using System;
using System.ComponentModel;
using UnityEngine;
using UnityEngine.Playables;
using UnityEngine.Timeline;

namespace AibisDream.FrameAnimation.Timeline
{
    [Serializable]
    [DisplayName("Frame Animation Clip")]
    public sealed class FrameAnimationTimelineClip : PlayableAsset, ITimelineClipAsset
    {
        private const double FallbackDurationSeconds = 1d;

        [SerializeField, Tooltip("要由 Timeline 播放的独立 FrameClip 资产。")]
        private FrameClip frameClip;
        [SerializeField, HideInInspector] private FrameClip synchronizedDurationSource;
        [SerializeField, HideInInspector] private bool hasSynchronizedDuration;

        public FrameClip FrameClip => frameClip;

        public override double duration => GetEffectiveDuration(frameClip);

        public ClipCaps clipCaps
        {
            get
            {
                var caps = ClipCaps.ClipIn | ClipCaps.SpeedMultiplier;
                if (frameClip != null && frameClip.DefaultEndBehavior == FrameClipEndBehavior.Loop)
                {
                    caps |= ClipCaps.Looping;
                }
                return caps;
            }
        }

        public override Playable CreatePlayable(PlayableGraph graph, GameObject owner)
        {
            var playable = ScriptPlayable<FrameAnimationTimelineBehaviour>.Create(graph);
            playable.GetBehaviour().FrameClip = frameClip;
            return playable;
        }

        internal void SetFrameClipForTests(FrameClip value)
        {
            frameClip = value;
        }

        internal bool TrySynchronizeSourceDuration(out double sourceDuration)
        {
            sourceDuration = duration;
            if (hasSynchronizedDuration && synchronizedDurationSource == frameClip)
            {
                return false;
            }

            synchronizedDurationSource = frameClip;
            hasSynchronizedDuration = true;
            return true;
        }

        internal static double GetEffectiveDuration(FrameClip value)
        {
            if (value == null || value.TotalDurationMs <= 0 || value.Speed <= 0f)
            {
                return FallbackDurationSeconds;
            }
            return value.TotalDurationMs / 1000d / value.Speed;
        }
    }

    internal sealed class FrameAnimationTimelineBehaviour : PlayableBehaviour
    {
        internal FrameClip FrameClip { get; set; }
    }
}