//-----------------------------------------------------------------------------
// TiledSprites.cs
//
// Microsoft XNA Community Game Platform
// Copyright (C) Microsoft Corporation. All rights reserved.
//-----------------------------------------------------------------------------

using System;
using System.Collections.Generic;

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Media;


namespace TiledSprites
{
    /// <summary>
    /// This sample showcases a variety of common sprite operations
    /// using SpriteBatch
    /// </summary>
    public class TiledSpritesGame : Game
    {
        /// <summary>
        /// Some tiles based on included media
        /// </summary>
        public enum TileName : int
        {
            Empty = 0,
            Base = 1,
            Detail1 = 2,
            Detail2 = 3,
            Detail3 = 4,
            Detail4 = 5,
            SoftDetail1 = 6,
            SoftDetail2 = 7,
            SoftDetail3 = 8,
            SoftDetail4 = 9,
            Rocks1 = 10,
            Rocks2 = 11,
            Rocks3 = 12,
            Rocks4 = 13,
            Clouds = 14
        }

        private const float MovementRate = 500f;
        private const float ZoomRate = 0.5f;
        private const float RotationRate = 1.5f;
        private const int numTiles = 200;
        private const float animationTime = 0.1f;
        private static readonly Vector2 animatedSpriteScale = new Vector2(.3f, .3f);

        //utility types
        GraphicsDeviceManager graphics;

        //input state storage
        KeyboardState lastKeyboardState = new KeyboardState();
        GamePadState lastGamePadState = new GamePadState ();
        GamePadState currentGamePadState = new GamePadState ();
        KeyboardState currentKeyboardState = new KeyboardState();
        private Random rand;

        //2D camera abstraction
        private Camera2D camera;
        private Vector2 screenCenter;
        private SpriteFont font;

        //tile information
        private SpriteSheet groundSheet;
        private SpriteSheet cloudSheet;
        private SpriteBatch spriteBatch;
        private TileGrid rockLayer;
        private TileGrid groundLayer;
        private TileGrid cloudLayer;
        private TileGrid detailLayer;

        //animated sprite
        private SpriteSheet animatedSpriteSheet;
        private AnimatedSprite animatedSprite;
        private Vector2 animatedSpritePosition;
        private float accumulator;


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

            graphics.PreferredBackBufferWidth = 640;
            graphics.PreferredBackBufferHeight = 480;
            

            rand = new Random();
        }

        /// <summary>
        /// Load the graphics content.
        /// </summary>
        protected override void LoadContent()
        {
            //When the backbuffer resolution changes, this part of the
            //LoadContent calback is used to reset the screen center
            screenCenter = new Vector2(
                (float)graphics.GraphicsDevice.Viewport.Width / 2f,
                (float)graphics.GraphicsDevice.Viewport.Height / 2f);

            font = Content.Load<SpriteFont>("font");

            // Load XNBs in Release mode
            var groundTexture = Content.Load<Texture2D>("ground");
            var cloudTexture = Content.Load<Texture2D>("clouds");

            spriteBatch = new SpriteBatch(graphics.GraphicsDevice);

            //set up the tile sheets with source rectangles
            //for each of the different sprites
            cloudSheet = new SpriteSheet(cloudTexture);
            cloudSheet.AddSourceSprite((int)TileName.Clouds,
        new Rectangle(0, 0, 1024, 1024));
            groundSheet = new SpriteSheet(groundTexture);
            groundSheet.AddSourceSprite((int)TileName.Base,
        new Rectangle(0, 0, 510, 510));
            groundSheet.AddSourceSprite((int)TileName.Detail1,
        new Rectangle(514, 0, 255, 255));
            groundSheet.AddSourceSprite((int)TileName.Detail2,
        new Rectangle(769, 0, 255, 255));
            groundSheet.AddSourceSprite((int)TileName.Detail3,
        new Rectangle(514, 256, 255, 255));
            groundSheet.AddSourceSprite((int)TileName.Detail4,
        new Rectangle(769, 256, 255, 255));
            groundSheet.AddSourceSprite((int)TileName.SoftDetail1,
        new Rectangle(514, 514, 255, 255));
            groundSheet.AddSourceSprite((int)TileName.SoftDetail2,
        new Rectangle(769, 514, 255, 255));
            groundSheet.AddSourceSprite((int)TileName.SoftDetail3,
        new Rectangle(514, 769, 255, 255));
            groundSheet.AddSourceSprite((int)TileName.SoftDetail4,
        new Rectangle(769, 769, 255, 255));
            groundSheet.AddSourceSprite((int)TileName.Rocks1,
        new Rectangle(0, 514, 255, 255));
            groundSheet.AddSourceSprite((int)TileName.Rocks2,
        new Rectangle(256, 514, 255, 255));
            groundSheet.AddSourceSprite((int)TileName.Rocks3,
        new Rectangle(0, 769, 255, 255));
            groundSheet.AddSourceSprite((int)TileName.Rocks4,
        new Rectangle(256, 769, 255, 255));

