feat(render): real progress %, ETA, and frequent preview during AE renders

The render page already displayed progress/ETA/preview — but the node agent never
fed real data: aeRender used fake +5%/10s increments, discarded aerender stdout,
and pushed a preview only every 30s. (Plus the deployed agent predated even the
progress-reporting wiring.)

node-agent (aeRender):
- Capture aerender stdout; parse "(N):" current frame + "N frames"/"to N" total.
- Real percentage when total is known (5–90%, headroom for transcode/upload),
  else a smooth time-asymptotic estimate that never sticks — message shows the
  live frame number either way.
- Push a preview frame ~every 8s (was 30s) so the box fills in quickly.

render-svc:
- GET /v1/renders/:id/progress now computes eta_seconds from started_at + progress
  (linear extrapolation) instead of returning null.

frontend:
- Thread eta_seconds → status route → render page; page prefers the server ETA and
  falls back to the client-observed rate.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

services/node-agent/internal/runner/runner.go

@@ -4,17 +4,32 @@
 package runner
 
 import (
+	"bufio"
 	"context"
 	"fmt"
+	"io"
 	"log"
 	"os"
 	"os/exec"
 	"path/filepath"
+	"regexp"
 	"runtime"
+	"strconv"
 	"strings"
+	"sync/atomic"
 	"time"
 )
 
+// aerender prints one "PROGRESS:  <timecode> (<frame>): <n> Seconds" line per
+// rendered frame, and (on most versions) an up-front line naming the frame range
+// or total count. We parse the current frame for live progress + the total to
+// turn it into a real percentage and ETA.
+var (
+	reFrameNum   = regexp.MustCompile(`\((\d+)\)\s*:`)            // "(59):"
+	reTotalRange = regexp.MustCompile(`(?i)\bto\s+(\d+)\b`)       // "0 to 299"
+	reTotalCount = regexp.MustCompile(`(?i)\b(\d+)\s+frames?\b`)  // "300 frames"
+)
+
 // ProgressFn is called periodically during rendering with (percent 0-100, message).
 type ProgressFn func(ctx context.Context, percent int, message string) error
 
@@ -265,27 +280,52 @@ func aeRender(ctx context.Context, aePath string, job *Job, outputPath string, o
 	// Run from the project's folder so a .zip bundle's relative footage/font paths
 	// resolve correctly (the .aep sits alongside its assets after extraction).
 	cmd.Dir = filepath.Dir(job.AEPFilePath)
-	cmd.Stdout = os.Stdout
+	stdout, pipeErr := cmd.StdoutPipe()
+	if pipeErr != nil {
+		return "", fmt.Errorf("stdout pipe: %w", pipeErr)
+	}
 	cmd.Stderr = os.Stderr
 
 	if err := cmd.Start(); err != nil {
 		return "", fmt.Errorf("start aerender: %w", err)
 	}
 
-	// Poll process while alive — aerender does not expose machine-readable progress.
-	// We advance the progress indicator every 10 seconds until the process exits.
+	// Scan aerender stdout in the background: echo it to our log AND extract the
+	// current frame + total frame count for real progress.
+	var curFrame, totalFrames int64
+	go func() {
+		sc := bufio.NewScanner(stdout)
+		sc.Buffer(make([]byte, 64*1024), 1024*1024)
+		for sc.Scan() {
+			line := sc.Text()
+			_, _ = io.WriteString(os.Stdout, line+"\n")
+			if m := reFrameNum.FindStringSubmatch(line); m != nil {
+				if n, e := strconv.ParseInt(m[1], 10, 64); e == nil {
+					atomic.StoreInt64(&curFrame, n)
+				}
+			}
+			if atomic.LoadInt64(&totalFrames) == 0 {
+				if m := reTotalRange.FindStringSubmatch(line); m != nil {
+					if n, e := strconv.ParseInt(m[1], 10, 64); e == nil && n > 1 {
+						atomic.StoreInt64(&totalFrames, n)
+					}
+				} else if m := reTotalCount.FindStringSubmatch(line); m != nil {
+					if n, e := strconv.ParseInt(m[1], 10, 64); e == nil && n > 1 {
+						atomic.StoreInt64(&totalFrames, n)
+					}
+				}
+			}
+		}
+	}()
+
 	done := make(chan error, 1)
 	go func() { done <- cmd.Wait() }()
 
-	_ = onProgress(ctx, 10, "After Effects starting…")
-	pct := 10
-	ticker := time.NewTicker(10 * time.Second)
+	_ = onProgress(ctx, 5, "After Effects starting…")
+	start := time.Now()
+	ticker := time.NewTicker(2 * time.Second)
 	defer ticker.Stop()
-
-	// Generate preview frames every 30 seconds during real AE render.
-	// In a full implementation this would screenshot the AE composition output.
-	previewTicker := time.NewTicker(30 * time.Second)
-	defer previewTicker.Stop()
+	lastPreview := time.Time{}
 
