using System;

namespace UnityEngine.XR.Simulation
{
    /// <summary>
    /// Marks an object in a simulation environment as a source from which to provide an environment probe.
    /// This component is required by the <see cref="SimulationEnvironmentProbeSubsystem"/> on all GameObjects
    /// which represent tracked reflection probes in an environment.
    /// </summary>
    [DisallowMultipleComponent]
    public class SimulatedEnvironmentProbe : MonoBehaviour
    {
        const string k_EnvironmentProbeShaderPropertyName = "_SimulationEnvironmentProbe";

        /// <summary>
        /// An optional pre-existing user-generated Cubemap asset. If not set, a cubemap will be generated when the environment probe is discovered during simulation.
        /// </summary>
        [SerializeField]
        [Tooltip("An optional pre-existing user-generated Cubemap asset. If not set, a cubemap will be generated when the environment probe is discovered during simulation.")]
        Cubemap m_Cubemap;

        /// <summary>
        /// Size in meters of the simulated environment probe. Sets both the box size of the underlying [Reflection Probe](xref:UnityEngine.ReflectionProbe) and the bounds for discovery.
        /// </summary>
        [SerializeField]
        [Tooltip("Size in meters of the simulated environment probe. Sets both the box size of the underlying Reflection Probe and the bounds for discovery.")]
        Vector3 m_Size = new(1.0f, 1.0f, 1.0f);

        bool m_HasChanged;

        internal int environmentProbeShaderPropertyId => m_EnvironmentProbeShaderPropertyId;
        int m_EnvironmentProbeShaderPropertyId;

        private void Awake()
        {
            m_EnvironmentProbeShaderPropertyId = Shader.PropertyToID(k_EnvironmentProbeShaderPropertyName);
        }

        /// <summary>
        /// Get whether the probe's cubemap value or size have been changed since the last Simulation probe subsystem update.
        /// </summary>
        /// <value>
        /// <see langword="true"/> if the probe's cubemap value or size have been changed. Otherwise, <see langword="false"/>
        /// </value>
        public bool hasChanged
        {
            get => m_HasChanged;
            internal set => m_HasChanged = value;
        }

        /// <summary>
        /// Get the cubemap for this probe.
        /// </summary>
        /// <value>The cubemap.</value>
        public Cubemap cubemap
        {
            get => m_Cubemap;
            internal set
            {
                m_Cubemap = value;
                m_HasChanged = true;
            }
        }

        /// <summary>
        /// Get the size of the simulated probe area.
        /// </summary>
        /// <value>The size of the simulated probe area.</value>
        public Vector3 size
        {
            get => m_Size;
            internal set
            {
                m_Size = value;
                m_HasChanged = true;
            }
        }
    }
}