            //Create the ground layer tile
            groundLayer = new TileGrid(510, 510, numTiles, numTiles,
        Vector2.Zero, groundSheet, graphics);

            //calculate the number of detial tiles, which are 
            //half the size of the base tiles, so there are
            //twice as many (minus one since they are being offset)
            int numDetailTiles = (numTiles * 2 - 1);

            //add an offset to break up the pattern
            detailLayer = new TileGrid(255, 255, numDetailTiles, numDetailTiles,
        new Vector2(127, 127), groundSheet, graphics);

            rockLayer = new TileGrid(255, 255, numDetailTiles, numDetailTiles,
        new Vector2(0, 0), groundSheet, graphics);

            int numCloudTiles = numTiles / 6 + 1;
            cloudLayer = new TileGrid(1024, 1024, numCloudTiles, numCloudTiles,
        Vector2.Zero, cloudSheet, graphics);

            //These loops fill the datas with some appropriate data.  
            //The clouds and ground clutter have been randomized.
            for (int i = 0; i < numTiles; i++)
            {
                for (int j = 0; j < numTiles; j++)
                {
                    groundLayer.SetTile(i, j, 1);
                }
            }

            for (int i = 0; i < numDetailTiles; i++)
            {
                for (int j = 0; j < numDetailTiles; j++)
                {
                    switch (rand.Next(20))
                    {
                        case 0:
                            detailLayer.SetTile(i, j, (int)TileName.Detail1);
                            break;
                        case 1:
                            detailLayer.SetTile(i, j, (int)TileName.Detail2);
                            break;
                        case 2:
                            detailLayer.SetTile(i, j, (int)TileName.Detail3);
                            break;
                        case 3:
                            detailLayer.SetTile(i, j, (int)TileName.Detail4);
                            break;
                        case 4:
                        case 5:
                            detailLayer.SetTile(i, j, (int)TileName.SoftDetail1);
                            break;
                        case 6:
                        case 7:
                            detailLayer.SetTile(i, j, (int)TileName.SoftDetail2);
                            break;
                        case 8:
                        case 9:
                            detailLayer.SetTile(i, j, (int)TileName.SoftDetail3);
                            break;
                        case 10:
                        case 11:
                            detailLayer.SetTile(i, j, (int)TileName.SoftDetail4);
                            break;
                    }
                }
            }
            for (int i = 0; i < numDetailTiles; i++)
            {
                for (int j = 0; j < numDetailTiles; j++)
                {
                    switch (rand.Next(25))
                    {
                        case 0:
                            rockLayer.SetTile(i, j, (int)TileName.Rocks1);
                            break;
                        case 1:
                            rockLayer.SetTile(i, j, (int)TileName.Rocks2);
                            break;
                        case 2:
                            rockLayer.SetTile(i, j, (int)TileName.Rocks3);
                            break;
                        case 3:
                        case 4:
                            rockLayer.SetTile(i, j, (int)TileName.Rocks4);
                            break;
                    }
                }
            }

            for (int i = 0; i < numCloudTiles; i++)
            {
                for (int j = 0; j < numCloudTiles; j++)
                {

                    cloudLayer.SetTile(i, j, (int)TileName.Clouds);

