#!/usr/bin/env bash
# One-shot jank A/B for the phone (usage: ADB_SERIAL=10.0.0.5:5555 ./scripts/jank_ab.sh)
#
# What it does:
#   1. Installs the release APK (build with ./scripts/build.sh aarch64 first).
#   2. Verifies thread priorities (thumb-* at nice 2, slint vsync at 0).
#   3. Runs TWO 30-second scroll windows — real textures, then grey 1x1
#      images — with logcat capture + cadence analysis in between.
#      THE USER MUST SCROLL WITH A FINGER during each window
#      (moderate drag, no fling — the reported repro).
#   4. Prints a comparison: % of scroll events on the 8.3 ms grid,
#      stall count (gap > 16 ms), worst gaps.
#
# Interpretation:
#   real janky + grey smooth  -> texture/GPU path is the culprit
#   both janky                -> base render/present/event path
#   both smooth               -> the priority fix worked; ship it

set -u
E="adb ${ADB_SERIAL:+-s $ADB_SERIAL}"
APK=target/release/apk/gallery.apk
PKG=wow.gmp.gallery
CMD=/sdcard/Download/.gallery_cmd
GREY=/sdcard/Download/.gallery_grey
PERF=/sdcard/Download/.gallery_perf.log

[ -f "$APK" ] || { echo "build first: ./scripts/build.sh aarch64"; exit 1; }

scroll_window() { # $1 = label, $2 = tag, $3 = seconds
  local out="/tmp/jank_$2.txt"
  $E shell "echo -n '' > $PERF" 2>/dev/null || true
  echo "### $1 — scroll now (moderate drag, no fling)..."
  sleep "$3"
  $E pull "$PERF" "$out" >/dev/null 2>&1
  python3 - "$out" << 'EOF'
import re, sys
ev = []
for line in open(sys.argv[1], errors="ignore"):
    m = re.match(r"SCR +([\d.]+)", line)
    if m: ev.append(float(m.group(1)))
if len(ev) < 10:
    print(f"  {sys.argv[1]}: only {len(ev)} scroll events — not enough data"); sys.exit()
gaps = [ev[i+1]-ev[i] for i in range(len(ev)-1)]
# drop the first gap (window edge) and any multi-event same-ms catch-ups
# are kept — they ARE the jank signature
gaps = gaps[1:]
on_grid = sum(1 for g in gaps if 6.5 <= g <= 10.5)
stalls = [g for g in gaps if g > 16]
import collections
buckets = collections.Counter()
for g in sorted(stalls): buckets['16-25' if g<25 else '25-40' if g<40 else '40-65' if g<65 else '>65'] += 1
print(f"  events={len(ev)}  on ~8ms grid={100*on_grid/len(gaps):.0f}%  "
      f"stalls(>16ms)={len(stalls)}  p95={sorted(gaps)[int(len(gaps)*0.95)]:.1f}ms  "
      f"worst={max(gaps):.1f}ms  stall buckets: {dict(buckets)}")
# tick-stall context: how many TICK stalls, any APLY nearby
EOF
  echo "  TICK-stall lines: $(grep -c '^TICK' $out 2>/dev/null)   APLY lines: $(grep -c '^APLY' $out 2>/dev/null)"
}

check_prios() {
  local pid; pid=$($E shell pidof $PKG)
  echo "### thread priorities (pid $pid)"
  $E shell "for t in /proc/$pid/task/*; do c=\$(cat \$t/comm 2>/dev/null); case \$c in slint*|thumb*) n=\$(awk -F')' '{print \$2}' \$t/stat | awk '{print \$17}'); echo \"  \$c nice=\$n\";; esac; done"
}

install_and_start() { # $1 = "grey" to enable the grey knob before launch
  $E install -r "$APK" >/dev/null
  if [ "${1:-}" = grey ]; then $E shell "touch $GREY"; else $E shell "rm -f $GREY"; fi
  $E shell am force-stop $PKG
  $E shell am start -n $PKG/android.app.NativeActivity >/dev/null
  sleep 8
}

echo "=== installing $APK ==="
install_and_start
check_prios
echo
echo "=== window 1: REAL textures (30 s) ==="
scroll_window "real" real 30
echo
echo "=== restarting with grey 1x1 images ==="
install_and_start grey
check_prios
echo
echo "=== window 2: GREY images (30 s) ==="
$E logcat -d 2>/dev/null | grep "grey images ON" || echo "  WARNING: grey knob not active!"
scroll_window "grey" grey 30

$E shell "rm -f $GREY $CMD"
echo
echo "done. Compare the two summaries above."
echo "  (raw captures: /tmp/jank_real.txt /tmp/jank_grey.txt)"