using System.Net.Http.Json;
using System.Text.Json.Serialization;
using EventSubscriber.Application;

namespace EventSubscriber.Api;

/// <summary>
/// HTTP client to the ACL service. The subscriber enriches the projection with the zaak's reference
/// (identificatie) by asking the ACL — the only code that may read ZGW (§8.1) — rather than reading
/// OpenZaak itself (adr-proposal #78).
/// </summary>
public sealed class AclHttpClient(HttpClient http) : IAclClient
{
    public async Task<string> GetZaakReferenceAsync(Uri zaakUrl, CancellationToken ct = default)
    {
        ArgumentNullException.ThrowIfNull(zaakUrl);

        using var response = await http.PostAsJsonAsync(
            new Uri(http.BaseAddress!, "zaken/reference"), new ReferenceRequest(zaakUrl.ToString()), ct);
        response.EnsureSuccessStatusCode();

        var body = await response.Content.ReadFromJsonAsync<ReferenceResponse>(ct)
            ?? throw new InvalidOperationException("The ACL returned an empty reference response.");
        return body.Reference;
    }

    private sealed record ReferenceRequest([property: JsonPropertyName("zaakUrl")] string ZaakUrl);

    private sealed record ReferenceResponse([property: JsonPropertyName("reference")] string Reference);
}