using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Valve.VR.InteractionSystem;


[RequireComponent(typeof(Collider))]
public class Backpack : MonoBehaviour {
    private class HapticPulse {
        public Hand Hand;
        public ushort Duration;

        public HapticPulse(Hand hand, ushort duration = 2000) {
            Hand = hand;
            Duration = duration;
        }
    }

    public Hand.AttachmentFlags GrabFlags;
    public Hand[] Hands;
    public List<Throwable> Contents = new List<Throwable>();

    private Collider Collider;
    private List<HapticPulse> PulseQueue = new List<HapticPulse>(4);
    private float NextHapticTime = 0;
    private bool[] HandReminded = new bool[] { false, false };

    private void Awake() {
        Collider = GetComponent<Collider>();
        if (Hands.Length > HandReminded.Length) {
            Debug.LogError($"Backpack has >{HandReminded.Length} hands assigned, please update HandReminded accordingly.");
        }
    }

    private void Update() {
        for (int I = 0; I < Hands.Length; I++) {
            bool HandInBag = IsHandInBag(Hands[I]);
            if (!HandReminded[I] && HandInBag) {
                HandReminded[I] = true;
                if (PulseQueue.Count == 0) {
                    PulseQueue.Add(new HapticPulse(Hands[I], 1000));
                }
            } else if (HandReminded[I] && !HandInBag) {
                HandReminded[I] = false;
                if (PulseQueue.Count == 0) {
                    PulseQueue.Add(new HapticPulse(Hands[I], 500));
                }
            }
        }

        if (Time.time >= NextHapticTime && PulseQueue.Count > 0) {
            HapticPulse NextPulse = PulseQueue[0];
            // Note: using the microsecond-based haptic pulses to avoid Vive wands getting stuck vibrating.
            // Don't know why it happens, and didn't find much info by googling.
            NextPulse.Hand.TriggerHapticPulse(NextPulse.Duration);
            NextHapticTime = Time.time + Time.deltaTime;
            PulseQueue.RemoveAt(0);
        }
    }

    private bool IsHandInBag(Hand hand) {
        Vector3 DeltaFromBag = hand.transform.position - Collider.ClosestPoint(hand.transform.position);
        return DeltaFromBag.magnitude < hand.hoverSphereRadius;
    }

    public void Grab(Hand hand) {
        if (IsHandInBag(hand) && Contents.Count > 0) {
            int Index = Contents.Count - 1;
            Throwable Item = Contents[Index];
            Item.gameObject.SetActive(true);
            hand.AttachObject(Item.gameObject, hand.IsGrabbingWithType(GrabTypes.Pinch) ? GrabTypes.Pinch : GrabTypes.Grip, GrabFlags);
            Contents.RemoveAt(Index);

            PulseQueue.Clear();
            PulseQueue.Add(new HapticPulse(hand, 2_000));
            PulseQueue.Add(new HapticPulse(hand, 4_000));
            PulseQueue.Add(new HapticPulse(hand, 8_000));
        }
    }

    public void Store(Hand hand) {
        if (hand.currentAttachedObject != null) {
            Throwable Item = hand.currentAttachedObject.GetComponent<Throwable>();
            if (IsHandInBag(hand) && Item != null) {
                Contents.Add(Item);
                hand.DetachObject(Item.gameObject);
                Item.gameObject.SetActive(false);

                PulseQueue.Clear();
                PulseQueue.Add(new HapticPulse(hand, 15_000));
            }
        }
    }
}