oott/src/mac_vendor_finder.rs

use log::{debug, error, info};
use serde::Deserialize;
use std::collections::HashMap;
use std::fs;
use std::sync::LazyLock;

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct MacRecord {
    pub mac_prefix: String,
    pub vendor_name: String,
    // private: bool,
    // block_type: String,
    // last_update: String,
}

// Initialize mac vendors database as a static lazy loaded unit
static MAC_VENDORS_DATABASE: LazyLock<HashMap<String, String>> = LazyLock::new(|| {
    info!("Loading MAC vendor database into memory");

    let mut database = HashMap::new();
    let data = match fs::read_to_string("data/mac-vendors-export.json") {
        Ok(value) => value,
        Err(error) => {
            error!("Error reading mac vendors database (data/mac-vendors-export.json): {error}");
            panic!("Error reading mac vendors database (data/mac-vendors-export.json): {error}");
        }
    };

    let json: Vec<MacRecord> = match serde_json::from_str(&data) {
        Ok(value) => value,
        Err(error) => {
            error!("Error parsing mac vendors database (data/mac-vendors-export.json): {error}");
            panic!("Error parsing mac vendors database (data/mac-vendors-export.json): {error}");
        }
    };

    debug!("Found {} records in the database", json.len());

    for el in json {
        database.insert(el.mac_prefix.to_uppercase(), el.vendor_name);
    }

    info!("MAC vendor database loaded");
    database
});

// Find a vendor based on the MAC prefix
pub fn find(mac_prefix: String) -> String {
    MAC_VENDORS_DATABASE
        .get(&mac_prefix.to_uppercase())
        .unwrap_or(&"".to_string())
        .to_string()
}