// Event 0: Lead initialized
{
  "lead-id": 12,
  "event-id": 0,
  "event-type": "lead-initialized",
  "first-name": "Casey",
  "last-name": "David", // Помилка в прізвищі!
  "phone-number": "555-2951",
  "timestamp": "2020-05-20T09:52:55.95Z"
}

// Event 1: First contact
{
  "lead-id": 12,
  "event-id": 1,
  "event-type": "contacted",
  "timestamp": "2020-05-20T12:32:08.24Z"
}

// Event 2: Followup scheduled
{
  "lead-id": 12,
  "event-id": 2,
  "event-type": "followup-set",
  "followup-on": "2020-05-27T12:00:00.00Z",
  "timestamp": "2020-05-20T12:32:08.24Z"
}

// Event 3: Contact details corrected
{
  "lead-id": 12,
  "event-id": 3,
  "event-type": "contact-details-updated",
  "first-name": "Casey",
  "last-name": "Davis", // ✅ Виправлено
  "phone-number": "555-8101", // Новий номер
  "timestamp": "2020-05-20T12:32:08.24Z"
}

// Event 4: Second contact
{
  "lead-id": 12,
  "event-id": 4,
  "event-type": "contacted",
  "timestamp": "2020-05-27T12:02:12.51Z"
}

// Event 5: Order submitted
{
  "lead-id": 12,
  "event-id": 5,
  "event-type": "order-submitted",
  "payment-deadline": "2020-05-30T12:02:12.51Z",
  "timestamp": "2020-05-27T12:02:12.51Z"
}

// Event 6: Payment confirmed
{
  "lead-id": 12,
  "event-id": 6,
  "event-type": "payment-confirmed",
  "status": "converted",
  "timestamp": "2020-05-27T12:38:44.12Z"
}

public class LeadProjection
{
    public long LeadId { get; private set; }
    public string FirstName { get; private set; }
    public string LastName { get; private set; }
    public string PhoneNumber { get; private set; }
    public LeadStatus Status { get; private set; }
    public int Version { get; private set; } // Лічильник модифікацій

    public void Apply(LeadInitialized @event)
    {
        LeadId = @event.LeadId;
        FirstName = @event.FirstName;
        LastName = @event.LastName;
        PhoneNumber = @event.PhoneNumber;
        Status = LeadStatus.NEW_LEAD;
        Version = 0;
    }

    public void Apply(ContactDetailsChanged @event)
    {
        FirstName = @event.FirstName;
        LastName = @event.LastName;
        PhoneNumber = @event.PhoneNumber;
        Version += 1;
    }

    public void Apply(Contacted @event)
    {
        Version += 1;
    }

    public void Apply(FollowupSet @event)
    {
        Status = LeadStatus.FOLLOWUP_SET;
        Version += 1;
    }

    public void Apply(OrderSubmitted @event)
    {
        Status = LeadStatus.PENDING_PAYMENT;
        Version += 1;
    }

    public void Apply(PaymentConfirmed @event)
    {
        Status = LeadStatus.CONVERTED;
        Version += 1;
    }
}

public class LeadSearchModelProjection
{
    public long LeadId { get; private set; }
    public HashSet<string> FirstNames { get; private set; } // ✅ Всі варіанти
    public HashSet<string> LastNames { get; private set; }  // ✅ Всі варіанти
    public HashSet<PhoneNumber> PhoneNumbers { get; private set; }
    public int Version { get; private set; }

    public void Apply(LeadInitialized @event)
    {
        LeadId = @event.LeadId;
        FirstNames = new HashSet<string>();
        LastNames = new HashSet<string>();
        PhoneNumbers = new HashSet<PhoneNumber>();

        // Додаємо початкові значення
        FirstNames.Add(@event.FirstName);
        LastNames.Add(@event.LastName);
        PhoneNumbers.Add(@event.PhoneNumber);
        Version = 0;
    }

    public void Apply(ContactDetailsChanged @event)
    {
        // ✅ Додаємо до множини, не перезаписуємо!
        FirstNames.Add(@event.FirstName);
        LastNames.Add(@event.LastName);
        PhoneNumbers.Add(@event.PhoneNumber);
        Version += 1;
    }

