Linked: AuraCamera

using UnityEngine;
using System.Collections;

public class AuraCamera : MonoBehaviour {

    //Spline
    [SerializeField] private SimpleSpline _startSpline = null;
    private SimpleSpline _currentSpline;

    //Player
    Player _playerScript;
    bool _playerIn;

    //Camera
    public float MoveSpeed = 5.0f;
    private Vector3 _cameraStartPos;
    private bool _activated;
    private bool _waiting;
    private float _deltaOnCurrentSpline;
    private const float SyncDelta =1f;
    private bool _syncSplineAndCameraPos;
    private bool _syncToPath;
    private float _speedBasedOnSplineDistance;

    void Start () {
        if (_startSpline != null) return;
        Debug.LogError("Start spline is missing");
        Destroy(this);
    }

    //Update when player can trigger AuraCamera
    IEnumerator PlayerInUpdate()
    {
        if (_playerIn) yield break;
        _playerIn = true;
        while (_playerIn)
        {
            CheckForSignal();
            yield return null;
        }
    }

    //Check if player want and can use the AuraCamera
    void CheckForSignal()
    {
        if (_activated) return;
        if (!InputManager.InteractDown()) return;
        if (_playerScript.BlockPlayerInput) return;
        _playerScript.BlockPlayerInput = true;
        _activated = true;
        _playerScript.CameraScript.StartAuraCamWhenPossible(this);
    }

    //Start AuraCamera
    public void StartFollowingTrack()
    {
        StartCoroutine(FollowTrack());
    }

    //Follow track of AuraCamera
    IEnumerator FollowTrack()
    {
        _playerScript.CameraScript.OverWriteCameraMovement = true;
        _playerScript.BlockPlayerInput = true;
        _activated = true;
        _deltaOnCurrentSpline = 0.0f;
        _currentSpline = _startSpline;
        _syncSplineAndCameraPos = true;
        _syncToPath = true;
        _cameraStartPos = _playerScript.CameraScript.transform.position;
        CalculateTheMoveSpeed();

        while (!FollowAuraTrack())
        {
            yield return null;
        }
        _playerScript.CameraScript.ResetTransform();
        _playerScript.BlockPlayerInput = false;
        _activated = false;

        _playerScript.CameraScript.OverWriteCameraMovement = false;
    }

    //Calculate the speed to move over the spline
    void CalculateTheMoveSpeed()
    {
        _speedBasedOnSplineDistance = MoveSpeed/_currentSpline.Length;
    }

    //Move the AuraCamera if needed
    bool FollowAuraTrack()
    {
        if (_currentSpline == null) return true;

        if (!_waiting)
        {
            MoveOnSpline(Time.deltaTime);
        }
        return false;
    }

    //Move the AuraCamera if needed
    void MoveOnSpline(float time)
    {
        _deltaOnCurrentSpline += time*_speedBasedOnSplineDistance;
        if (_deltaOnCurrentSpline >= 1) //Reached end current spline
        {
            if (_syncSplineAndCameraPos && !_syncToPath)
            {
                //Place camera back to player
                _playerScript.CameraScript.transform.position = _playerScript.CameraScript.GetPositionCameraShouldBe();
            }
            else
            {
                _playerScript.CameraScript.Set2DPos(_currentSpline.Parameters.EndPoint);
            }
            _syncSplineAndCameraPos = false;
            StartCoroutine(StayOnSpline());
        }
        else
        {
            var position = _currentSpline.CalculateSplinePoint(_deltaOnCurrentSpline);
            if (_syncSplineAndCameraPos)
            {
                if (_syncToPath)
                {
                    if (_deltaOnCurrentSpline < SyncDelta)
                    {
                        var delta = _deltaOnCurrentSpline;
                        delta *= (1/SyncDelta);
                        position = Vector3.Lerp(_cameraStartPos, position, delta);
                    }
                    else
                    {
                        _syncSplineAndCameraPos = false;
                    }
                }
                else
                {
                    if (_deltaOnCurrentSpline > 1-SyncDelta)
                    {
                        var positionToGetTo = _playerScript.CameraScript.GetPositionCameraShouldBe();
                        var delta = _deltaOnCurrentSpline-(1-SyncDelta);
                        delta *= (1 / SyncDelta);
                        position = Vector3.Lerp(position, positionToGetTo, delta);
                    }
                }
            }
            _playerScript.CameraScript.Set2DPos(position);
        }
    }

    //Stand still so the player can clearly see the focus point
    IEnumerator StayOnSpline()
    {
        _waiting = true;

        yield return new WaitForSeconds(_currentSpline.WaitTime);

        _waiting = false;
        _currentSpline = _currentSpline.NextSpline;

        //Check if done
        if (_currentSpline == null) yield break;

        //Check if on last spline
        if (_currentSpline.NextSpline == null)
        {
            _syncToPath = false;
            _syncSplineAndCameraPos = true;
        }
        _deltaOnCurrentSpline = 0.0f;
        CalculateTheMoveSpeed();
    }

    //Player enters bounds to trigger AuraCamera
    public void OnTriggerEnter(Collider other)
    {
        var playerScript = other.GetComponent<Player>();
        if(playerScript!=null)
        {
            _playerScript = playerScript;
            StartCoroutine(PlayerInUpdate());
        }
    }

    //Player leaves bounds to trigger AuraCamera
    public void OnTriggerExit(Collider other)
    {
        var playerScript = other.GetComponent<Player>();
        if (playerScript != null)
        {
            _playerIn = false;
        }
    }
}