Game::Game() :
camera_(0),
background_(0),
player_(0),
collision_(0),
bullet_(0)
{
camera_ = new OrthoCamera();
camera_->SetPosition(XMFLOAT3(0.0f, 0.0f, 0.0f));
camera_->SetFrustum(800.0f, 600.0f, -100.0f, 100.0f);
background_ = new Background(800.0f, 600.0f);
collision_ = new Collision();
}

Game::~Game()
{
delete camera_;
delete background_;
delete player_;
DeleteAllBullets();
DeleteAllAsteroids();
DeleteAllExplosions();
delete collision_;
}

void Game::DoCollision(GameEntity *a, GameEntity *b)
{
Ship *player = static_cast<Ship *>(a == player_ ? a : (b == player_ ?
b : 0));
Bullet *bullet = static_cast<Bullet *>(IsBullet(a) ? a : (IsBullet(b)
? b : 0));
Asteroid *asteroid = static_cast<Asteroid *>(IsAsteroid(a) ? a :
(IsAsteroid(b) ? b : 0));

if (player_->shieldActive)
    return;
else
{
    if (player && asteroid)
    {
        AsteroidHit(asteroid);
        DeletePlayer();
    }
}


if (bullet && asteroid)
{
    AsteroidHit(asteroid);
    DeleteAllBullets();
}
}

void Game::AsteroidHit(Asteroid *asteroid)
{
int oldSize = asteroid->GetSize();
if (oldSize > 1)
{
    int smallerSize = oldSize -1;
    XMVECTOR position = asteroid->GetPosition();
    SpawnAsteroidAt(position, smallerSize);
    SpawnAsteroidAt(position, smallerSize);
}
DeleteAsteroid(asteroid);
}

void Game::DeleteAsteroid(Asteroid *asteroid)
{
asteroids_.remove(asteroid);
delete asteroid;
}

void Game::DeletePlayer()
{
delete player_;
player_ = 0;
}

void Game::DeleteAllBullets()
{
for (BulletList::const_iterator bulletIt = bullet_.begin(),
    end = bullet_.end();
    bulletIt != end;
    ++bulletIt)
{
    delete (*bulletIt);
}

bullet_.clear();
}

void Game::SpawnAsteroids(int numAsteroids)
{
float halfWidth = 800.0f * 0.5f;
float halfHeight = 600.0f * 0.5f;
for (int i = 0; i < numAsteroids; i++)
{
    float x = Random::GetFloat(-halfWidth, halfWidth);
    float y = Random::GetFloat(-halfHeight, halfHeight);
    XMVECTOR position = XMVectorSet(x, y, 0.0f, 0.0f);
    SpawnAsteroidAt(position, 3);
}
}

void Game::SpawnAsteroidAt(XMVECTOR position, int size)
{
const float MAX_ASTEROID_SPEED = 1.0f;

float angle = Random::GetFloat(Maths::TWO_PI);
XMMATRIX randomRotation = XMMatrixRotationZ(angle);
XMVECTOR velocity = XMVectorSet(0.0f, Random::GetFloat(MAX_ASTEROID_SPEED),
0.0f, 0.0f);
velocity = XMVector3TransformNormal(velocity, randomRotation);

Asteroid *asteroid = new Asteroid(position, velocity, size);
asteroid->EnableCollisions(collision_, size * 5.0f);
asteroids_.push_back(asteroid);
}