// Asteroids.js
// Copyright (c) 2010–2023 James Socol <me@jamessocol.com>
// See LICENSE.txt for license terms.

// Game settings
GAME_HEIGHT = 480;
GAME_WIDTH = 640;
FRAME_PERIOD = 60; // 1 frame / x frames/sec
LEVEL_TIMEOUT = 2000; // How long to wait after clearing a level.

// Player settings
ROTATE_SPEED = Math.PI / 10; // How fast do players turn?  (radians)
MAX_SPEED = 15; // Maximum player speed
THRUST_ACCEL = 1;
DEATH_TIMEOUT = 2000; // milliseconds
INVINCIBLE_TIMEOUT = 1500; // How long to stay invincible after resurrecting?
PLAYER_LIVES = 3;
POINTS_PER_SHOT = 1; // How many points does a shot cost? (Should be >= 0.)
POINTS_TO_EXTRA_LIFE = 1000; // How many points to get a 1-up?

// Bullet settings
BULLET_SPEED = 20;
MAX_BULLETS = 3;
MAX_BULLET_AGE = 25;

// Asteroid settings
ASTEROID_COUNT = 2; // This + current level = number of asteroids.
ASTEROID_GENERATIONS = 3; // How many times to they split before dying?
ASTEROID_CHILDREN = 2; // How many does each death create?
ASTEROID_SPEED = 3;
ASTEROID_SCORE = 10; // How many points is each one worth?

var Asteroids = function(home) {
  // Constructor
  // Order matters.

  // Set up logging.
  this.log_level = Asteroids.LOG_DEBUG;
  this.log = Asteroids.logger(this);

  // Create the info pane, player, and playfield.
  home.innerHTML = "";
  this.info = Asteroids.infoPane(this, home);
  this.playfield = Asteroids.playfield(this, home);
  this.player = Asteroids.player(this);

  // Set up the event listeners.
  this.keyState = Asteroids.keyState(this);
  this.listen = Asteroids.listen(this);

  // Useful functions.
  this.asteroids = Asteroids.asteroids(this);
  this.overlays = Asteroids.overlays(this);
  this.highScores = Asteroids.highScores(this);
  this.level = Asteroids.level(this);
  this.gameOver = Asteroids.gameOver(this);

  // Play the game.
  Asteroids.play(this);
  return this;
};

Asteroids.infoPane = function(game, home) {
  var pane = document.createElement("div");
  pane.innerHTML = "ASTEROIDS";

  var lives = document.createElement("span");
  lives.className = "lives";
  lives.innerHTML = "LIVES: " + PLAYER_LIVES;

  var score = document.createElement("span");
  score.className = "score";
  score.innerHTML = "SCORE: 0";

  var level = document.createElement("span");
  level.className = "level";
  level.innerHTML = "LEVEL: 1";

  pane.appendChild(lives);
  pane.appendChild(score);
  pane.appendChild(level);
  home.appendChild(pane);

  return {
    setLives: function(game, l) {
      lives.innerHTML = "LIVES: " + l;
    },
    setScore: function(game, s) {
      score.innerHTML = "SCORE: " + s;
    },
    setLevel: function(game, _level) {
      level.innerHTML = "LEVEL: " + _level;
    },
    getPane: function() {
      return pane;
    }
  };
};

Asteroids.playfield = function(game, home) {
  var canvas = document.createElement("canvas");
  canvas.width = GAME_WIDTH;
  canvas.height = GAME_HEIGHT;
  home.appendChild(canvas);
  return canvas;
};

Asteroids.logger = function(game) {
  if (typeof console != "undefined" && typeof console.log != "undefined") {
    return {
      info: function(msg) {
        if (game.log_level <= Asteroids.LOG_INFO) console.log(msg);
      },
      debug: function(msg) {
        if (game.log_level <= Asteroids.LOG_DEBUG) console.log(msg);
      },
      warning: function(msg) {
        if (game.log_level <= Asteroids.LOG_WARNING) console.log(msg);
      },
      error: function(msg) {
        if (game.log_level <= Asteroids.LOG_ERROR) console.log(msg);
      },
      critical: function(msg) {
        if (game.log_level <= Asteroids.LOG_CRITICAL) console.log(msg);
      }
    };
  } else {
    return {
      info: function(msg) {},
      debug: function(msg) {},
      warning: function(msg) {},
      error: function(msg) {},
      critical: function(msg) {}
    };
  }
};

