/**
 * Copyright 2019 The Knights Of Unity, created by Pawel Stolarczyk
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


using System;
using DemoGame.Scripts.Utils;
using UnityEngine;
using UnityEngine.UI;

namespace DemoGame.Scripts.Menus
{

    /// <summary>
    /// Manages visibility of the gameobject.
    /// </summary>
    public class SingletonMenu<T> : Singleton<T>, IMenu where T : MonoBehaviour
    {
        #region Fields

        /// <summary>
        /// Reference to <see cref="CanvasGroup"/> used to show or hide the gameobject.
        /// </summary>
        [SerializeField] private CanvasGroup _canvasGroup = null;

        /// <summary>
        /// Button returning from this panel to main menu.
        /// </summary>
        [SerializeField] protected Button _backButton = null;

        #endregion

        #region Properties

        /// <summary>
        /// If true, <see cref="Show"/> method was called and 
        /// this panel is visible to the viewer.
        /// </summary>
        public bool IsShown { get; protected set; }

        #endregion

        #region Methods

        /// <summary>
        /// Makes this menu visible to the viewer.
        /// </summary>
        [ContextMenu("Show")]
        public virtual void Show()
        {
            _canvasGroup.alpha = 1;
            _canvasGroup.blocksRaycasts = true;
            IsShown = true;
        }

        /// <summary>
        /// Hides this menu.
        /// </summary>
        [ContextMenu("Hide")]
        public virtual void Hide()
        {
            _canvasGroup.alpha = 0;
            _canvasGroup.blocksRaycasts = false;
            IsShown = false;

        }

        /// <summary>
        /// Sets the handler for <see cref="_backButton"/>.
        /// </summary>
        public virtual void SetBackButtonHandler(Action onBack)
        {
            _backButton?.onClick.AddListener(() => onBack());
        }

        #endregion

    }

}