    // Інші події ігноруємо (не впливають на пошук)
    public void Apply(Contacted @event) { Version += 1; }
    public void Apply(FollowupSet @event) { Version += 1; }
    public void Apply(OrderSubmitted @event) { Version += 1; }
    public void Apply(PaymentConfirmed @event) { Version += 1; }
}

LeadId: 12
FirstNames: ["Casey"]
LastNames: ["David", "Davis"] // ✅ Обидва варіанти!
PhoneNumbers: ["555-2951", "555-8101"] // ✅ Обидва номери!
Version: 6

public class AnalysisModelProjection
{
    public long LeadId { get; private set; }
    public int Followups { get; private set; } // ✅ Лічильник followups
    public LeadStatus Status { get; private set; }
    public int Version { get; private set; }

    public void Apply(LeadInitialized @event)
    {
        LeadId = @event.LeadId;
        Followups = 0;
        Status = LeadStatus.NEW_LEAD;
        Version = 0;
    }

    public void Apply(FollowupSet @event)
    {
        Status = LeadStatus.FOLLOWUP_SET;
        Followups += 1; // ✅ Підрахор followups!
        Version += 1;
    }

    public void Apply(OrderSubmitted @event)
    {
        Status = LeadStatus.PENDING_PAYMENT;
        Version += 1;
    }

    public void Apply(PaymentConfirmed @event)
    {
        Status = LeadStatus.CONVERTED;
        Version += 1;
    }

    // Інші Игрноруємо
    public void Apply(Contacted @event) { Version += 1; }
    public void Apply(ContactDetailsChanged @event) { Version += 1; }
}

LeadId: 12
Followups: 1
Status: CONVERTED
Version: 6

interface IEventStore
{
    // ✅ Завантаження всіх подій конкретної сутності
    IEnumerable<Event> Fetch(Guid instanceId);

    // ✅ Додавання нових подій
    void Append(Guid instanceId, Event[] newEvents, int expectedVersion);
}

public class TicketAPI
{
    private IEventStore _eventStore;

    public void RequestEscalation(TicketId id, EscalationReason reason)
    {
        // ✅ Крок 1: Завантажуємо події
        var events = _eventStore.Fetch(id);

        // ✅ Крок 2: Реконструюємо стан
        var ticket = new Ticket();
        foreach (var @event in events)
        {
            ticket.Apply(@event);
        }

        // ✅ Крок 3: Виконуємо команду
        ticket.RequestEscalation(reason);

        // ✅ Крок 4: Зберігаємо нові події
        var newEvents = ticket.GetUncommittedEvents();
        _eventStore.Append(id, newEvents, ticket.Version);
    }
}

public class Ticket
{
    private TicketId _id;
    private TicketStatus _status;
    private Priority _priority;
    private List<IDomainEvent> _uncommittedEvents = new();
    public int Version { get; private set; }

    // ✅ State reconstruction від подій
    public void Apply(TicketInitialized @event)
    {
        _id = @event.TicketId;
        _status = TicketStatus.Open;
        _priority = @event.Priority;
        Version++;
    }

    public void Apply(TicketEscalated @event)
    {
        _status = TicketStatus.Escalated;
        _priority = IncreasePriority(_priority);
        Version++;
    }

    // ✅ Command: генерує події
    public void RequestEscalation(EscalationReason reason)
    {
        if (_status == TicketStatus.Closed)
        {
            throw new InvalidOperationException("Cannot escalate closed ticket");
        }

        // Генеруємо подію замість прямої зміни стану
        var @event = new TicketEscalated(_id, reason, DateTime.UtcNow);
        _uncommittedEvents.Add(@event);

        // Застосовуємо до поточного стану
        Apply(@event);
    }

    public IReadOnlyList<IDomainEvent> GetUncommittedEvents()
    {
        return _uncommittedEvents;
    }
}

public void LoadAggregate(Guid aggregateId)
{
    // ✅ Спочатку пробуємо завантажити snapshot
    var snapshot = _snapshotStore.GetLatest(aggregateId);

    int fromVersion = 0;
    if (snapshot != null)
    {
        ticket.LoadFromSnapshot(snapshot);
        fromVersion = snapshot.Version;
    }

    // ✅ Завантажуємо тільки події ПІСЛЯ snapshot
    var events = _eventStore.Fetch(aggregateId, fromVersion);
    foreach (var @event in events)
    {
        ticket.Apply(@event);
    }
}