chore(admin): drop unused classifyNafSegment + harden SQL segment expr

Address the two minor findings from the post-implementation audit:
- Remove `classifyNafSegment` + the `NafSegment` type. The router
  builds a SQL CASE instead of bucketing rows in TypeScript, so the
  helper was dead code; trimming it keeps the `~/modules/shared` barrel
  lean. Tests now assert the two constants still used by the router
  (DOMINANT_NAF_SECTIONS, OTHER_NAF_SEGMENT).
- Replace `sql.raw(dominantList)` with `sql.join` in
  `buildSegmentExpression` so each dominant letter goes through Drizzle
  parameter binding. Safe today (constant is a compile-time `as const`
  array) but removes the `sql.raw` sink as defence in depth.

Author: LucasCharrier

packages/app/src/modules/shared/__tests__/nafSections.test.ts

@@ -1,33 +1,25 @@
 import { describe, expect, it } from "vitest";
 
 import {
-	classifyNafSegment,
 	DOMINANT_NAF_SECTIONS,
+	NAF_SECTION_CODES,
 	OTHER_NAF_SEGMENT,
 } from "../nafSections";
 
-describe("classifyNafSegment", () => {
-	it("returns the letter prefix for dominant sections", () => {
-		for (const section of DOMINANT_NAF_SECTIONS) {
-			expect(classifyNafSegment(`${section}01.11Z`)).toBe(section);
-		}
-	});
-
-	it("returns 'Autres' for non-dominant but valid sections", () => {
-		// A, B, D, E, F, H, I, J, K, L, O, P, R, S, T, U are non-dominant.
-		expect(classifyNafSegment("A01.11Z")).toBe(OTHER_NAF_SEGMENT);
-		expect(classifyNafSegment("K64.19Z")).toBe(OTHER_NAF_SEGMENT);
-		expect(classifyNafSegment("U99.00Z")).toBe(OTHER_NAF_SEGMENT);
+describe("DOMINANT_NAF_SECTIONS", () => {
+	it("keeps the five manually curated sections", () => {
+		expect([...DOMINANT_NAF_SECTIONS]).toEqual(["C", "G", "M", "N", "Q"]);
 	});
 
-	it("normalises the letter case", () => {
-		expect(classifyNafSegment("c10.11z")).toBe("C");
+	it("only references valid NAF section letters", () => {
+		for (const code of DOMINANT_NAF_SECTIONS) {
+			expect(NAF_SECTION_CODES).toContain(code);
+		}
 	});
+});
 
-	it("returns null for null, empty, or invalid prefixes", () => {
-		expect(classifyNafSegment(null)).toBeNull();
-		expect(classifyNafSegment("")).toBeNull();
-		expect(classifyNafSegment("99.00Z")).toBeNull(); // starts with digit
-		expect(classifyNafSegment("Z99.00Z")).toBeNull(); // Z is not a NAF section
+describe("OTHER_NAF_SEGMENT", () => {
+	it("uses the French 'Autres' label for the aggregated bucket", () => {
+		expect(OTHER_NAF_SEGMENT).toBe("Autres");
 	});
 });

packages/app/src/modules/shared/index.ts

@@ -2,9 +2,8 @@ export { CompanySizeFilter } from "./CompanySizeFilter";
 export { FileUpload } from "./FileUpload";
 export { getDsfrModal } from "./getDsfrModal";
 export { NafSectorFilter } from "./NafSectorFilter";
-export type { NafSectionCode, NafSegment } from "./nafSections";
+export type { NafSectionCode } from "./nafSections";
 export {
-	classifyNafSegment,
 	DOMINANT_NAF_SECTIONS,
 	NAF_SECTION_CODES,
 	NAF_SECTIONS,

packages/app/src/modules/shared/nafSections.ts

@@ -78,22 +78,3 @@ export const DOMINANT_NAF_SECTIONS: readonly NafSectionCode[] = [
 
 /** Label used for the aggregated series bucketing all non-dominant sections. */
 export const OTHER_NAF_SEGMENT = "Autres";
-
-export type NafSegment = NafSectionCode | typeof OTHER_NAF_SEGMENT;
-
-/**
- * Map a full NAF code (e.g. `"62.01Z"`) to its chart segment. Dominant
- * sections keep their letter; everything else collapses into `"Autres"`.
- * Returns `null` when the code is null / empty / unknown.
- */
-export function classifyNafSegment(nafCode: string | null): NafSegment | null {
-	if (!nafCode) return null;
-	const prefix = nafCode.charAt(0).toUpperCase();
-	if (DOMINANT_NAF_SECTIONS.includes(prefix as NafSectionCode)) {
-		return prefix as NafSectionCode;
-	}
-	// Reject obviously invalid prefixes so upstream doesn't silently fold
-	// corrupt data into "Autres".
-	if (!NAF_SECTION_CODES.includes(prefix as NafSectionCode)) return null;
-	return OTHER_NAF_SEGMENT;
-}

packages/app/src/server/api/routers/adminStats.ts

@@ -239,11 +239,15 @@ function buildSegmentExpression(
 		end`;
 	}
 	// NAF: collapse non-dominant sections into a single "Autres" segment.
-	const dominantList = DOMINANT_NAF_SECTIONS.map((code) => `'${code}'`).join(
-		", ",
+	// Each dominant letter goes through parameter binding via `sql.join` —
+	// prevents the helper from becoming an injection sink if the constant
+	// is ever sourced from outside the module.
+	const dominantParams = sql.join(
+		DOMINANT_NAF_SECTIONS.map((code) => sql`${code}`),
+		sql`, `,
 	);
 	return sql<string>`case
-		when upper(left(${companies.nafCode}, 1)) in (${sql.raw(dominantList)})
+		when upper(left(${companies.nafCode}, 1)) in (${dominantParams})
 		then upper(left(${companies.nafCode}, 1))
 		else ${OTHER_NAF_SEGMENT}
 	end`;