using System;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;

namespace Game
{
    class IntroScreen : Scene
    {
        private SpriteBatch _spriteBatch;
        private Texture2D _backgroundScreen;
        private const String BackgroundName = "Backgrounds/IntroScreen";
        private double _startTime;
        private Color _color;
        private bool _started;

        public override void Draw(GameTime gameTime, GraphicsDevice graphicsDevice)
        {
            _spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.AlphaBlend);
            _spriteBatch.Draw(_backgroundScreen, new Vector2(0, 0), _color);
            _spriteBatch.End();
        }

        public override void Update(GameTime gameTime, ContentManager content, KeyboardState keyboardState, KeyboardState oldKeyboardState, GamePadState gamePadState, GamePadState oldGamePadState)
        {

            if (_started) {
                _startTime = gameTime.TotalGameTime.TotalMilliseconds;
                _started = false;
            }

            double deltaTime = gameTime.TotalGameTime.TotalMilliseconds - _startTime;

            if ((deltaTime >2000) && (deltaTime < 3000))
                Brighter(4);

            if ((keyboardState.IsKeyUp(Keys.Space)) && (oldKeyboardState.IsKeyDown(Keys.Space)) ||
            ((gamePadState.Buttons.A == ButtonState.Released) && (oldGamePadState.Buttons.A == ButtonState.Pressed)))
            {
                ForceExitLevelToMenu();
            }

        }

        public override void LoadContent(ContentManager content, GraphicsDevice graphicsDevice)
        {
            _spriteBatch = new SpriteBatch(graphicsDevice);
            _backgroundScreen = content.Load<Texture2D>(BackgroundName);
            _color = new Color(255,255,255,255);
            SetBrightness(0);
            _started = true;

        }

        private void SetBrightness(byte level)
        {
            _color.A = level;
        }

        private void Brighter(byte amount)
        {
            if ((_color.A + amount) < 255) _color.A += amount; else _color.A = 255;
        }

        private void Darker(byte amount)
        {
            if ((_color.A - amount) > 0) _color.A -= amount; else _color.A = 0;
        }

        public override void ForceExitLevelToMenu()
        {
            NextScene = SceneManager.Scenes.MAIN_MENU;
            ExitScene = true;
        }
    }
}