local CHECKOUTED_IN_LOWERDIR=false;

# 性能优化
if [ -e "/tmp/CHECKOUT_IN_COW" ]; then
  if [[ "$PLUGIN_TARGET_REF" =~ ^refs/heads/.* ]]; then
    local BRANCH_NAME=$(echo "$PLUGIN_TARGET_REF" | cut -c12-)

    if [ $(git rev-parse HEAD 2>/dev/null) = "$PLUGIN_TARGET_SHA" ] && [ $(git branch --show-current) = "$BRANCH_NAME" ]; then
      _log "git branch --show-current"
      git branch --show-current

      _log "git rev-parse HEAD";
      git rev-parse HEAD;

      CHECKOUTED_IN_LOWERDIR=true;
    fi
  else
    if [ $(git rev-parse HEAD 2>/dev/null) = "$PLUGIN_TARGET_SHA" ]; then
      _log "git rev-parse HEAD";
      git rev-parse HEAD;

      CHECKOUTED_IN_LOWERDIR=true;
    fi
  fi
fi

if [ -e "/tmp/FETCHED_IN_CLONE" ]; then
  _log "skip fetch due to fetched in clone"
elif [ "$CHECKOUTED_IN_LOWERDIR" = true ]; then
  _log "skip fetch due to fetched in cow"
else
  # 刚 git init 从来没有 git fetch 的情况，显示进度，防止超时
  _log "git for-each-ref refs/tags/ refs/heads/ refs/remotes/ |wc -l"
  REF_COUNT=$(git for-each-ref refs/tags/ refs/heads/ refs/remotes/ |wc -l)
  echo $REF_COUNT
  ret=$?

  if [[ $REF_COUNT -eq 0 ]]; then
    _log "It maybe a empty repo. show progress"
    MAYBE_EMPTY_REPO=1
  fi

  # clear tags,remotes,heads
  _log 'git for-each-ref --format="delete \"%(refname)\"" refs/tags/ refs/heads/ refs/remotes/ |git update-ref --stdin'
  git for-each-ref --format="delete \"%(refname)\"" refs/tags/ refs/heads/ refs/remotes/ |git update-ref --stdin

  local OPTIONS="-v --progress --force --no-recurse-submodules"
  local REFMAP=""

  if [[ "$PLUGIN_TARGET_REF" =~ ^refs/heads/.* ]]; then
    REFMAP="--refmap=+refs/heads/*:refs/remotes/origin/*"
  elif [[ "$PLUGIN_TARGET_REF" =~ ^refs/tags/.* ]]; then
    REFMAP="--refmap=+refs/tags/*:refs/tags/*"
  else
    REFMAP=""
  fi

  _log "git fetch $OPTIONS $REFMAP origin \"${PLUGIN_TARGET_REF}\""
  git fetch $OPTIONS $REFMAP origin "${PLUGIN_TARGET_REF}"
  fetch_ret=$?

  # 如果fetch失败了
  if [[ $fetch_ret -ne 0 ]] && [[ $MAYBE_EMPTY_REPO -eq 1 ]]; then

    # 再换个准确的办法判断是不是空仓
    _log "git count-objects -v"
    count_object_result=$(git count-objects -v)
    count=$(echo "$count_object_result" | grep count: | cut -c8-)
    packs=$(echo "$count_object_result" | grep packs: | cut -c8-)

    if [[ $count == "0" ]] && [[ $packs == "0" ]]; then
      _log "It's empty repo"
      touch "/tmp/IS_EMPTY_REPO"
      exit 0;
    else
      _log "exit due to fetch failed."
      exit $fetch_ret;
    fi
  fi
fi

if [ -e "/tmp/CHECKOUTED_IN_CLONE" ]; then
  _log "skip checkout due to checkouted in clone";

  if ! [ "$PLUGIN_NEED_MERGE" = true ]; then
    _log "skip checkout submodules due to checkouted in clone";
    exit 0
  fi
elif [ "$CHECKOUTED_IN_LOWERDIR" = true ]; then
  _log "skip checkout due to checkouted in cow"
else
  # do checkout
  if [[ "$PLUGIN_TARGET_REF" =~ ^refs/heads/.* ]]; then
    _log "git update-ref refs/fetched/${PLUGIN_TARGET_SHA} FETCH_HEAD"
    git update-ref refs/fetched/${PLUGIN_TARGET_SHA} FETCH_HEAD
    
    local BRANCH_NAME=$(echo "$PLUGIN_TARGET_REF" | cut -c12-)

    _log "git checkout --progress -f -B \"$BRANCH_NAME\" \"${PLUGIN_TARGET_SHA:-FETCH_HEAD}\""
    git checkout --progress -f -B "$BRANCH_NAME" "${PLUGIN_TARGET_SHA:-FETCH_HEAD}"
    ret=$?; [ $ret -ne 0 ] && exit $ret;

    _log "git clean -ffdx"
    git clean -ffdx

    _log "git branch -u \"origin/$BRANCH_NAME\""
    git branch -u "origin/$BRANCH_NAME"

    _log "git branch --show-current"
    git branch --show-current
  elif [[ "$PLUGIN_TARGET_REF" =~ ^refs/tags/.* ]]; then
    _log "git update-ref refs/fetched/${PLUGIN_TARGET_SHA} FETCH_HEAD"
    git update-ref refs/fetched/${PLUGIN_TARGET_SHA} FETCH_HEAD

    _log "git checkout --progress -f \"${PLUGIN_TARGET_SHA:-FETCH_HEAD}\""
    git checkout --progress -f "${PLUGIN_TARGET_SHA:-FETCH_HEAD}"
    ret=$?; [ $ret -ne 0 ] && exit $ret;

    _log "git clean -ffdx"
    git clean -ffdx
  else
    _log "git update-ref refs/fetched/${PLUGIN_TARGET_SHA} FETCH_HEAD"
    git update-ref refs/fetched/${PLUGIN_TARGET_SHA} FETCH_HEAD

    _log "git checkout --progress -f \"${PLUGIN_TARGET_SHA:-FETCH_HEAD}\""
    git checkout --progress -f "${PLUGIN_TARGET_SHA:-FETCH_HEAD}"
    ret=$?; [ $ret -ne 0 ] && exit $ret;

    _log "git clean -ffdx"
    git clean -ffdx
  fi
fi

git cat-file -e "${PLUGIN_TARGET_SHA:-FETCH_HEAD}^{commit}"
if ! [ "$?" == 0 ]; then
  _log -e "Error: ${PLUGIN_TARGET_SHA} not found!"
  exit 1
fi