using UnityEngine;
using UnityEngine.Serialization;

namespace UnityEngine.ProBuilder
{
    /// <summary>
    /// Stores parameters that define how ProBuilder unwraps UV2s when Auto UV mode is on.
    /// </summary>
    [System.Serializable]
    public sealed class UnwrapParameters
    {
        internal const float k_HardAngle = 88f;
        internal const float k_PackMargin = 20f;
        internal const float k_AngleError = 8f;
        internal const float k_AreaError = 15f;

        [Tooltip("Angle between neighbor triangles that will generate seam.")]
        [Range(1f, 180f)]
        [SerializeField]
        [FormerlySerializedAs("hardAngle")]
        float m_HardAngle = k_HardAngle;

        [Tooltip("Measured in pixels, assuming mesh will cover an entire 1024x1024 lightmap.")]
        [Range(1f, 64f)]
        [SerializeField]
        [FormerlySerializedAs("packMargin")]
        float m_PackMargin = k_PackMargin;

        [Tooltip("Measured in percents. Angle error measures deviation of UV angles from geometry angles. Area error "
             + "measures deviation of UV triangles area from geometry triangles if they were uniformly scaled.")]
        [Range(1f, 75f)]
        [SerializeField]
        [FormerlySerializedAs("angleError")]
        float m_AngleError = k_AngleError;

        [Range(1f, 75f)]
        [SerializeField]
        [FormerlySerializedAs("areaError")]
        float m_AreaError = k_AreaError;

        /// <summary>
        /// Gets or sets the angle that generates seams between neighbor triangles.
        /// </summary>
        public float hardAngle { get { return m_HardAngle; } set { m_HardAngle = value; } }

        /// <summary>
        /// Gets or sets the pack margin in pixels for a mesh that covers an entire 1024x1024 lightmap.
        /// </summary>
        public float packMargin { get { return m_PackMargin; } set { m_PackMargin = value; } }

        /// <summary>
        /// Gets or sets the deviation of UV angles from geometry angles, as a percentage.
        /// </summary>
        public float angleError { get { return m_AngleError; } set { m_AngleError = value; } }

        /// <summary>
        /// Gets or sets the deviation of the UV triangles area from geometry triangles if they were uniformly scaled, as a percentage.
        /// </summary>
        public float areaError { get { return m_AreaError; } set { m_AreaError = value; } }

        /// <summary>
        /// Creates a set of UnwrapParameters using default values.
        /// </summary>
        public UnwrapParameters()
        {
            Reset();
        }

        /// <summary>
        /// Creates a set of unwrap parameters by copying values from another set.
        /// </summary>
        /// <param name="other">The UnwrapParameters to copy properties from.</param>
        public UnwrapParameters(UnwrapParameters other)
        {
            if (other == null)
                throw new System.ArgumentNullException("other");

            hardAngle = other.hardAngle;
            packMargin = other.packMargin;
            angleError = other.angleError;
            areaError = other.areaError;
        }

        /// <summary>
        /// Resets the unwrap parameter values to their defaults.
        /// </summary>
        public void Reset()
        {
            hardAngle = k_HardAngle;
            packMargin = k_PackMargin;
            angleError = k_AngleError;
            areaError = k_AreaError;
        }

        /// <summary>
        /// Returns a string representation of the UnwrapParameters.
        /// </summary>
        /// <returns>String formatted as follows:
        ///
        /// `hardAngle: [hardAngle]`
        ///
        /// `packMargin: [packMargin]`
        ///
        /// `angleError: [angleError]`
        ///
        /// `areaError: [areaError]`</returns>
        public override string ToString()
        {
            return string.Format("hardAngle: {0}\npackMargin: {1}\nangleError: {2}\nareaError: {3}",
                hardAngle,
                packMargin,
                angleError,
                areaError);
        }
    }
}