an offset flipped sprite, need to draw an extra slice to the top
                    if (currDrawPosition.Y > position.Y && y == 0)
                    {
                        if (flipVertical)
                        {
                            int sliceHeight = (int)((currDrawPosition.Y - position.Y) * scale.Y);

                            Vector2 slicePos = currDrawPosition;
                            slicePos.Y = position.Y;
                            Rectangle sliceRect = texPerspective;
                            sliceRect.Y = SourceRect.Y;
                            sliceRect.Height = (int)(sliceHeight / scale.Y);

                            spriteBatch.Draw(texture, slicePos, sliceRect, drawColor, rotation, Vector2.Zero, scale, effects, depth ?? this.depth);

                            currDrawPosition.Y = slicePos.Y + sliceHeight;
                        }
                    }

                    //make sure the bottommost tiles don't go over the bottom
                    if (y == yTiles - 1)
                    {
                        int diff = (int)(((currDrawPosition.Y + texPerspective.Height * scale.Y) - (position.Y + targetSize.Y)) / scale.Y);
                        texPerspective.Height -= diff;
                        if (flipVertical)
                        {
                            texPerspective.Y += diff;
                        }
                    }

                    spriteBatch.Draw(texture, currDrawPosition,
                        texPerspective, drawColor, rotation, Vector2.Zero, scale, effects, depth ?? this.depth);

                    currDrawPosition.Y += texPerspective.Height * scale.Y;
                }

                currDrawPosition.X += texPerspective.Width * scale.X;
            }
        }

        partial void DisposeTexture()
        {
            disposeStackTrace = Environment.StackTrace;
            if (texture != null)
            {
                //check if another sprite is using the same texture
                lock (list)
                {
                    if (!FilePath.IsNullOrEmpty()) //file can be empty if the sprite is created directly from a Texture2D instance
                    {
                        Identifier pathKey = FullPath.ToIdentifier();
                        if (!pathKey.IsEmpty && textureRefCounts.ContainsKey(pathKey))
                        {
                            textureRefCounts[pathKey].RefCount--;
                            if (textureRefCounts[pathKey].RefCount <= 0)
                            {
                                textureRefCounts.Remove(pathKey);
                            }
                            else
                            {
                                texture = null;
                                FilePath = ContentPath.Empty;
                                return;
                            }
                        }
                    }
                }

                //if not, free the texture
                CrossThread.RequestExecutionOnMainThread(() =>
                {
                    texture.Dispose();
                });
                texture = null;
            }
        }
    }
}