using System.Collections.Generic;
using DatReaderWriter.DBObjs;
// Environment collides with System.Environment under implicit usings — alias it.
using DatEnvironment = DatReaderWriter.DBObjs.Environment;

namespace AcDream.Core.World;

/// <summary>
/// Parsed DAT closure produced by <c>LandblockBuildFactory</c> under the shared
/// reader gate and consumed by the render-thread presentation publishers.
/// Publication makes zero DatCollection calls, so the update thread never
/// blocks on worker DAT access. Entries retain their original DAT IDs.
/// </summary>
public sealed record PhysicsDatBundle(
    LandBlockInfo? Info,
    IReadOnlyDictionary<uint, EnvCell> EnvCells,
    IReadOnlyDictionary<uint, DatEnvironment> Environments,
    IReadOnlyDictionary<uint, Setup> Setups,
    IReadOnlyDictionary<uint, GfxObj> GfxObjs)
{
    /// <summary>Empty bundle for far-tier landblocks (no cells / buildings /
    /// entities) and for non-streaming <see cref="LoadedLandblock"/> construction.</summary>
    public static readonly PhysicsDatBundle Empty = new(
        null,
        new Dictionary<uint, EnvCell>(),
        new Dictionary<uint, DatEnvironment>(),
        new Dictionary<uint, Setup>(),
        new Dictionary<uint, GfxObj>());

    /// <summary>
    /// Drops parsed collision-bearing GfxObj and Environment/CellStruct graphs
    /// after their immutable package assets have been resolved. The remaining
    /// records are the small publication facts still consumed by building,
    /// placement, and static-light owners.
    /// </summary>
    public PhysicsDatBundle WithoutCollisionGraphs() => new(
        Info,
        EnvCells,
        Empty.Environments,
        Setups,
        Empty.GfxObjs);
}