Initial commit

Watches district.in showtimes and sends a max-priority phone notification the
moment tickets for a given movie, date, format and cinema go on sale.

src/config.js

@@ -0,0 +1,62 @@
+// Configuration is read entirely from environment variables (see .env.example).
+// Load a .env file with Node's built-in flag: node --env-file-if-exists=.env src/index.js
+
+function required(name) {
+  const v = process.env[name];
+  if (!v) throw new Error(`${name} is required — copy .env.example to .env and fill it in`);
+  return v;
+}
+
+const num = (name, fallback) => {
+  const v = process.env[name];
+  if (v === undefined || v === "") return fallback;
+  const n = Number(v);
+  if (Number.isNaN(n)) throw new Error(`${name} must be a number, got "${v}"`);
+  return n;
+};
+
+export function loadConfig() {
+  const targetDate = required("TARGET_DATE");
+  if (!/^\d{4}-\d{2}-\d{2}$/.test(targetDate)) {
+    throw new Error(`TARGET_DATE must be YYYY-MM-DD, got "${targetDate}"`);
+  }
+  const tzOffsetMinutes = num("TZ_OFFSET_MINUTES", 330);
+
+  // Retire at local midnight following the target date, unless overridden.
+  const expiryUtc = process.env.EXPIRY_UTC ||
+    new Date(Date.parse(`${targetDate}T00:00:00Z`) + 86400000 - tzOffsetMinutes * 60000).toISOString();
+
+  return {
+    // what to watch
+    movieCode: required("MOVIE_CODE"),
+    contentId: required("CONTENT_ID"),
+    cityKey: required("CITY_KEY"),
+    lat: required("LAT"),
+    lng: required("LNG"),
+    targetDate,
+    cinemaId: process.env.CINEMA_ID || "",          // empty = any cinema
+    formatTag: process.env.FORMAT_TAG ?? "imax_2d", // empty + empty match = any format
+    formatMatch: process.env.FORMAT_MATCH ?? "IMAX",
+    formatLabel: process.env.FORMAT_LABEL || "IMAX",
+    bookingUrl: process.env.BOOKING_URL || "",
+
+    // notifications
+    ntfyUrl: (process.env.NTFY_URL || "https://ntfy.sh").replace(/\/+$/, ""),
+    ntfyTopic: required("NTFY_TOPIC"),
+    ntfyToken: process.env.NTFY_TOKEN || "",
+
+    // behaviour
+    intervalMs: num("CHECK_INTERVAL_SECONDS", 60) * 1000,
+    failureThreshold: num("FAILURE_THRESHOLD", 6),
+    tzOffsetMinutes,
+    heartbeatHour: num("HEARTBEAT_HOUR", 9), // -1 disables the daily heartbeat
+    currency: process.env.CURRENCY || "₹",
+    expiryUtc,
+
+    // runtime
+    statePath: process.env.STATE_PATH || "./state.json",
+    port: num("PORT", 8080),
+    proxyUrl: process.env.PROXY_URL || "",
+    dispatcher: null, // set by attachProxy() when PROXY_URL is present
+  };
+}