using SharpDlt.Internal;

namespace SharpDlt;

/// <summary>
/// A DLT message consisting of its headers and its payload.
/// </summary>
/// <param name="StorageHeader">Storage Header of the message, if the message was stored in a file.</param>
/// <param name="StandardHeader">Standard Header of the message.</param>
/// <param name="ExtendedHeader">Extended Header of the message, if it is transmitted.</param>
/// <param name="Payload">Payload of the message, if it carries one.</param>
public sealed record DltMessage(
    StorageHeader? StorageHeader,
    StandardHeader StandardHeader,
    ExtendedHeader? ExtendedHeader,
    DltPayload? Payload
)
{
    /// <summary>Gets a value indicating whether the message is in verbose mode.</summary>
    public bool IsVerbose => ExtendedHeader?.Verbose ?? false;

    /// <summary>Gets the payload as a verbose payload, or <see langword="null"/> if it is not verbose.</summary>
    public VerbosePayload? VerbosePayload => Payload as VerbosePayload;

    /// <summary>Gets the payload as a non-verbose payload, or <see langword="null"/> if it is verbose.</summary>
    public NonVerbosePayload? NonVerbosePayload => Payload as NonVerbosePayload;

    /// <summary>Parses a single DLT message from the beginning of <paramref name="data"/>.</summary>
    /// <param name="data">The data of one complete DLT message.</param>
    /// <param name="options">Options controlling the parsing, <see cref="DltReaderOptions.Default"/> if omitted.</param>
    /// <exception cref="DltParseException">The data is malformed.</exception>
    public static DltMessage Parse(ReadOnlySpan<byte> data, DltReaderOptions? options = null)
    {
        options ??= DltReaderOptions.Default;
        return DltMessageParser.Parse(data, options.HasStorageHeader, options.StringEncoding);
    }

    /// <summary>
    /// Gets an overview of the message in the format
    /// <c>[time ][timestamp ]counter[ ecuid][ apid][ ctid][ session][ type][ subtype] mode[ args][ payload]</c>.
    /// </summary>
    public override string ToString() => DltMessageParser.Describe(this);
}