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

namespace Arugula
{
    public class Expirable : MonoBehaviour
    {
        [Header("Expiration")]
        public bool autoStart = true;
        public bool autoDestroy = true;
        public float lifespan = 10;
        public TimeMode timeMode;
        public float interval = 1;

        public float LifespanRemaining
        {
            get
            {
                if (!expiring)
                    return lifespan;
                return expireTime - time;
            }
        }

        public float NormalizedLifespanRemaining
        {
            get
            {
                return LifespanRemaining / lifespan;
            }
        }

        public float IntervalLifespanRemaining
        {
            get
            {
                if (interval == 0) return LifespanRemaining;

                return LifespanRemaining.Snap(interval, false);
            }
        }

        public bool Expiring => expired;
        public bool Expired => expired;

        public event Action<Expirable> OnStarted = delegate { };
        public event Action<Expirable, float> OnInterval = delegate { };
        public event Action<Expirable> OnExpired = delegate { };

        float expireTime;
        float pauseTime;
        bool expiring = false;
        float time => (timeMode == TimeMode.Scaled ? Time.time : Time.unscaledTime);
        bool expired = false;
        float lastInterval = float.MaxValue;

        public void StartClock()
        {
            if (expired)
                return;

            expiring = true;
            expireTime = time + lifespan;
        }

        public void StopClock()
        {
            if (expired)
                return;

            expiring = false;
        }

        public void Expire()
        {
            expired = true;
            OnExpired(this);
            if (autoDestroy)
                Destroy(gameObject);
        }

        public virtual void Start()
        {
            if (autoStart)
                StartClock();
        }

        public virtual void Update()
        {
            if (expired)
                return;

            if (expiring)
            {
                if (interval > 0)
                {
                    if (IntervalLifespanRemaining != lastInterval)
                    {
                        lastInterval = IntervalLifespanRemaining;
                        OnInterval(this, lastInterval);
                    }
                }

                if (time >= expireTime)
                {
                    Expire();
                }
            }
        }
    }
}
