(function (window) {
        var Game = {
          init: function () {
            this.c = document.getElementById("game");
            this.c.width = this.c.width;
            this.c.height = this.c.height;
            this.ctx = this.c.getContext("2d");
            this.color = "rgba(20,20,20,.7)";
            this.bullets = [];
            this.enemyBullets = [];
            this.enemies = [];
            this.particles = [];
            this.bulletIndex = 0;
            this.enemyBulletIndex = 0;
            this.enemyIndex = 0;
            this.particleIndex = 0;
            this.maxParticles = 10;
            this.maxEnemies = 6;
            this.enemiesAlive = 0;
            this.currentFrame = 0;
            this.maxLives = 3;
            this.life = 0;
            this.binding();
            this.player = new Player();
            this.score = 0;
            this.paused = false;
            this.shooting = false;
            this.oneShot = false;
            this.isGameOver = false;
            this.requestAnimationFrame =
              window.requestAnimationFrame ||
              window.webkitRequestAnimationFrame ||
              window.mozRequestAnimationFrame;
            for (var i = 0; i < this.maxEnemies; i++) {
              new Enemy();
              this.enemiesAlive++;
            }
            this.invincibleMode(2000);

            this.loop();
          },

          binding: function () {
            window.addEventListener("keydown", this.buttonDown);
            window.addEventListener("keyup", this.buttonUp);
            window.addEventListener("keypress", this.keyPressed);
            this.c.addEventListener("click", this.clicked);
          },

          clicked: function () {
            if (!Game.paused) {
              Game.pause();
            } else {
              if (Game.isGameOver) {
                Game.init();
              } else {
                Game.unPause();
                Game.loop();
                Game.invincibleMode(1000);
              }
            }
          },

          keyPressed: function (e) {
            if (e.keyCode === 32) {
              if (!Game.player.invincible && !Game.oneShot) {
                Game.player.shoot();
                Game.oneShot = true;
              }
              if (Game.isGameOver) {
                Game.init();
              }
              e.preventDefault();
            }
          },

          buttonUp: function (e) {
            if (e.keyCode === 32) {
              Game.shooting = false;
              Game.oneShot = false;
              e.preventDefault();
            }
            if (e.keyCode === 37 || e.keyCode === 65) {
              Game.player.movingLeft = false;
            }
            if (e.keyCode === 39 || e.keyCode === 68) {
              Game.player.movingRight = false;
            }
          },

          buttonDown: function (e) {
            if (e.keyCode === 32) {
              Game.shooting = true;
            }
            if (e.keyCode === 37 || e.keyCode === 65) {
              Game.player.movingLeft = true;
            }
            if (e.keyCode === 39 || e.keyCode === 68) {
              Game.player.movingRight = true;
            }
          },

          random: function (min, max) {
            return Math.floor(Math.random() * (max - min) + min);
          },

          invincibleMode: function (s) {
            this.player.invincible = true;
            setTimeout(function () {
              Game.player.invincible = false;
            }, s);
          },

          collision: function (a, b) {
            return !(
              a.y + a.height < b.y ||
              a.y > b.y + b.height ||
              a.x + a.width < b.x ||
              a.x > b.x + b.width
            );
          },

          clear: function () {
            this.ctx.fillStyle = Game.color;
            this.ctx.fillRect(0, 0, this.c.width, this.c.height);
          },

          pause: function () {
            this.paused = true;
          },

          unPause: function () {
            this.paused = false;
          },

          gameOver: function () {
            this.isGameOver = true;
            this.clear();
            var message = "Game Over";
            var message2 = "Score: " + Game.score;
            var message3 = "Click or press Spacebar to Play Again";
            this.pause();
            this.ctx.fillStyle = "white";
            this.ctx.font = "bold 30px Lato, sans-serif";
            this.ctx.fillText(
              message,
              this.c.width / 2 - this.ctx.measureText(message).width / 2,
              this.c.height / 2 - 50
            );
            this.ctx.fillText(
              message2,
              this.c.width / 2 - this.ctx.measureText(message2).width / 2,
              this.c.height / 2 - 5
            );
            this.ctx.font = "bold 16px Lato, sans-serif";
            this.ctx.fillText(
              message3,
              this.c.width / 2 - this.ctx.measureText(message3).width / 2,
              this.c.height / 2 + 30
            );
          },

          updateScore: function () {
            this.ctx.fillStyle = "white";
            this.ctx.font = "16px Lato, sans-serif";
            this.ctx.fillText("Score: " + this.score, 8, 20);
            this.ctx.fillText("Lives: " + (this.maxLives - this.life), 8, 40);
          },

          loop: function () {
            if (!Game.paused) {
              Game.clear();
              for (var i in Game.enemies) {
                var currentEnemy = Game.enemies[i];
                currentEnemy.draw();
                currentEnemy.update();
                if (Game.currentFrame % currentEnemy.shootingSpeed === 0) {
                  currentEnemy.shoot();
                }
              }
              for (var x in Game.enemyBullets) {
                Game.enemyBullets[x].draw();
                Game.enemyBullets[x].update();
              }
              for (var z in Game.bullets) {
                Game.bullets[z].draw();
                Game.bullets[z].update();
              }
              if (Game.player.invincible) {
                if (Game.currentFrame % 20 === 0) {
                  Game.player.draw();
                }
              } else {
                Game.player.draw();
              }

              for (var i in Game.particles) {
                Game.particles[i].draw();
              }
              Game.player.update();
              Game.updateScore();
              Game.currentFrame = Game.requestAnimationFrame.call(
                window,
                Game.loop
              );
            }
          },
        };

        var Player = function () {
          this.width = 60;
          this.height = 20;
          this.x = Game.c.width / 2 - this.width / 2;
          this.y = Game.c.height - this.height;
          this.movingLeft = false;
          this.movingRight = false;
          this.speed = 8;
          this.invincible = false;
          this.color = "white";
        };

