using Unity.Entities;

namespace ProjectM.Simulation
{
    /// <summary>
    /// A fixed-yield resource generator — the FRONT of the M7 auto-gather chain (Harvester -> Conveyor ->
    /// Fabricator). Each period it deposits <see cref="Yield"/> of <see cref="ResourceId"/> into its OWN
    /// server-only <see cref="MachineOutput"/> buffer (a conveyor pulls it onward). Server-only data (NO
    /// [GhostField]); the client only ever sees <c>PlacedStructure.Type</c>. Reuses
    /// <c>PlacedStructure.NextTick</c>/<c>LastProcessedTick</c> for the deterministic, within-session catch-up
    /// cadence (see <c>HarvesterProductionSystem</c>).
    /// </summary>
    public struct Harvester : IComponentData
    {
        /// <summary>Resource id produced (a byte; see <see cref="ResourceId"/>).</summary>
        public byte ResourceId;
        /// <summary>Units produced per elapsed period.</summary>
        public int Yield;
        /// <summary>Server ticks between productions.</summary>
        public int PeriodTicks;
    }

    /// <summary>
    /// A recipe machine — the BACK of the M7 chain. Consumes <see cref="InAmount"/> of <see cref="InResourceId"/>
    /// per run from its own <see cref="MachineInput"/> buffer (fed by a conveyor) and deposits <see cref="OutAmount"/>
    /// of <see cref="OutResourceId"/> into the GLOBAL ledger. Strictly input-limited (never mints from an empty
    /// slot). Server-only data.
    /// </summary>
    public struct Fabricator : IComponentData
    {
        public byte InResourceId;
        public int InAmount;
        public byte OutResourceId;
        public int OutAmount;
        public int PeriodTicks;

        /// <summary>EB-2: 0 = consume the input from the MachineInput buffer (the M7 conveyor chain); !=0 = consume
        /// the input from the SHARED ledger (a base-loop ledger-fed Fabricator, e.g. Ore -> Charge). Server-only, NO [GhostField].</summary>
        public byte InputFromLedger;
    }

    /// <summary>
    /// A directional transport belt — the MIDDLE of the M7 chain. Each period it pulls one item off an adjacent
    /// upstream <see cref="MachineOutput"/> (when empty) and advances a held <see cref="ConveyorItem"/> exactly one
    /// cell toward <see cref="Direction"/>. <see cref="Direction"/> is a byte (0=+X,1=-X,2=+Z,3=-Z) — never an enum
    /// (the cross-assembly enum-in-Burst hazard). Server-only data.
    /// </summary>
    public struct Conveyor : IComponentData
    {
        /// <summary>Belt facing: 0=+X, 1=-X, 2=+Z, 3=-Z (see <c>ConveyorMath.DirOffset</c>).</summary>
        public byte Direction;
        public int PeriodTicks;
    }

    /// <summary>
    /// A machine's INPUT staging buffer (server-only, NO [GhostField] -> never replicated). A DISTINCT element type
    /// from the global ledger's <see cref="StorageEntry"/> (so <c>GetSingleton&lt;StorageEntry&gt;</c> stays
    /// unambiguous) and from <see cref="MachineOutput"/> (so a machine can carry both without a buffer-type clash).
    /// </summary>
    public struct MachineInput : IBufferElementData
    {
        public byte ResourceId;
        public int Count;
    }

    /// <summary>A machine's OUTPUT staging buffer (server-only, NO [GhostField]). See <see cref="MachineInput"/>.</summary>
    public struct MachineOutput : IBufferElementData
    {
        public byte ResourceId;
        public int Count;
    }

    /// <summary>
    /// The single in-flight item a conveyor carries. An ENABLEABLE component (enabled = the belt is occupied) so a
    /// transport step is a bit-flip + field copy, never a structural change. Baked DISABLED (an empty belt).
    /// Server-only.
    /// </summary>
    public struct ConveyorItem : IComponentData, IEnableableComponent
    {
        public byte ResourceId;
        public int Count;
    }

    /// <summary>
    /// Marks a structure PLACED by a player at runtime (BuildPlaceSystem) or restored from a save — i.e. the
    /// persistable set, as opposed to anything baked into the subscene. SaveWriteSystem scans only these and
    /// BaseRestoreSystem re-adds the tag, so save/restore is the single source of truth for player builds.
    /// Server-only (not replicated).
    /// </summary>
    public struct RuntimePlacedTag : IComponentData { }
}