1 files changed, 248 insertions, 0 deletions
diff --git a/src/notifications/push.ts b/src/notifications/push.ts
new file mode 100644
index 0000000..1e0308d
--- /dev/null
+++ b/src/notifications/push.ts
@@ -0,0 +1,248 @@
+import Expo, { ExpoPushMessage, ExpoPushTicket } from "expo-server-sdk";
+import { logger } from "../lib/pino";
+
+/** Expo SDK client for sending push notifications */
+let expo: Expo;
+try {
+  expo = new Expo();
+  logger.info("Expo push notification client initialized");
+} catch (error) {
+  logger.fatal({ error }, "Failed to initialize Expo push notification client");
+  throw error;
+}
+
+/** Data structure for push notification payloads */
+export type PushNotificationData = {
+  title: string;
+  body: string;
+  data?: Record<string, unknown>;
+  sound?: "default" | null;
+  badge?: number;
+  channelId?: string;
+};
+
+/**
+ * Sends a push notification to one device.
+ * Validates the token format and notification data before sending.
+ */
+export async function sendPushNotification(
+  pushToken: string,
+  notification: PushNotificationData,
+): Promise<{ success: boolean; error?: string }> {
+  try {
+    if (!pushToken || typeof pushToken !== "string") {
+      logger.warn("Invalid push token: empty or not a string");
+      return { success: false, error: "Invalid push token" };
+    }
+
+    if (!notification || typeof notification !== "object") {
+      logger.error({ pushToken }, "Invalid notification data");
+      return { success: false, error: "Invalid notification data" };
+    }
+
+    if (!notification.title || !notification.body) {
+      logger.error({ pushToken }, "Notification missing title or body");
+      return { success: false, error: "Notification must have title and body" };
+    }
+
+    if (!Expo.isExpoPushToken(pushToken)) {
+      logger.warn({ pushToken }, "Invalid Expo push token format");
+      return { success: false, error: "Invalid push token" };
+    }
+
+    const message: ExpoPushMessage = {
+      to: pushToken,
+      sound: notification.sound ?? "default",
+      title: notification.title,
+      body: notification.body,
+      data: notification.data ?? {},
+      channelId: notification.channelId ?? "default",
+    };
+
+    if (notification.badge !== undefined) {
+      message.badge = notification.badge;
+    }
+
+    try {
+      const tickets = await expo.sendPushNotificationsAsync([message]);
+      const ticket = tickets[0];
+
+      if (!ticket) {
+        logger.error({ pushToken }, "No ticket returned from Expo");
+        return { success: false, error: "No ticket returned" };
+      }
+
+      if (ticket.status === "error") {
+        logger.error(
+          { pushToken, error: ticket.message },
+          "Push notification error from Expo",
+        );
+        return { success: false, error: ticket.message };
+      }
+
+      logger.info(
+        { pushToken, ticketId: (ticket as { id: string }).id },
+        "Push notification sent successfully",
+      );
+      return { success: true };
+    } catch (error) {
+      logger.error(
+        { error, pushToken },
+        "Failed to send push notification to Expo",
+      );
+      return {
+        success: false,
+        error: error instanceof Error ? error.message : "Unknown error",
+      };
+    }
+  } catch (error) {
+    logger.error(
+      { error, pushToken },
+      "Unexpected error in sendPushNotification",
+    );
+    return {
+      success: false,
+      error: error instanceof Error ? error.message : "Unknown error",
+    };
+  }
+}
+
+/**
+ * Sends push notifications to multiple devices in batches.
+ * Filters out invalid tokens and chunks requests to avoid rate limits.
+ */
+export async function sendPushNotifications(
+  pushTokens: string[],
+  notification: PushNotificationData,
+): Promise<{ success: boolean; results: ExpoPushTicket[] }> {
+  try {
+    if (!Array.isArray(pushTokens)) {
+      logger.error("pushTokens is not an array");
+      return { success: false, results: [] };
+    }
+
+    if (pushTokens.length === 0) {
+      logger.warn("Empty pushTokens array provided");
+      return { success: false, results: [] };
+    }
+
+    if (!notification || typeof notification !== "object") {
+      logger.error(
+        { tokenCount: pushTokens.length },
+        "Invalid notification data for bulk send",
+      );
+      return { success: false, results: [] };
+    }
+
+    if (!notification.title || !notification.body) {
+      logger.error(
+        { tokenCount: pushTokens.length },
+        "Bulk notification missing title or body",
+      );
+      return { success: false, results: [] };
+    }
+
+    const validTokens = pushTokens.filter((token) => {
+      const isValid = Expo.isExpoPushToken(token);
+      if (!isValid) {
+        logger.warn(
+          { token },
+          "Invalid Expo push token in bulk send, filtering out",
+        );
+      }
+      return isValid;
+    });
+
+    if (validTokens.length === 0) {
+      logger.warn(
+        { originalCount: pushTokens.length },
+        "No valid tokens after filtering",
+      );
+      return { success: false, results: [] };
+    }
+
+    logger.info(
+      {
+        validTokenCount: validTokens.length,
+        totalTokenCount: pushTokens.length,
+      },
+      "Sending bulk push notifications",
+    );
+
+    const messages: ExpoPushMessage[] = validTokens.map((token) => ({
+      to: token,
+      sound: notification.sound ?? "default",
+      title: notification.title,
+      body: notification.body,
+      data: notification.data ?? {},
+      channelId: notification.channelId ?? "default",
+    }));
+
+    try {
+      const chunks = expo.chunkPushNotifications(messages);
+      const tickets: ExpoPushTicket[] = [];
+
+      for (let i = 0; i < chunks.length; i++) {
+        const chunk = chunks[i];
+        try {
+          const ticketChunk = await expo.sendPushNotificationsAsync(chunk!);
+          tickets.push(...ticketChunk);
+          logger.debug(
+            {
+              chunkIndex: i,
+              chunkSize: chunk!.length,
+              totalChunks: chunks.length,
+            },
+            "Push notification chunk sent",
+          );
+        } catch (chunkError) {
+          logger.error(
+            { error: chunkError, chunkIndex: i, chunkSize: chunk!.length },
+            "Failed to send push notification chunk",
+          );
+        }
+      }
+
+      const errorTickets = tickets.filter(
+        (ticket) => ticket.status === "error",
+      );
+      const hasErrors = errorTickets.length > 0;
+
+      if (hasErrors) {
+        logger.warn(
+          { errorCount: errorTickets.length, totalCount: tickets.length },
+          "Some push notifications failed",
+        );
+        errorTickets.forEach((ticket) => {
+          if (ticket.status === "error") {
+            logger.error(
+              { error: ticket.message, details: ticket.details },
+              "Push notification ticket error",
+            );
+          }
+        });
+      } else {
+        logger.info(
+          { sentCount: tickets.length },
+          "All push notifications sent successfully",
+        );
+      }
+
+      return { success: !hasErrors, results: tickets };
+    } catch (error) {
+      logger.error(
+        { error, tokenCount: validTokens.length },
+        "Failed to send bulk push notifications",
+      );
+      return { success: false, results: [] };
+    }
+  } catch (error) {
+    logger.error({ error }, "Unexpected error in sendPushNotifications");
+    return { success: false, results: [] };
+  }
+}
+
+/** Checks whether a token string is a valid Expo push token */
+export function isValidPushToken(token: string): boolean {
+  return Expo.isExpoPushToken(token);
+}