using Unity.Entities;

namespace ProjectM.Simulation
{
    /// <summary>
    /// Pure, deterministic deposit/withdraw/total helpers for a machine's server-only <see cref="MachineInput"/> /
    /// <see cref="MachineOutput"/> staging buffers — the byte-id, non-replicated twin of <see cref="StorageMath"/>
    /// (which serves the [GhostField] global <see cref="StorageEntry"/> ledger). No RNG/wall-clock. DynamicBuffer is
    /// a handle, so mutations apply to the underlying entity buffer. Overloaded per buffer type because the two
    /// element types are deliberately distinct (a machine can carry both without a singleton-buffer clash). Deposit
    /// is a no-op for count &lt;= 0 or resource id 0; Withdraw clamps to available and drops a row at zero.
    /// </summary>
    public static class MachineSlotMath
    {
        // ---- MachineOutput ----
        public static void Deposit(DynamicBuffer<MachineOutput> buffer, byte resourceId, int count)
        {
            if (count <= 0 || resourceId == 0) return;
            for (int i = 0; i < buffer.Length; i++)
                if (buffer[i].ResourceId == resourceId)
                {
                    var e = buffer[i]; e.Count += count; buffer[i] = e; return;
                }
            buffer.Add(new MachineOutput { ResourceId = resourceId, Count = count });
        }

        public static int Withdraw(DynamicBuffer<MachineOutput> buffer, byte resourceId, int count)
        {
            if (count <= 0 || resourceId == 0) return 0;
            for (int i = 0; i < buffer.Length; i++)
                if (buffer[i].ResourceId == resourceId)
                {
                    var e = buffer[i];
                    int taken = e.Count < count ? e.Count : count;
                    e.Count -= taken;
                    if (e.Count <= 0) buffer.RemoveAt(i); else buffer[i] = e;
                    return taken;
                }
            return 0;
        }

        public static int TotalOf(DynamicBuffer<MachineOutput> buffer, byte resourceId)
        {
            int total = 0;
            for (int i = 0; i < buffer.Length; i++)
                if (buffer[i].ResourceId == resourceId) total += buffer[i].Count;
            return total;
        }

        // ---- MachineInput ----
        public static void Deposit(DynamicBuffer<MachineInput> buffer, byte resourceId, int count)
        {
            if (count <= 0 || resourceId == 0) return;
            for (int i = 0; i < buffer.Length; i++)
                if (buffer[i].ResourceId == resourceId)
                {
                    var e = buffer[i]; e.Count += count; buffer[i] = e; return;
                }
            buffer.Add(new MachineInput { ResourceId = resourceId, Count = count });
        }

        public static int Withdraw(DynamicBuffer<MachineInput> buffer, byte resourceId, int count)
        {
            if (count <= 0 || resourceId == 0) return 0;
            for (int i = 0; i < buffer.Length; i++)
                if (buffer[i].ResourceId == resourceId)
                {
                    var e = buffer[i];
                    int taken = e.Count < count ? e.Count : count;
                    e.Count -= taken;
                    if (e.Count <= 0) buffer.RemoveAt(i); else buffer[i] = e;
                    return taken;
                }
            return 0;
        }

        public static int TotalOf(DynamicBuffer<MachineInput> buffer, byte resourceId)
        {
            int total = 0;
            for (int i = 0; i < buffer.Length; i++)
                if (buffer[i].ResourceId == resourceId) total += buffer[i].Count;
            return total;
        }
    }
}