using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
using FaceGame.Utility;

namespace FaceGame {
    public class Game {

        int playerCount;

        // Tile dimensions & Map
        float TileWidth, TileHeight; // individual tile width/height
        Effect MapEffect;
        List<Entity> Map;
        Texture2D MapTexture;
        VertexBuffer MapVertexBuffer;
        IndexBuffer MapIndexBuffer;

        // Camera
        Camera camera;
        Pair<int, int> mousePosition;
        Vector3 cameraRotation;

        public Game(int playerCount) {

            this.playerCount = playerCount;

            // Init Camera
            camera = new Camera(Global.Graphics.Viewport.AspectRatio, MathHelper.ToRadians(45.0f), 1.0f, 1000.0f);
            camera.setPosition(0.0f, 10.0f, 0.0f);
            camera.setLookAt(0.0f, 0.0f, 1.0f);
            mousePosition = new Pair<int, int>(0, 0);
            cameraRotation = Vector3.Zero;

            CreateMap(150, 150);

        }

        private void CreateMap(ushort WidthInTiles, ushort HeightInTiles) {

            // Init the map
            Map = new List<Entity>();

            // set the mapWidth/height here
            ushort MapWidth = (ushort)(WidthInTiles + 1);
            ushort MapHeight = (ushort)(HeightInTiles + 1);

            TileWidth = 10.0f;
            TileHeight = 10.0f;

            Vector2 texCoord = Vector2.Zero;

            // create each vertex
            VertexPositionNormalTexture[] vertices = new VertexPositionNormalTexture[MapHeight * MapWidth];
            for (ushort i = 0; i < MapHeight; i++) {
                for (ushort j = 0; j < MapWidth; j++) {

                    texCoord.X = (float)j * 1.0f;
                    texCoord.Y = (float)i * 1.0f;

                    vertices[j + (i * MapHeight)] = new VertexPositionNormalTexture(
                        new Vector3(j * TileWidth, (float)Math.Sin(i) * 5.0f, i * TileHeight),
                        Vector3.Up,
                        texCoord);

                }
            }


            List<ushort> indexList = new List<ushort>();

            for (ushort y = 0; y < MapHeight - 1; y++) {
                for (ushort x = 0; x < MapWidth - 1; x++) {

                    ushort topleft = (ushort)(x + y * MapHeight);
                    ushort topright = (ushort)( (x + 1) + y * MapHeight);
                    ushort botleft = (ushort)(x + (y + 1) * MapHeight);
                    ushort botright = (ushort)( (x + 1) + (y + 1) * MapHeight);
                    indexList.Add(topleft);
                    indexList.Add(topright);
                    indexList.Add(botleft);

                    indexList.Add(topright);
                    indexList.Add(botright);
                    indexList.Add(botleft);



                }

            }

            ushort[] indexes = indexList.ToArray();

            MapVertexBuffer = new VertexBuffer(Global.Graphics, VertexPositionNormalTexture.VertexDeclaration, vertices.Length, BufferUsage.None);
            MapVertexBuffer.SetData<VertexPositionNormalTexture>(vertices);

            MapIndexBuffer = new IndexBuffer(Global.Graphics, IndexElementSize.SixteenBits, indexes.Length, BufferUsage.None);
            MapIndexBuffer.SetData<ushort>(indexes);

            MapEffect = Global.Content.Load<Effect>("Effects/TileEffect");
            MapTexture = Global.Content.Load<Texture2D>("Textures/Grass");

        }

        public void Update(GameTime gameTime) {
            //update stuff
            if (Global.KeyState.IsKeyDown(Keys.Escape)) Global.main.Exit();

            UpdateCamera();

        }

        private void UpdateCamera() {

            // finish moving the camera
            if (Global.MouseState.RightButton == ButtonState.Released &&
                Global.PrevMouseState.RightButton == ButtonState.Pressed) {

                // right just released
                Global.main.IsMouseVisible = true;
                Mouse.SetPosition(mousePosition.First, mousePosition.Second);

