feat: add fallback to wg show command for transfer metrics when dump command fails

Add read_transfer_totals_from_show function to parse transfer statistics from wg show output as fallback when wg show dump command fails. Add parse_human_wireguard_bytes helper to convert human-readable byte values (B, KiB, MiB, GiB, TiB) to u64. Update read_transfer_totals to call fallback instead of returning error when dump command fails.

desktop-client/tunnel-helper/src/main.rs

@@ -712,7 +712,7 @@ fn read_transfer_totals(profile: &Path) -> Result<(u64, u64), String> {
         .map_err(|err| format!("Unable to query tunnel transfer counters: {err}"))?;
 
     if !output.status.success() {
-        return Err("Unable to read WireGuard transfer counters.".into());
+        return read_transfer_totals_from_show(tunnel_name);
     }
 
     let stdout = String::from_utf8_lossy(&output.stdout);
@@ -732,6 +732,66 @@ fn read_transfer_totals(profile: &Path) -> Result<(u64, u64), String> {
     Ok((rx_bytes, tx_bytes))
 }
 
+fn read_transfer_totals_from_show(tunnel_name: &str) -> Result<(u64, u64), String> {
+    let mut command = Command::new(find_wg_cli()?);
+    command.arg("show").arg(tunnel_name);
+    #[cfg(target_os = "windows")]
+    command.creation_flags(CREATE_NO_WINDOW);
+
+    let output = command
+        .output()
+        .map_err(|err| format!("Unable to query tunnel transfer text: {err}"))?;
+
+    if !output.status.success() {
+        return Err("Unable to read WireGuard transfer counters.".into());
+    }
+
+    let stdout = String::from_utf8_lossy(&output.stdout);
+    let mut rx_bytes = 0_u64;
+    let mut tx_bytes = 0_u64;
+
+    for line in stdout.lines() {
+        let trimmed = line.trim();
+        if let Some(rest) = trimmed.strip_prefix("transfer:") {
+            let parts: Vec<&str> = rest.split(',').collect();
+            if let Some(received) = parts.first() {
+                rx_bytes = rx_bytes.saturating_add(parse_human_wireguard_bytes(received));
+            }
+            if let Some(sent) = parts.get(1) {
+                tx_bytes = tx_bytes.saturating_add(parse_human_wireguard_bytes(sent));
+            }
+        }
+    }
+
+    Ok((rx_bytes, tx_bytes))
+}
+
+fn parse_human_wireguard_bytes(value: &str) -> u64 {
+    let cleaned = value
+        .replace("received", "")
+        .replace("sent", "")
+        .trim()
+        .to_string();
+    let mut parts = cleaned.split_whitespace();
+    let amount = parts
+        .next()
+        .map(|raw| raw.replace(',', "."))
+        .and_then(|raw| raw.parse::<f64>().ok())
+        .unwrap_or(0.0);
+    let unit = parts.next().unwrap_or("B");
+
+    let multiplier = match unit {
+        "B" => 1.0,
+        "KiB" => 1024.0,
+        "MiB" => 1024.0 * 1024.0,
+        "GiB" => 1024.0 * 1024.0 * 1024.0,
+        "TiB" => 1024.0 * 1024.0 * 1024.0 * 1024.0,
+        _ => 1.0,
+    };
+
+    (amount * multiplier) as u64
+}
+
 #[cfg(target_os = "windows")]
 fn find_wg_cli() -> Result<PathBuf, String> {
     let candidates = [