refactor to have 3 promises race instead of timeouts

packages/doorman-client/functions/buzzer-activated.js

@@ -13,7 +13,7 @@ async function getConfig(context, buzzer) {
 
 function notifyDiscord(context, msg, u, optionalJsonStr) {
   return fetch(context.DOORMAN_URL + 
-    `/api/door/notify?discordUser=${u}&msg=${encodeURIComponent(msg)}&json=${encodeURIComponent(optionalJsonStr)}`
+    `/api/door/notify?discordUser=${u}&msg=${encodeURIComponent(msg)}&json=${encodeURIComponent(optionalJsonStr)}`,
   ).catch(err => console.log(err))
 }
 
@@ -42,8 +42,6 @@ function dialFallbackTwiml(twiml, config) {
 }
 
 exports.handler = async function(context, event, callback) {
-  let twiml = new Twilio.twiml.VoiceResponse();
-
   let config = event.config;
 
   // get by api or parse it out from query
@@ -59,45 +57,83 @@ exports.handler = async function(context, event, callback) {
 
   // reject the call if this is not configured
   if (!config || !config.door) {
+    let twiml = new Twilio.twiml.VoiceResponse();
     twiml.reject();
     callback(null, twiml);
     return;
   }
 
-  // TODO: await on this?
   // let users know someone is currently buzzing, and allow unlock by discord user
   let msg = `🔔 Someone is dialing right now @ Door "${config.door}" [Click to unlock](${context.DOORMAN_URL}/api/door/auth?door=${config.door}&key=`;
-  let discordNotifs = Promise.all(config.discordUsers.map((u) => 
+  
+  // TODO: should we await for one delivery?
+  Promise.race(config.discordUsers.map((u) => 
     notifyDiscord(context, msg + u + ')', u)
   ));
 
-  // poll Doorman, to see if we should unlock
-  const interval = setInterval(() => {
-    fetch(context.DOORMAN_URL + `/api/door/status?door=${config.door}`)
-      .then(async res => {
-        if (res.status === 200) {
-          clearInterval(interval);
-          // put this before awaiting notify
-          // so it would be appended above any dial Verb from fallback
-          doorOpenTwiml(twiml, config);
+  let discordLock = false;
 
-          const body = await res.json();
-          await notifyAllDiscord(context, config, `🔓 Doorman buzzed someone up @ Door "${config.door}"`, JSON.stringify(body.fingerprint));
-          callback(null, twiml);
-        }
-      })
-      .catch(err => console.log(err));
-  }, 500);
+  const unlockPromise = new Promise((resolve, reject) => {
+    const interval = setInterval(() => {
+      fetch(context.DOORMAN_URL + `/api/door/status?door=${config.door}`)
+        .then(async res => {
+          if (res.status === 200) {
+            clearInterval(interval);
+            const body = await res.json();
+            const twiml = new Twilio.twiml.VoiceResponse();
+            doorOpenTwiml(twiml, config);
+            if (!discordLock) {
+              console.log(
+                "UnlockPromise: I was the fastest, so I will attempt to notify discord users before resolving with unlock"
+              );
+              discordLock = true;
+              await notifyAllDiscord(context, config, `🔓 Doorman buzzed someone up @ Door "${config.door}"`, JSON.stringify(body.fingerprint));
+              resolve(twiml);
+            } else {
+              console.log(
+                "UnlockPromise: dropping out of the race, graceful fallback is already notifiying discord users"
+              );
+            }
+          }
+        }).catch(err => console.log(err));
+    }, 500)
+  });
 
-  // redirect to call after 6s
-  setTimeout(async () => {
-    dialFallbackTwiml(twiml, config);
-    await notifyAllDiscord(
-      context, 
-      config, 
-      `📞 Somebody buzzed the door and it dialed through to fallback phone numbers @ Door "${config.door}"`
-    );
+  const gracefulFallbackPromise = new Promise((resolve, reject) => {
+    setTimeout(async () => {
+      const twiml = new Twilio.twiml.VoiceResponse();
+      dialFallbackTwiml(twiml, config);
 
-    callback(null, twiml);
-  }, 6000);
+      if (!discordLock) {
+        console.log(
+          "GracefulFallbackPromise: I was the fastest, so I will attempt to notify discord users before resolving with a call"
+        );
+        discordLock = true;
+        await notifyAllDiscord(
+          context, 
+          config, 
+          `📞 Somebody buzzed the door and it dialed through to fallback phone numbers @ Door "${config.door}"`
+        );
+        resolve(twiml);
+      } else {
+        console.log(
+          "GracefulFallbackPromise: dropping out of the race, unlock is already notifying discord users"
+        );
+      }
+    }, 6000);
+  });
+
+  const ungracefulFallbackPromise = new Promise((resolve, reject) => {
+    setTimeout(async () => {
+      const twiml = new Twilio.twiml.VoiceResponse();
+      dialFallbackTwiml(twiml, config);
+      console.error(
+        "UngracefulFallbackPromise: Cutting it too close to timeout! Skipping notifying users and calling fallback"
+      );
+      resolve(twiml);
+    }, 8000);
+  });
+
+  const twiml = await Promise.race([unlockPromise, gracefulFallbackPromise, ungracefulFallbackPromise]);
+  callback(null, twiml);
 };