#!/usr/bin/env bash
set -euo pipefail

# ===== 可调参数 =====
CKPT_ROOT="/home/test/checkpoints/q3-32b-ds4"   # 若实际是 .../checkpoint-62/global_step62，请把 CKPT_ROOT 改成 .../checkpoint-62
TAG="global_step62"
HOSTS=(tn01 tn02 tn03 tn04 tn05 tn06)
AGGREGATOR_HOST="tn06"            # 本脚本运行/汇总所在机器
EXPECTED_SHARDS_PER_HOST=4        # 每机应写出分片数（按你的并行布局）
MAX_SHARD_SIZE="5GB"

STRICT_PRECHECK=true              # true: 预检不通过就退出；false: 仅告警
SSH_OPTS="-o BatchMode=yes -o StrictHostKeyChecking=accept-new -o ConnectTimeout=8"
RSYNC_OPTS="-a --info=progress2 --human-readable --partial --inplace"
# ====================

# ===== 派生参数（一般不用改） =====
EXPECTED_TOTAL_SHARDS=$(( EXPECTED_SHARDS_PER_HOST * ${#HOSTS[@]} ))
STAGING_BASE="${CKPT_ROOT}/_staging"
STAGING_TAG_DIR="${STAGING_BASE}/${TAG}"
OUT_DIR="${CKPT_ROOT}/merged-${TAG}"
export OUT_DIR
# =================================

echo "== 预检查 SSH =="
for h in "${HOSTS[@]}"; do
  ssh ${SSH_OPTS} "$h" "true" >/dev/null || { echo "!! 无法免密 SSH 到 $h"; exit 1; }
done

echo "== 0/5 逐节点分片预检（统计各机 ${CKPT_ROOT}/${TAG} 下的 *model_states.pt）=="
remote_total=0
agg_cnt=0
for h in "${HOSTS[@]}"; do
  c=$(ssh ${SSH_OPTS} "$h" "find '${CKPT_ROOT}/${TAG}' -maxdepth 1 -type f -name '*model_states.pt' 2>/dev/null | wc -l" || echo 0)
  c=$(echo "$c" | tr -d ' ')
  printf " - %-8s: %s 分片\n" "$h" "$c"
  if [[ "$h" == "$AGGREGATOR_HOST" ]]; then
    agg_cnt=$c
  else
    remote_total=$(( remote_total + c ))
    # 每台机最简单的 sanity：至少应有 EXPECTED_SHARDS_PER_HOST 个
    if (( c < EXPECTED_SHARDS_PER_HOST )); then
      echo "!! 预警：$h 分片仅 $c 个（期望 ${EXPECTED_SHARDS_PER_HOST}）" >&2
    fi
  fi
done
expected_remote_total=$(( EXPECTED_TOTAL_SHARDS - EXPECTED_SHARDS_PER_HOST ))
echo " - 远端合计（不含 ${AGGREGATOR_HOST}）：$remote_total（期望 ${expected_remote_total}）"
echo " - ${AGGREGATOR_HOST} 自身：$agg_cnt（期望 ${EXPECTED_SHARDS_PER_HOST}）"

precheck_ok=true
if (( remote_total != expected_remote_total )); then
  echo "!! 远端总分片不等：实际 ${remote_total} / 期望 ${expected_remote_total}" >&2
  precheck_ok=false
fi
if (( agg_cnt < EXPECTED_SHARDS_PER_HOST )); then
  echo "!! ${AGGREGATOR_HOST} 本机分片不足：实际 ${agg_cnt} / 期望 ${EXPECTED_SHARDS_PER_HOST}" >&2
  precheck_ok=false
fi
if [[ "${STRICT_PRECHECK}" == "true" && "${precheck_ok}" == "false" ]]; then
  echo "!! STRICT_PRECHECK 开启：预检不通过，停止执行" >&2
  exit 2
fi
[[ "${precheck_ok}" == "true" ]] && echo "OK: 预检通过（远端=${remote_total}、本机=${agg_cnt}，总计期望=${EXPECTED_TOTAL_SHARDS}）" || echo "WARN: 预检未通过（分片数量与期望不符），已启用宽松模式，继续执行..."

