#!/bin/bash
# insert block of line into the file

export LANG=en_EN.UTF-8
export PATH=$PATH:/sbin:/usr/sbin

[[ -z $DEBUG  ]] && DEBUG=0
TMP=/opt/webdir/logs
LOG=$TMP/bx_blocklines.log
[[ $DEBUG -gt 0  ]] 2>/dev/null && echo -n "" > $LOG

debug() {
    msg=$1

    [[ $DEBUG -gt 1  ]] && printf "%s: %d: %s\n" "$(date +%F-%H-%M-%S)" "$$" "$msg" >> $LOG
}

# print error message
print_error() {
  msg=$1
  echo "{\"changed\":false,\"failed\":true,\"msg\":\"$msg\"}"
  if [[ -f $TMPFILE && $DEBUG -eq 0 ]]; then
      rm -f $TMPFILE
  fi
  exit 1
}

# print timezone info
print_ok() {
  msg=$1

  echo "{\"changed\":true,\"msg\":\"$msg\"}"
  if [[ -f $TMPFILE && $DEBUG -eq 0 ]]; then
      rm -f $TMPFILE
  fi
 
  exit 0
}

print_notchanged() {
  msg=$1

  echo "{\"changed\":false,\"msg\":\"$msg\"}"
  if [[ -f $TMPFILE && $DEBUG -eq 0 ]]; then
      rm -f $TMPFILE
  fi
 
  exit 0

}

revert_commit() {
    pushd /etc >/dev/null 2>&1
    TMPFILE=$(mktemp /tmp/hg_XXXXXX)
    # get mercurial history
    hg log | grep '^\(changeset\|summary\):' > $TMPFILE 2>&1
    for rtn in ${PIPESTATUS[*]}; do
        [[ $rtn -gt 0 ]] && \
            error "Cannot get hg log for /etc"
    done

    # get changeset number
    CHANGESET=$(cat $TMPFILE | grep "$commit" -B1 | \
        tail -n 2 | grep "^changeset:" | \
        awk -F':' '{print $2}' | sed -e "s/\s\+//")
    if [[ $CHANGESET -gt 0 ]] 2>/dev/null; then
        hg revert -r $CHANGESET $dest > $TMPFILE 2>&1
        hg_rtn=$?
        if [[ $hg_rtn -gt 0 ]]; then
            print_error "Revert operation return error=$hg_rtn: $(head $TMPFILE)"
        else
            print_ok "Revert configs for dest=$dest to changeset=$CHANGESET"
        fi
    else
        print_notchanged "Not found commit=$commit"
    fi

    popd >/dev/null 2>&1
}

# get ansible variables
source ${1} 2>/dev/null

[[ -z $commit ]] && print_error "Not defined a commit=."
[[ -z $dest ]] && print_error "Not defined a dest=."
[[ -z $state ]] && state="revert"
debug "commit=$commit state=$state"

case "$state" in
    "revert") revert_commit;;
    *) print_error "Unknown state option";;
esac