using System.Collections.Generic;

namespace UnityEngine.Animations.Rigging
{
    /// <summary>
    /// The MultiReferential constraint data.
    /// </summary>
    [System.Serializable]
    public struct MultiReferentialConstraintData : IAnimationJobData, IMultiReferentialConstraintData
    {
        [SyncSceneToStream, SerializeField] int m_Driver;
        [SyncSceneToStream, SerializeField] List<Transform> m_SourceObjects;

        /// <summary>The driver index. This is a value in between 0 and the number of sourceObjects.</summary>
        public int driver
        {
            get => m_Driver;
            set => m_Driver = Mathf.Clamp(value, 0, m_SourceObjects.Count - 1);
        }

        /// <summary>The list of Transforms that are affected by the specified driver.</summary>
        public List<Transform> sourceObjects
        {
            get
            {
                if (m_SourceObjects == null)
                    m_SourceObjects = new List<Transform>();

                return m_SourceObjects;
            }

            set
            {
                m_SourceObjects = value;
                m_Driver = Mathf.Clamp(m_Driver, 0, m_SourceObjects.Count - 1);
            }
        }

        /// <inheritdoc />
        Transform[] IMultiReferentialConstraintData.sourceObjects => m_SourceObjects.ToArray();
        /// <inheritdoc />
        int IMultiReferentialConstraintData.driverValue => m_Driver;
        /// <inheritdoc />
        string IMultiReferentialConstraintData.driverIntProperty => ConstraintsUtils.ConstructConstraintDataPropertyName(nameof(m_Driver));

        /// <inheritdoc />
        bool IAnimationJobData.IsValid()
        {
            if (m_SourceObjects.Count < 2)
                return false;

            foreach (var src in m_SourceObjects)
                if (src == null)
                    return false;

            return true;
        }

        /// <inheritdoc />
        void IAnimationJobData.SetDefaultValues()
        {
            m_Driver = 0;
            m_SourceObjects = new List<Transform>();
        }

        /// <summary>
        /// Updates the driver index to match the number of source objects.
        /// </summary>
        public void UpdateDriver() =>
            m_Driver = Mathf.Clamp(m_Driver, 0, m_SourceObjects != null ? m_SourceObjects.Count - 1 : 0);
    }

    /// <summary>
    /// MultiReferential constraint.
    /// </summary>
    [DisallowMultipleComponent, AddComponentMenu("Animation Rigging/Multi-Referential Constraint")]
    [HelpURL("https://docs.unity3d.com/Packages/com.unity.animation.rigging@1.3/manual/constraints/MultiReferentialConstraint.html")]
    public class MultiReferentialConstraint : RigConstraint<
        MultiReferentialConstraintJob,
        MultiReferentialConstraintData,
        MultiReferentialConstraintJobBinder<MultiReferentialConstraintData>
        >
    {
        /// <inheritdoc />
        protected override void OnValidate()
        {
            base.OnValidate();
            m_Data.UpdateDriver();
        }
    }
}