import type { ConfirmRow } from "@/lib/server/collection-confirm-service";
import type { CollectionDocType } from "@/lib/types";

type AiDoc = NonNullable<ConfirmRow["ai_doc"]>;

const MONTHS = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];

/**
 * Union of the document findings across a card's distinct reads, then each
 * row's own line findings (`ai_check.findings`), deduped, in order.
 */
export function cardFindings(rows: ConfirmRow[]): string[] {
  const seenReads = new Set<string>();
  const seen = new Set<string>();
  const out: string[] = [];
  const add = (finding: string) => {
    if (!finding || seen.has(finding)) return;
    seen.add(finding);
    out.push(finding);
  };
  for (const row of rows) {
    const doc = row.ai_doc;
    if (!doc || seenReads.has(doc.read_id)) continue;
    seenReads.add(doc.read_id);
    for (const finding of doc.findings ?? []) add(finding);
  }
  for (const row of rows) {
    for (const finding of row.ai_check?.findings ?? []) add(finding);
  }
  return out;
}

/** The card's newest document (first non-null wins on equal dates). */
export function cardDocument(rows: ConfirmRow[]): AiDoc | null {
  let best: AiDoc | null = null;
  for (const row of rows) {
    const doc = row.ai_doc;
    if (!doc) continue;
    if (!best || (doc.doc_date ?? "") > (best.doc_date ?? "")) best = doc;
  }
  return best;
}

/**
 * Pre-fill for the confirm dialog: the number and date of the card's
 * document (the same newest document the chip shows), only when it is a
 * tax invoice — a delivery note's number is not the invoice number.
 */
export function aiInvoiceDefaults(
  rows: ConfirmRow[],
): { number: string; date?: string } | undefined {
  const doc = cardDocument(rows);
  if (!doc || doc.doc_type !== "tax_invoice") return undefined;
  const number = (doc.document_no ?? "").trim();
  if (!number) return undefined;
  const date = doc.doc_date ?? "";
  return /^\d{4}-\d{2}-\d{2}$/.test(date) ? { number, date } : { number };
}

/** Toast for an Add to POS response: plain success, or the counts when any row didn't go in. */
export function posResultToast(
  results: Array<{ status: string }>,
): { level: "success" | "warning"; message: string } {
  const count = (status: string) => results.filter((r) => r.status === status).length;
  const created = count("created");
  const failed = count("failed");
  const needsSku = count("needs_sku");
  if (failed === 0 && needsSku === 0) {
    return { level: "success", message: `Added ${created} item${created === 1 ? "" : "s"} to the POS` };
  }
  const parts = [`${created} added`];
  if (failed > 0) parts.push(`${failed} failed`);
  if (needsSku > 0) parts.push(`${needsSku} need${needsSku === 1 ? "s" : ""} a SKU`);
  return { level: "warning", message: parts.join(", ") };
}

export function docTypeLabel(type: CollectionDocType): string {
  if (type === "tax_invoice") return "Tax invoice";
  if (type === "delivery_note") return "Delivery note";
  return "Document";
}

/** "2026-10-16" -> "16 Oct 2026"; anything else is returned as is. */
export function formatDocDate(iso: string): string {
  const m = /^(\d{4})-(\d{2})-(\d{2})/.exec((iso ?? "").trim());
  if (!m) return iso ?? "";
  const month = Number(m[2]) - 1;
  if (month < 0 || month > 11) return iso;
  return `${Number(m[3])} ${MONTHS[month]} ${m[1]}`;
}

export function documentChipLabel(doc: AiDoc): string {
  const head = [docTypeLabel(doc.doc_type), doc.document_no].filter(Boolean).join(" ");
  return [head, formatDocDate(doc.doc_date), "read from driver photo"]
    .filter(Boolean)
    .join(" · ");
}