                }
            }

            // Set up AnimatedSprite
            var ballTexture = Content.Load<Texture2D>("ball");

            animatedSpriteSheet = new SpriteSheet(ballTexture);
            animatedSprite = new AnimatedSprite(animatedSpriteSheet, 254, 254, 1,
                4, 4, new Point(1, 0), 15);


            // Set Up a 2D Camera
            camera = new Camera2D();

            ResetToInitialPositions();

            //assuming a resolution change, need to update the sprite's "position"
            animatedSprite.Origin = camera.Position - animatedSpritePosition;
            animatedSprite.Position = screenCenter;

        }

        /// <summary>
        /// Reset the camera to the center of the tile grid
        /// and reset the position of the animted sprite
        /// </summary>
        private void ResetToInitialPositions()
        {
            //set up the 2D camera
            //set the initial position to the center of the
            //tile field
            camera.Position = new Vector2(numTiles * 255);
            camera.Rotation = 0f;
            camera.Zoom = 1f;
            camera.MoveUsingScreenAxis = true;

            //the animated sprite has no concept of a camera, so 
            //making the sprite camera relative is the job
            //of the game program
            animatedSpritePosition = camera.Position;
            animatedSprite.ScaleValue = animatedSpriteScale;
            animatedSprite.Position = screenCenter;


            CameraChanged();
        }



        /// <summary>
        /// Update the game world.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Update(GameTime gameTime)
        {
            HandleInput();

            //Set the camera's state to Unchanged for this frame
            //this will save us from having to update visibility if the camera
            //does not move
            camera.ResetChanged();

            //Call sample-specific input handling function
            HandleKeyboardInput((float)gameTime.ElapsedGameTime.TotalSeconds);

            HandleGamePadInput ((float)gameTime.ElapsedGameTime.TotalSeconds);

            if (camera.IsChanged)
            {
                CameraChanged();
            }


            //thottle the animation update speed to the frame animation
            //time
            accumulator += (float)gameTime.ElapsedGameTime.TotalSeconds;
            if (accumulator > animationTime)
            {
                animatedSprite.IncrementAnimationFrame();
                accumulator -= animationTime;
            }

            base.Update(gameTime);
        }

        /// <summary>
        /// Handle Game Pad input during Update
        /// </summary>
        public void HandleGamePadInput (float elapsed)
        {
            if (currentGamePadState.IsConnected) {
                //the left thumbstick moves the animated sprite around the world
                if ((Math.Abs (currentGamePadState.ThumbSticks.Left.X) > .1f) || 
            (Math.Abs (currentGamePadState.ThumbSticks.Left.Y) > .1f)) {
                    //Sprite movement is being updated relative to the camera
                    //rotation
                    animatedSpritePosition.X += (float)Math.Cos (-camera.Rotation) * 
            currentGamePadState.ThumbSticks.Left.X * elapsed * MovementRate;
                    animatedSpritePosition.Y += (float)Math.Sin (-camera.Rotation) * 
            currentGamePadState.ThumbSticks.Left.X * elapsed * MovementRate;
                    animatedSpritePosition.Y -= (float)Math.Cos (camera.Rotation) * 
            currentGamePadState.ThumbSticks.Left.Y * elapsed * MovementRate;
                    animatedSpritePosition.X -= (float)Math.Sin (camera.Rotation) * 
            currentGamePadState.ThumbSticks.Left.Y * elapsed * MovementRate;

                    //since the sprite position has changed, the Origin must be updated
                    //on the animated sprite object
                    animatedSprite.Origin = (camera.Position - animatedSpritePosition)
 / animatedSpriteScale.X;
                }
                //right thumbstick controls the camera position
                if ((Math.Abs (currentGamePadState.ThumbSticks.Right.X) > .1f) || 
            (Math.Abs (currentGamePadState.ThumbSticks.Right.Y) > .1f)) {
                    float dX = currentGamePadState.ThumbSticks.Right.X * elapsed * 
            MovementRate;
                    float dY = currentGamePadState.ThumbSticks.Right.Y * elapsed * 
            MovementRate;
                    camera.MoveRight (ref dX);
                    camera.MoveUp (ref dY);
                }
                //the triggers control rotation
                if ((Math.Abs (currentGamePadState.Triggers.Left) > .1f) || 
            (Math.Abs (currentGamePadState.Triggers.Right) > .1f)) {
                    float dX = currentGamePadState.Triggers.Left * 
            elapsed * RotationRate;
                    dX += -currentGamePadState.Triggers.Right * 
            elapsed * RotationRate;
                    camera.Rotation += dX;
                }
                //the A and B buttons control zoom
                if ((currentGamePadState.Buttons.A == ButtonState.Pressed) || 
            (currentGamePadState.Buttons.B == ButtonState.Pressed)) {
                    float delta = elapsed * ZoomRate;
                    if (currentGamePadState.Buttons.B == ButtonState.Pressed)
                        delta = -delta;

