namespace NATS.Server.Mqtt;

/// <summary>
/// JetStream API helper context for MQTT account/session operations.
/// Go reference: mqtt.go mqttJSA.
/// </summary>
public sealed class MqttJsa
{
    /// <summary>Account that owns the MQTT JetStream operations.</summary>
    public string AccountName { get; set; } = string.Empty;
    /// <summary>Reply subject prefix used for MQTT JetStream API calls.</summary>
    public string ReplyPrefix { get; set; } = string.Empty;
    /// <summary>Optional JetStream domain for cross-domain routing.</summary>
    public string? Domain { get; set; }
}

/// <summary>
/// MQTT JetStream publish request shape.
/// Go reference: mqtt.go mqttJSPubMsg.
/// </summary>
public sealed class MqttJsPubMsg
{
    /// <summary>Target NATS subject for the publish operation.</summary>
    public string Subject { get; set; } = string.Empty;
    /// <summary>Published payload bytes.</summary>
    public byte[] Payload { get; set; } = [];
    /// <summary>Optional reply subject for request/reply semantics.</summary>
    public string? ReplyTo { get; set; }
}

/// <summary>
/// Retained-message delete notification payload.
/// Go reference: mqtt.go mqttRetMsgDel.
/// </summary>
public sealed class MqttRetMsgDel
{
    /// <summary>MQTT topic whose retained message should be removed.</summary>
    public string Topic { get; set; } = string.Empty;
    /// <summary>JetStream sequence of the retained message record.</summary>
    public ulong Sequence { get; set; }
}

/// <summary>
/// Persisted MQTT session metadata.
/// Go reference: mqtt.go mqttPersistedSession.
/// </summary>
public sealed class MqttPersistedSession
{
    /// <summary>MQTT client identifier for the persisted session.</summary>
    public string ClientId { get; set; } = string.Empty;
    /// <summary>Last issued packet identifier for this session.</summary>
    public int LastPacketId { get; set; }
    /// <summary>Maximum number of unacknowledged QoS deliveries allowed.</summary>
    public int MaxAckPending { get; set; }
}

/// <summary>
/// Reference to a retained message in storage.
/// Go reference: mqtt.go mqttRetainedMsgRef.
/// </summary>
public sealed class MqttRetainedMessageRef
{
    /// <summary>JetStream sequence containing the retained MQTT payload.</summary>
    public ulong StreamSequence { get; set; }
    /// <summary>NATS subject mapped from the retained MQTT topic.</summary>
    public string Subject { get; set; } = string.Empty;
}

/// <summary>
/// MQTT subscription metadata.
/// Go reference: mqtt.go mqttSub.
/// </summary>
public sealed class MqttSub
{
    /// <summary>MQTT topic filter for this subscription.</summary>
    public string Filter { get; set; } = string.Empty;
    /// <summary>Requested MQTT QoS level.</summary>
    public byte Qos { get; set; }
    /// <summary>Optional JetStream durable consumer name.</summary>
    public string? JsDur { get; set; }
    /// <summary>Indicates whether this is a permanent subscription.</summary>
    public bool Prm { get; set; }
    /// <summary>Reserved flag kept for Go protocol parity.</summary>
    public bool Reserved { get; set; }
}

/// <summary>
/// Parsed MQTT filter metadata.
/// Go reference: mqtt.go mqttFilter.
/// </summary>
public sealed class MqttFilter
{
    /// <summary>Original MQTT topic filter.</summary>
    public string Filter { get; set; } = string.Empty;
    /// <summary>QoS level attached to the filter.</summary>
    public byte Qos { get; set; }
    /// <summary>Parsed token optimization hint used for dispatch lookups.</summary>
    public string? TopicToken { get; set; }
}

/// <summary>
/// Parsed NATS headers associated with an MQTT publish flow.
/// Go reference: mqtt.go mqttParsedPublishNATSHeader.
/// </summary>
public sealed class MqttParsedPublishNatsHeader
{
    /// <summary>Subject extracted from MQTT publish headers, when present.</summary>
    public string? Subject { get; set; }
    /// <summary>Mapped subject after account/topic translation.</summary>
    public string? Mapped { get; set; }
    /// <summary>Indicates the packet represents a PUBLISH flow.</summary>
    public bool IsPublish { get; set; }
    /// <summary>Indicates the packet represents a PUBREL flow.</summary>
    public bool IsPubRel { get; set; }
}