Auto-populate device_type from vendor mapping on first device discovery

Loads vendor-device-type.json at compile time (same pattern as mac-vendors-export.json)
and sets device_type when a new device is detected by the ARP scanner.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

TODO.md

@@ -8,7 +8,7 @@
 - [x] Record an activity log in the database
   - [x] One event for each device appearance
 - [x] Add date filter to device event list method (from)
-- [ ] Add a data set (json) to store maps from vendors -> device type; modify the device creation so that it uses it automatically
+- [x] Add a data set (json) to store maps from vendors -> device type; modify the device creation so that it uses it automatically
 
 ## Frontend
 

backend/src/device_finders/arp/packet_send_receive.rs

@@ -1,4 +1,5 @@
 use crate::mac_vendor_finder;
+use crate::vendor_device_type_finder;
 use crate::model::devices::Device;
 use chrono::Local;
 use duration_string::DurationString;
@@ -106,12 +107,14 @@ pub async fn listen_for_packets(
                         "Found online  device - IP addr={} - MAC addr={} - vendor={}",
                         packet_ip_address, packet_mac_address, packet_vendor
                     );
-                    devices.push(Device::new(
+                    let mut device = Device::new(
                         packet_mac_address,
                         packet_ip_address,
                         packet_vendor,
                         Local::now().to_utc(),
-                    ));
+                    );
+                    device.device_type = vendor_device_type_finder::find(&device.vendor);
+                    devices.push(device);
                 }
             }
         }

backend/src/main.rs

@@ -6,6 +6,7 @@ mod db;
 mod device_finders;
 mod events;
 mod mac_vendor_finder;
+mod vendor_device_type_finder;
 mod model;
 mod retention;
 mod scanner;

backend/src/vendor_device_type_finder.rs

@@ -0,0 +1,53 @@
+use lazy_static::lazy_static;
+use log::{debug, error, info};
+use std::collections::HashMap;
+
+// Initialize vendor device type database as a static lazy loaded unit
+lazy_static! {
+    static ref VENDOR_DEVICE_TYPE_DATABASE: HashMap<String, String> = {
+        info!("Loading vendor device type database into memory");
+
+        let data = include_str!("../data/vendor-device-type.json");
+
+        let database: HashMap<String, String> = match serde_json::from_str(data) {
+            Ok(value) => value,
+            Err(error) => {
+                error!(
+                    "Error parsing vendor device type database (data/vendor-device-type.json): {error}"
+                );
+                panic!(
+                    "Error parsing vendor device type database (data/vendor-device-type.json): {error}"
+                );
+            }
+        };
+
+        debug!("Found {} records in the database", database.len());
+        info!("Vendor device type database loaded");
+        database
+    };
+}
+
+// Find a device type based on the vendor name
+pub fn find(vendor: &str) -> String {
+    VENDOR_DEVICE_TYPE_DATABASE
+        .get(vendor)
+        .unwrap_or(&"".to_string())
+        .to_string()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn known_vendor_returns_device_type() {
+        let result = find("Apple, Inc.");
+        assert!(!result.is_empty(), "Expected a device type for Apple, Inc.");
+    }
+
+    #[test]
+    fn unknown_vendor_returns_empty_string() {
+        let result = find("This Vendor Does Not Exist XYZ");
+        assert_eq!(result, "");
+    }
+}