Asteroids.asteroids = function(game) {
  var asteroids = [];

  return {
    push: function(obj) {
      return asteroids.push(obj);
    },
    pop: function() {
      return asteroids.pop();
    },
    splice: function(i, j) {
      return asteroids.splice(i, j);
    },
    get length() {
      return asteroids.length;
    },
    getIterator: function() {
      return asteroids;
    },
    generationCount: function(_gen) {
      var total = 0;
      for (var i = 0; i < asteroids.length; i++) {
        if (asteroids[i].getGeneration() == _gen) total++;
      }
      game.log.debug("Found " + total + " asteroids in generation " + _gen);
      return total;
    }
  };
};

/**
 * Creates an overlays controller.
 */
Asteroids.overlays = function(game) {
  var overlays = [];

  return {
    draw: function(ctx) {
      for (var i = 0; i < overlays.length; i++) {
        overlays[i].draw(ctx);
      }
    },
    add: function(obj) {
      if (-1 == overlays.indexOf(obj) && typeof obj.draw != "undefined") {
        overlays.push(obj);
        return true;
      }
      return false;
    },
    remove: function(obj) {
      var i = overlays.indexOf(obj);
      if (-1 != i) {
        overlays.splice(i, 1);
        return true;
      }
      return false;
    }
  };
};

/**
 * Creates a player object.
 */
Asteroids.player = function(game) {
  // implements IScreenObject
  var position = [GAME_WIDTH / 2, GAME_HEIGHT / 2],
    velocity = [0, 0],
    direction = -Math.PI / 2,
    dead = false,
    invincible = false,
    lastRez = null,
    lives = PLAYER_LIVES,
    score = 0,
    radius = 3,
    path = [
      [10, 0],
      [-5, 5],
      [-5, -5],
      [10, 0]
    ];

  return {
    getPosition: function() {
      return position;
    },
    getVelocity: function() {
      return velocity;
    },
    getSpeed: function() {
      return Math.sqrt(Math.pow(velocity[0], 2) + Math.pow(velocity[1], 2));
    },
    getDirection: function() {
      return direction;
    },
    getRadius: function() {
      return radius;
    },
    getScore: function() {
      return score;
    },
    addScore: function(pts) {
      score += pts;
    },
    lowerScore: function(pts) {
      score -= pts;
      if (score < 0) {
        score = 0;
      }
    },
    getLives: function() {
      return lives;
    },
    rotate: function(rad) {
      if (!dead) {
        direction += rad;
        game.log.info(direction);
      }
    },
    thrust: function(force) {
      if (!dead) {
        velocity[0] += force * Math.cos(direction);
        velocity[1] += force * Math.sin(direction);

        if (this.getSpeed() > MAX_SPEED) {
          velocity[0] = MAX_SPEED * Math.cos(direction);
          velocity[1] = MAX_SPEED * Math.sin(direction);
        }

        game.log.info(velocity);
      }
    },
    move: function() {
      Asteroids.move(position, velocity);
    },
    draw: function(ctx) {
      let color = "#fff";
      if (invincible) {
        const dt = (new Date() - lastRez) / 200;
        const c = Math.floor(Math.cos(dt) * 16).toString(16);
        color = `#${c}${c}${c}`;
      }
      Asteroids.drawPath(ctx, position, direction, 1, path, color);
    },
    isDead: function() {
      return dead;
    },
    isInvincible: function() {
      return invincible;
    },
    extraLife: function(game) {
      game.log.debug("Woo, extra life!");
      lives++;
    },
    die: function(game) {
      if (!dead) {
        game.log.info("You died!");
        dead = true;
        invincible = true;
        lives--;
        position = [GAME_WIDTH / 2, GAME_HEIGHT / 2];
        velocity = [0, 0];
        direction = -Math.PI / 2;
        if (lives > 0) {
          setTimeout(
            (function(player, _game) {
              return function() {
                player.resurrect(_game);
              };
            })(this, game),
            DEATH_TIMEOUT
          );
        } else {
          game.gameOver();
        }
      }
    },
    resurrect: function(game) {
      if (dead) {
        dead = false;
        invincible = true;
        lastRez = new Date();
        setTimeout(function() {
          invincible = false;
          game.log.debug("No longer invincible!");
        }, INVINCIBLE_TIMEOUT);
        game.log.debug("You ressurrected!");
      }
    },
    fire: function(game) {
      if (!dead) {
        game.log.debug("You fired!");
        var _pos = [position[0], position[1]],
          _dir = direction;

        this.lowerScore(POINTS_PER_SHOT);

        return Asteroids.bullet(game, _pos, _dir);
      }
    }
  };
};

