Production
Bounded Context

public void BookLabor(int? sequence, string employeeCode, decimal minutes, decimal hourlyRate)
{
    EnsureStatus(ProductionStatus.InProgress);

    // Lệnh có công đoạn thì BẮT BUỘC chỉ rõ công đoạn: không có thì không tính được
    // hiệu suất chuẩn/thực tế từng khâu, mất phần lớn giá trị của việc chấm công.
    if (_operations.Count > 0 && sequence is null)
        Throw("Lệnh có công đoạn — phải chỉ rõ công đoạn khi chấm công.", "OPERATION_REQUIRED");

    if (_operations.Count == 0 && sequence is not null)
        Throw("Lệnh không có công đoạn nào.", "NO_OPERATIONS");

    var cost = decimal.Round(minutes / 60m * hourlyRate, 2);
    Raise(new ProductionLaborBooked(
        Id, sequence, employeeCode, minutes, hourlyRate, cost, DateTimeOffset.UtcNow));
}

namespace ERP.MES.Core.Production.ValueObjects;

public record OrderId(Guid Value)
{
    public static OrderId New()          => new(Guid.NewGuid());
    public static OrderId From(Guid id)  => new(id);
    public static OrderId From(string s) => new(Guid.Parse(s));
    public override string ToString()    => Value.ToString();
}

public record OrderNumber
{
    public string Value { get; }

    public OrderNumber(string value)
    {
        if (string.IsNullOrWhiteSpace(value))
            throw new ArgumentException("Order number không được để trống.");
        var v = value.Trim().ToUpper();
        if (v.Length > 50)
            throw new ArgumentException("Order number tối đa 50 ký tự.");
        Value = v;
    }

    public static OrderNumber Generate(int sequence, int year = 0)
    {
        var y = year == 0 ? DateTime.UtcNow.Year : year;
        return new OrderNumber($"PO-{y}-{sequence:D6}");
    }

    public override string ToString() => Value;
}

public record ProductSpec(Guid ProductId, string Code, string Name)
{
    public ProductSpec(Guid productId, string code, string name)
        : this(productId, code, name)
    {
        if (productId == Guid.Empty) throw new ArgumentException("ProductId không hợp lệ.");
        if (string.IsNullOrWhiteSpace(code)) throw new ArgumentException("Product code trống.");
        if (string.IsNullOrWhiteSpace(name)) throw new ArgumentException("Product name trống.");
    }
}

public record Quantity
{
    public decimal Value { get; }
    public string  Unit  { get; }

    public Quantity(decimal value, string unit)
    {
        if (string.IsNullOrWhiteSpace(unit)) throw new ArgumentException("Unit trống.");
        if (value < 0) throw new ArgumentException("Quantity không được âm.");
        Value = value;
        Unit  = unit.Trim().ToUpper();
    }

    public static Quantity Zero(string unit) => new(0, unit);

    public Quantity Add(Quantity other)
    {
        if (Unit != other.Unit)
            throw new InvalidOperationException($"Không thể cộng {Unit} với {other.Unit}");
        return new Quantity(Value + other.Value, Unit);
    }

    public bool IsGreaterThan(Quantity other)   => Unit == other.Unit && Value > other.Value;
    public bool IsGreaterOrEqual(Quantity other) => Unit == other.Unit && Value >= other.Value;

    public override string ToString() => $"{Value:G} {Unit}";
}

public record MachineId(Guid Value)
{
    public static MachineId From(Guid id) => new(id);
    public override string ToString() => Value.ToString();
}

public record OperatorId(Guid Value)
{
    public static OperatorId From(Guid id) => new(id);
    public override string ToString() => Value.ToString();
}

public enum ProductionStatus
{
    Planned    = 1,
    Released   = 2,
    InProgress = 3,
    OnHold     = 4,
    Completed  = 5,
    Cancelled  = 6
}

public enum Shift { Morning, Afternoon, Night }

namespace ERP.MES.Core.Production.Events;

using ERP.MES.Core.Production.ValueObjects;
using ERP.MES.Core.Shared;

public sealed record ProductionOrderCreated(
    OrderId     OrderId,
    OrderNumber OrderNumber,
    ProductSpec Product,
    Quantity    PlannedQty,
    MachineId   MachineId,
    Shift       Shift,
    string      TenantId,
    DateTimeOffset OccurredAt
) : DomainEvent(OrderId.Value, OccurredAt);

public sealed record ProductionOrderReleased(
    OrderId        OrderId,
    string         ReleasedBy,
    DateTimeOffset OccurredAt
) : DomainEvent(OrderId.Value, OccurredAt);

public sealed record ProductionStarted(
    OrderId        OrderId,
    OperatorId     OperatorId,
    DateTimeOffset OccurredAt
) : DomainEvent(OrderId.Value, OccurredAt);

public sealed record ProductionOutputRecorded(
    OrderId        OrderId,
    Quantity       Quantity,
    DateTimeOffset OccurredAt
) : DomainEvent(OrderId.Value, OccurredAt);

