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

namespace Ashwild.Settings
{
    /// <summary>
    /// A reusable dropdown. Pure UI: it knows nothing about which setting it drives. The panel
    /// calls <see cref="Init"/> once to register the selection action, supplies the option list via
    /// <see cref="SetOptions"/> (resolutions, monitors… are all built by the panel) and selects the
    /// current entry through <see cref="SetValue"/>.
    /// </summary>
    [DisallowMultipleComponent]
    public class SettingDropdownWidget : MonoBehaviour
    {
        #region Serialized Fields

        [Header("References")]
        [SerializeField] private TMP_Dropdown dropdown;

        #endregion

        #region State

        private Action<int> onChanged;

        #endregion

        #region Public API

        /// <summary>
        /// Registers the action to run when the user picks an option. Call once.
        /// </summary>
        public void Init(Action<int> onChanged)
        {
            if (dropdown == null)
            {
                Debug.LogError($"[SettingDropdownWidget] '{name}' has no Dropdown assigned.", this);
                return;
            }

            this.onChanged = onChanged;
            dropdown.onValueChanged.RemoveListener(HandleChanged);
            dropdown.onValueChanged.AddListener(HandleChanged);
        }

        /// <summary>
        /// Replaces the dropdown's options. Call before <see cref="SetValue"/> on refresh.
        /// </summary>
        public void SetOptions(IEnumerable<string> options)
        {
            if (dropdown == null) return;
            dropdown.ClearOptions();
            dropdown.AddOptions(new List<string>(options));
        }

        /// <summary>
        /// Selects the given index (clamped to the current options) without invoking the action.
        /// </summary>
        public void SetValue(int index)
        {
            if (dropdown == null) return;
            dropdown.SetValueWithoutNotify(Mathf.Clamp(index, 0, dropdown.options.Count - 1));
            dropdown.RefreshShownValue();
        }

        #endregion

        #region Event Handlers

        /// <summary>
        /// Runs the apply action with the chosen index.
        /// </summary>
        private void HandleChanged(int index) => onChanged?.Invoke(index);

        #endregion
    }
}