SamsonGame/Assets/Scripts/Game/UI/Elements/RewardTimerButton.cs

using System;
using System.Collections;
using UnityEngine;
using UnityEngine.UI;

namespace RND
{

    public class RewardTimerButton : RewardButton
    {
        [Header("Fields")] [SerializeField] private Image _timer;
        [SerializeField] private Text _power;

        [Header("Settings")] [SerializeField, Range(1, 100)] private int _maximumPower = 5;
        [SerializeField, Range(1, 100)] private int _minimumPower = 2;
        [SerializeField] private Color _timerLoadColour;

        public int Power { get; private set; } = 5;

        private Color _textColour;

        protected override void Init()
        {
            _textColour = _power.color;
        }

        public override void Begin()
        {
            base.Begin();

            Power = _maximumPower;
            _minimumPower = Mathf.Clamp(_minimumPower, 1, _maximumPower);
            _timer.fillAmount = 0f;

            _timer.gameObject.Hide();
            _power.gameObject.Hide();
        }

        protected override void OnRewardLoaded()
        {
            base.OnRewardLoaded();

            StartCoroutine(PowerReduceRoutine());
        }

        private IEnumerator PowerReduceRoutine()
        {
            _power.text = $"x{Power}";
            _power.color = _timerLoadColour;
            _power.gameObject.Show();

            _timer.fillAmount = 0f;
            _timer.color = _timerLoadColour;
            _timer.gameObject.Show();

            const float firstReduceDelay = 0.33f;
            yield return new WaitForSeconds(firstReduceDelay);

            while (Power > _minimumPower)
            {
                _power.text = $"x{Power}";
                float currentFill = _timer.fillAmount;

                const float mainReduceDelay = 1f;
                yield return Tween.DoTween(mainReduceDelay,
                    t => { _timer.fillAmount = Mathf.Lerp(currentFill, 1f, t); });

                _timer.fillAmount = 0f;
                Power--;
            }

            _power.text = $"x{Power}";
            _power.color = _textColour;
            _timer.color = _textColour;
            yield return null;
        }

        protected void OnDisable()
        {
            StopAllCoroutines();
        }
    }
}