storing latest 3 iot data entries and deleting remaining

src/controllers/tanksController.js

@@ -663,21 +663,36 @@ exports.IotDevice = async (req, reply) => {
   try {
     const { hardwareId, tankHeight, maxLevel, minLevel, mode } = req.body;
 
-    // create a new tank document
-    const tank = new IotData({ hardwareId, tankHeight, maxLevel, minLevel, mode });
+    // create a new tank document with the current date and time
+    const currentDate = new Date();
+    const date = currentDate.toLocaleDateString('en-IN');
+    const time = currentDate.toLocaleTimeString('en-IN', {hour12:false, timeZone: 'Asia/Kolkata' });
+    const tank = new IotData({ hardwareId, tankHeight, maxLevel, minLevel, mode, date, time });
 
     // save the document to MongoDB
     await tank.save();
 
-    // send a success response
-    reply.code(200).send({ message: 'Data saved successfully' });
+    // get all the tank documents for the current hardwareId sorted in descending order of date and time
+    const tanks = await IotData.find({ hardwareId }).sort({ date: -1, time: -1 });
+
+    // if the number of documents for the current hardwareId is greater than three, remove the oldest documents until there are only three left
+    if (tanks.length > 3) {
+      const oldestDocuments = tanks.slice(3);
+      for (const doc of oldestDocuments) {
+        await IotData.deleteOne({ _id: doc._id });
+      }
+    }
+
+    // get the latest three tank documents for the current hardwareId sorted in descending order of date and time
+    const latestTanks = await IotData.find({ hardwareId }).sort({ date: -1, time: -1 }).limit(3);
+
+    // send the latest three documents in descending order of date and time
+    reply.code(200).send({ latestTanks: latestTanks.reverse() });
   } catch (err) {
     // send an error response
     reply.code(500).send({ error: err.message });
   }
-}
-
-
+};
 
 
 exports.getIotD = async(req, reply) => {

src/models/tanks.js

@@ -46,8 +46,13 @@ const IOttankSchema = new mongoose.Schema({
     tankHeight: { type: String, required: true },
     maxLevel: { type: String, required: true },
     minLevel: { type: String, required: true },
+    date: { type: String, required: true },
+    time: { type: String, required: true },
     mode: { type: Number, required: true }
   });
+
+
+