using System;
using TMPro;
using UnityEngine;
using UnityEngine.UI;

namespace Ashwild.Settings
{
    /// <summary>
    /// A reusable slider + value label. It is pure UI: it knows nothing about which setting it
    /// drives. The hosting panel calls <see cref="Init"/> once to hand it its range, label format
    /// and the action to run when the user moves it; afterwards the panel pushes the current value
    /// through <see cref="SetValue"/>. The range is applied to the slider in <see cref="Init"/>, so
    /// a control can never be stuck at the slider's default 0–1 range.
    /// </summary>
    [DisallowMultipleComponent]
    public class SettingSliderWidget : MonoBehaviour
    {
        #region Serialized Fields

        [Header("References")]
        [SerializeField] private Slider slider;
        [SerializeField] private TMP_Text valueLabel;

        #endregion

        #region State

        private Action<float> onChanged;
        private float labelScale = 1f;
        private string labelFormat = "{0:F0}";

        #endregion

        #region Public API

        /// <summary>
        /// Configures the slider with its range and label format, and registers the action to run
        /// when the user drags it. Call once (the apply action is not invoked by <see cref="SetValue"/>).
        /// </summary>
        public void Init(float min, float max, float labelScale, string labelFormat, Action<float> onChanged)
        {
            if (slider == null)
            {
                Debug.LogError($"[SettingSliderWidget] '{name}' has no Slider assigned.", this);
                return;
            }

            this.labelScale = labelScale;
            this.labelFormat = labelFormat;
            this.onChanged = onChanged;

            slider.minValue = min;
            slider.maxValue = max;
            slider.onValueChanged.RemoveListener(HandleSliderChanged);
            slider.onValueChanged.AddListener(HandleSliderChanged);
        }

        /// <summary>
        /// Displays the given value without invoking the apply action.
        /// </summary>
        public void SetValue(float value)
        {
            if (slider == null) return;
            slider.SetValueWithoutNotify(value);
            UpdateLabel(value);
        }

        #endregion

        #region Event Handlers

        /// <summary>
        /// Updates the label and runs the apply action with the user-driven value.
        /// </summary>
        private void HandleSliderChanged(float value)
        {
            UpdateLabel(value);
            onChanged?.Invoke(value);
        }

        #endregion

        #region Internal Helpers

        /// <summary>
        /// Formats and shows the scaled value, when a label is wired.
        /// </summary>
        private void UpdateLabel(float value)
        {
            if (valueLabel != null) valueLabel.text = string.Format(labelFormat, value * labelScale);
        }

        #endregion
    }
}