                    camera.Zoom += delta;
                    if (camera.Zoom < .5f)
                        camera.Zoom = .5f;
                    if (camera.Zoom > 2f)
                        camera.Zoom = 2f;
                }
                if ((currentGamePadState.Buttons.RightStick == ButtonState.Pressed) && 
            (lastGamePadState.Buttons.RightStick == ButtonState.Released)) {
                    ResetToInitialPositions ();
                }
            }
        }

        /// <summary>
        /// Handle Keyboard input during Update
        /// </summary>
        public void HandleKeyboardInput(float elapsed)
        {
            //check for camera movement
            float dX = ReadKeyboardAxis(currentKeyboardState, Keys.Left, Keys.Right) *
        elapsed * MovementRate;
            float dY = ReadKeyboardAxis(currentKeyboardState, Keys.Down, Keys.Up) *
        elapsed * MovementRate;
            camera.MoveRight(ref dX);
            camera.MoveUp(ref dY);

            //check for animted sprite movement
            animatedSpritePosition.X += (float)Math.Cos(-camera.Rotation) *
        ReadKeyboardAxis(currentKeyboardState, Keys.A, Keys.D) *
        elapsed * MovementRate;
            animatedSpritePosition.Y += (float)Math.Sin(-camera.Rotation) *
        ReadKeyboardAxis(currentKeyboardState, Keys.A, Keys.D) *
        elapsed * MovementRate;

            animatedSpritePosition.X -= (float)Math.Sin(camera.Rotation) *
        ReadKeyboardAxis(currentKeyboardState, Keys.S, Keys.W) *
        elapsed * MovementRate;
            animatedSpritePosition.Y -= (float)Math.Cos(camera.Rotation) *
        ReadKeyboardAxis(currentKeyboardState, Keys.S, Keys.W) *
        elapsed * MovementRate;

            //since the sprite position has changed, the Origin must be updated
            //on the animated sprite object
            animatedSprite.Origin = (camera.Position - animatedSpritePosition)
 / animatedSpriteScale.X;

            //check for camera rotation
            dX = ReadKeyboardAxis(currentKeyboardState, Keys.E, Keys.Q) *
        elapsed * RotationRate;
            camera.Rotation += dX;


            //check for camera zoom
            dX = ReadKeyboardAxis(currentKeyboardState, Keys.X, Keys.Z) *
        elapsed * ZoomRate;

            //limit the zoom
            camera.Zoom += dX;
            if (camera.Zoom < .5f)
                camera.Zoom = .5f;
            if (camera.Zoom > 2f)
                camera.Zoom = 2f;

            //check for camera reset
            if (currentKeyboardState.IsKeyDown(Keys.R) &&
        lastKeyboardState.IsKeyDown(Keys.R))
            {
                ResetToInitialPositions();
            }
        }

        /// <summary>
        /// This function is called when the camera's values have changed
        /// and is used to update the properties of the tiles and animated sprite
        /// </summary>
        public void CameraChanged()
        {
            //set rotation
            groundLayer.CameraRotation = detailLayer.CameraRotation =
        cloudLayer.CameraRotation = rockLayer.CameraRotation =
        animatedSprite.Rotation = camera.Rotation;

            //set zoom
            groundLayer.CameraZoom = detailLayer.CameraZoom =
        rockLayer.CameraZoom = camera.Zoom;
            animatedSprite.ScaleValue = animatedSpriteScale * camera.Zoom;
            cloudLayer.CameraZoom = camera.Zoom + 1.0f;

