using UnityEngine;
using System.Collections;
using System;
using UnityEngine.Events;
using UnityEngine.XR.Interaction.Toolkit;
using NaughtyAttributes;

public class StepScript : MonoBehaviour
{
    [Header("Step Info")]
    /// <summary>
    /// Add a description to the step to explain what is supposed to be
    /// </summary>
    [Tooltip("Add a description to the step to explain what is supposed to be")]
    [TextArea(3, 10)]
    public string description;

    /// <summary>
    /// If true, the game object is enabled at game start
    /// </summary>
    [Tooltip("If true, the game object is visible at game start")]
    public bool isEnabledBeforeStart = true;

    /// <summary>
    /// If true, the game object will stay enabled after the step is completed
    /// </summary>
    [Tooltip("If true, the game object will stay visible after the step is completed")]
    public bool isEnabledAfterEnd = true;


    /// <summary>
    /// Refresh rate of the step, used to update the step
    /// </summary>
    public float RefreshRate = 0.2f;

    [HorizontalLine(1, EColor.Blue)]


    /// <summary>
    /// If true, the step is completed at start, so no other completion event is needed
    /// </summary>
    [Tooltip("If true, the step is completed at start, so no other completion event is needed. It can still use pre and post callbacks")]
    public bool startCompleted = false;

    /// <summary>
    /// If true, the step is completed when the item is grabbed it needs the XRGrabInteractable component 
    /// to detect when the item is grabbed. At least one completion event must be set to avoid an infinite loop
    /// </summary>
    [Tooltip("If true, the step is completed when the item is grabbed it needs the XRGrabInteractable component " +
               "to detect when the item is grabbed. At least one completion event must be set to avoid an infinite loop")]
    [InfoBox("Use this if no other complention events are added", EInfoBoxType.Warning)]
    [HideIf("startCompleted")]
    public bool completeOnItemGrabbed = true;

    /// <summary>
    /// These will be subscribed, so that they will act as completion events
    /// </summary>
    //[Tooltip("These will be subscribed, so that they will act as completion events. They can be used with the rab event.")]
    //[HideIf("startCompleted")]
    //public UnityEvent StepCompletionEvents;

    [HorizontalLine(1, EColor.Blue)]

    [Header("Callbacks")]

    /// <summary>
    /// If true, run the specified callbacks when the step starts
    /// </summary>
    [Tooltip("If true, run the specified callbacks when the step starts")]
    public bool useOnStart = false;

    /// <summary>
    /// Event called when the step starts
    /// </summary>
    [ShowIf("useOnStart")]
    [Tooltip("Event called when the step starts, before the update loop")]
    public UnityEvent OnStart;

    /// <summary>
    /// If true, run the specified callbacks when the step is updated
    /// </summary>
    [HideIf("startCompleted")]
    [Tooltip("This run the main callbacks that run until the step is complete by another event. The refresh rate is the same of the HapticManager")]
    public UnityEvent OnUpdate;

    /// <summary>
    /// If true, run the specified callbacks when the step is complete
    /// </summary>
    [Tooltip("If true, run the specified callbacks when the step is complete")]
    public bool useOnEnd = false;

    /// <summary>
    /// If true, run the specified callbacks when the step is complete
    /// </summary>
    /// <returns></returns>
    [ShowIf("useOnEnd")]
    [Tooltip("If true, run the specified callbacks when the step is complete")]
    public UnityEvent OnEnd;

    /// <summary>
    /// If true, once the OnEnd callback are called, a delay is started, this allows to
    /// run another set of callback after these
    /// </summary>
    [Tooltip("If true, once the OnEnd callback are called, a delay is started, this allows to " +
        "run another set of callback after these")]
    public bool useDelayedEnd = false;

    /// <summary>
    ///  Delay after the list ends, used to wait for delayed effects
    /// </summary>
    [ShowIf("useDelayedEnd")]
    [MinValue(0.0f), MaxValue(60)]
    [Tooltip("Delay after the list ends, used to wait for delayed effects, runned before the OnEndPostDelay")]
    public float endTimeDurationSeconds = 5f;

    /// <summary>
    /// Event called after the list ends, after a delay
    /// </summary>
    [ShowIf("useDelayedEnd")]
    [Tooltip("Event called after the list ends, after a delay")]
    public UnityEvent OnEndPostDelay;

    /// <summary>
    /// Flag to check if the step is complete
    /// </summary>
    private bool isStepComplete;

    /// <summary>
    /// Reference to the XRGrabInteractable component, used to detect when the item is grabbed
    /// </summary>
    private XRGrabInteractable grabInteractable;

    void Start()
    {
        if(startCompleted)
        {
            completeOnItemGrabbed = false;
            OnUpdate = null;
        }

        if (gameObject == null)
        {
            throw new Exception("This script cannot access a gameObject");
        }
        else if (gameObject.transform == null)
        {
            throw new Exception("This script cannot access a gameObject transform");
        }
        else if (completeOnItemGrabbed) {
            grabInteractable = gameObject.GetComponent<XRGrabInteractable>();

            if (grabInteractable == null)
            {
                throw new Exception("This script cannot access a XRGrabInteractable component");
            }
        }

        gameObject.SetActive(isEnabledBeforeStart);
    }

    /// <summary>
    /// Run the step, this is called by the StepsListScript
    public IEnumerator StepRun()
    {
        Debug.Log("Step: " + name + " started");

        isStepComplete = startCompleted;

        gameObject.SetActive(true);

        if (useOnStart)
        {
            OnStart.Invoke();
        }

        if (!startCompleted)
        {
            grabInteractable = gameObject.GetComponent<XRGrabInteractable>();
            SubscribeToCompletionEvents();

            do
            {
                OnUpdate.Invoke();
                // Debug.Log("Step: " + name + " updated");
                yield return new WaitForSeconds(RefreshRate);
            } while (!isStepComplete);

            UnSubscribeToCompletionEvents();
        }

        if (useOnEnd)
        {
            OnEnd.Invoke();
        }

        if (useDelayedEnd)
        {
            yield return new WaitForSeconds(endTimeDurationSeconds);
            OnEndPostDelay.Invoke();
        }

        gameObject.SetActive(isEnabledAfterEnd);

        Debug.Log("Step complete");
    }

    /// <summary>
    /// Callback for to set the step as complete from any event that calls it
    /// </summary>
    /// <param name="arg0"></param>
    public void StepCompletionListener(SelectEnterEventArgs arg0)
    {
        isStepComplete = true;
        Debug.Log("Step completed by grabbing an item");
    }

    /// <summary>
    /// Subscribe to the completion events
    /// </summary>
    private void SubscribeToCompletionEvents()
    {
        // subscribe to the grab event, if needed
        if (completeOnItemGrabbed)
        {
            grabInteractable.selectEntered.AddListener(StepCompletionListener);
        }
    }

    /// <summary>
    /// Unsubscribe to the completion events
    /// </summary>
    private void UnSubscribeToCompletionEvents()
    {
        if (completeOnItemGrabbed)
        {
            grabInteractable.selectEntered.RemoveListener(StepCompletionListener);
        }
    }
}