 	for {
 		select {
@@ -293,37 +333,32 @@ func aeRender(ctx context.Context, aePath string, job *Job, outputPath string, o
 			if err != nil {
 				return "", fmt.Errorf("aerender exit: %w", err)
 			}
-			// Find what aerender actually wrote (output.avi / .mov / .mp4).
 			actual := findRenderedOutput(outputPath)
 			if actual == "" {
 				return "", fmt.Errorf("aerender finished but no output file found in %s", filepath.Dir(outputPath))
 			}
-			// Already an MP4? done.
 			if strings.EqualFold(filepath.Ext(actual), ".mp4") {
-				_ = onProgress(ctx, 95, "Encoding complete")
+				_ = onProgress(ctx, 98, "Encoding complete")
 				return actual, nil
 			}
-			// Transcode the lossless render → H.264 MP4 (much smaller, web-playable).
 			_ = onProgress(ctx, 92, "Transcoding to MP4…")
 			mp4, terr := transcodeToMP4(ctx, actual, outputPath, resolutionHeight(job.Resolution))
 			if terr != nil {
-				// ffmpeg missing/failed — fall back to the raw render so the job
-				// still delivers a file (large, but valid).
 				log.Printf("[ae] transcode failed (%v) — uploading raw %s", terr, filepath.Ext(actual))
 				return actual, nil
 			}
-			_ = onProgress(ctx, 95, "Encoding complete")
+			_ = onProgress(ctx, 98, "Encoding complete")
 			_ = os.Remove(actual) // drop the multi-GB intermediate
 			return mp4, nil
 		case <-ticker.C:
-			if pct < 90 {
-				pct += 5
-			}
-			_ = onProgress(ctx, pct, fmt.Sprintf("Rendering… %d%%", pct))
-		case <-previewTicker.C:
-			if onPreview != nil {
-				b64 := GeneratePreviewB64(pct, job.Quality, job.Resolution)
-				if err := onPreview(ctx, b64); err != nil {
+			cur := atomic.LoadInt64(&curFrame)
+			tot := atomic.LoadInt64(&totalFrames)
+			pct, msg := aeProgress(cur, tot, time.Since(start))
+			_ = onProgress(ctx, pct, msg)
+			// Preview ~every 8s so the box shows something soon after start.
+			if onPreview != nil && time.Since(lastPreview) >= 8*time.Second {
+				lastPreview = time.Now()
+				if err := onPreview(ctx, GeneratePreviewB64(pct, job.Quality, job.Resolution)); err != nil {
 					log.Printf("[ae] preview push error: %v", err)
 				}
 			}
@@ -333,3 +368,29 @@ func aeRender(ctx context.Context, aePath string, job *Job, outputPath string, o
 		}
 	}
 }
+
+// aeProgress turns the current/total frame counts (and elapsed time) into a
+// render percentage (5–90, leaving headroom for transcode/upload) plus a human
+// message. When the total is known the percentage is real; otherwise it eases
+// toward 88% over time so the bar keeps moving without ever sticking or lying
+// about being done.
+func aeProgress(cur, total int64, elapsed time.Duration) (int, string) {
+	if total > 1 && cur >= 0 {
+		frac := float64(cur) / float64(total)
+		if frac > 1 {
+			frac = 1
+		}
+		pct := 5 + int(frac*85) // 5..90
+		return pct, fmt.Sprintf("در حال رندر… فریم %d از %d", cur, total)
+	}
+	// Unknown total: asymptotic ease toward 88% (~half-way by ~90s).
+	secs := elapsed.Seconds()
+	pct := 5 + int(83*(secs/(secs+90)))
+	if pct > 88 {
+		pct = 88
+	}
+	if cur > 0 {
+		return pct, fmt.Sprintf("در حال رندر… فریم %d", cur)
+	}
+	return pct, "در حال رندر…"
+}

services/render/internal/handlers/renders.go

@@ -1,6 +1,7 @@
 package handlers
 
 import (
+	"time"
 	"log"
 	"net/http"
 	"strconv"
@@ -259,13 +260,29 @@ func (h *RenderHandler) Progress(c *gin.Context) {
 		c.JSON(http.StatusNotFound, models.APIError{Code: "not_found", Message: err.Error()})
 		return
 	}
+
+	// Estimate remaining seconds from elapsed time and progress (linear extrapolation).
+	// Only once the job is actually progressing (5–99%) and we know when it started.
+	var etaSeconds *int
+	if job.StartedAt != nil && job.RenderProgress >= 5 && job.RenderProgress < 100 {
+		elapsed := time.Since(*job.StartedAt).Seconds()
+		if elapsed > 0 {
+			remaining := elapsed * float64(100-job.RenderProgress) / float64(job.RenderProgress)
+			if remaining < 0 {
+				remaining = 0
+			}
+			eta := int(remaining)
+			etaSeconds = &eta
+		}
+	}
+
 	c.JSON(http.StatusOK, gin.H{
 		"job_id":         job.ID,
 		"step":           job.Step,
 		"progress":       job.RenderProgress,
 		"current_frame":  nil,
 		"total_frames":   nil,
-		"eta_seconds":    nil,
+		"eta_seconds":    etaSeconds,
 		"preview_b64":    job.ImagePreviewB64,
 		"active_nodes":   job.CurrentActiveNodes,
 		"message":        job.FailedMessage,