#!/bin/sh

EPIPE_EMACS=${EPIPE_EMACS:-emacs}
show="NO"
buffer_name=""
interval=1

usage() {
    self=$(basename $0)
    echo "$self redirects stdin to an emacs buffer"
    echo -e "Example: 'echo \"foo\" | epipe'"
    echo
    echo -e "\t-e CMD\t Use emacs CMD."
    echo -e "\t-b NAME\t Piped-to buffer should have NAME."
    echo -e "\t-I INT\t Use INT as revert interval."
    echo -e "\t-v\t Verbose mode also prints output to stdout."
    echo -e "\t-h\t Shows this message."
}

while [ $# -gt 0 ]
do
    case $1 in
        -v) show="YES"; shift;;
        -e) shift; EPIPE_EMACS=$1; shift;;
        -b) shift; buffer_name=$1; shift;;
        -I) shift; interval=$1; shift;;
        -h) usage; exit 0; shift;;
        *) echo "Unknown option: '$1'"; usage; exit 1;;
    esac
done

tmpfile=$(mktemp --tmpdir=/tmp epipe.XXXXXX)
elisp="
(let ((find-file-hook
       '((lambda ()
           (turn-on-auto-revert-tail-mode)
           (setq auto-revert-interval ${interval})
           (auto-revert-set-timer)
           (goto-char (point-max))
           (cd \"$(pwd)\")
           (unless (string-empty-p \"$buffer_name\")
             (rename-buffer \"$buffer_name\"))))))
  (find-file \"$tmpfile\"))"
${EPIPE_EMACS} --eval "$elisp" > /dev/null &

if [ "$show" = "NO" ]
then
    cat > $tmpfile
else
    tee $tmpfile
fi