using UnityEngine;

namespace InteractiveVideo
{
    /// <summary>
    /// The single place where the two coordinate conventions meet.
    ///
    /// TRACKING coordinates (the JSON, all of <see cref="TrackedObjectInstance"/>):
    ///   x 0 = left, 1 = right;  y 0 = TOP, 1 = bottom.
    ///
    /// VIDEO UV (the RenderTexture the VideoPlayer writes, the mask RenderTexture, the shader):
    ///   x 0 = left, 1 = right;  y 0 = BOTTOM, 1 = top.
    ///
    /// Nothing else in the code base may flip Y. If a convention ever changes, change it here.
    /// </summary>
    public static class VideoCoordinates
    {
        public static Vector2 TrackingToUv(Vector2 tracking) => new Vector2(tracking.x, 1f - tracking.y);

        public static Vector2 UvToTracking(Vector2 uv) => new Vector2(uv.x, 1f - uv.y);

        /// <summary>Rect in tracking space (yMin = top edge) to a rect in UV space (yMin = bottom edge).</summary>
        public static Rect TrackingToUv(Rect tracking) =>
            Rect.MinMaxRect(tracking.xMin, 1f - tracking.yMax, tracking.xMax, 1f - tracking.yMin);

        public static bool IsInsideUnitSquare(Vector2 p) => p.x >= 0f && p.x <= 1f && p.y >= 0f && p.y <= 1f;
    }
}