using System.Text.Json;
using BigRegister.Api.Data;
using BigRegister.Domain.Applications;
using BigRegister.Domain.Diplomas;
using BigRegister.Domain.Documents;
using BigRegister.Domain.People;
using BigRegister.Domain.Registrations;

namespace BigRegister.Api.Contracts;

/// <summary>Domain → wire DTO mapping (the anti-corruption boundary, server side).</summary>
public static class Mappers
{
  private static string D(DateOnly d) => d.ToString("yyyy-MM-dd");

  public static RegistrationStatusDto ToDto(this RegistrationStatus s) => s switch
  {
    RegistrationStatus.Geregistreerd g => new(s.Tag.ToString(), HerregistratieDatum: D(g.HerregistratieDatum)),
    RegistrationStatus.Geschorst g => new(s.Tag.ToString(), GeschorstTot: D(g.GeschorstTot), Reden: g.Reden),
    RegistrationStatus.Doorgehaald d => new(s.Tag.ToString(), DoorgehaaldOp: D(d.DoorgehaaldOp), Reden: d.Reden),
    _ => throw new ArgumentOutOfRangeException(nameof(s), s, "Unknown RegistrationStatus variant"),
  };

  public static RegistrationDto ToDto(this Registration r) => new(
      r.BigNummer, r.Naam, r.Beroep, D(r.Registratiedatum), D(r.Geboortedatum), r.Status.ToDto());

  public static AdresDto ToDto(this Adres a) => new(a.Straat, a.Postcode, a.Woonplaats);

  public static PersonDto ToDto(this Person p) => new(p.Naam, D(p.Geboortedatum), p.Adres.ToDto());

  public static PolicyQuestionDto ToDto(this PolicyQuestion q) => new(
      q.Id, q.Vraag, q.Type == QuestionType.JaNee ? "ja-nee" : "tekst");

  public static DuoDiplomaDto ToDto(this Diploma d) => new(
      d.Id, d.Naam, d.Instelling, d.Jaar,
      DiplomaRules.ProfessionFor(d),
      DiplomaRules.QuestionsFor(d).Select(q => q.ToDto()).ToList());

  public static DocumentCategoryDto ToDto(this DocumentCategory c) => new(
      c.CategoryId, c.Label, c.Description, c.Required, c.AcceptedTypes, c.MaxSizeMb, c.Multiple, c.AllowPostDelivery);

  /// <summary>Wire projection of an <see cref="AanvraagStatus"/> — the null "Concept" case
  /// is the one place a status has no <see cref="AanvraagStatusTag"/>, so it becomes the wire
  /// convention's magic string here at the boundary rather than living inside the domain type.
  /// Shared by <see cref="ToStatusDto"/> and <c>ZgwZaakMapper</c>, so both status producers
  /// agree on the projection (WP-68 F3).</summary>
  public static AanvraagStatusDto ToDto(this AanvraagStatus s) => new(
      s.Tag?.ToString() ?? "Concept", s.StepIndex, s.StepCount, s.Referentie, s.Manual, s.Reden);

  // Aanvraag status is COMPUTED ON READ (see the StatusAt extension, Data/AanvraagMapper.cs) —
  // this is now a one-line projection of that onto the wire DTO (WP-68 F3, WP-73).
  public static AanvraagStatusDto ToStatusDto(this Aanvraag a, DateTimeOffset now) => a.StatusAt(now).ToDto();

  /// <summary>SubmittedAt only exists once Submitted/Decided (WP-73) — null for a Concept,
  /// same as the wire DTO's own nullable field.</summary>
  private static string? SubmittedAtOf(Aanvraag a) => a switch
  {
    Aanvraag.Concept => null,
    Aanvraag.Submitted s => s.SubmittedAt.ToString("o"),
    Aanvraag.Decided d => d.SubmittedAt.ToString("o"),
    _ => null,
  };

  /// <summary>Draft only exists pre-submission (WP-73) — null once Submitted/Decided (nothing
  /// reads it past that point; see <c>AanvraagMapper.ApplyTo</c>'s Submitted branch).</summary>
  private static JsonElement? DraftOf(Aanvraag a) => a is Aanvraag.Concept c ? c.Draft : null;

  public static ApplicationSummaryDto ToSummaryDto(this Aanvraag a, DateTimeOffset now) => new(
      a.Id, a.Type, a.ToStatusDto(now), a.DocumentIds,
      a.CreatedAt.ToString("o"), a.UpdatedAt.ToString("o"), SubmittedAtOf(a));

  /// Admin summary — same shape plus the owner (WP-36; the user-facing list leaves Owner null).
  public static ApplicationSummaryDto ToAdminSummaryDto(this Aanvraag a, DateTimeOffset now) =>
      a.ToSummaryDto(now) with { Owner = a.Owner };

  public static ApplicationDetailDto ToDetailDto(this Aanvraag a, DateTimeOffset now) => new(
      a.Id, a.Type, a.ToStatusDto(now), DraftOf(a), a.DocumentIds,
      a.CreatedAt.ToString("o"), a.UpdatedAt.ToString("o"), SubmittedAtOf(a));
}