using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
using Microsoft.Xna.Framework.Net;
using Microsoft.Xna.Framework.Storage;

namespace BasicEffectTest1
{
    /// <summary>
    /// This is the main type for your game
    /// </summary>
    public class Game1 : Microsoft.Xna.Framework.Game
    {
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;


        // モデルの宣言
        private Model myModel;

        // テクスチャの宣言
        private Texture2D myTexture;

        // カスタムエフェクトの宣言
        private Effect myEffect;


        // カスタム頂点構造体の定義
        public struct VertexPositionColorTextureCoordinateNormal
        {
            public Vector3 Position;
            public float Color;
            public Vector2 TextureCoordinate;
            public Vector3 Normal;

            public VertexPositionColorTextureCoordinateNormal(Vector3 position, float color, Vector2 textureCoordinate, Vector3 normal)
            {
                this.Position = position;
                this.Color = color;
                this.TextureCoordinate = textureCoordinate;
                this.Normal = normal;
            }

            public static readonly VertexElement[] VertexElements
                = {
                new VertexElement(
                    0,
                    0,
                    VertexElementFormat.Vector3,
                    VertexElementMethod.Default,
                    VertexElementUsage.Position,
                    0
                ),

                new VertexElement(
                    0,
                    sizeof(float) * 3,
                    VertexElementFormat.Color,
                    VertexElementMethod.Default,
                    VertexElementUsage.Color,
                    0
                ),

                new VertexElement(
                    0,
                    sizeof(float) * (3 + 1),
                    VertexElementFormat.Vector2,
                    VertexElementMethod.Default,
                    VertexElementUsage.TextureCoordinate,
                    0
                ),

                new VertexElement(
                    0, 
                    sizeof(float) * (3 + 1 + 2),
                    VertexElementFormat.Vector3,
                    VertexElementMethod.Default,
                    VertexElementUsage.Normal,
                    0
                )
            };
        }

        // カスタム頂点の宣言
        private VertexPositionColorTextureCoordinateNormal[] verData = new VertexPositionColorTextureCoordinateNormal[4];


        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
        }

        /// <summary>
        /// Allows the game to perform any initialization it needs to before starting to run.
        /// This is where it can query for any required services and load any non-graphic
        /// related content.  Calling base.Initialize will enumerate through any components
        /// and initialize them as well.
        /// </summary>
        protected override void Initialize()
        {
            // TODO: Add your initialization logic here

            base.Initialize();
        }

        /// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
        {
            // Create a new SpriteBatch, which can be used to draw textures.
            spriteBatch = new SpriteBatch(GraphicsDevice);

            // TODO: use this.Content to load your game content here

            // モデルの呼び出し
            myModel = Content.Load<Model>("MyModel");

            // テクスチャの呼び出し
            myTexture = Content.Load<Texture2D>("SpearMan01Attack01");

            // カスタムエフェクトの呼び出し
            myEffect = Content.Load<Effect>("BasicEffect");
        }

        /// <summary>
        /// UnloadContent will be called once per game and is the place to unload
        /// all content.
        /// </summary>
        protected override void UnloadContent()
        {
            // TODO: Unload any non ContentManager content here
        }

        /// <summary>
        /// Allows the game to run logic such as updating the world,
        /// checking for collisions, gathering input, and playing audio.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Update(GameTime gameTime)
        {
            // Allows the game to exit
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                this.Exit();

            // TODO: Add your update logic here

            base.Update(gameTime);
        }

        /// <summary>
        /// This is called when the game should draw itself.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.CornflowerBlue);

            // TODO: Add your drawing code here


            // ワールド座標変換行列
            Matrix world = Matrix.CreateScale(100.0f) *
                Matrix.CreateRotationX(MathHelper.ToRadians(90)) *
                Matrix.CreateTranslation(Vector3.Zero);

            // ビュー座標変換行列
            Matrix view = Matrix.CreateLookAt(
                new Vector3(0, 0, 400),
                Vector3.Zero,
                Vector3.Up);

            // 射影変換行列
            Viewport viewport = graphics.GraphicsDevice.Viewport;
            float aspectRatio = (float)viewport.Width / (float)viewport.Height;
            Matrix projection = Matrix.CreatePerspectiveFieldOfView(
                MathHelper.PiOver4,
                aspectRatio,
                10, 1000);

            // ワールド、ビュー、射影変換行列の設定
            myEffect.Parameters["World"].SetValue(world);
            myEffect.Parameters["View"].SetValue(view);
            myEffect.Parameters["Projection"].SetValue(projection);

            // 描画モードを「Textured」に設定（BasicEffect Shader付属ドキュメント参照）
            myEffect.Parameters["ShaderIndex"].SetValue(2);
            myEffect.Parameters["BasicTexture"].SetValue(myTexture);


            // GraphicDeviceに頂点の型を設定する
            graphics.GraphicsDevice.VertexDeclaration = new VertexDeclaration(
                GraphicsDevice,
                VertexPositionColorTextureCoordinateNormal.VertexElements);


            foreach (ModelMesh mesh in myModel.Meshes)
            {
                // 頂点バッファデータのコピーを取得する
                mesh.VertexBuffer.GetData<VertexPositionColorTextureCoordinateNormal>(verData);

                // テクスチャ座標を書き替える（テスト）
                verData[0].TextureCoordinate = new Vector2(0.3f, 0.3f);

                // 書き替えたデータをセットする（エラーになる）
                // mesh.VertexBuffer.SetData<VertexPositionColorTextureCoordinateNormal>(verData);


                foreach (ModelMeshPart modelMeshPart in mesh.MeshParts)
                {
                    // カスタムエフェクトを適用する
                    modelMeshPart.Effect = myEffect;

                    // エフェクトを開始する
                    myEffect.Begin();
                    foreach (EffectPass pass in myEffect.CurrentTechnique.Passes)
                    {
                        // エフェクトパスを開始する
                        pass.Begin();

                        // 頂点を描画する
                        graphics.GraphicsDevice.DrawUserPrimitives<VertexPositionColorTextureCoordinateNormal>(
                            PrimitiveType.TriangleStrip,
                            verData,
                            modelMeshPart.StreamOffset,
                            modelMeshPart.PrimitiveCount);

                        // エフェクトパスを終了する
                        pass.End();
                    }

                    // エフェクトを終了する
                    myEffect.End();
                }
                
                // モデルを描画する
                // mesh.Draw();
            }


            base.Draw(gameTime);
        }
    }
}