            //For an extra special effect, the camera zoom is figured into the cloud
            //alpha. The clouds will appear to fade out as camera zooms in.
            cloudLayer.Color = new Color(new Vector4(
            1.0f, 1.0f, 1.0f, 2 / (2f * camera.Zoom + 1.0f)));

            //set position
            groundLayer.CameraPosition = camera.Position;
            detailLayer.CameraPosition = camera.Position;
            rockLayer.CameraPosition = camera.Position;
            //to acheive a paralax effect, scale down cloud movement
            cloudLayer.CameraPosition = camera.Position / 3.0f;

            //The animcated sprite's origin is set so that rotation
            //will occur around the camera center (accounting for scale)
            animatedSprite.Origin = (camera.Position - animatedSpritePosition)
 / animatedSpriteScale.X;

            //changes have been accounted for, reset the changed value so that this
            //function is not called unnecessarily
            camera.ResetChanged();
        }

        /// <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)
        {
            //since we're drawing in order from back to front,
            //depth buffer is disabled
            // TODO graphics.GraphicsDevice.RenderState.DepthBufferEnable = false;
            graphics.GraphicsDevice.Clear(Color.MonoGameOrange);

            //draw the background layers
            groundLayer.Color = Color.LightGray;

            groundLayer.Draw(spriteBatch);
            detailLayer.Draw(spriteBatch);
            rockLayer.Draw(spriteBatch);

            animatedSprite.Draw(spriteBatch, Color.AntiqueWhite, BlendState.AlphaBlend);

            //draw the clouds
            cloudLayer.Draw(spriteBatch);

            spriteBatch.Begin();
            spriteBatch.DrawString(font, "Use the arrow keys to move the camera.", new Vector2(20, 20), Color.Black);
            spriteBatch.DrawString(font, "Use the WASD keys to move the animated sprite.", new Vector2(20, 40), Color.Black);
            spriteBatch.DrawString(font, "Use the Q and E keys to rotate the camera.", new Vector2(20, 60), Color.Black);
            spriteBatch.DrawString(font, "Use the Z and X keys to zoom in and out.", new Vector2(20, 80), Color.Black);
            spriteBatch.DrawString(font, "Press R to reset the camera.", new Vector2(20, 100), Color.Black);
            spriteBatch.DrawString(font, "Press Escape to exit.", new Vector2(20, 120), Color.Black);
            spriteBatch.DrawString(font, "Use the GamePad to control the camera and animated sprite.", new Vector2(20, 140), Color.Black);
            spriteBatch.DrawString(font, "Press Back on the GamePad to exit.", new Vector2(20, 160), Color.Black);
            spriteBatch.DrawString(font, "Camera Position: " + camera.Position.ToString(), new Vector2(20, 180), Color.Black);
            spriteBatch.DrawString(font, "Camera Rotation: " + camera.Rotation.ToString("F2"), new Vector2(20, 200), Color.Black);
            spriteBatch.DrawString(font, "Camera Zoom: " + camera.Zoom.ToString("F2"), new Vector2(20, 220), Color.Black);
            spriteBatch.End();


            base.Draw(gameTime);
        }



        /// <summary>
        /// Handles input for quitting the game.
        /// </summary>
        private void HandleInput()
        {
            lastKeyboardState = currentKeyboardState;
            lastGamePadState = currentGamePadState;

            currentKeyboardState = Keyboard.GetState();
            currentGamePadState = GamePad.GetState (PlayerIndex.One);

            // Check for exit.
            if (currentKeyboardState.IsKeyDown(Keys.Escape) ||
        currentGamePadState.Buttons.Back == ButtonState.Pressed)
            {
                Exit();
            }
        }

        /// <summary>
        /// Uses a pair of keys to simulate a positive or negative axis input.
        /// </summary>
        private static float ReadKeyboardAxis(KeyboardState keyState, Keys downKey,
                        Keys upKey)
        {
            float value = 0;

            if (keyState.IsKeyDown(downKey))
                value -= 1.0f;

            if (keyState.IsKeyDown(upKey))
                value += 1.0f;

            return value;
        }
    }
}