namespace DorkNet.Server.Services;

/// <summary>Single source of truth for the deployment apex domain.
/// Read from <c>DORKNET_DOMAIN</c> env var (or config key
/// <c>Domain:Apex</c>) at startup. Defaults to <c>localhost</c>. Replaces
/// per-controller <c>[Host("api.rec.net","api.localhost")]</c> filters —
/// allowed hosts are derived as <c>{apex}</c> + <c>*.{apex}</c>, fed
/// into HostFilteringMiddleware. Subdomain-discriminating handlers
/// (Cdn vs Img on path "/{*path}") branch on
/// <c>Request.Host.Host.Split('.')[0]</c>.</summary>
public sealed class DomainConfig
{
    public string Apex { get; }
    public DomainConfig(string apex) { Apex = apex; }
    public string Sub(string prefix) => $"{prefix}.{Apex}";
    public static bool MatchesSubdomain(string host, string prefix)
        => host.StartsWith(prefix + ".", StringComparison.OrdinalIgnoreCase);
}