From a7ab9243c0668fd36c2328ebec513efac6d5538f Mon Sep 17 00:00:00 2001
From: Claus Lohmar <claus.lohmar@lohmar.co.uk>
Date: Fri, 24 Jul 2026 09:48:43 +0000
Subject: [PATCH] feat: SCP probes remote file size via SSH before pull

Runs 'ssh stat -c%s' or 'ls -l' to get total bytes before starting
SCP transfer. Progress bar now shows real percentage and ETA
instead of indeterminate spinner.
---
 frontend/app.py             | 34 +++++++++++++++++++++++++++++++++-
 frontend/templates/scp.html |  6 ++++--
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/frontend/app.py b/frontend/app.py
index b92200e..4ab0501 100644
--- a/frontend/app.py
+++ b/frontend/app.py
@@ -472,8 +472,25 @@ def scp_start(
         "-P", str(scp_port),
         remote, str(dest),
     ]
-
     logger.info("Starting SCP pull: %s → %s", remote, dest)
+
+    # ── Probe file size via SSH ────────────────────────────────────
+    file_size = 0
+    try:
+        probe_cmd = [
+            "sshpass", "-e",
+            "ssh", "-o", "StrictHostKeyChecking=no", "-o", "ConnectTimeout=10",
+            "-p", str(scp_port), f"{scp_user}@{scp_host}",
+            f"stat -c%s '{scp_path}' 2>/dev/null || ls -l '{scp_path}' 2>/dev/null | awk '{{print $5}}'"
+        ]
+        probe = subprocess.run(probe_cmd, env=env, capture_output=True, text=True, timeout=15)
+        if probe.returncode == 0 and probe.stdout.strip().isdigit():
+            file_size = int(probe.stdout.strip())
+            logger.info("Remote file size: %.1f GiB", file_size / (1024**3))
+    except Exception:
+        logger.info("Could not probe remote file size")
+
+    # ── Start SCP ──────────────────────────────────────────────────
     try:
         proc = subprocess.Popen(cmd, env=env, stdout=subprocess.DEVNULL,
                                 stderr=subprocess.PIPE, text=True)
@@ -485,12 +502,14 @@ def scp_start(
         "proc": proc,
         "dest": dest,
         "start_time": time.time(),
+        "total_size": file_size,
     }
 
     return JSONResponse({
         "phase": "pulling",
         "filename": filename,
         "session_id": session_id,
+        "total_size_gb": round(file_size / (1024**3), 1) if file_size else None,
     })
 
 
@@ -540,12 +559,25 @@ def scp_progress(session_id: str, filename: str):
 
     elapsed = max(time.time() - info.get("start_time", 0), 1)
     speed_mbps = round(current_bytes / elapsed / 1_000_000, 1)
+    total = info.get("total_size", 0)
+
+    eta_str = None
+    pct = 0
+    if total > 0 and current_bytes > 0:
+        pct = min(round((current_bytes / total) * 100), 99)
+        remaining = total - current_bytes
+        eta = remaining / max(current_bytes / elapsed, 1)
+        if eta > 60:
+            eta_str = f"~{round(eta / 60)} min remaining"
 
     return JSONResponse({
         "phase": "pulling",
         "file_size_bytes": current_bytes,
         "file_size_gb": round(current_bytes / (1024**3), 1),
         "speed_mbps": speed_mbps,
+        "pct": pct,
+        "eta": eta_str,
+        "total_size_gb": round(total / (1024**3), 1) if total else None,
     })
 
 
diff --git a/frontend/templates/scp.html b/frontend/templates/scp.html
index c20cf3c..741db34 100644
--- a/frontend/templates/scp.html
+++ b/frontend/templates/scp.html
@@ -95,7 +95,8 @@ async function startScpPull(e) {
     }
 
     const filename = data.filename;
-    setScpPhase('Pulling file from remote server...', 0, true);
+    const totalGb = data.total_size_gb;
+    setScpPhase('Pulling file...' + (totalGb ? ' (' + totalGb + ' GiB total)' : ''), 0, true);
     for (;;) {
       await new Promise(r => setTimeout(r, 2000));
       try {
@@ -123,7 +124,8 @@ async function startScpPull(e) {
           const gb = (pdata.file_size_gb || 0).toFixed(1);
           let label = 'Pulling file... ' + gb + ' GiB';
           if (pdata.speed_mbps) label += ' (' + pdata.speed_mbps + ' MB/s)';
-          setScpPhase(label, 0, true);
+          if (pdata.eta) label += ' — ' + pdata.eta;
+          setScpPhase(label, pdata.pct || 0, !pdata.pct);
         }
       } catch (_) {}
     }