public sealed record ProductionOrderPaused(
    OrderId        OrderId,
    string         Reason,
    string         ReasonCode,
    DateTimeOffset OccurredAt
) : DomainEvent(OrderId.Value, OccurredAt);

public sealed record ProductionOrderResumed(
    OrderId        OrderId,
    DateTimeOffset OccurredAt
) : DomainEvent(OrderId.Value, OccurredAt);

public sealed record ProductionOrderCompleted(
    OrderId        OrderId,
    Quantity       ActualQty,
    DateTimeOffset OccurredAt
) : DomainEvent(OrderId.Value, OccurredAt);

public sealed record ProductionOrderCancelled(
    OrderId        OrderId,
    string         Reason,
    DateTimeOffset OccurredAt
) : DomainEvent(OrderId.Value, OccurredAt);

namespace ERP.MES.Core.Production;

using ERP.MES.Core.Production.Events;
using ERP.MES.Core.Production.Exceptions;
using ERP.MES.Core.Production.ValueObjects;
using ERP.MES.Core.Shared;

public sealed class ProductionOrder : AggregateRoot<OrderId>
{
    public OrderNumber    OrderNumber { get; private set; } = null!;
    public ProductSpec    Product     { get; private set; } = null!;
    public Quantity       PlannedQty  { get; private set; } = null!;
    public Quantity       ActualQty   { get; private set; } = null!;
    public ProductionStatus Status    { get; private set; }
    public MachineId      MachineId   { get; private set; } = null!;
    public OperatorId?    OperatorId  { get; private set; }
    public Shift          Shift       { get; private set; }
    public string         TenantId    { get; private set; } = null!;

    private const decimal MaxOutputBuffer = 1.1m; // 10% buffer

    private ProductionOrder() { } // EF / reconstitution

    // ── Factory ──────────────────────────────────────────────────
    public static ProductionOrder Create(
        OrderNumber number,
        ProductSpec product,
        Quantity    plannedQty,
        MachineId   machineId,
        Shift       shift,
        string      tenantId)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(tenantId);

        var order = new ProductionOrder();
        order.Raise(new ProductionOrderCreated(
            OrderId.New(), number, product, plannedQty,
            machineId, shift, tenantId,
            DateTimeOffset.UtcNow));
        return order;
    }

    // ── Reconstitution từ Event Store ───────────────────────────
    public static ProductionOrder Reconstitute(IEnumerable<DomainEvent> events)
    {
        var order = new ProductionOrder();
        foreach (var e in events)
            order.Apply(e);
        return order;
    }

    // ── Commands ─────────────────────────────────────────────────
    public void Release(string releasedBy)
    {
        EnsureStatus(ProductionStatus.Planned);
        Raise(new ProductionOrderReleased(Id, releasedBy, DateTimeOffset.UtcNow));
    }

    public void Start(OperatorId operatorId)
    {
        if (Status is not (ProductionStatus.Planned or ProductionStatus.Released))
            throw new ProductionDomainException(
                "Chỉ bắt đầu sản xuất từ trạng thái Planned hoặc Released.",
                "INVALID_STATUS_FOR_START");

        Raise(new ProductionStarted(Id, operatorId, DateTimeOffset.UtcNow));
    }

    public void RecordOutput(Quantity qty)
    {
        EnsureStatus(ProductionStatus.InProgress);

        var newTotal = ActualQty.Add(qty);
        var maxAllowed = new Quantity(PlannedQty.Value * MaxOutputBuffer, PlannedQty.Unit);
        if (newTotal.IsGreaterThan(maxAllowed))
            throw new ProductionDomainException(
                $"Tổng sản lượng ({newTotal}) vượt quá giới hạn cho phép ({maxAllowed}).",
                "OUTPUT_EXCEEDS_LIMIT");

        Raise(new ProductionOutputRecorded(Id, qty, DateTimeOffset.UtcNow));
    }

    public void Pause(string reason, string reasonCode)
    {
        EnsureStatus(ProductionStatus.InProgress);
        ArgumentException.ThrowIfNullOrWhiteSpace(reason);
        Raise(new ProductionOrderPaused(Id, reason, reasonCode, DateTimeOffset.UtcNow));
    }

    public void Resume()
    {
        EnsureStatus(ProductionStatus.OnHold);
        Raise(new ProductionOrderResumed(Id, DateTimeOffset.UtcNow));
    }

    public void Complete()
    {
        EnsureStatus(ProductionStatus.InProgress);
        Raise(new ProductionOrderCompleted(Id, ActualQty, DateTimeOffset.UtcNow));
    }

    public void Cancel(string reason)
    {
        if (Status == ProductionStatus.Completed)
            throw new ProductionDomainException(
                "Không thể hủy lệnh đã hoàn thành.",
                "CANNOT_CANCEL_COMPLETED");

        if (Status == ProductionStatus.InProgress)
            ArgumentException.ThrowIfNullOrWhiteSpace(reason);

