feat(linux): add no-paper capture pipeline self-test

src-tauri/src/lib.rs

@@ -96,6 +96,82 @@ fn poll_login(state: State<'_, AppState>) -> Result<LoginPoll, String> {
     fieldlens::poll_login(&state.shared).map_err(|error| error.to_string())
 }
 
+#[cfg(target_os = "linux")]
+fn build_self_test_pdf() -> Vec<u8> {
+    let objects = [
+        "1 0 obj\n<< /Type /Catalog /Pages 2 0 R >>\nendobj\n".to_string(),
+        "2 0 obj\n<< /Type /Pages /Kids [3 0 R] /Count 1 >>\nendobj\n".to_string(),
+        "3 0 obj\n<< /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] /Resources << /Font << /F1 5 0 R >> >> /Contents 4 0 R >>\nendobj\n".to_string(),
+        {
+            let stream = "BT /F1 18 Tf 72 720 Td (FieldLens capture self-test) Tj ET\n";
+            format!("4 0 obj\n<< /Length {} >>\nstream\n{}endstream\nendobj\n", stream.len(), stream)
+        },
+        "5 0 obj\n<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica >>\nendobj\n".to_string(),
+    ];
+
+    let mut pdf = b"%PDF-1.4\n".to_vec();
+    let mut offsets = Vec::new();
+    for object in &objects {
+        offsets.push(pdf.len());
+        pdf.extend_from_slice(object.as_bytes());
+    }
+
+    let xref = pdf.len();
+    pdf.extend_from_slice(format!("xref\n0 {}\n", objects.len() + 1).as_bytes());
+    pdf.extend_from_slice(b"0000000000 65535 f \n");
+    for offset in offsets {
+        pdf.extend_from_slice(format!("{offset:010} 00000 n \n").as_bytes());
+    }
+    pdf.extend_from_slice(
+        format!(
+            "trailer\n<< /Size {} /Root 1 0 R >>\nstartxref\n{}\n%%EOF\n",
+            objects.len() + 1,
+            xref
+        )
+        .as_bytes(),
+    );
+    pdf
+}
+
+#[tauri::command]
+fn run_capture_self_test() -> Result<String, String> {
+    #[cfg(target_os = "linux")]
+    {
+        let path = std::env::temp_dir().join(format!(
+            "fieldlens-capture-self-test-{}.pdf",
+            uuid::Uuid::new_v4()
+        ));
+        std::fs::write(&path, build_self_test_pdf()).map_err(|error| error.to_string())?;
+
+        let output = std::process::Command::new("lp")
+            .args(["-d", "FieldLens-Test-Capture"])
+            .arg(&path)
+            .output()
+            .map_err(|error| error.to_string());
+        let _ = std::fs::remove_file(&path);
+        let output = output?;
+
+        if !output.status.success() {
+            return Err(format!(
+                "CUPS self-test submission failed: {}",
+                String::from_utf8_lossy(&output.stderr).trim()
+            ));
+        }
+
+        let detail = String::from_utf8_lossy(&output.stdout).trim().to_string();
+        return Ok(if detail.is_empty() {
+            "Self-test submitted to FieldLens Test Capture.".into()
+        } else {
+            detail
+        });
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    {
+        Err("Capture self-test is currently available on Linux only.".into())
+    }
+}
+
 #[tauri::command]
 fn sync_pending(state: State<'_, AppState>) -> Result<SyncResult, String> {
     fieldlens::sync_pending(&state.shared).map_err(|error| error.to_string())
@@ -127,6 +203,7 @@ pub fn run() {
             get_virtual_printer_status,
             install_virtual_printer,
             remove_virtual_printer,
+            run_capture_self_test,
             begin_login,
             poll_login,
             sync_pending

src/main.ts

@@ -152,6 +152,7 @@ app.innerHTML = `
 
           <div class="actions printer-actions">
             <button class="btn primary" id="install-printer">Create / repair printers</button>
+            <button class="btn ghost" id="self-test">Run capture self-test</button>
             <button class="btn ghost danger" id="remove-printer">Remove</button>
           </div>
 
@@ -471,6 +472,22 @@ el('install-printer').addEventListener('click', async () => {
   }
 })
 
+el('self-test').addEventListener('click', async () => {
+  const button = el<HTMLButtonElement>('self-test')
+  const state = el('virtual-printer-state')
+  button.disabled = true
+  state.textContent = 'Submitting a no-paper capture self-test…'
+  try {
+    const result = await invoke<string>('run_capture_self_test')
+    state.textContent = result
+    window.setTimeout(() => { void refreshStatus() }, 1200)
+  } catch (error) {
+    state.textContent = `Self-test failed: ${String(error)}`
+  } finally {
+    button.disabled = false
+  }
+})
+
 el('remove-printer').addEventListener('click', async () => {
   const button = el<HTMLButtonElement>('remove-printer')
   const state = el('virtual-printer-state')

src/styles.css

@@ -532,3 +532,8 @@ select:focus {
   .job { grid-template-columns: 1fr; }
   .job-meta { justify-content: flex-start; text-align: left; }
 }
+
+#self-test {
+  color: #9fcef5;
+  border-color: #294865;
+}