echo "== 1/5 准备 staging 目录（干净环境）=="
rm -rf "${STAGING_TAG_DIR}"
mkdir -p "${STAGING_TAG_DIR}"

echo "== 2/5 收集分片到 staging =="
for h in "${HOSTS[@]}"; do
  if ssh ${SSH_OPTS} "$h" "test -d '${CKPT_ROOT}/${TAG}'"; then
    echo " - 收集 ${h}:${CKPT_ROOT}/${TAG}/ -> ${STAGING_TAG_DIR}/"
    rsync ${RSYNC_OPTS} -e "ssh ${SSH_OPTS}" \
      "${h}:${CKPT_ROOT}/${TAG}/" "${STAGING_TAG_DIR}/" || true
  else
    echo " - ${h} 无 ${CKPT_ROOT}/${TAG}，跳过"
  fi
done

echo "== 3/5 在 staging 校验总分片数（应为 ${EXPECTED_TOTAL_SHARDS}）=="
mapfile -t SHARDS < <(find "${STAGING_TAG_DIR}" -maxdepth 1 -type f -name "*model_states.pt" | sort -u)
CNT=${#SHARDS[@]}
echo " - staging 中发现分片数：${CNT}"
if (( CNT != EXPECTED_TOTAL_SHARDS )); then
  echo "!! 分片总数不等：staging 实际 ${CNT} / 期望 ${EXPECTED_TOTAL_SHARDS}。请检查是否缺片或命名不一致。" >&2
  exit 3
fi

echo "== 4/5 合并为 safetensors 到：${OUT_DIR} =="
mkdir -p "${OUT_DIR}"

# 探测 zero_to_fp32.py 是否支持新参数；不支持就用 API
USE_Z2FP32_SCRIPT=false
if [[ -f "${CKPT_ROOT}/zero_to_fp32.py" ]]; then
  if python "${CKPT_ROOT}/zero_to_fp32.py" --help 2>&1 | grep -q -- "--safe_serialization"; then
    USE_Z2FP32_SCRIPT=true
  fi
fi

if $USE_Z2FP32_SCRIPT; then
  python "${CKPT_ROOT}/zero_to_fp32.py" \
    "${STAGING_BASE}" \
    "${OUT_DIR}" \
    --tag "${TAG}" \
    --safe_serialization \
    --max_shard_size "${MAX_SHARD_SIZE}"
else
  python - <<PY
from deepspeed.utils.zero_to_fp32 import convert_zero_checkpoint_to_fp32_state_dict
convert_zero_checkpoint_to_fp32_state_dict(
    checkpoint_dir=r"${STAGING_BASE}",
    output_dir=r"${OUT_DIR}",
    tag=r"${TAG}",
    safe_serialization=True,
    max_shard_size=r"${MAX_SHARD_SIZE}",
)
print("合并完成：", r"${OUT_DIR}")
PY
fi

echo "== 4.1 拷贝 config/tokenizer 工件（如存在）=="
for f in config.json generation_config.json tokenizer_config.json tokenizer.json merges.txt vocab.json special_tokens_map.json added_tokens.json; do
  [[ -f "${CKPT_ROOT}/${f}" ]] && cp -n "${CKPT_ROOT}/${f}" "${OUT_DIR}/"
done

echo "== 5/5 自检（索引与 config）=="
python - <<'PY'
import os, json, sys
out_dir = os.environ.get("OUT_DIR")
idx = os.path.join(out_dir, "model.safetensors.index.json")
if os.path.exists(idx):
    with open(idx) as f: j = json.load(f)
    print(f"OK: 找到 safetensors 索引：{idx}（参数条目 {len(j.get('weight_map', {}))}）")
else:
    print("NOTE: 未找到 model.safetensors.index.json（可能是单分片）")
try:
    from transformers import AutoConfig
    cfg = AutoConfig.from_pretrained(out_dir)
    print("OK: 读取到 config：", cfg.model_type, "hidden:", getattr(cfg,'hidden_size',None), "layers:", getattr(cfg,'num_hidden_layers',None))
except Exception as e:
    print("WARN: 读取 config 失败（若无 config.json 可忽略）：", e, file=sys.stderr)
PY

echo "== 完成：${OUT_DIR} =="