        Raise(new ProductionOrderCancelled(Id, reason, DateTimeOffset.UtcNow));
    }

    // ── Apply (Event Sourcing) ────────────────────────────────────
    protected override void Apply(DomainEvent @event)
    {
        switch (@event)
        {
            case ProductionOrderCreated e:
                Id         = e.OrderId;
                OrderNumber = e.OrderNumber;
                Product    = e.Product;
                PlannedQty = e.PlannedQty;
                ActualQty  = Quantity.Zero(e.PlannedQty.Unit);
                MachineId  = e.MachineId;
                Shift      = e.Shift;
                TenantId   = e.TenantId;
                Status     = ProductionStatus.Planned;
                break;

            case ProductionOrderReleased:
                Status = ProductionStatus.Released;
                break;

            case ProductionStarted e:
                Status     = ProductionStatus.InProgress;
                OperatorId = e.OperatorId;
                break;

            case ProductionOutputRecorded e:
                ActualQty = ActualQty.Add(e.Quantity);
                break;

            case ProductionOrderPaused:
                Status = ProductionStatus.OnHold;
                break;

            case ProductionOrderResumed:
                Status = ProductionStatus.InProgress;
                break;

            case ProductionOrderCompleted:
                Status = ProductionStatus.Completed;
                break;

            case ProductionOrderCancelled:
                Status = ProductionStatus.Cancelled;
                break;
        }
    }

    // ── Guard ─────────────────────────────────────────────────────
    private void EnsureStatus(ProductionStatus expected)
    {
        if (Status != expected)
            throw new ProductionDomainException(
                $"Lệnh đang ở trạng thái {Status}, không thể thực hiện khi không phải {expected}.",
                "INVALID_STATUS");
    }
}

// ── AggregateRoot.cs ─────────────────────────────────────────────
namespace ERP.MES.Core.Shared;

public abstract class AggregateRoot<TId>
{
    private readonly List<DomainEvent> _events = [];

    public TId Id      { get; protected set; } = default!;
    public int Version { get; private set; }

    public IReadOnlyList<DomainEvent> DomainEvents => _events.AsReadOnly();

    protected void Raise(DomainEvent @event)
    {
        Apply(@event);
        _events.Add(@event);
        Version++;
    }

    protected abstract void Apply(DomainEvent @event);

    public void ClearDomainEvents() => _events.Clear();
}

// ── DomainEvent.cs ───────────────────────────────────────────────
namespace ERP.MES.Core.Shared;

public abstract record DomainEvent(
    Guid           AggregateId,
    DateTimeOffset OccurredAt)
{
    public Guid   EventId   { get; } = Guid.NewGuid();
    public string EventType { get; } = nameof(DomainEvent);
}

// ── IRepository.cs ───────────────────────────────────────────────
namespace ERP.MES.Core.Shared;

public interface IRepository<TAggregate, TId>
    where TAggregate : AggregateRoot<TId>
{
    Task<TAggregate?> GetByIdAsync(TId id, CancellationToken ct = default);
    Task SaveAsync(TAggregate aggregate, CancellationToken ct = default);
}

namespace ERP.MES.Application.Production.Commands;

using ERP.MES.Core.Production;
using ERP.MES.Core.Production.ValueObjects;
using ERP.MES.Core.Shared;

// ── Command (immutable record) ───────────────────────────────────
public sealed record StartProductionOrderCommand(
    Guid   OrderId,
    Guid   OperatorId,
    string TenantId) : ICommand<StartProductionOrderResult>;

// ── Result ───────────────────────────────────────────────────────
public sealed record StartProductionOrderResult(
    Guid   OrderId,
    string Status,
    string OperatorId);

// ── Handler ──────────────────────────────────────────────────────
public sealed class StartProductionOrderHandler(
    IProductionOrderRepository repository)
    : ICommandHandler<StartProductionOrderCommand, StartProductionOrderResult>
{
    public async Task<StartProductionOrderResult> HandleAsync(
        StartProductionOrderCommand command,
        CancellationToken ct)
    {
        var orderId    = OrderId.From(command.OrderId);
        var operatorId = OperatorId.From(command.OperatorId);

        var order = await repository.GetByIdAsync(orderId, ct)
            ?? throw new NotFoundException($"Production Order {command.OrderId} không tìm thấy.");

        // Business rule enforcement xảy ra bên trong aggregate
        order.Start(operatorId);

        await repository.SaveAsync(order, ct);

        return new StartProductionOrderResult(
            command.OrderId,
            order.Status.ToString(),
            command.OperatorId.ToString());
    }
}

// ── Repository interface (domain layer) ─────────────────────────
public interface IProductionOrderRepository
    : IRepository<ProductionOrder, OrderId>
{
    Task<ProductionOrder?> GetByOrderNumberAsync(
        OrderNumber number,
        string tenantId,
        CancellationToken ct = default);
}