#!/usr/bin/env bash
# Density benchmark: N concurrent games in one JVM, sampling memory.
#
#   MM_HOME    extracted MegaMek release
#   JAVA_HOME  a JDK
#   MM_JAR     defaults to the stock jar; point at the patched one to compare
#
#   ./tests/bench.sh --games 8 --settle-round 3 --csv /tmp/out.csv
#   python3 tests/summarize.py /tmp/out.csv
#
# Not part of ./test.sh - it takes minutes and wants a quiet machine. It answers
# a question about the product (how many matches fit on a box) rather than
# gating a change.
#
# NOTE: this needs a JDK and an extracted MegaMek release, neither of which
# exists outside the Docker build now that the host build is gone. Run it inside
# a build stage, e.g.
#
#   docker build --target arena -t arena-build .
#   docker run --rm arena-build /src/tests/bench.sh --games 2
#
# See TODO.md - giving it a first-class way to run is outstanding.
#
# The numbers it produced for the spike: ~730MB RSS per concurrent match, flat
# across heap cap and match size, with CPU well short of the constraint.
set -euo pipefail

HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
ROOT="$(cd "$HERE/.." && pwd)"
: "${MM_HOME:?MM_HOME is required}"
: "${JAVA_HOME:?JAVA_HOME is required}"

HEAP="${HEAP:-6g}"
MM_JAR="${MM_JAR:-$MM_HOME/MegaMek.jar}"
CLASSES="${CLASSES:-/tmp/bench-classes}"

[ -d "$CLASSES" ] || OUT="$CLASSES" "$HERE/build.sh"

CP="$CLASSES:$MM_JAR"
for jar in "$MM_HOME"/lib/*.jar; do CP="$CP:$jar"; done

# MegaMek resolves data/ relative to the working directory.
cd "$MM_HOME"

exec "$JAVA_HOME/bin/java" \
  -Xmx"$HEAP" \
  -Dlog4j2.configurationFile="$ROOT/megamek/log4j2-quiet.xml" \
  -Dsentry.dsn="" \
  --add-opens java.base/java.util=ALL-UNNAMED \
  --add-opens java.base/java.util.concurrent=ALL-UNNAMED \
  -classpath "$CP" \
  bench.MMBench "$@"