// Event structure containing information used to apply damage to an object.
class DamageEvent : ZilchEvent
{
    var Damage : Real = 0.0;
    // The contact normal towards the object that is taking damage.
    var Normal : Real3 = Real3(0.0, 0.0, 0.0);
    // The point in world space where the damage is being applied.
    // Can be used to spawn effects at the point of contact.
    var WorldPoint : Real3 = Real3(0.0, 0.0, 0.0);
}

class EnemyHealth : ZilchComponent
{
    // The max health we can have
    [Property]
    var MaxHealth : Real = 50.0;
    // How much health we currently have. Separated from MaxHealth so that we can clamp to max health.
    var CurrentHealth : Real = 50.0;
    
    // If we reach zero health should we call destroy on ourself?
    [Property]
    var DestroyAtZeroHealth : Boolean = true;
    
    // A scalar to modify how much damage this object takes.
    [Property]
    var DamageScalar : Real = 1.0;
    
    // When we die, we sound out a death event.
    sends Death : ZilchEvent;
    
    function Initialize(init : CogInitializer)
    {
        this.CurrentHealth = this.MaxHealth;
        Zero.Connect(this.Owner, Events.ApplyDamage, this.OnApplyDamage);
    }
    
    function OnApplyDamage(damageEvent : DamageEvent)
    {
        this.ApplyDamage(damageEvent.Damage);
    }
    
    function ApplyDamage(damage : Real)
    {
        // Compute the total damage based upon our damage scalar.
        damage = damage * this.DamageScalar;
        
        this.CurrentHealth -= damage;
        // Clamp our current health (in my case I don't want to have
        // to heal through negative health so I clamp to 0).
        this.CurrentHealth = Math.Clamp(this.CurrentHealth, 0.0, this.MaxHealth);
        
        // If we have no health.
        if(this.CurrentHealth <= 0.0)
        {
            // Let anyone listening know we just died.
            var toSend = ZilchEvent();
            this.Owner.DispatchEvent(Events.Death, toSend);
            
            // And if the property is set destroy ourself.
            if(this.DestroyAtZeroHealth)
            {
                this.Owner.Destroy();
            }
        }
    }
}