// Animancer // https://kybernetik.com.au/animancer // Copyright 2018-2024 Kybernetik //

#pragma warning disable CS0649 // Field is never assigned to, and will always have its default value.

using Animancer.TransitionLibraries;
using UnityEngine;
using UnityEngine.UI;

namespace Animancer.Samples.TransitionLibraries
{
    /// <summary>
    /// An example component which creates buttons for playing each transition in a library.
    /// </summary>
    /// 
    /// <remarks>
    /// <strong>Sample:</strong>
    /// <see href="https://kybernetik.com.au/animancer/docs/samples/transition-libraries/serialization">
    /// Serialization</see>
    /// </remarks>
    /// 
    /// https://kybernetik.com.au/animancer/api/Animancer.Samples.TransitionLibraries/TransitionLibraryButtons
    /// 
    [AddComponentMenu(Strings.SamplesMenuPrefix + "Transition Libraries - Transition Library Buttons")]
    [AnimancerHelpUrl(typeof(TransitionLibraryButtons))]
    public class TransitionLibraryButtons : MonoBehaviour
    {
        /************************************************************************************************************************/

        [SerializeField] private RectTransform _PlayButtonTemplate;
        [SerializeField] private float _PlayButtonSpacing = 10;
        [SerializeField] private AnimancerComponent _Animancer;

        /************************************************************************************************************************/

        protected virtual void OnEnable()
        {
            Transform parent = _PlayButtonTemplate.parent;
            TransitionLibraryDefinition definition = _Animancer.Transitions.Definition;

            for (int i = 0; i < definition.Transitions.Length; i++)
            {
                TransitionAssetBase transition = definition.Transitions[i];

                RectTransform button = Instantiate(_PlayButtonTemplate, parent);

                button.GetComponent<Button>().onClick.AddListener(() => Play(transition));
                button.GetComponentInChildren<Text>().text = transition.name;

                Vector2 position = button.anchoredPosition;
                position.y -= i * (button.sizeDelta.y + _PlayButtonSpacing);
                button.anchoredPosition = position;

                // If the animation isn't looping, give it an End Event to play the default animation.
                // We need to initialize all the events on startup so that they're ready if one gets
                // played from a loaded file since the loading script doesn't know about the events.

                AnimancerState state = _Animancer.States.GetOrCreate(transition);
                state.AssertOwnership(this);
                if (!state.IsLooping)
                    state.Events(this).OnEnd ??= () => Play(definition.Transitions[0]);
            }

            _PlayButtonTemplate.gameObject.SetActive(false);

            Play(definition.Transitions[0]);
        }

        /************************************************************************************************************************/

        private void Play(ITransition transition)
        {
            _Animancer.Play(transition);
        }

        /************************************************************************************************************************/
    }
}
