namespace ZB.MOM.WW.ScadaBridge.DelmiaNotifier;

/// <summary>Final outcome of the notify operation, mapped 1:1 to the YES/NO + exit-code contract.</summary>
internal sealed record NotifyResult(bool Ok, string Reason);

/// <summary>
/// Connect-failure-only failover loop: tries each base URL in order. A node that responds at all is
/// authoritative — its answer is final (success, business rejection, or HTTP error alike). Only a
/// failure to connect rolls over to the next URL; if every URL fails to connect the last error is reported.
/// </summary>
internal static class Notifier
{
    /// <summary>
    /// Runs the connect-failure-only failover loop across <paramref name="baseUrls"/>,
    /// sending <paramref name="payload"/> via <paramref name="sender"/> until a node
    /// responds (connects) or every URL fails to connect.
    /// </summary>
    /// <param name="baseUrls">Base URLs to try in order.</param>
    /// <param name="payload">The recipe-download payload to send.</param>
    /// <param name="sender">The sender used to POST the payload to each base URL.</param>
    /// <param name="ct">Cancellation token.</param>
    /// <returns>A task that resolves to the final notify outcome.</returns>
    public static async Task<NotifyResult> RunAsync(
        string[] baseUrls, RecipeDownload payload, IRecipeSender sender, CancellationToken ct)
    {
        var lastError = "no base URLs configured";

        foreach (var baseUrl in baseUrls)
        {
            var outcome = await sender.SendAsync(baseUrl, payload, ct);

            if (outcome.Kind == AttemptKind.ConnectFailed)
            {
                lastError = outcome.Error ?? "connection failed";
                continue; // unreachable node → try the next
            }

            // Connected — this node's answer is authoritative; never fail over past it.
            if (IsSuccessStatus(outcome.StatusCode))
            {
                if (outcome.Body is { Result: true })
                {
                    return new NotifyResult(true, outcome.Body.ResultText ?? string.Empty);
                }

                var reason = outcome.Body?.ResultText;
                return new NotifyResult(false, string.IsNullOrEmpty(reason) ? "request rejected" : reason);
            }

            return new NotifyResult(false, $"HTTP {outcome.StatusCode}");
        }

        return new NotifyResult(false, $"all URLs unreachable: {lastError}");
    }

    private static bool IsSuccessStatus(int status) => status is >= 200 and < 300;
}