            }

            // start to move the camera
            if (Global.MouseState.RightButton == ButtonState.Pressed &&
                Global.PrevMouseState.RightButton == ButtonState.Released) {

                // right just pressed
                Global.main.IsMouseVisible = false;
                mousePosition.First = Global.MouseState.X;
                mousePosition.Second = Global.MouseState.Y;

            }

            // rotate the camera
            if (Global.MouseState.RightButton == ButtonState.Pressed) {

                Vector3 cameraPosition = camera.position;

                float mouseDiffX = (Global.MouseState.X - Global.PrevMouseState.X);
                float mouseDiffY = (Global.MouseState.Y - Global.PrevMouseState.Y);

                cameraRotation.X -= mouseDiffX * 0.01f;
                cameraRotation.Y += mouseDiffY * 0.01f;

                if (cameraRotation.Y > 1.5f) cameraRotation.Y = 1.5f;
                if (cameraRotation.Y < -1.5f) cameraRotation.Y = -1.5f;

                // rotX = up/down
                // rotY = left/right
                Matrix cameraMatrix = Matrix.CreateRotationX(cameraRotation.Y) * Matrix.CreateRotationY(cameraRotation.X);

                if (Global.KeyState.IsKeyDown(Keys.W)) {

                    // move forward
                    cameraPosition.X += (float)Math.Sin(cameraRotation.X);
                    cameraPosition.Y -= (float)Math.Sin(cameraRotation.Y);
                    cameraPosition.Z += (float)Math.Cos(cameraRotation.X);

                } else if (Global.KeyState.IsKeyDown(Keys.S)) {

                    // move backwards
                    cameraPosition.X -= (float)Math.Sin(cameraRotation.X);
                    cameraPosition.Y += (float)Math.Sin(cameraRotation.Y);
                    cameraPosition.Z -= (float)Math.Cos(cameraRotation.X);

                }

                if (Global.KeyState.IsKeyDown(Keys.A)) {

                    // move left
                    cameraPosition.X += (float)Math.Sin(cameraRotation.X + MathHelper.PiOver2);
                    cameraPosition.Z += (float)Math.Cos(cameraRotation.X + MathHelper.PiOver2);

                } else if (Global.KeyState.IsKeyDown(Keys.D)) {

                    // move right
                    cameraPosition.X += (float)Math.Sin(cameraRotation.X - MathHelper.PiOver2);
                    cameraPosition.Z += (float)Math.Cos(cameraRotation.X - MathHelper.PiOver2);

                }

                camera.setPosition(cameraPosition);
                camera.setLookAt(camera.position + Vector3.Transform(new Vector3(0.0f, 0.0f, 1.0f), cameraMatrix));

            }

        }

        public void Draw(GameTime gameTime) {

            RasterizerState r = new RasterizerState();
            r.CullMode = CullMode.CullCounterClockwiseFace;
            //r.FillMode = FillMode.WireFrame;

            Global.Graphics.DepthStencilState = DepthStencilState.Default;
            Global.Graphics.BlendState = BlendState.Opaque;
            Global.Graphics.RasterizerState = r;
            Global.Graphics.VertexSamplerStates[0] = SamplerState.AnisotropicClamp;

            DrawMap();

        }

        private void DrawMap() {

            MapEffect.CurrentTechnique = MapEffect.Techniques["GeneralTechnique"];
            MapEffect.Parameters["View"].SetValue(camera.view);
            MapEffect.Parameters["Projection"].SetValue(camera.projection);
            MapEffect.Parameters["TileTexture"].SetValue(MapTexture); // the tile texture can be set individually

            Global.Graphics.SetVertexBuffer(MapVertexBuffer);
            Global.Graphics.Indices = MapIndexBuffer;

            MapEffect.Parameters["World"].SetValue(Matrix.CreateTranslation(0.0f, 0.0f, 0.0f));
            MapEffect.CurrentTechnique.Passes[0].Apply();

            Global.Graphics.DrawIndexedPrimitives(PrimitiveType.TriangleList,
                0, 0, MapVertexBuffer.VertexCount, 0, MapIndexBuffer.IndexCount);

        }
    }
}