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

public class IKAnimation : MonoBehaviour
{
    [SerializeField] private float distanceToStep;
    
    [SerializeField] private Transform body;
    [SerializeField] private List<IKTarget> targets;

    [SerializeField] private float timeAnimation;
    [SerializeField] private List<float> timing;

    private int timeIndex;
    private Vector3 oldPos;
    private float timeToNext;
    
    private void Awake()
    {
        for(var index = 0; index < targets.Count; index++)
        {
            var ikTarget = targets[index];
            ikTarget.FixedPosition = ikTarget.IK.position;
            ikTarget.OffsetPosition = ikTarget.IK.localPosition;
            ikTarget.Timing = timing[index];
        }
        oldPos = transform.position;
    }

    private void LateUpdate()
    {
        if(Vector3.Distance(oldPos, transform.position) > distanceToStep)
        {
            StartCoroutine(ToSteps());
            IEnumerator ToSteps()
            {
                for(var index = 0; index < targets.Count; index++)
                {
                    var ikTarget = targets[index];
                    var origPosition = transform.position + ikTarget.OffsetPosition;

                    Debug.DrawRay(origPosition, Vector3.up, Color.magenta);

                    var distance = Vector3.Distance(ikTarget.FixedPosition, origPosition);
                    if(distance > distanceToStep)
                    {
                        if(ikTarget.IsAnimation == false && ikTarget.Timing <= 0f)
                        {
                            ikTarget.IsAnimation = true;

                            timeIndex += 1;
                            if(timeIndex >= timing.Count) timeIndex = 0;
                            ikTarget.Timing = timing[index];

                            StartCoroutine(Animation());

                            IEnumerator Animation()
                            {
                                var t = timeAnimation;
                                var oldPos = ikTarget.FixedPosition;
                                var newPos = origPosition;
                                var dir = (oldPos - newPos).normalized * distanceToStep;
                                newPos -= dir;
                                while(t >= 0)
                                {
                                    Debug.DrawRay(newPos, Vector3.up, Color.cyan);
                                    var lerp = Vector3.Lerp(oldPos, newPos, timeAnimation - t);
                                    ikTarget.FixedPosition = lerp;
                                    t -= Time.deltaTime;
                                    yield return null;
                                }
                                ikTarget.FixedPosition = newPos;
                                yield return null;
                                ikTarget.IsAnimation = false;
                            }
                        }
                        yield return new WaitForSeconds(timeAnimation);
                        ikTarget.Timing -= Time.deltaTime;
                    }
                    ikTarget.IK.position = ikTarget.FixedPosition;
                }
            }
        }
        foreach(var ikTarget in targets)
        {
            ikTarget.IK.position = ikTarget.FixedPosition;
        }
    }
}

[Serializable]
public class IKTarget
{
    public Transform IK;
    public Vector3 FixedPosition;
    public Vector3 OffsetPosition;
    public bool IsAnimation;
    public float Timing;
}