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

namespace uc
{
    public enum ActivityEventType
    {
        Enter,
        Finish,
        Leave,
        Killed
    }

    public class ActivityBase : MonoBehaviour
    {
        bool is_finished = false;
        public bool IsFinished { set { is_finished = value; } get { return is_finished; } }

        float activity_duration = 0.0f;
        public float Duration { get { return activity_duration; } }

        bool is_entering = false;
        public bool IsEntering { get { return is_entering; } }

        float stamp = 0.0f;

        [Serializable]
        public class Entry
        {
            public ActivityEventType eventID = ActivityEventType.Enter;
            public UnityEvent callback = new UnityEvent();
        }

        [SerializeField]
        private List<Entry> m_Delegates;

        public List<Entry> triggers
        {
            get
            {
                if (m_Delegates == null)
                    m_Delegates = new List<Entry>();
                return m_Delegates;
            }
            set { m_Delegates = value; }
        }

        protected virtual void OnEnter() { }
        public void Enter()
        {
            gameObject.SetActive(true);
            is_entering = true;
            is_finished = false;
            stamp = Time.time;
            activity_duration = 0.0f;
            OnEnter();
            OnEnterEvent();
        }

        protected virtual void OnUpdate() { }
        private void Update()
        {
            activity_duration = Time.time - stamp;
            OnUpdate();
        }

        protected virtual void OnLeave() { }
        public void Leave()
        {
            is_entering = false;
            is_finished = true;
            stamp = Time.time;
            OnLeave();
            OnLeaveEvent();
        }

        protected virtual void OnFinish() { }
        public void Finish()
        {
            OnFinish();
            OnFinishEvent();
        }

        protected virtual void OnKilled() { }
        public void Killed()
        {
            Leave();
            OnKilled();
            OnKillEvent();
        }

        private void Execute(ActivityEventType id)
        {
            for (int i = 0, imax = triggers.Count; i < imax; ++i)
            {
                var ent = triggers[i];
                if (ent.eventID == id && ent.callback != null)
                    ent.callback.Invoke();
            }
        }

        private void OnEnterEvent()
        {
            Execute(ActivityEventType.Enter);
        }

        private void OnFinishEvent()
        {
            Execute(ActivityEventType.Finish);
        }

        private void OnLeaveEvent()
        {
            Execute(ActivityEventType.Leave);
        }

        private void OnKillEvent()
        {
            Execute(ActivityEventType.Killed);
        }
    }
}