using UnityEngine;

namespace NightclubArcadia.Player.Math
{
    /// <summary>
    /// Pure math helpers shared by click-to-move and camera pan.
    /// </summary>
    public static class MotionInputMath
    {
        /// <summary>
        /// Converts a NavMeshAgent desired velocity into the camera-relative
        /// Vector2 that ThirdPersonController expects on StarterAssetsInputs.move.
        /// </summary>
        public static Vector2 WorldToCameraRelativeInput(Vector3 worldVelocity, float agentSpeed, float cameraYaw)
        {
            if (worldVelocity.sqrMagnitude < 0.0001f || agentSpeed <= 0f)
            {
                return Vector2.zero;
            }

            var horizontal = new Vector3(worldVelocity.x, 0f, worldVelocity.z);
            var magnitude = horizontal.magnitude;
            var fraction = Mathf.Clamp01(magnitude / agentSpeed);
            var local = Quaternion.Euler(0f, -cameraYaw, 0f) * horizontal.normalized;
            return new Vector2(local.x, local.z) * fraction;
        }

        /// <summary>
        /// Converts screen-space pointer delta into a world-plane pan offset.
        /// Drag direction is inverted so the world follows the cursor.
        /// </summary>
        public static Vector3 ScreenDeltaToWorldPan(
            Vector2 pixelDelta,
            Vector3 camRight,
            Vector3 camForward,
            float metresPerPixel)
        {
            var forward = Vector3.ProjectOnPlane(camForward, Vector3.up).normalized;
            return (-pixelDelta.x * camRight + -pixelDelta.y * forward) * metresPerPixel;
        }
    }
}