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


namespace Battle
{

    public class ArrowsSpawner : MonoBehaviour
    {
        public const float GRAVITY_FORCE = 9.81f;

        public float MaxZ;
        public float MaxAngle; //shoot angle when distance = maxZ
        public float ArrowTime; //shoot angle when distance = maxZ
        public Vector3 target;

        [HideInInspector]
        public float z; //distance from target
        [HideInInspector]
        public Vector3 v0; //velocity of arrow when shooted
        [HideInInspector]
        public float angle; //angle from the ground when shooted
        [HideInInspector]
        public ParticleSystem arrowParticleSystem;

        void Awake()
        {
            arrowParticleSystem = GetComponentInChildren<ParticleSystem>();
        }

        public void ShootArrow(Entity enemy)
        {
            if (enemy != null)
            {
                CalculateShootParametersAndAimAtTarget(enemy);
                var path = (enemy.AgentManager.Agent.velocity * ArrowTime);
                Vector3 foreseenPosition = this.target + path;
                //TODO: Wtf liczymy dla aktualnej pozycji wroga, a strzelamy potem do pozycji przewidywannej?
                ShootArrow(foreseenPosition);
            }
        }

        public void ShootArrow(Vector3 target)
        {
            this.target = target;
            CalculateShootParametersAndAimAtTarget();
            EmitArrow();
        }

        public void CalculateShootParametersAndAimAtTarget(Entity enemy)
        {
            arrowParticleSystem.trigger.SetCollider(0, enemy.transform);
            this.target = enemy.AgentManager.Agent.nextPosition;
            CalculateShootParametersAndAimAtTarget();
        }

        public void CalculateShootParametersAndAimAtTarget(Vector3 position)
        {
            this.target = position;
            CalculateShootParametersAndAimAtTarget();
        }

        public void CalculateShootParametersAndAimAtTarget()
        {
            //Celuj cz.1
            transform.LookAt(target);
            transform.eulerAngles = new Vector3(0.0f, transform.eulerAngles.y, 0.0f);

            //Oblicz parametry cz.1
            z = Vector3.Distance(transform.position, target);
            z = Mathf.Min(z, MaxZ);
            angle = MaxAngle * (Mathf.Max(z, 0.5f) / MaxZ);

            //Celuj cz.2
            arrowParticleSystem.transform.localEulerAngles = new Vector3(angle, 180.0f, 0.0f);

            //Oblicz parametry cz.2
            float speed = Mathf.Sqrt((z * arrowParticleSystem.main.gravityModifierMultiplier * GRAVITY_FORCE) / Mathf.Sin(2 * (Mathf.Deg2Rad * angle)));
            v0 = -arrowParticleSystem.transform.forward * speed;
            ArrowTime = (z / new Vector2(v0.x, v0.z).magnitude);
        }

        public void EmitArrow()
        {
            ParticleSystem.EmitParams emitParams = new ParticleSystem.EmitParams();
            emitParams.velocity = v0;
            arrowParticleSystem.Emit(emitParams, 1);
        }
    }

}