#!/usr/bin/env bash
# sac_train.sh — #49 training orchestration for SAC_LSTM_Bot.
#
# Drives chunked self-play via tools/training_runner/RunTraining.java (which
# owns server lifecycle, opponent connection and dead-bot liveness detection
# through weights/round_counter.txt), samples opponents by weight per chunk,
# runs deterministic evaluation (SACLSTM_EVAL_MODE=1) every N chunks, and keeps
# the best checkpoint (weights/sac_best.zip) by a moving-average composite over
# the eval opponent set (campaign v2 lever 1, #59).
#
# Config (env vars):
#   SAC_OPPONENTS     "Name:weight,Name:weight,..."  (default below)
#   SAC_TOTAL_ROUNDS  total training-round budget      (default 100)
#   SAC_CHUNK_SIZE    rounds per RunTraining battle    (default 10)
#   SAC_EVAL_INTERVAL eval every N chunks              (default 2)
#   SAC_EVAL_ROUNDS   rounds per evaluation battle     (default 10)
#   SAC_EVAL_OPPONENTS comma-separated eval set       (default Corners,Crazy,Target)
#                     — each cycle evaluates EVERY one; results all land in
#                       eval_log.jsonl (lines carry "opponent":"Name")
#   SAC_MAX_CRASHES   consecutive crashes before abort (default 5)
#   SAC_LOG_FILE / SAC_EVAL_LOG_FILE                    (JSON-lines logs)
#   SACLSTM_*         passed through to the bot (UTD_RATIO, BATCH_SIZE, ...)
set -uo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
RUNNER_DIR="$REPO_ROOT/tools/training_runner"
JAR="${TANK_ROYALE_JAR:-/home/davide/Projects/tank-royale/runner/examples/lib/robocode-tankroyale-runner.jar}"

export PPO_BOT_DIR="$SCRIPT_DIR"                 # runner launches THIS bot dir
export BOT_NAME="${BOT_NAME:-SAC_LSTM_Bot}"      # RunTraining result matching
export SAMPLE_BOTS_DIR="${SAMPLE_BOTS_DIR:-/home/davide/Projects/tank-royale/sample-bots/java/build/archive}"
# Liveness contract (#49): RunTraining.java watches $BOT_DIR/weights/round_counter.txt
# and integration.bumpRoundCounter() writes it next to the weights — so the bot's
# weights path is pinned here, NOT env-overridable.
export SACLSTM_WEIGHTS_PATH="$SCRIPT_DIR/weights/sac_latest.zip"
WEIGHTS_DIR="$(dirname "$SACLSTM_WEIGHTS_PATH")"

OPPONENTS="${SAC_OPPONENTS:-Corners:3,Crazy:2,RamFire:1,Target:1}"
TOTAL_ROUNDS="${SAC_TOTAL_ROUNDS:-100}"
CHUNK_SIZE="${SAC_CHUNK_SIZE:-10}"
EVAL_INTERVAL="${SAC_EVAL_INTERVAL:-2}"
EVAL_ROUNDS="${SAC_EVAL_ROUNDS:-10}"
EVAL_OPPONENTS="${SAC_EVAL_OPPONENTS:-Corners,Crazy,Target}"
MA_WINDOW=5   # lever 1 (#59): per-opponent moving average over last N evals
MAX_CRASHES="${SAC_MAX_CRASHES:-5}"
LOG_FILE="${SAC_LOG_FILE:-$SCRIPT_DIR/training_log.jsonl}"
EVAL_LOG_FILE="${SAC_EVAL_LOG_FILE:-$SCRIPT_DIR/eval_log.jsonl}"
CLASSES_DIR="/tmp/opencode/sac_train_classes"

echo "=== SAC_LSTM_Bot training harness ==="
echo "Opponents: $OPPONENTS | budget: $TOTAL_ROUNDS rounds in chunks of $CHUNK_SIZE"
echo "Eval: every $EVAL_INTERVAL chunks, $EVAL_ROUNDS rounds vs [$EVAL_OPPONENTS], MA-$MA_WINDOW composite best-gating"
echo "Weights: $SACLSTM_WEIGHTS_PATH"

# ── compile bot + java runner ─────────────────────────────────────────────────
(cd "$SCRIPT_DIR" && nimble build -d:release) || { echo ">>> bot build failed"; exit 1; }
mkdir -p "$WEIGHTS_DIR" "$CLASSES_DIR"
# Startup sweep: atomic saves leave sac_latest.zip.tmp.*.part corpses behind if
# a run is SIGKILLed (libzip modify-path, see notebook forensics) — clear them.
rm -f "$WEIGHTS_DIR"/sac_latest.zip.tmp.*.part "$WEIGHTS_DIR"/sac_latest.zip.tmp
javac -cp "$JAR" -d "$CLASSES_DIR" "$RUNNER_DIR/RunTraining.java" || { echo ">>> javac failed"; exit 1; }

# ── weighted opponent pick over "Name:w,Name:w" ───────────────────────────────
pick_opponent() {
  local total=0 p name w r
  local pairs
  IFS=',' read -ra pairs <<< "$OPPONENTS"
  for p in "${pairs[@]}"; do total=$(( total + ${p##*:} )); done
  r=$(( RANDOM % total ))
  for p in "${pairs[@]}"; do
    name="${p%%:*}"; w="${p##*:}"
    if (( r < w )); then echo "$name"; return; fi
    r=$(( r - w ))
  done
  echo "${pairs[0]%%:*}"
}

run_battle() {  # $1=opponent $2=rounds $3=log file
  PPOB_LOG_FILE="$3" java -cp "$CLASSES_DIR:$JAR" RunTraining "$1" "$2"
}

