using Godot;

namespace EyeTracking
{
    /// <summary>
    /// Handles eye convergence logic to create more natural gaze behavior
    /// by reducing individual eye deviations and promoting coordinated eye movement
    /// </summary>
    public static class EyeConvergence
    {
        /// <summary>
        /// Apply convergence logic to reduce individual eye deviations and create more natural gaze behavior
        /// </summary>
        /// <param name="leftGaze">Left eye gaze vector</param>
        /// <param name="rightGaze">Right eye gaze vector</param>
        /// <param name="convergenceStrength">Strength of convergence (0.0 = no convergence, 1.0 = full convergence)</param>
        /// <returns>Tuple of converged left and right gaze vectors</returns>
        public static (Vector2 leftGaze, Vector2 rightGaze) ApplyConvergence(Vector2 leftGaze, Vector2 rightGaze, float convergenceStrength = 0.5f)
        {
            // Calculate the average gaze direction (where both eyes should converge)
            Vector2 averageGaze = new Vector2(
                (leftGaze.X + rightGaze.X) * 0.5f,
                (leftGaze.Y + rightGaze.Y) * 0.5f
            );

            // Calculate the individual eye deviations from the average
            Vector2 leftDeviation = new Vector2(
                leftGaze.X - averageGaze.X,
                leftGaze.Y - averageGaze.Y
            );
            Vector2 rightDeviation = new Vector2(
                rightGaze.X - averageGaze.X,
                rightGaze.Y - averageGaze.Y
            );

            // Detect cross-eyed gaze (eyes pointing toward each other)
            bool isCrossEyed = (leftGaze.X > 0.1f && rightGaze.X < -0.1f);
            
            // For cross-eyed gaze, preserve more of the original individual characteristics
            float effectiveConvergenceStrength = isCrossEyed ? convergenceStrength * 0.3f : convergenceStrength;

            // Apply convergence strength to reduce individual deviations
            Vector2 convergedLeft = new Vector2(
                averageGaze.X + leftDeviation.X * (1.0f - effectiveConvergenceStrength),
                averageGaze.Y + leftDeviation.Y * (1.0f - effectiveConvergenceStrength)
            );
            Vector2 convergedRight = new Vector2(
                averageGaze.X + rightDeviation.X * (1.0f - effectiveConvergenceStrength),
                averageGaze.Y + rightDeviation.Y * (1.0f - effectiveConvergenceStrength)
            );

            return (convergedLeft, convergedRight);
        }
    }
}