using System.Text.Json;
using System.Text.Json.Serialization;
using BigRegister.Api.Contracts;
using BigRegister.Api.Data;
using BigRegister.Domain.Authorization;
using BigRegister.Stamdata;
using Microsoft.Extensions.Logging;

namespace BigRegister.Api.Zgw;

/// <summary>
/// The <see cref="IDocumentSource"/> backed by a real OpenZaak / ZGW Documenten API (DRC,
/// WP-51). An upload always lands locally first (<see cref="DocumentStore"/> stays the record
/// of truth for preview/download/audit, same reasoning as <see cref="OpenZaakZaakSource"/>'s
/// dual-write for aanvragen, WP-50) and is then ALSO registered as a DRC
/// enkelvoudiginformatieobject, whose url is persisted (<see cref="DocumentStore.SetDrcUrl"/>)
/// so <see cref="LinkToZaak"/> can find it later without a re-upload. Selected only when
/// <c>Zgw:Enabled=true</c>; the default stays <see cref="LocalDocumentSource"/>.
///
/// Auth: a fresh HS256 JWT per request (<see cref="ZgwTokenProvider"/>), same as
/// <see cref="OpenZaakZaakSource"/> — creating a document needs write scope on Documenten;
/// linking one to a zaak needs write scope on Zaken (the zaakinformatieobject resource).
/// </summary>
public sealed class OpenZaakDocumentSource(
    HttpClient http, ZgwTokenProvider tokens, ZgwOptions options, ILogger<OpenZaakDocumentSource>? log = null)
    : IDocumentSource
{
  private readonly ZgwHttpClient zgw = new(http, tokens);

  // WP-59: per-document-type confidentiality (stamdata, ADR-0004) — "openbaar" if the
  // category isn't in the table, so an unconfigured category never fails the upload.
  private static readonly IReadOnlyDictionary<string, string> ConfidentialiteitByCategory =
      StamdataFile.Load<DocumentConfidentialiteit>("documentconfidentialiteit")
          .ToDictionary(r => r.CategoryId, r => r.Vertrouwelijkheidaanduiding);

  private static string ConfidentialiteitFor(string categoryId) =>
      ConfidentialiteitByCategory.GetValueOrDefault(categoryId, "openbaar");

  // ponytail: sync-over-async — IDocumentSource is sync to match the local store + the
  // existing sync upload/submit endpoints, same reasoning as OpenZaakZaakSource.
  public UploadResponse Upload(
      string localId, string categoryId, string wizardId, string fileName, string contentType,
      byte[] content, CallerIdentity caller) =>
      UploadAsync(localId, categoryId, wizardId, fileName, contentType, content, caller)
          .GetAwaiter().GetResult();

  // WP-60: once DocumentStore.Add (below) has committed, the local document is the record of
  // truth (per the class doc above) — a ZGW failure past that point is caught, logged, and
  // leaves DrcUrl null rather than throwing. DrcUrl == null is already the meaningful "not
  // registered in ZGW yet" detector LinkToZaak skips on, so no separate flag column is needed
  // here the way ApplicationStore.ZgwError is for the zaak side (see openzaak-integration.md's
  // "Write resilience" section for why the two write paths differ).
  private async Task<UploadResponse> UploadAsync(
      string localId, string categoryId, string wizardId, string fileName, string contentType,
      byte[] content, CallerIdentity caller)
  {
    var doc = DocumentStore.Add(localId, categoryId, wizardId, fileName, contentType, content, caller.Bsn);

    try
    {
      if (!options.InformatieobjecttypeUrls.TryGetValue(categoryId, out var informatieobjecttypeUrl))
        throw new InvalidOperationException(
            $"Zgw:InformatieobjecttypeUrls has no entry for category '{categoryId}'.");

      var eio = await zgw.PostAsync<Eio>($"{options.DrcBaseUrl}/enkelvoudiginformatieobjecten", new CreateEioRequest(
          Bronorganisatie: options.Bronorganisatie,
          Creatiedatum: DateOnly.FromDateTime(doc.UploadedAt.UtcDateTime),
          Titel: fileName,
          Auteur: options.UserRepresentation,
          Taal: "nld",
          Formaat: contentType,
          Bestandsnaam: fileName,
          Inhoud: Convert.ToBase64String(content),
          Informatieobjecttype: informatieobjecttypeUrl,
          Identificatie: doc.DocumentId,
          Vertrouwelijkheidaanduiding: ConfidentialiteitFor(categoryId)), caller);

      DocumentStore.SetDrcUrl(doc.DocumentId, eio.Url);
    }
    catch (Exception ex)
    {
      log?.LogError(ex, "zgw divergence document={DocumentId} category={CategoryId}", doc.DocumentId, categoryId);
    }

    return new UploadResponse(doc.DocumentId, doc.LocalId);
  }

  /// <summary>Local link always happens (dual-write, same reasoning as upload); additionally,
  /// once a zaak exists, POST a zaakinformatieobject for every document that has a DRC url —
  /// documents uploaded before Zgw:Enabled was ever true (or under a config gap) simply have
  /// no DrcUrl yet and are skipped, matching "nothing extra to link" for the local case.
  /// WP-60: unlike Upload, a ZGW failure here still throws — DocumentStore.Link (the local
  /// half) already ran above, so the caller (Program.cs's submit endpoint) catching this and
  /// recording it as a flagged divergence is what closes the gap, not a try/catch in here.</summary>
  public void LinkToZaak(IReadOnlyList<string> documentIds, string? zaakUrl, CallerIdentity caller)
  {
    DocumentStore.Link(documentIds);
    if (zaakUrl is null) return;
    LinkToZaakAsync(documentIds, zaakUrl, caller).GetAwaiter().GetResult();
  }

  private async Task LinkToZaakAsync(IReadOnlyList<string> documentIds, string zaakUrl, CallerIdentity caller)
  {
    foreach (var documentId in documentIds)
    {
      var drcUrl = DocumentStore.Get(documentId)?.DrcUrl;
      if (drcUrl is null) continue;
      await zgw.PostAsync<JsonElement>($"{options.ZrcBaseUrl}/zaakinformatieobjecten",
          new CreateZaakInformatieobjectRequest(zaakUrl, drcUrl), caller);
    }
  }

  private sealed record Eio([property: JsonPropertyName("url")] string Url);

  private sealed record CreateEioRequest(
      [property: JsonPropertyName("bronorganisatie")] string Bronorganisatie,
      [property: JsonPropertyName("creatiedatum")] DateOnly Creatiedatum,
      [property: JsonPropertyName("titel")] string Titel,
      [property: JsonPropertyName("auteur")] string Auteur,
      [property: JsonPropertyName("taal")] string Taal,
      [property: JsonPropertyName("formaat")] string Formaat,
      [property: JsonPropertyName("bestandsnaam")] string Bestandsnaam,
      [property: JsonPropertyName("inhoud")] string Inhoud,
      [property: JsonPropertyName("informatieobjecttype")] string Informatieobjecttype,
      [property: JsonPropertyName("identificatie")] string Identificatie,
      [property: JsonPropertyName("vertrouwelijkheidaanduiding")] string Vertrouwelijkheidaanduiding);

  private sealed record CreateZaakInformatieobjectRequest(
      [property: JsonPropertyName("zaak")] string Zaak,
      [property: JsonPropertyName("informatieobject")] string Informatieobject);
}