using System.Numerics;

namespace AcDream.Core.Physics;

/// <summary>
/// Retail <c>Frame</c> (acclient.h:30647) — named <c>CellFrame</c> here to avoid
/// colliding with <c>DatReaderWriter.Types.Frame</c> (the dat placement/animation
/// frame, used in physics-adjacent code such as <c>ShadowShapeBuilder</c>).
/// <see cref="Origin"/> is LOCAL to the owning cell: outdoor → X/Y ∈ [0,192) within
/// the landblock, Z = height; indoor → the EnvCell-relative placement.
/// <see cref="Orientation"/> replaces retail's <c>m_fl2gv</c> 3×3 local→global
/// matrix (equivalent rotation).
/// </summary>
public readonly record struct CellFrame(Vector3 Origin, Quaternion Orientation);

/// <summary>
/// Retail <c>Position</c> (acclient.h:30658): the (which-cell, where-inside) pair.
/// One type for indoor and outdoor. The full 32-bit cell id (high 16 = landblock
/// prefix, low 16 = cell index) plus the cell-local <see cref="CellFrame"/>. Neither
/// half is ever reconstructed from a streaming center — see #145 design spec. The
/// <c>Frame</c> member keeps retail's name.
/// </summary>
public readonly record struct Position(uint ObjCellId, CellFrame Frame)
{
    public Position(uint objCellId, Vector3 origin, Quaternion orientation)
        : this(objCellId, new CellFrame(origin, orientation)) { }
}