diff --git a/src/controllers/storeController.js b/src/controllers/storeController.js
index f838858b..b9a6f63a 100644
--- a/src/controllers/storeController.js
+++ b/src/controllers/storeController.js
@@ -11,7 +11,7 @@ const fastify = require("fastify")({
   },
 });
 
-const {SensorStock,Order,EstimationOrder,Iotprice, Install, ProfilePictureInstall, SensorQuotation,generateinstallationId,Store,WaterLeverSensor,MotorSwitchSenso,Insensors,generatequatationId, HardwareCart, ServiceCart, Sales} = require("../models/store");
+const {Repairorder,SensorStock,Order,EstimationOrder,Iotprice, Install, ProfilePictureInstall, SensorQuotation,generateinstallationId,Store,WaterLeverSensor,MotorSwitchSenso,Insensors,generatequatationId, HardwareCart, ServiceCart, Sales} = require("../models/store");
 const { User,Counter, generateBookingId,resetCounter,generateCustomerId,ProfilePicture} = require('../models/User')
 
 
@@ -2669,4 +2669,159 @@ exports.getallocatedsensorstouser= async (req, reply) => {
     console.error("Error fetching iots:", err);
     return reply.status(500).send({ error: "Internal server error" });
   }
+};
+
+
+
+const crypto = require("crypto");
+
+
+
+exports.replaceAndRepair = async (req, reply) => {
+  try {
+    const { customerId } = req.params;
+    const { items } = req.body;
+
+    if (!customerId || !Array.isArray(items) || items.length === 0) {
+      return reply.code(400).send({ error: "customerId and items[] are required" });
+    }
+
+    const replacements = [];
+
+    for (const item of items) {
+      const { type, hardwareId } = item;
+      console.log(`🔍 Processing ${type} with hardwareId: ${hardwareId}`);
+
+      const existing = await Insensors.findOne({ hardwareId, type, customerId });
+
+      if (!existing) {
+        console.warn(`⚠️ No existing ${type} found for hardwareId: ${hardwareId}`);
+        continue;
+      }
+
+      // Mark existing as repair
+      await Insensors.updateOne(
+        { _id: existing._id },
+        { $set: { status: "repair", outforrepairdate: new Date().toISOString() } }
+      );
+      console.log(`🛠 Marked old ${type} ${hardwareId} as repair`);
+
+      // Find replacement
+      const replacement = await Insensors.findOne({
+        type,
+        status: "available",
+        storeId: existing.storeId
+      });
+
+      if (!replacement) {
+        console.warn(`⚠️ No available replacement found for ${type} at store ${existing.storeId}`);
+        continue;
+      }
+
+      console.log(`✅ Found replacement ${replacement.hardwareId} for ${type}`);
+
+      const updateData = {
+        status: "blocked",
+        customerId: existing.customerId,
+        tankName: existing.tankName,
+        tankLocation: existing.tankLocation,
+        storeId: existing.storeId,
+        model: existing.model,
+        tankhardwareId: existing.tankhardwareId,
+        masterId: existing.masterId,
+        masterName: existing.masterName,
+        location: existing.location
+      };
+
+      await Insensors.updateOne({ _id: replacement._id }, { $set: updateData });
+      console.log(`✅ Updated replacement ${type} ${replacement.hardwareId} with previous config`);
+
+      // === Cascade updates ===
+      if (type === "master") {
+        const connectedSlaves = await Insensors.find({
+          type: "slave",
+          connected_to: hardwareId,
+          customerId
+        });
+
+        for (const slave of connectedSlaves) {
+          await Insensors.updateOne(
+            { _id: slave._id },
+            { $set: { connected_to: replacement.hardwareId } }
+          );
+          console.log(`🔁 Updated slave ${slave.hardwareId} → connected_to: ${replacement.hardwareId}`);
+        }
+      }
+
+      if (type === "slave") {
+        await Insensors.updateOne(
+          { _id: replacement._id },
+          { $set: { connected_to: existing.connected_to } }
+        );
+        console.log(`🔁 New slave ${replacement.hardwareId} → connected_to: ${existing.connected_to}`);
+
+        const connectedSensors = await Insensors.find({
+          type: "sensor",
+          connected_to: hardwareId,
+          customerId
+        });
+
+        for (const sensor of connectedSensors) {
+          await Insensors.updateOne(
+            { _id: sensor._id },
+            { $set: { connected_to: replacement.hardwareId } }
+          );
+          console.log(`🔁 Updated sensor ${sensor.hardwareId} → connected_to: ${replacement.hardwareId}`);
+        }
+      }
+
+      if (type === "sensor") {
+        await Insensors.updateOne(
+          { _id: replacement._id },
+          { $set: { connected_to: existing.connected_to } }
+        );
+        console.log(`🔁 Sensor ${replacement.hardwareId} connected to same slave: ${existing.connected_to}`);
+      }
+
+      // Log replacement
+      replacements.push({
+        type,
+        oldHardwareId: hardwareId,
+        newHardwareId: replacement.hardwareId
+      });
+
+      console.log(`📦 Logged replacement: ${type} ${hardwareId} ➜ ${replacement.hardwareId}`);
+    }
+
+    console.log("🧾 Final replacements:", replacements);
+
+    // Create repair log
+    const packageId = "PKG-" + crypto.randomBytes(4).toString("hex").toUpperCase();
+    const otp = Math.floor(100000 + Math.random() * 900000).toString();
+
+    const repairLog = new Repairorder({
+      customerId,
+      packageId,
+      otp,
+      replacements,
+      createdAt: new Date()
+    });
+
+    await repairLog.save();
+    console.log("✅ RepairLog saved");
+
+    return reply.send({
+      status_code: 200,
+      message: "Repaired and replaced successfully",
+      data: {
+        packageId,
+        otp,
+        replacements,
+        createdAt: repairLog.createdAt
+      }
+    });
+  } catch (err) {
+    console.error("❌ Error during replacement:", err);
+    return reply.code(500).send({ error: "Internal Server Error" });
+  }
 };
\ No newline at end of file
diff --git a/src/models/store.js b/src/models/store.js
index 6d9ce7ce..4d71e225 100644
--- a/src/models/store.js
+++ b/src/models/store.js
@@ -1077,6 +1077,31 @@ const materialRecievedPicturesSchema = new Schema({
   }
 });
 
