#!/usr/bin/env bash
# Raw CAN over MQTT, measured on the car Orin against a vcan0 (project-yukart decision 4).
# Runs on the Orin; sudo once, to create vcan0. Prints one JSON line per run: the
# sink's and the bridge's reports, and mosquitto's CPU over the run.
#
#   usage: bus-bench.sh BUS_BENCH_BINARY CAPTURE.log [secs]
#   env:   BATCHES  batch windows in ms, 0 = one message per frame   ("0 10")
#          FLAGS    extra options for both roles, e.g. --nagle
#          GAP_MS   cangen gap for the full-bus run (0.15: ~4500 frames/s here, past what
#                   500 kbit/s can carry with 8-byte frames)
set -euo pipefail

BIN="$1"; CAPTURE="$2"; SECS="${3:-20}"
BATCHES="${BATCHES:-0 10}"; FLAGS="${FLAGS:-}"

if ! ip link show vcan0 >/dev/null 2>&1; then
  sudo modprobe vcan
  sudo ip link add vcan0 type vcan
fi
sudo ip link set vcan0 up txqueuelen 10000

ticks() { awk '{print $14 + $15}' "/proc/$1/stat"; }
HZ=$(getconf CLK_TCK)
OUT=$(mktemp -d)

# run NAME BATCH_MS GENERATOR...: the generator feeds vcan0 for a little over SECS seconds.
run() {
  local name="$1" batch="$2"; shift 2
  # shellcheck disable=SC2086
  "$BIN" sink --secs "$SECS" $FLAGS > "$OUT/sink" 2>/dev/null &
  local sink=$!
  sleep 0.5
  # shellcheck disable=SC2086
  "$BIN" bridge --batch-ms "$batch" --secs $((SECS + 3)) $FLAGS > "$OUT/bridge" 2>/dev/null &
  local bridge=$!
  sleep 0.5
  local broker m0 m1 t0 t1
  broker=$(pgrep -x mosquitto); m0=$(ticks "$broker"); t0=$(date +%s.%N)
  timeout "$((SECS + 1))" "$@" >/dev/null 2>&1 || true
  m1=$(ticks "$broker"); t1=$(date +%s.%N)
  wait "$sink" "$bridge"
  python3 - "$name" "$batch" "$FLAGS" "$OUT" "$((m1 - m0))" "$HZ" "$t0" "$t1" <<'PY'
import json, sys
name, batch, flags, out, ticks, hz, t0, t1 = sys.argv[1:]
r = {"run": name, "batch_ms": int(batch), "flags": flags,
     "sink": json.load(open(f"{out}/sink")), "bridge": json.load(open(f"{out}/bridge")),
     "mosquitto_cpu_pct": round(100 * int(ticks) / int(hz) / (float(t1) - float(t0)), 1)}
for k in ("role",):
    r["sink"].pop(k); r["bridge"].pop(k)
print(json.dumps(r))
PY
}

LOOPS=$(( (SECS + 9) / 10 + 1 ))    # the capture is 10 s; loop past the run's end
for batch in $BATCHES; do
  run "car replay"  "$batch" canplayer -l "$LOOPS" -I "$CAPTURE" vcan0=can_pcan
  run "full bus"    "$batch" cangen vcan0 -g "${GAP_MS:-0.15}" -L 8
  run "flood"       "$batch" cangen vcan0 -g 0 -L 8
done