/**
 * Paramètres d’affichage qui doivent survivre au passage par le détail d’une
 * facture BAP. Seules ces clés sont sérialisées afin d’éviter de propager des
 * paramètres de navigation arbitraires.
 */
export type BapFilters = {
  searchQuery: string;
  statusFilter: string;
  selectedYear: string;
  selectedMonth: string;
  recipientFilter: string;
  entityFilter: string;
  ventilationFilter: string;
  sortField: "invoiceDate" | "createdAt";
  sortDir: "asc" | "desc";
};

const BAP_STATUSES = new Set([
  "all",
  "exported",
  "not_exported",
  "export_error",
  "bap_validated",
  "bap_pending",
  "to_complete",
]);

function asSearchParams(search: string): URLSearchParams {
  return new URLSearchParams(search.startsWith("?") ? search.slice(1) : search);
}

function isMonth(value: string | null): value is string {
  return value !== null && /^(0[1-9]|1[0-2])$/.test(value);
}

function isYear(value: string | null): value is string {
  return value === "all" || (value !== null && /^\d{4}$/.test(value));
}

function isSafeFilterValue(value: string | null): value is string {
  return value !== null && value.length > 0 && value.length <= 200;
}

/** Lit et valide les filtres BAP transmis dans l’URL. */
export function parseBapFilters(search: string, defaultYear: string): BapFilters {
  const params = asSearchParams(search);
  const status = params.get("status");
  const year = params.get("year");
  const month = params.get("month");
  const sort = params.get("sort");
  const direction = params.get("dir");

  return {
    searchQuery: params.get("q") || "",
    statusFilter: status && BAP_STATUSES.has(status) ? status : "all",
    selectedYear: isYear(year) ? year : defaultYear,
    selectedMonth: month === "all" || isMonth(month) ? month : "all",
    recipientFilter: isSafeFilterValue(params.get("recipient")) ? params.get("recipient")! : "all",
    entityFilter: ["all", "santinova", "itinova"].includes(params.get("entity") || "") ? params.get("entity")! : "all",
    ventilationFilter: isSafeFilterValue(params.get("ventilation")) ? params.get("ventilation")! : "all",
    sortField: sort === "invoiceDate" ? "invoiceDate" : "createdAt",
    sortDir: direction === "asc" ? "asc" : "desc",
  };
}

/** Construit une URL de détail qui conserve explicitement le contexte BAP. */
export function buildBapDetailLocation(invoiceId: number, filters: BapFilters): string {
  const params = new URLSearchParams({
    returnTo: "bap",
    q: filters.searchQuery,
    status: filters.statusFilter,
    year: filters.selectedYear,
    month: filters.selectedMonth,
    recipient: filters.recipientFilter,
    entity: filters.entityFilter,
    ventilation: filters.ventilationFilter,
    sort: filters.sortField,
    dir: filters.sortDir,
  });

  return `/invoices/${invoiceId}?${params.toString()}`;
}

/** Retourne la liste d’origine. Sans contexte BAP, le comportement historique est conservé. */
export function getBapReturnLocation(search: string): string {
  const params = asSearchParams(search);
  if (params.get("returnTo") !== "bap") return "/invoices";

  const allowed = new URLSearchParams();
  for (const key of ["q", "status", "year", "month", "recipient", "entity", "ventilation", "sort", "dir"]) {
    const value = params.get(key);
    if (value) allowed.set(key, value);
  }
  const query = allowed.toString();
  return query ? `/invoices-bap?${query}` : "/invoices-bap";
}