using System;
using System.IO;
using NpgsqlTypes;

namespace Npgsql.Replication;

/// <summary>
/// A message representing a section of the WAL data stream.
/// </summary>
public class XLogDataMessage : ReplicationMessage
{
    /// <summary>
    /// A section of the WAL data stream that is raw WAL data in physical replication or decoded with the selected
    /// logical decoding plugin in logical replication. It is only valid until the next <see cref="XLogDataMessage"/>
    /// is requested from the stream.
    /// </summary>
    /// <remarks>
    /// A single WAL record is never split across two XLogData messages.
    /// When a WAL record crosses a WAL page boundary, and is therefore already split using continuation records,
    /// it can be split at the page boundary. In other words, the first main WAL record and its continuation
    /// records can be sent in different XLogData messages.
    /// </remarks>
    public Stream Data { get; private set; } = default!;

    internal XLogDataMessage Populate(
        NpgsqlLogSequenceNumber walStart, NpgsqlLogSequenceNumber walEnd, DateTime serverClock, Stream data)
    {
        base.Populate(walStart, walEnd, serverClock);

        Data = data;

        return this;
    }
}