added a dedicated error handler service

src/error-message/error-message.service.ts

@@ -0,0 +1,40 @@
+// src/common/services/error-message.service.ts
+import { Injectable } from '@nestjs/common';
+type ErrorMessageKey = keyof typeof ErrorMessageService.prototype.messages;
+
+@Injectable()
+export class ErrorMessageService {
+  public readonly messages = {
+    NOT_FOUND: '{entity} not found', // Single key for "not found" errors
+    INVALID_MINUTES: 'Invalid minutes value',
+    INVALID_TIME_FORMAT: 'Invalid time format',
+    USER_NOT_FOUND: '{entity} not found', // Can reuse NOT_FOUND if desired
+    INTERNAL_SERVER_ERROR: 'Internal server error',
+    ERROR_ADDING_TEMP_PASSWORD:
+      'Error adding {type} temporary password from Tuya',
+    INVALID_UUID: 'Invalid {entity} UUID',
+    USER_ALREADY_BELONGS: 'This user already belongs to this {entity}',
+    USER_HAS_NO_ENTITIES: 'This user has no {entity}',
+    DEVICE_OPERATION_FAILED: 'All device operations failed',
+    REQUEST_FAILED: 'Error processing {operation} request',
+    COOLDOWN_ERROR:
+      'Please wait {time} more seconds before requesting a new OTP.',
+  };
+
+  getMessage(
+    key: ErrorMessageKey,
+    params?: Record<string, string | number>,
+  ): string {
+    let message = this.messages[key] || 'Unknown error';
+
+    // Replace placeholders with provided params
+    if (params) {
+      Object.keys(params).forEach((param) => {
+        const regex = new RegExp(`{${param}}`, 'g');
+        message = message.replace(regex, params[param].toString());
+      });
+    }
+
+    return message;
+  }
+}