Energy.cs

// for health, mana, etc.
using UnityEngine;
using UnityEngine.Events;
using Mirror;

namespace uMMORPG
{
    public abstract class Energy : NetworkBehaviour
    {
        // current value
        // set & get: keep between min and max
        [SyncVar] int _current = 0;
        public int current
        {
            get { return Mathf.Min(_current, max); }
            set
            {
                bool emptyBefore = _current == 0;
                _current = Mathf.Clamp(value, 0, max);
                if (_current == 0 && !emptyBefore) onEmpty.Invoke();
            }
        }

        // maximum value (may depend on buffs, items, etc.)
        public abstract int max { get; }

        // recovery rate (may depend on buffs, items etc.)
        public abstract int recoveryRate { get; }

        // don't recover while dead. all energy scripts need to check Health.
        public Health health;

        // spawn with full energy? important for monsters, etc.
        public bool spawnFull = true;

        [Header("Events")]
        public UnityEvent onEmpty;

        public override void OnStartServer()
        {
            // set full energy on start if needed
            if (spawnFull) current = max;

            // recovery every second
            InvokeRepeating(nameof(Recover), 1, 1);
        }

        // get percentage
        public float Percent() =>
            (current != 0 && max != 0) ? (float)current / (float)max : 0;

        // recover once a second
        [Server]
        public void Recover()
        {
            if (enabled && health.current > 0)
                current += recoveryRate;
        }
    }
}