Asteroids.bullet = function(game, _pos, _dir) {
  // implements IScreenObject
  var position = [_pos[0], _pos[1]],
    velocity = [0, 0],
    direction = _dir,
    age = 0,
    radius = 1,
    path = [
      [0, 0],
      [-4, 0]
    ];

  velocity[0] = BULLET_SPEED * Math.cos(_dir);
  velocity[1] = BULLET_SPEED * Math.sin(_dir);

  return {
    getPosition: function() {
      return position;
    },
    getVelocity: function() {
      return velocity;
    },
    getSpeed: function() {
      return Math.sqrt(Math.pow(velocity[0], 2) + Math.pow(velocity[1], 2));
    },
    getRadius: function() {
      return radius;
    },
    getAge: function() {
      return age;
    },
    birthday: function() {
      age++;
    },
    move: function() {
      Asteroids.move(position, velocity);
    },
    draw: function(ctx) {
      Asteroids.drawPath(ctx, position, direction, 1, path);
    }
  };
};

Asteroids.keyState = function(_) {
  var state = {
    [Asteroids.LEFT]: false,
    [Asteroids.UP]: false,
    [Asteroids.RIGHT]: false,
    [Asteroids.DOWN]: false,
    [Asteroids.FIRE]: false
  };

  return {
    on: function(key) {
      state[key] = true;
    },
    off: function(key) {
      state[key] = false;
    },
    getState: function(key) {
      if (typeof state[key] != "undefined") return state[key];
      return false;
    }
  };
};

Asteroids.listen = function(game) {
  const keyMap = {
    ArrowLeft: Asteroids.LEFT,
    KeyA: Asteroids.LEFT,
    ArrowRight: Asteroids.RIGHT,
    KeyD: Asteroids.RIGHT,
    ArrowUp: Asteroids.UP,
    KeyW: Asteroids.UP,
    Space: Asteroids.FIRE
  };

  window.addEventListener(
    "keydown",
    function(e) {
      const state = keyMap[e.code];
      if (state) {
        e.preventDefault();
        e.stopPropagation();
        game.keyState.on(state);
        return false;
      }
      return true;
    },
    true
  );

  window.addEventListener(
    "keyup",
    function(e) {
      const state = keyMap[e.code];
      if (state) {
        e.preventDefault();
        e.stopPropagation();
        game.keyState.off(state);
        return false;
      }
      return true;
    },
    true
  );
};

Asteroids.asteroid = function(game, _gen) {
  // implements IScreenObject
  var position = [0, 0],
    velocity = [0, 0],
    direction = 0,
    generation = _gen,
    radius = 7,
    path = [
      [1, 7],
      [5, 5],
      [7, 1],
      [5, -3],
      [7, -7],
      [3, -9],
      [-1, -5],
      [-4, -2],
      [-8, -1],
      [-9, 3],
      [-5, 5],
      [-1, 3],
      [1, 7]
    ];

  return {
    getPosition: function() {
      return position;
    },
    setPosition: function(pos) {
      position = pos;
    },
    getVelocity: function() {
      return velocity;
    },
    setVelocity: function(vel) {
      velocity = vel;
      direction = Math.atan2(vel[1], vel[0]);
    },
    getSpeed: function() {
      return Math.sqrt(Math.pow(velocity[0], 2) + Math.pow(velocity[1], 2));
    },
    getRadius: function() {
      return radius * generation;
    },
    getGeneration: function() {
      return generation;
    },
    move: function() {
      Asteroids.move(position, velocity);
    },
    draw: function(ctx) {
      Asteroids.drawPath(ctx, position, direction, generation, path);
      // ctx.setTransform(1, 0, 0, 1, position[0], position[1]);
      // ctx.beginPath();
      // ctx.arc(0, 0, radius*generation, 0, Math.PI*2, false);
      // ctx.stroke();
      // ctx.closePath();
    }
  };
};

Asteroids.collision = function(a, b) {
  // if a.getPosition() inside b.getBounds?
  var a_pos = a.getPosition(),
    b_pos = b.getPosition();

  function sq(x) {
    return Math.pow(x, 2);
  }

  var distance = Math.sqrt(sq(a_pos[0] - b_pos[0]) + sq(a_pos[1] - b_pos[1]));

  if (distance <= a.getRadius() + b.getRadius()) return true;
  return false;
};

