using System;
using UnityEngine.Playables;

[Serializable]
public class TMPAppenderBehaviour : PlayableBehaviour
{
    public string text;
}

[Serializable]
public class TMPAppenderClip : PlayableAsset, ITimelineClipAsset,IPropertyPreview
{
    public TMPAppenderBehaviour template = new TMPAppenderBehaviour ();

    public ClipCaps clipCaps
    {
        get { return ClipCaps.Blending; }
    }

    public override Playable CreatePlayable (PlayableGraph graph, GameObject owner)
    {
        var playable = ScriptPlayable<TMPAppenderBehaviour>.Create (graph, template);
        return playable;
    }

    public void GatherProperties(PlayableDirector director, IPropertyCollector driver)
    {
        driver.AddFromName<TextMeshProUGUI>("m_Text");
    }
}


[TrackClipType(typeof(TMPAppenderClip))]
[TrackBindingType(typeof(TextMeshProUGUI))]
public class TMPAppenderTrack : TrackAsset
{
    public override Playable CreateTrackMixer(PlayableGraph graph, GameObject go, int inputCount)
    {
        return ScriptPlayable<TMPAppenderMixerBehaviour>.Create (graph, inputCount);
    }

    // Please note this assumes only one component of type TextMeshProUGUI on the same gameobject.
    public override void GatherProperties (PlayableDirector director, IPropertyCollector driver)
    {
#if UNITY_EDITOR
        TextMeshProUGUI trackBinding = director.GetGenericBinding(this) as TextMeshProUGUI;
        if (trackBinding == null)
            return;

        // These field names are procedurally generated estimations based on the associated property names.
        // If any of the names are incorrect you will get a DrivenPropertyManager error saying it has failed to register the name.
        // In this case you will need to find the correct backing field name.
        // The suggested way of finding the field name is to:
        // 1. Make sure your scene is serialized to text.
        // 2. Search the text for the track binding component type.
        // 3. Look through the field names until you see one that looks correct.
        driver.AddFromName<TextMeshProUGUI>(trackBinding.gameObject, "m_Text");
#endif
        base.GatherProperties (director, driver);
    }
}


public class TMPAppenderMixerBehaviour : PlayableBehaviour
{
    string m_DefaultText;

    string m_AssignedText;

    TextMeshProUGUI m_TrackBinding;

    public override void ProcessFrame(Playable playable, FrameData info, object playerData)
    {
        m_TrackBinding = playerData as TextMeshProUGUI;

        if (m_TrackBinding == null)
            return;

        if (m_TrackBinding.text != m_AssignedText)
            m_DefaultText = m_TrackBinding.text;

        int inputCount = playable.GetInputCount ();

        float totalWeight = 0f;
        float greatestWeight = 0f;
        int currentInputs = 0;

        for (int i = 0; i < inputCount; i++)
        {
            float inputWeight = playable.GetInputWeight(i);
            ScriptPlayable<TMPAppenderBehaviour> inputPlayable = (ScriptPlayable<TMPAppenderBehaviour>)playable.GetInput(i);
            TMPAppenderBehaviour input = inputPlayable.GetBehaviour ();

            totalWeight += inputWeight;

            if (inputWeight > greatestWeight)
            {
                m_AssignedText = input.text;
                m_TrackBinding.text = m_AssignedText;
                greatestWeight = inputWeight;
            }

            if (!Mathf.Approximately (inputWeight, 0f))
                currentInputs++;
        }

        if (currentInputs != 1 && 1f - totalWeight > greatestWeight)
        {
            m_TrackBinding.text = m_DefaultText;
        }
    }
}