using ZB.MOM.WW.Telemetry;

namespace ZB.MOM.WW.ScadaBridge.Host;

/// <summary>
/// The one place ScadaBridge fills <see cref="ZbTelemetryOptions"/>, shared by the
/// <c>AddZbTelemetry</c> registration (metrics + traces) and the pre-host <c>AddZbSerilog</c>
/// logger (logs), so the three signals carry the same Resource and go to the same endpoint.
/// </summary>
/// <remarks>
/// The logger is built on its own pre-host container (see <see cref="ScadaBridgeLogging"/>), where
/// no <c>AddZbTelemetry</c> registration exists for Telemetry 0.3.0's OTLP log sink to follow, so the
/// exporter settings are passed to <c>AddZbSerilog</c> explicitly (scadaproj#55).
/// </remarks>
internal static class ScadaBridgeTelemetryConfig
{
    /// <summary>The operator section: <c>Exporter</c>, <c>OtlpEndpoint</c>, <c>ServiceVersion</c>,
    /// <c>ExportLogs</c>, <c>ResourceAttributes:*</c>.</summary>
    internal const string SectionName = "ScadaBridge:Telemetry";

    /// <summary>
    /// Applies the service name, the <c>ScadaBridge:Telemetry</c> keys and then the node identity.
    /// <paramref name="siteId"/> / <paramref name="nodeRole"/> are applied LAST so the Resource always
    /// matches the <c>SiteId</c>/<c>NodeRole</c> log enrichers (both come from <c>ScadaBridge:Node</c>);
    /// a <c>ScadaBridge:Telemetry:SiteId</c>/<c>:NodeRole</c> key cannot make them diverge.
    /// <c>service.version</c> defaults from the entry assembly (the git SHA).
    /// </summary>
    /// <param name="options">The options to fill.</param>
    /// <param name="configuration">The application configuration.</param>
    /// <param name="siteId">The node's site id (<c>ScadaBridge:Node:SiteId</c>, default <c>central</c>).</param>
    /// <param name="nodeRole">The node's role (<c>ScadaBridge:Node:Role</c>).</param>
    internal static void Apply(ZbTelemetryOptions options, IConfiguration configuration, string? siteId, string? nodeRole)
    {
        ArgumentNullException.ThrowIfNull(options);
        ArgumentNullException.ThrowIfNull(configuration);

        options.ServiceName = ScadaBridgeLogging.ServiceName;
        options.ApplyConfiguration(configuration.GetSection(SectionName));
        options.SiteId = siteId;
        options.NodeRole = nodeRole;
    }
}