using JetBrains.Annotations;
using Robust.Shared.Map;
using Robust.Shared.Prototypes;

namespace Content.Shared.Tabletop;

[UsedImplicitly]
public sealed partial class TabletopCheckerSetup : TabletopSetup
{
    [DataField(required: true)]
    public EntProtoId PrototypePieceWhite;

    [DataField(required: true)]
    public EntProtoId PrototypeCrownWhite;

    [DataField(required: true)]
    public EntProtoId PrototypePieceBlack;

    [DataField(required: true)]
    public EntProtoId PrototypeCrownBlack;

    public override void SetupTabletop(TabletopSession session, IEntityManager entityManager)
    {
        session.Entities.Add(
            entityManager.SpawnEntity(BoardPrototype, session.Position.Offset(-1, 0))
        );

        SpawnPieces(session, entityManager, session.Position.Offset(-4.5f, 3.5f));
    }

    private void SpawnPieces(TabletopSession session, IEntityManager entityManager, MapCoordinates left)
    {
        static float GetOffset(float offset) => offset * 1f /* separation */;

        var pieces = new EntityUid[42];
        var pieceIndex = 0;

        // Pieces.
        for (var offsetY = 0; offsetY < 3; offsetY++)
        {
            var checker = offsetY % 2;

            for (var offsetX = 0; offsetX < 8; offsetX += 2)
            {
                // Prevents an extra piece on the middle row.
                if (checker + offsetX > 8) continue;

                pieces[pieceIndex] = entityManager.SpawnEntity(
                    PrototypePieceBlack,
                    left.Offset(GetOffset(offsetX + (1 - checker)), GetOffset(offsetY * -1))
                );
                pieces[pieceIndex] = entityManager.SpawnEntity(
                    PrototypePieceWhite,
                    left.Offset(GetOffset(offsetX + checker), GetOffset(offsetY - 7))
                );
                pieceIndex += 2;
            }
        }

        const int numCrowns = 3;
        const float overlap = 0.25f;
        const float xOffset = 9f / 32;
        const float xOffsetBlack = 9 + xOffset;
        const float xOffsetWhite = 8 + xOffset;

        // Crowns.
        for (var i = 0; i < numCrowns; i++)
        {
            var step = -(overlap * i);
            pieces[pieceIndex] = entityManager.SpawnEntity(
                PrototypeCrownBlack,
                left.Offset(GetOffset(xOffsetBlack), GetOffset(step))
            );
            pieces[pieceIndex + 1] = entityManager.SpawnEntity(
                PrototypeCrownWhite,
                left.Offset(GetOffset(xOffsetWhite), GetOffset(step))
            );
            pieceIndex += 2;
        }

        // Spares.
        for (var i = 0; i < 6; i++)
        {
            var step = -(overlap * (numCrowns + 2) + overlap * i);
            pieces[pieceIndex] = entityManager.SpawnEntity(
                PrototypePieceBlack,
                left.Offset(GetOffset(xOffsetBlack), GetOffset(step))
            );
            pieces[pieceIndex] = entityManager.SpawnEntity(
                PrototypePieceWhite,
                left.Offset(GetOffset(xOffsetWhite), GetOffset(step))
            );
            pieceIndex += 2;
        }

        for (var i = 0; i < pieces.Length; i++)
        {
            session.Entities.Add(pieces[i]);
        }
    }
}