WFDASH-WEBAPP/src/lib/server/pos-letterhead-service.ts

import { getAdminPocketBase } from "./pocketbase-admin";
import { type Letterhead } from "../letterhead";

/**
 * Server-side read model for the POS letterhead picker.
 *
 * The till needs a list of available letterheads so the operator can
 * pick which one this device runs under (CNL, ISHERWOOD, Westcott
 * Group, etc.), plus a "fetch by id" path so the till can grab the
 * full record (address, phone, logo URL, VAT rate) at boot.
 *
 * The `letterhead_settings` PB collection is shared with the main
 * WFDASH app (which uses it for the PDF flow). We don't change
 * anything there — just expose what already exists.
 */

export type PosLetterheadListItem = {
  id: string;
  display_name: string;
  company: string;
  vat_percent: number;
  accent_color: string;
  has_logo: boolean;
  is_active: boolean;
};

export type PosLetterheadFull = PosLetterheadListItem & {
  address: string;
  phone: string;
  email: string;
  vat_number: string;
  registration_number: string;
  footer_text: string;
  logo_url: string | null;
  collection_id: string;
};

function toListItem(r: Letterhead): PosLetterheadListItem {
  return {
    id: r.id,
    display_name: r.display_name,
    company: r.company,
    vat_percent: Number(r.vat_percent ?? 0),
    accent_color: r.accent_color || "",
    has_logo: !!r.logo,
    is_active: !!r.is_active,
  };
}

/**
 * The till's logo URL must be **same-origin**, not the raw PocketBase
 * URL that `letterheadLogoUrl()` builds.
 *
 * The thermal-print path rasterizes the logo through a `<canvas>`
 * (see `imageToRaster` in public/pos/epos-print.js) and canvas
 * `getImageData()` throws a SecurityError on a cross-origin image —
 * so a raw `{PB_BASE}/api/files/...` URL silently yields no logo on
 * every printed slip. Routing through this app's own file proxy keeps
 * it same-origin so the canvas stays untainted.
 *
 * See AGENTS.md — "File URLs go through `/api/v1/files/`, never
 * `/api/files/`". `letterhead_settings` is whitelisted in that proxy.
 */
function posLetterheadLogoUrl(r: Letterhead): string | null {
  if (!r.logo) return null;
  return `/api/v1/files/letterhead_settings/${r.id}/${r.logo}`;
}

function toFull(r: Letterhead): PosLetterheadFull {
  return {
    ...toListItem(r),
    address: r.address || "",
    phone: r.phone || "",
    email: r.email || "",
    vat_number: r.vat_number || "",
    registration_number: r.registration_number || "",
    footer_text: r.footer_text || "",
    logo_url: posLetterheadLogoUrl(r),
    collection_id: r.collectionId,
  };
}

/**
 * List every letterhead that's marked active. The till uses this to
 * populate its picker UI. Inactive rows are skipped because they
 * shouldn't be selectable from the device.
 *
 * We don't sort here — `display_name` is already human-ordered in
 * the PB admin (CNL, ISHERWOOD, WESTSCOTT, ...) so the natural
 * insertion order is the order the operator set up.
 */
export async function listActiveLetterheads(): Promise<PosLetterheadListItem[]> {
  const pb = await getAdminPocketBase();
  const rows = await pb.collection("letterhead_settings").getFullList<Letterhead>({
    filter: "is_active = true",
  });
  return rows.map(toListItem);
}

/**
 * Fetch a single letterhead by id, with the full set of fields the
 * till needs at sale time (address, phone, logo URL, VAT rate, etc).
 *
 * Throws if the id doesn't exist — that's a config bug (the till
 * cached a stale id), not a user error, so the route will surface
 * a 500 and the till should re-list and re-pick.
 */
export async function getPosLetterheadById(id: string): Promise<PosLetterheadFull> {
  if (!id) {
    throw new Error("letterhead id is required");
  }
  const pb = await getAdminPocketBase();
  let row: Letterhead;
  try {
    row = await pb.collection("letterhead_settings").getOne<Letterhead>(id);
  } catch (e) {
    throw new Error(`Letterhead ${id} not found: ${(e as Error).message}`);
  }
  return toFull(row);
}