From b1cc4f316bca53ac37c59ba429633152b2c45e64 Mon Sep 17 00:00:00 2001
From: Daniel Lugo <danlugo92@gmail.com>
Date: Sat, 18 Apr 2020 19:43:05 -0400
Subject: [PATCH] last seen node

---
 services/gunDB/Mediator/index.js              |  2 +
 services/gunDB/contact-api/jobs/index.js      |  4 +-
 .../gunDB/contact-api/jobs/lastSeenNode.js    | 40 +++++++++++++++++
 services/gunDB/contact-api/key.js             |  2 +
 services/gunDB/contact-api/utils/index.js     | 43 ++++++++++++++++---
 5 files changed, 85 insertions(+), 6 deletions(-)
 create mode 100644 services/gunDB/contact-api/jobs/lastSeenNode.js

diff --git a/services/gunDB/Mediator/index.js b/services/gunDB/Mediator/index.js
index e233199a..167c9460 100644
--- a/services/gunDB/Mediator/index.js
+++ b/services/gunDB/Mediator/index.js
@@ -282,6 +282,7 @@ const authenticate = async (alias, pass, __user) => {
     // move this to a subscription; implement off() ? todo
     API.Jobs.onAcceptedRequests(_user, mySEA)
     API.Jobs.onOrders(_user, gun, mySEA)
+    API.Jobs.lastSeenNode(_user)
     return _user._.sea.pub
   }
 
@@ -313,6 +314,7 @@ const authenticate = async (alias, pass, __user) => {
 
     API.Jobs.onAcceptedRequests(_user, mySEA)
     API.Jobs.onOrders(_user, gun, mySEA)
+    API.Jobs.lastSeenNode(_user)
 
     return ack.sea.pub
   } else {
diff --git a/services/gunDB/contact-api/jobs/index.js b/services/gunDB/contact-api/jobs/index.js
index 55c993e1..8818d047 100644
--- a/services/gunDB/contact-api/jobs/index.js
+++ b/services/gunDB/contact-api/jobs/index.js
@@ -11,8 +11,10 @@
 
 const onAcceptedRequests = require('./onAcceptedRequests')
 const onOrders = require('./onOrders')
+const lastSeenNode = require('./lastSeenNode')
 
 module.exports = {
   onAcceptedRequests,
-  onOrders
+  onOrders,
+  lastSeenNode
 }
diff --git a/services/gunDB/contact-api/jobs/lastSeenNode.js b/services/gunDB/contact-api/jobs/lastSeenNode.js
new file mode 100644
index 00000000..881d41b2
--- /dev/null
+++ b/services/gunDB/contact-api/jobs/lastSeenNode.js
@@ -0,0 +1,40 @@
+/**
+ * @format
+ */
+
+const logger = require('winston')
+
+const ErrorCode = require('../errorCode')
+const Key = require('../key')
+const { LAST_SEEN_NODE_INTERVAL } = require('../utils')
+
+/**
+ * @typedef {import('../SimpleGUN').GUNNode} GUNNode
+ * @typedef {import('../SimpleGUN').ListenerData} ListenerData
+ * @typedef {import('../SimpleGUN').ISEA} ISEA
+ * @typedef {import('../SimpleGUN').UserGUNNode} UserGUNNode
+ */
+
+/**
+ * @param {UserGUNNode} user
+ * @throws {Error} NOT_AUTH
+ * @returns {void}
+ */
+const lastSeenNode = user => {
+  if (!user.is) {
+    logger.warn('onOrders() -> tried to sub without authing')
+    throw new Error(ErrorCode.NOT_AUTH)
+  }
+
+  setInterval(() => {
+    if (user.is) {
+      user.get(Key.LAST_SEEN_NODE).put(Date.now(), ack => {
+        if (ack.err) {
+          logger.error(`Error inside lastSeenNode job: ${ack.err}`)
+        }
+      })
+    }
+  }, LAST_SEEN_NODE_INTERVAL)
+}
+
+module.exports = lastSeenNode
diff --git a/services/gunDB/contact-api/key.js b/services/gunDB/contact-api/key.js
index 6f380432..a1b26023 100644
--- a/services/gunDB/contact-api/key.js
+++ b/services/gunDB/contact-api/key.js
@@ -38,3 +38,5 @@ exports.BIO = 'bio'
 exports.SEED_BACKUP = 'seedBackup'
 
 exports.LAST_SEEN_APP = 'lastSeenApp'
+
+exports.LAST_SEEN_NODE = 'lastSeenNode'
diff --git a/services/gunDB/contact-api/utils/index.js b/services/gunDB/contact-api/utils/index.js
index 63432cd7..93b3dd4c 100644
--- a/services/gunDB/contact-api/utils/index.js
+++ b/services/gunDB/contact-api/utils/index.js
@@ -1,7 +1,7 @@
-/* eslint-disable init-declarations */
 /**
  * @format
  */
+/* eslint-disable init-declarations */
 const logger = require('winston')
 
 const ErrorCode = require('../errorCode')
@@ -30,11 +30,11 @@ const mySecret = () => Promise.resolve(require('../../Mediator').getMySecret())
  * @returns {Promise<T>}
  */
 const timeout10 = promise => {
-   /** @type {NodeJS.Timeout} */
+  /** @type {NodeJS.Timeout} */
   // @ts-ignore
   let timeoutID
   return Promise.race([
-    promise.then((v) => {
+    promise.then(v => {
       clearTimeout(timeoutID)
       return v
     }),
@@ -57,7 +57,7 @@ const timeout5 = promise => {
   // @ts-ignore
   let timeoutID
   return Promise.race([
-    promise.then((v) => {
+    promise.then(v => {
       clearTimeout(timeoutID)
       return v
     }),
@@ -314,6 +314,37 @@ const dataHasSoul = listenerData =>
  */
 const defaultName = pub => 'anon' + pub.slice(0, 8)
 
+const LAST_SEEN_NODE_INTERVAL = 10000
+
+/**
+ * @param {string} pub
+ * @returns {Promise<boolean>}
+ */
+const isNodeOnline = async pub => {
+  const SET_LAST_SEEN_APP_INTERVAL = 15000
+
+  /**
+   * @param {any} lastSeen
+   * @returns {boolean}
+   */
+  const isAppOnline = lastSeen =>
+    typeof lastSeen === 'number' &&
+    Date.now() - lastSeen < SET_LAST_SEEN_APP_INTERVAL * 2
+
+  const userNode = require('../../Mediator')
+    .getGun()
+    .user(pub)
+
+  const isOnlineApp = isAppOnline(await userNode.get(Key.LAST_SEEN_APP).then())
+  const lastSeenNode = await userNode.get(Key.LAST_SEEN_NODE).then()
+
+  return (
+    isOnlineApp ||
+    (typeof lastSeenNode === 'number' &&
+      Date.now() - lastSeenNode < LAST_SEEN_NODE_INTERVAL * 2)
+  )
+}
+
 module.exports = {
   asyncMap,
   asyncFilter,
@@ -328,5 +359,7 @@ module.exports = {
   mySecret,
   promisifyGunNode: require('./promisifygun'),
   asyncForEach,
-  timeout5
+  timeout5,
+  LAST_SEEN_NODE_INTERVAL,
+  isNodeOnline
 }