Asteroids.level = function(game) {
  var level = 0,
    speed = ASTEROID_SPEED,
    hspeed = ASTEROID_SPEED / 2;

  return {
    getLevel: function() {
      return level;
    },
    levelUp: function(game) {
      level++;
      game.log.debug("Congrats! On to level " + level);
      while (
        game.asteroids.generationCount(ASTEROID_GENERATIONS) <
        level + ASTEROID_COUNT
      ) {
        var a = Asteroids.asteroid(game, ASTEROID_GENERATIONS);
        a.setPosition([
          Math.random() * GAME_WIDTH,
          Math.random() * GAME_HEIGHT
        ]);
        a.setVelocity([
          Math.random() * speed - hspeed,
          Math.random() * speed - hspeed
        ]);
        game.asteroids.push(a);
      }
    }
  };
};

Asteroids.gameOver = function(game) {
  return function() {
    game.log.debug("Game over!");

    if (game.player.getScore() > 0) {
      game.highScores.addScore("Player", game.player.getScore());
    }

    game.overlays.add({
      // implements IOverlay
      draw: function(ctx) {
        ctx.font = "30px System, monospace";
        ctx.textAlign = "center";
        ctx.textBaseline = "middle";
        ctx.setTransform(1, 0, 0, 1, 0, 0);
        ctx.fillText("GAME OVER", GAME_WIDTH / 2, GAME_HEIGHT / 2);

        var scores = game.highScores.getScores();
        ctx.font = "12px System, monospace";
        for (var i = 0; i < scores.length; i++) {
          ctx.fillText(
            scores[i].name + "   " + scores[i].score,
            GAME_WIDTH / 2,
            GAME_HEIGHT / 2 + 20 + 14 * i
          );
        }
      }
    });
  };
};

Asteroids.highScores = function(game) {
  var scores = [];

  if ((t = localStorage.getItem("high-scores"))) {
    scores = JSON.parse(t);
  }

  return {
    getScores: function() {
      return scores;
    },
    addScore: function(_name, _score) {
      scores.push({ name: _name, score: _score });
      scores.sort(function(a, b) {
        return b.score - a.score;
      });
      if (scores.length > 10) {
        scores.length = 10;
      }
      game.log.debug("Saving high scores.");
      var str = JSON.stringify(scores);
      localStorage.setItem("high-scores", str);
    }
  };
};

Asteroids.drawPath = function(ctx, position, direction, scale, path, color) {
  if (!color) {
    color = "#fff";
  }
  ctx.strokeStyle = color;
  ctx.setTransform(
    Math.cos(direction) * scale,
    Math.sin(direction) * scale,
    -Math.sin(direction) * scale,
    Math.cos(direction) * scale,
    position[0],
    position[1]
  );

  ctx.beginPath();
  ctx.moveTo(path[0][0], path[0][1]);
  for (i = 1; i < path.length; i++) {
    ctx.lineTo(path[i][0], path[i][1]);
  }
  ctx.stroke();
  ctx.closePath();
  ctx.strokeStyle = "#fff";
};

Asteroids.move = function(position, velocity) {
  position[0] += velocity[0];
  if (position[0] < 0) position[0] = GAME_WIDTH + position[0];
  else if (position[0] > GAME_WIDTH) position[0] -= GAME_WIDTH;

  position[1] += velocity[1];
  if (position[1] < 0) position[1] = GAME_HEIGHT + position[1];
  else if (position[1] > GAME_HEIGHT) position[1] -= GAME_HEIGHT;
};

Asteroids.stars = function() {
  var stars = [];
  for (var i = 0; i < 50; i++) {
    stars.push([Math.random() * GAME_WIDTH, Math.random() * GAME_HEIGHT]);
  }

  return {
    draw: function(ctx) {
      var ii = stars.length;
      for (var i = 0; i < ii; i++) {
        ctx.fillRect(stars[i][0], stars[i][1], 1, 1);
      }
    }
  };
};

Asteroids.play = function(game) {
  var ctx = game.playfield.getContext("2d");
  ctx.fillStyle = "white";
  ctx.strokeStyle = "white";

  var speed = ASTEROID_SPEED,
    hspeed = ASTEROID_SPEED / 2;

  game.level.levelUp(game);

  var bullets = [],
    last_fire_state = false,
    last_asteroid_count = 0;

  var extra_lives = 0;

  // Add a star field.
  game.overlays.add(Asteroids.stars());

  game.pulse = setInterval(function() {
    var kill_asteroids = [],
      new_asteroids = [],
      kill_bullets = [];

    ctx.save();
    ctx.clearRect(0, 0, GAME_WIDTH, GAME_HEIGHT);

