namespace LehrerApp.Sync.Models;

/// <summary>
/// Ein einzelnes Ereignis im Event-Log.
/// Wird verschlüsselt zum Server übertragen – der Server versteht den Payload nicht.
/// </summary>
public class SyncEvent
{
    public Guid EventId { get; init; } = Guid.NewGuid();
    public string DeviceId { get; init; } = "";
    public DeviceType DeviceType { get; init; }
    public DateTime Timestamp { get; init; } = DateTime.UtcNow;
    public long SequenceNr { get; init; }           // monoton steigend pro Gerät
    public string EntityType { get; init; } = "";   // "Student", "Exam", "Grade" ...
    public string EntityId { get; init; } = "";
    public string Operation { get; init; } = "";    // "Create", "Update", "Delete"
    public string Payload { get; init; } = "";      // JSON, AES-256 verschlüsselt
}

/// <summary>
/// Eintrag im lokalen Konflikt-Log – für UI-Anzeige.
/// </summary>
public class ConflictEntry
{
    public Guid Id { get; init; } = Guid.NewGuid();
    public DateTime DetectedAt { get; init; } = DateTime.UtcNow;
    public SyncEvent LocalEvent { get; init; } = null!;
    public SyncEvent RemoteEvent { get; init; } = null!;
    public string Resolution { get; init; } = "";   // "LocalWon", "RemoteWon", "Pending"
    public bool Reviewed { get; set; }
}

/// <summary>
/// Antwort des Servers auf einen Pull-Request.
/// </summary>
public class PullResponse
{
    public List<SyncEvent> Events { get; init; } = [];
    public long ServerSequenceNr { get; init; }
}

/// <summary>
/// Antwort des Servers auf einen Push-Request.
/// </summary>
public class PushResponse
{
    public bool Success { get; init; }
    public long ServerSequenceNr { get; init; }
    public List<Guid> ConflictingEventIds { get; init; } = [];
}

public enum DeviceType { Desktop, Companion }

/// <summary>
/// Sync-Status für UI-Anzeige.
/// </summary>
public class SyncStatus
{
    public SyncState State { get; set; } = SyncState.Idle;
    public DateTime? LastSyncAt { get; set; }
    public int PendingEvents { get; set; }
    public int ConflictCount { get; set; }
    public string? ErrorMessage { get; set; }
}

public enum SyncState { Idle, Syncing, Error, Offline }