using UnityEngine;
using System.Collections;
using System.Collections.Generic;

[RequireComponent(typeof(Rigidbody2D))]
public class ContactDamage : MonoBehaviour {

    public float minImpulse = 100.0f;
    public float maxImpulse = 300.0f;

    public float maxDamage = 100.0f;
    private List<ContactDamage> _ignore = new List<ContactDamage>();

    public void AddIgnoreObject(ContactDamage other) {
        _ignore.Add(other);
    }

    void FixedUpdate() {
        _ignore.Clear();
    }

    void OnImpulse(float impulse, Vector2 point, GameObject impulseSource) {
        if (impulse >= minImpulse) {
            float k = 1.0f - (impulse - maxImpulse) / (minImpulse - maxImpulse);
            float damage = k * maxDamage;

            var health = GetComponent<Health>();
            if (health != null) {
                health.ApplyDamage(damage, impulseSource, point);
            }
        }
    }

	void OnCollisionEnter2D(Collision2D col) {
	    var otherHuman = col.transform.GetComponent<HumanController>();
        var thisHuman = GetComponent<HumanController>();
	    if (otherHuman != null && thisHuman != null) {
	        return;
	    }

	    var otherDamageController = col.transform.GetComponent<ContactDamage>();
	    if (otherDamageController != null){
            if (_ignore.Contains(otherDamageController)) {
	            Debug.Log("Skip damage on " + name);
	            return;
	        }
	        else {
	            otherDamageController.AddIgnoreObject(this);
	        }
	    }


        float impulse;
	    var rb = GetComponent<Rigidbody2D>();
        var v1 = rb.GetWorldPointVelocityEx(col.contacts[0].point);
	    Vector2 v2 = Vector2.zero;
	    float m2;
	    Vector2 relativeVelocity;

	    if (col.rigidbody != null && !col.rigidbody.isKinematic) {
	        v2 = col.rigidbody.GetWorldPointVelocityEx(col.contacts[0].point);
	        m2 = col.rigidbody.mass;
	    }
	    else {
	        v2 = Vector2.zero;
	        m2 = 0;
	    }

	    relativeVelocity = v2 - v1;
	    impulse = (rb.mass*v1 + m2*v2).magnitude;

     

        Debug.LogFormat("Collision! Impulse = {0} on object {1} ({4}), relative velocity = {2}, self velocity = {3}", impulse, name, relativeVelocity.magnitude, v1.magnitude, col.transform.name);
	    OnImpulse(impulse, col.contacts[0].point, col.gameObject);
	    if (otherDamageController != null) {
            otherDamageController.OnImpulse(impulse, col.contacts[0].point, gameObject);
	    }

	}
	
}