        Player.prototype.die = function () {
          if (Game.life < Game.maxLives) {
            Game.invincibleMode(2000);
            Game.life++;
          } else {
            Game.pause();
            Game.gameOver();
          }
        };

        Player.prototype.draw = function () {
          Game.ctx.fillStyle = this.color;
          Game.ctx.fillRect(this.x, this.y, this.width, this.height);
        };

        Player.prototype.update = function () {
          if (this.movingLeft && this.x > 0) {
            this.x -= this.speed;
          }
          if (this.movingRight && this.x + this.width < Game.c.width) {
            this.x += this.speed;
          }
          if (Game.shooting && Game.currentFrame % 10 === 0) {
            this.shoot();
          }
          for (var i in Game.enemyBullets) {
            var currentBullet = Game.enemyBullets[i];
            if (
              Game.collision(currentBullet, this) &&
              !Game.player.invincible
            ) {
              this.die();
              delete Game.enemyBullets[i];
            }
          }
        };

        Player.prototype.shoot = function () {
          Game.bullets[Game.bulletIndex] = new Bullet(this.x + this.width / 2);
          Game.bulletIndex++;
        };

        var Bullet = function (x) {
          this.width = 8;
          this.height = 20;
          this.x = x;
          this.y = Game.c.height - 10;
          this.vy = 8;
          this.index = Game.bulletIndex;
          this.active = true;
          this.color = "white";
        };

        Bullet.prototype.draw = function () {
          Game.ctx.fillStyle = this.color;
          Game.ctx.fillRect(this.x, this.y, this.width, this.height);
        };

        Bullet.prototype.update = function () {
          this.y -= this.vy;
          if (this.y < 0) {
            delete Game.bullets[this.index];
          }
        };

        var Enemy = function () {
          this.width = 60;
          this.height = 20;
          this.x = Game.random(0, Game.c.width - this.width);
          this.y = Game.random(10, 40);
          this.vy = Game.random(1, 3) * 0.1;
          this.index = Game.enemyIndex;
          Game.enemies[Game.enemyIndex] = this;
          Game.enemyIndex++;
          this.speed = Game.random(2, 3);
          this.shootingSpeed = Game.random(30, 80);
          this.movingLeft = Math.random() < 0.5 ? true : false;
          this.color = "hsl(" + Game.random(0, 360) + ", 60%, 50%)";
        };

        Enemy.prototype.draw = function () {
          Game.ctx.fillStyle = this.color;
          Game.ctx.fillRect(this.x, this.y, this.width, this.height);
        };

        Enemy.prototype.update = function () {
          if (this.movingLeft) {
            if (this.x > 0) {
              this.x -= this.speed;
              this.y += this.vy;
            } else {
              this.movingLeft = false;
            }
          } else {
            if (this.x + this.width < Game.c.width) {
              this.x += this.speed;
              this.y += this.vy;
            } else {
              this.movingLeft = true;
            }
          }

          for (var i in Game.bullets) {
            var currentBullet = Game.bullets[i];
            if (Game.collision(currentBullet, this)) {
              this.die();
              delete Game.bullets[i];
            }
          }
        };

        Enemy.prototype.die = function () {
          this.explode();
          delete Game.enemies[this.index];
          Game.score += 15;
          Game.enemiesAlive = Game.enemiesAlive > 1 ? Game.enemiesAlive - 1 : 0;
          if (Game.enemiesAlive < Game.maxEnemies) {
            Game.enemiesAlive++;
            setTimeout(function () {
              new Enemy();
            }, 2000);
          }
        };

        Enemy.prototype.explode = function () {
          for (var i = 0; i < Game.maxParticles; i++) {
            new Particle(this.x + this.width / 2, this.y, this.color);
          }
        };

        Enemy.prototype.shoot = function () {
          new EnemyBullet(this.x + this.width / 2, this.y, this.color);
        };

        var EnemyBullet = function (x, y, color) {
          this.width = 8;
          this.height = 20;
          this.x = x;
          this.y = y;
          this.vy = 6;
          this.color = color;
          this.index = Game.enemyBulletIndex;
          Game.enemyBullets[Game.enemyBulletIndex] = this;
          Game.enemyBulletIndex++;
        };

        EnemyBullet.prototype.draw = function () {
          Game.ctx.fillStyle = this.color;
          Game.ctx.fillRect(this.x, this.y, this.width, this.height);
        };

        EnemyBullet.prototype.update = function () {
          this.y += this.vy;
          if (this.y > Game.c.height) {
            delete Game.enemyBullets[this.index];
          }
        };

        var Particle = function (x, y, color) {
          this.x = x;
          this.y = y;
          this.vx = Game.random(-5, 5);
          this.vy = Game.random(-5, 5);
          this.color = color || "orange";
          Game.particles[Game.particleIndex] = this;
          this.id = Game.particleIndex;
          Game.particleIndex++;
          this.life = 0;
          this.gravity = 0.05;
          this.size = 40;
          this.maxlife = 100;
        };

        Particle.prototype.draw = function () {
          this.x += this.vx;
          this.y += this.vy;
          this.vy += this.gravity;
          this.size *= 0.89;
          Game.ctx.fillStyle = this.color;
          Game.ctx.fillRect(this.x, this.y, this.size, this.size);
          this.life++;
          if (this.life >= this.maxlife) {
            delete Game.particles[this.id];
          }
        };

        Game.init();
      })(window);