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

# ===== 可调参数 =====
CKPT_ROOT="/home/test/checkpoints/q3-32b-ds4"
TAG="global_step62"
HOSTS=(tn01 tn02 tn03 tn04 tn05 tn06)
OUT_DIR="${CKPT_ROOT}/merged-${TAG}"
MAX_SHARD_SIZE="5GB"
SSH_OPTS="-o BatchMode=yes -o StrictHostKeyChecking=accept-new -o ConnectTimeout=8"
RSYNC_OPTS="-a --info=progress2 --human-readable --partial --inplace"
# ====================

echo "== 预检查 SSH 与远端目录 =="
for h in "${HOSTS[@]}"; do
  if ! ssh ${SSH_OPTS} "$h" "true" >/dev/null 2>&1; then
    echo "!! 无法免密 SSH 到 $h（检查 ~/.ssh/config/authorized_keys/防火墙）" >&2
    exit 1
  fi
  if ! ssh ${SSH_OPTS} "$h" "test -d '${CKPT_ROOT}/${TAG}'"; then
    echo "!! $h 上缺少目录 ${CKPT_ROOT}/${TAG}，确认训练是否在该机产生了分片" >&2
  fi
done

echo "== 1/4 开始按节点同步分片（仅 ${TAG}，带进度）=="
mkdir -p "${CKPT_ROOT}"
LOCAL_HOST="$(hostname -s || hostname)"
for h in "${HOSTS[@]}"; do
  [[ "$h" == "$LOCAL_HOST" ]] && { echo " - 跳过本机 $h"; continue; }
  echo " - 从 $h 拉取 ${CKPT_ROOT}/${TAG}/mp_rank_*/"
  # 只拉取该 step 下的 mp_rank_* 目录，避免无关文件
  rsync ${RSYNC_OPTS} -e "ssh ${SSH_OPTS}" \
    --include="${TAG}/" --include="${TAG}/mp_rank_*/" --include="${TAG}/mp_rank_*/**" \
    --exclude="*" \
    "${h}:${CKPT_ROOT}/" "${CKPT_ROOT}/"
done

echo "== 2/4 校验是否凑齐分片目录 =="
if [[ ! -d "${CKPT_ROOT}/${TAG}" ]]; then
  echo "!! 未发现 ${CKPT_ROOT}/${TAG}" >&2; exit 1
fi
MP_CNT=$(find "${CKPT_ROOT}/${TAG}" -maxdepth 1 -type d -name "mp_rank_*" | wc -l | tr -d ' ')
echo " - 已发现 mp_rank_* 目录数：${MP_CNT}"
if [[ "${MP_CNT}" -eq 0 ]]; then
  echo "!! 没有任何 mp_rank_* 分片，请检查同步" >&2; exit 1
fi

echo "== 3/4 合并为 safetensors 输出到：${OUT_DIR} =="
python - <<PY
import os
from deepspeed.utils.zero_to_fp32 import convert_zero_checkpoint_to_fp32_state_dict
ckpt_dir = r"${CKPT_ROOT}"
out_dir  = r"${OUT_DIR}"
tag      = r"${TAG}"
os.makedirs(out_dir, exist_ok=True)
convert_zero_checkpoint_to_fp32_state_dict(
    checkpoint_dir=ckpt_dir,
    output_dir=out_dir,
    tag=tag,
    safe_serialization=True,
    max_shard_size="${MAX_SHARD_SIZE}",
)
print("合并完成：", out_dir)
PY

echo "== 3.1 拷贝 config/tokenizer 工件（如存在）=="
pushd "${CKPT_ROOT}" >/dev/null
for f in config.json generation_config.json tokenizer_config.json tokenizer.json merges.txt vocab.json special_tokens_map.json added_tokens.json; do
  [[ -f "$f" ]] && cp -n "$f" "${OUT_DIR}/"
done
popd >/dev/null

echo "== 4/4 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("WARN: 未找到 model.safetensors.index.json", file=sys.stderr)
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} =="