using UnityEngine;
using System.Collections;

namespace FORGE3D
{
    [RequireComponent(typeof(LineRenderer))]
    public class F3DCurvedBeam : MonoBehaviour
    {
        public Transform dest;
        public float beamScale; // Default beam scale to be kept over distance 
        public float UVTime; // UV Animation speed  
        LineRenderer lineRenderer; // Line rendered component 
        public int curvePoints;
        public float curveHeight;
        float initialBeamOffset; // Initial UV offset 

        void Start()
        {
            // Get line renderer component
            lineRenderer = GetComponent<LineRenderer>();

            // Randomize uv offset
            initialBeamOffset = Random.Range(0f, 5f);

            lineRenderer.positionCount = curvePoints;
        }

        void Update()
        {
            lineRenderer.material.SetTextureOffset("_MainTex", new Vector2(Time.time * UVTime + initialBeamOffset, 0f));

            float distToDest = Vector3.Distance(transform.position, dest.position);

            lineRenderer.SetPosition(0, transform.position);

            float piRate = Mathf.PI / (curvePoints - 1);

            for (int i = 1; i < curvePoints - 1; i++)
            {
                float distRatio = (distToDest / (curvePoints - 1)) * i;
                Vector3 midPos = Vector3.Normalize(dest.position - transform.position) * distRatio;

                float cHeight = Mathf.Sin(piRate * i) * curveHeight;
                midPos += transform.up * cHeight;

                lineRenderer.SetPosition(i, transform.position + midPos);
            }

            lineRenderer.SetPosition(curvePoints - 1, dest.position);

            float propMult = distToDest * (beamScale / 10f);

            // Set beam scaling according to its length
            lineRenderer.material.SetTextureScale("_MainTex", new Vector2(propMult, 1f));
        }
    }
}