fix: District settings read per field, so DISTRICT_* always wins

A leftover v1 MOVIE_CODE used to switch the whole District block to the old names,
silently discarding DISTRICT_CONTENT_ID even when it was set deliberately. The
monitor then watched the wrong film and still reported 'closed', which is the
failure mode this project exists to avoid.

Each field now prefers the DISTRICT_* value and falls back to its v1 name, an
explicitly emptied value is respected, and any v1 name still in use is warned
about at startup. District is enabled by DISTRICT_CONTENT_ID rather than the
movie code, which is optional: District answers without it, and a film with no
showtimes yet has none.

src/config.js

@@ -22,36 +22,50 @@ const num = (name, fallback) => {
   return n;
 };
 
-/** Old single-provider variable names, still honoured so v1 .env files keep working. */
-function legacyDistrict() {
-  if (!process.env.MOVIE_CODE || process.env.DISTRICT_MOVIE_CODE) return null;
-  return {
-    movieCode: env("MOVIE_CODE"),
-    contentId: env("CONTENT_ID"),
-    cityKey: env("CITY_KEY"),
-    lat: env("LAT"),
-    lng: env("LNG"),
-    venueId: env("CINEMA_ID"),
-    formatTag: process.env.FORMAT_TAG ?? "imax_2d",
-    formatMatch: process.env.FORMAT_MATCH ?? "IMAX",
-    bookingUrl: env("BOOKING_URL"),
-  };
+/**
+ * District settings. v1 used flat names (MOVIE_CODE, CINEMA_ID and so on) and those are
+ * still honoured, but per field, so a stale leftover cannot override a DISTRICT_* value
+ * that was set deliberately. Enabled by the content id, since the movie code is optional.
+ */
+const LEGACY = {
+  DISTRICT_MOVIE_CODE: "MOVIE_CODE",
+  DISTRICT_CONTENT_ID: "CONTENT_ID",
+  DISTRICT_CITY_KEY: "CITY_KEY",
+  DISTRICT_LAT: "LAT",
+  DISTRICT_LNG: "LNG",
+  DISTRICT_CINEMA_ID: "CINEMA_ID",
+  DISTRICT_FORMAT_TAG: "FORMAT_TAG",
+  DISTRICT_FORMAT_MATCH: "FORMAT_MATCH",
+  DISTRICT_BOOKING_URL: "BOOKING_URL",
+};
+
+const pick = (name) => process.env[name] ?? process.env[LEGACY[name]];
+
+export function legacyNamesInUse() {
+  return Object.entries(LEGACY)
+    .filter(([nu, old]) => process.env[nu] === undefined && process.env[old] !== undefined)
+    .map(([, old]) => old);
 }
 
 function districtConfig() {
-  const legacy = legacyDistrict();
-  if (legacy) return legacy;
-  if (!process.env.DISTRICT_MOVIE_CODE) return null;
+  const contentId = pick("DISTRICT_CONTENT_ID");
+  if (!contentId) return null; // District not configured
+  const need = (name) => {
+    const v = pick(name);
+    if (!v) throw new Error(`${name} is required when District is configured (see .env.example)`);
+    return v;
+  };
   return {
-    movieCode: required("DISTRICT_MOVIE_CODE"),
-    contentId: required("DISTRICT_CONTENT_ID"),
-    cityKey: required("DISTRICT_CITY_KEY"),
-    lat: required("DISTRICT_LAT"),
-    lng: required("DISTRICT_LNG"),
-    venueId: env("DISTRICT_CINEMA_ID"),
-    formatTag: process.env.DISTRICT_FORMAT_TAG ?? "imax_2d",
-    formatMatch: process.env.DISTRICT_FORMAT_MATCH ?? "IMAX",
-    bookingUrl: env("DISTRICT_BOOKING_URL"),
+    // Optional: District answers without it, and an unreleased film has no format code yet.
+    movieCode: pick("DISTRICT_MOVIE_CODE") ?? "",
+    contentId,
+    cityKey: need("DISTRICT_CITY_KEY"),
+    lat: need("DISTRICT_LAT"),
+    lng: need("DISTRICT_LNG"),
+    venueId: pick("DISTRICT_CINEMA_ID") ?? "",
+    formatTag: pick("DISTRICT_FORMAT_TAG") ?? "imax_2d",
+    formatMatch: pick("DISTRICT_FORMAT_MATCH") ?? "IMAX",
+    bookingUrl: pick("DISTRICT_BOOKING_URL") ?? "",
   };
 }
 
@@ -83,6 +97,10 @@ export function loadConfig() {
     new Date(Date.parse(`${targetDate}T00:00:00Z`) + 86400000 - tzOffsetMinutes * 60000).toISOString();
 
   const built = { district: districtConfig(), bookmyshow: bookmyshowConfig() };
+  const stale = legacyNamesInUse();
+  if (stale.length) {
+    console.warn(`warning: using v1 variable names ${stale.join(", ")}. Rename them to DISTRICT_* to avoid confusion.`);
+  }
   // PROVIDERS is an explicit allow-list; without it, every configured provider runs.
   const wanted = env("PROVIDERS").split(",").map((s) => s.trim()).filter(Boolean);
   for (const w of wanted) {
@@ -90,7 +108,7 @@ export function loadConfig() {
   }
   const keys = (wanted.length ? wanted : Object.keys(built)).filter((k) => built[k]);
   if (!keys.length) {
-    throw new Error("No provider configured. Set DISTRICT_MOVIE_CODE and/or BMS_EVENT_CODE (see .env.example)");
+    throw new Error("No provider configured. Set DISTRICT_CONTENT_ID and/or BMS_EVENT_CODE (see .env.example)");
   }
   for (const w of wanted) {
     if (!built[w]) throw new Error(`PROVIDERS lists "${w}" but its settings are missing (see .env.example)`);