    // Be nice and award extra lives first.
    var t_extra_lives = game.player.getScore() / POINTS_TO_EXTRA_LIFE;
    t_extra_lives = Math.floor(t_extra_lives);
    if (t_extra_lives > extra_lives) {
      game.player.extraLife(game);
    }
    extra_lives = t_extra_lives;

    if (game.keyState.getState(Asteroids.UP)) {
      game.player.thrust(THRUST_ACCEL);
    }

    if (game.keyState.getState(Asteroids.LEFT)) {
      game.player.rotate(-ROTATE_SPEED);
    }

    if (game.keyState.getState(Asteroids.RIGHT)) {
      game.player.rotate(ROTATE_SPEED);
    }

    var fire_state = game.keyState.getState(Asteroids.FIRE);
    if (
      fire_state &&
      fire_state != last_fire_state &&
      bullets.length < MAX_BULLETS
    ) {
      var b = game.player.fire(game);
      bullets.push(b);
    }
    last_fire_state = fire_state;

    if (!game.player.isDead()) {
      game.player.move();
      game.player.draw(ctx);
    }

    for (var k = 0; k < bullets.length; k++) {
      if (!bullets[k]) continue;

      if (bullets[k].getAge() > MAX_BULLET_AGE) {
        kill_bullets.push(k);
        continue;
      }
      bullets[k].birthday();
      bullets[k].move();
      bullets[k].draw(ctx);
    }

    for (var r = kill_bullets.length - 1; r >= 0; r--) {
      bullets.splice(r, 1);
    }

    var asteroids = game.asteroids.getIterator();
    for (var i = 0; i < game.asteroids.length; i++) {
      var killit = false;
      asteroids[i].move();
      asteroids[i].draw(ctx);

      // Destroy the asteroid
      for (var j = 0; j < bullets.length; j++) {
        if (!bullets[j]) continue;
        if (Asteroids.collision(bullets[j], asteroids[i])) {
          game.log.debug("You shot an asteroid!");
          // Destroy the bullet.
          bullets.splice(j, 1);
          killit = true; // JS doesn't have "continue 2;"
          continue;
        }
      }

      // Kill the asteroid?
      if (killit) {
        var _gen = asteroids[i].getGeneration() - 1;
        if (_gen > 0) {
          // Create children ;)
          for (var n = 0; n < ASTEROID_CHILDREN; n++) {
            var a = Asteroids.asteroid(game, _gen);
            var _pos = [
              asteroids[i].getPosition()[0],
              asteroids[i].getPosition()[1]
            ];
            a.setPosition(_pos);
            a.setVelocity([
              Math.random() * speed - hspeed,
              Math.random() * speed - hspeed
            ]);
            new_asteroids.push(a);
          }
        }
        game.player.addScore(ASTEROID_SCORE);
        kill_asteroids.push(i);
        continue;
      }

      // Kill the player?
      if (
        !game.player.isDead() &&
        !game.player.isInvincible() &&
        Asteroids.collision(game.player, asteroids[i])
      ) {
        game.player.die(game);
      }
    }

    kill_asteroids.sort(function(a, b) {
      return a - b;
    });
    for (var m = kill_asteroids.length - 1; m >= 0; m--) {
      game.asteroids.splice(kill_asteroids[m], 1);
    }

    for (var o = 0; o < new_asteroids.length; o++) {
      game.asteroids.push(new_asteroids[o]);
    }

    ctx.restore();

    // Do we need to level up?
    if (0 == game.asteroids.length && last_asteroid_count != 0) {
      setTimeout(function() {
        game.level.levelUp(game);
      }, LEVEL_TIMEOUT);
    }

    last_asteroid_count = game.asteroids.length;

    // Draw overlays.
    game.overlays.draw(ctx);

    // Update the info pane.
    game.info.setLives(game, game.player.getLives());
    game.info.setScore(game, game.player.getScore());
    game.info.setLevel(game, game.level.getLevel());
  }, FRAME_PERIOD);
};

// Some boring constants.
Asteroids.LOG_ALL = 0;
Asteroids.LOG_INFO = 1;
Asteroids.LOG_DEBUG = 2;
Asteroids.LOG_WARNING = 3;
Asteroids.LOG_ERROR = 4;
Asteroids.LOG_CRITICAL = 5;
Asteroids.LOG_NONE = 6;

Asteroids.LEFT = 37;
Asteroids.UP = 38;
Asteroids.RIGHT = 39;
Asteroids.DOWN = 40;
Asteroids.FIRE = 32;

// Load it up!
window.onload = Asteroids(document.getElementById("asteroids"));