# ── Lever 1 (#59): eval rotation + MA best-gating ─────────────────────────────
# best_score.txt FORMAT CHANGE: it used to store the single-opponent integer
# win rate (%); that semantics is retired. It now stores the COMPOSITE score —
# the mean over SAC_EVAL_OPPONENTS of each opponent's moving average (last
# MA_WINDOW eval win rates, %). sac_best.zip is rewritten only when the
# composite strictly improves.
ma_hist_file() { echo "$WEIGHTS_DIR/ma_history_$1.txt"; }

composite_of() {  # reads one "w w w ..." history line per opponent on stdin
  awk -v W="$MA_WINDOW" '
    NF > 0 { n=NF; k=(n>W)?W:n; s=0; for(j=n-k+1;j<=n;j++) s+=$j; tot+=s/k; c++ }
    END { if (c>0) printf "%.4f", tot/c; else print "-1" }'
}

eval_checkpoint() {
  # ponytail: opponent names are split by whitespace — fine for Tank Royale bot
  # names (no spaces); switch to a mapfile IFS=',\n' read if that ever changes.
  local opps=(${EVAL_OPPONENTS//,/ })
  local tmp="$EVAL_LOG_FILE.tmp" otmp opp wins rounds wr composite best
  : > "$tmp"
  for opp in "${opps[@]}"; do
    otmp="$EVAL_LOG_FILE.$opp.tmp"
    : > "$otmp"
    echo ">>> [eval] $EVAL_ROUNDS deterministic rounds vs $opp"
    if ! SACLSTM_EVAL_MODE=1 run_battle "$opp" "$EVAL_ROUNDS" "$otmp"; then
      rm -f "$otmp" "$tmp"
      echo ">>> [eval] crashed vs $opp — keeping previous best"
      return 0
    fi
    wins=$(grep -c '"win":true' "$otmp" || true)
    rounds=$(grep -c '"type":"game"' "$otmp" || true)
    if (( rounds == 0 )); then
      rm -f "$otmp" "$tmp"
      echo ">>> [eval] no results vs $opp — keeping previous best"
      return 0
    fi
    wr=$(( 100 * wins / rounds ))
    echo ">>> [eval] win rate: $wins/$rounds ($wr%) vs $opp"
    cat "$otmp" >> "$tmp"; rm -f "$otmp"
    # Per-opponent history: append this cycle's win rate, keep last MA_WINDOW.
    printf '%s\n' "$(cat "$(ma_hist_file "$opp")" 2>/dev/null)" "$wr" \
      | tail -n "$MA_WINDOW" | tr '\n' ' ' > "$(ma_hist_file "$opp")"
  done
  mv "$tmp" "$EVAL_LOG_FILE"
  composite=$(for opp in "${opps[@]}"; do cat "$(ma_hist_file "$opp")"; echo; done | composite_of)
  # ponytail: best-score state is a plain file next to the checkpoint; survives
  # harness restarts, no lock needed (single harness instance assumed).
  best=$(cat "$WEIGHTS_DIR/best_score.txt" 2>/dev/null)
  [ -z "$best" ] && best=-1
  if awk -v a="$composite" -v b="$best" 'BEGIN{exit !(a+0 > b+0)}' \
     && [ -f "$SACLSTM_WEIGHTS_PATH" ]; then
    echo "$composite" > "$WEIGHTS_DIR/best_score.txt"
    cp "$SACLSTM_WEIGHTS_PATH" "$WEIGHTS_DIR/sac_best.zip"
    echo ">>> [eval] new best composite ($composite) -> sac_best.zip"
  fi
}

NUM_CHUNKS=$(( (TOTAL_ROUNDS + CHUNK_SIZE - 1) / CHUNK_SIZE ))
fails=0
chunk=1
# while, not `for chunk in $(seq ...)`: a crash on the FINAL chunk must rerun
# it (#54 — seq list is exhausted by then, so ((chunk--));continue fell through
# and the harness exited 0 with the budget incomplete).
while (( chunk <= NUM_CHUNKS )); do
  ROUNDS=$CHUNK_SIZE
  (( TOTAL_ROUNDS - (chunk - 1) * CHUNK_SIZE < CHUNK_SIZE )) && \
    ROUNDS=$(( TOTAL_ROUNDS - (chunk - 1) * CHUNK_SIZE ))
  OPP=$(pick_opponent)
  echo "=== Chunk $chunk/$NUM_CHUNKS: $ROUNDS rounds vs $OPP ==="
  if ! run_battle "$OPP" "$ROUNDS" "$LOG_FILE"; then
    fails=$(( fails + 1 ))
    if (( fails >= MAX_CRASHES )); then
      echo ">>> aborted: $fails consecutive crashes (bot process dying?)"
      exit 1
    fi
    # Crash recovery: RunTraining's liveness detection exited; the bot reloads
    # its latest checkpoint on restart, so just rerun this chunk.
    echo ">>> crash #$fails — restarting chunk from latest checkpoint"
    (( chunk-- )); continue
  fi
  fails=0
  (( chunk % EVAL_INTERVAL == 0 )) && eval_checkpoint
  ((chunk += 1))
done

echo ">>> training complete: $NUM_CHUNKS chunks. Logs:"
echo "    training: $LOG_FILE"
echo "    eval:     $EVAL_LOG_FILE"
[ -f "$WEIGHTS_DIR/sac_best.zip" ] && \
  echo "    best:     $WEIGHTS_DIR/sac_best.zip (composite $(cat "$WEIGHTS_DIR/best_score.txt"))"
exit 0