+const RepairorderSchema = new mongoose.Schema({
+  customerId: { type: String, required: true },
+  packageId: { type: String, required: true },
+  otp: { type: String, required: true },
+  replacements: [
+    {
+      type: {
+        type: String,
+        enum: ["master", "slave", "sensor"],
+        required: true
+      },
+      oldHardwareId: { type: String, required: true },
+      newHardwareId: { type: String, required: true }
+    }
+  ],
+  createdAt: { type: Date, default: Date.now }
+});
+
+
+
+
+const Repairorder = mongoose.model('Repairorder', RepairorderSchema);
+
+
+
 const Iotprice = mongoose.model('Iotprice', iotpriceSchema);
   const Insensors = mongoose.model('Insensors', insensorsSchema);
   const MasterSlaveData = mongoose.model('MasterSlaveData', masterSlaveDataSchema);
@@ -1106,4 +1131,4 @@ const Iotprice = mongoose.model('Iotprice', iotpriceSchema);
 
   
 
-  module.exports = {Support,MaterialRecievedPictures,PlumbingWorkPictures,ElectrictyWorkPictures,MasterSlaveData,SensorStock,Order,EstimationOrder,Iotprice,Sales, Install,Survey, ProfilePictureInstall, SensorQuotation,generateinstallationId,Store,ProfilePictureStore,WaterLeverSensor,MotorSwitchSensor,Insensors,generatequatationId, HardwareCart, ServiceCart};
+  module.exports = {Repairorder,Support,MaterialRecievedPictures,PlumbingWorkPictures,ElectrictyWorkPictures,MasterSlaveData,SensorStock,Order,EstimationOrder,Iotprice,Sales, Install,Survey, ProfilePictureInstall, SensorQuotation,generateinstallationId,Store,ProfilePictureStore,WaterLeverSensor,MotorSwitchSensor,Insensors,generatequatationId, HardwareCart, ServiceCart};
diff --git a/src/routes/storeRoute.js b/src/routes/storeRoute.js
index 59881457..b4d8b85b 100644
--- a/src/routes/storeRoute.js
+++ b/src/routes/storeRoute.js
@@ -2012,5 +2012,75 @@ fastify.get("/api/getallocatedsensors/:customerId", {
   handler: storeController.getallocatedsensorstouser,
 });
 
+
+
+fastify.post("/api/repair/replace/:customerId", {
+    schema: {
+      tags: ["Install"],
+      summary: "Mark old sensors as repair and replace them with available ones",
+      description: "This API replaces sensors (master/slave/sensor) with available ones and logs the repair action",
+      params: {
+        type: "object",
+        properties: {
+          customerId: { type: "string", description: "Customer ID" },
+        },
+        required: ["customerId"]
+      },
+      body: {
+        type: "object",
+        properties: {
+          items: {
+            type: "array",
+            items: {
+              type: "object",
+              properties: {
+                type: { type: "string", enum: ["master", "slave", "sensor"] },
+                hardwareId: { type: "string" }
+              },
+              required: ["type", "hardwareId"]
+            }
+          }
+        },
+        required: ["items"]
+      },
+      response: {
+        200: {
+          description: "Successful replacement and repair log creation",
+          type: "object",
+          properties: {
+            status_code: { type: "integer" },
+            message: { type: "string" },
+            data: {
+              type: "object",
+              properties: {
+                packageId: { type: "string" },
+                otp: { type: "string" },
+                replacements: {
+                  type: "array",
+                  items: {
+                    type: "object",
+                    properties: {
+                      type: { type: "string" },
+                      oldHardwareId: { type: "string" },
+                      newHardwareId: { type: "string" },
+                    }
+                  }
+                },
+                createdAt: { type: "string" }
+              }
+            }
+          }
+        }
+      },
+      security: [
+        {
+          basicAuth: []
+        }
+      ]
+    },
+    handler: storeController.replaceAndRepair
+  });
+
+
 next();
 };