#!/usr/bin/env bash

NAME=""
COMMAND_FILE=""
ENV_FILE=""
MAIL_NOTIFICATION=""
PID=$$

USAGE="Usage: `basename $0` [-h] [-n name] [-e env-file] [-m mail-address] COMMAND+"

while getopts hn:e:m:N: OPT; do
    case "$OPT" in
        h)
            echo $USAGE
            exit 1
            ;;
        n)
            NAME=$OPTARG
            ;;
        e)
            ENV_FILE=$OPTARG
            ;;
        m)
            MAIL_NOTIFICATION=$OPTARG
            ;;
        \?)
            echo $USAGE >&2
            exit 1
            ;;
    esac
done

shift $((OPTIND - 1))

if [ -z "${NAME}" ] ; then
    echo "A job name is required." >&2
    exit 1
fi

if [ $# -lt 1 ] ; then
    echo "A command is required." >&2
    exit 1
fi

RUN_SCRIPT=$(mktemp)

cat <<EOF > "${RUN_SCRIPT}"
#!/bin/sh

FN="${RUN_SCRIPT}"
JOB_NAME="${NAME}"
MAIL_NOTIFICATION="${MAIL_NOTIFICATION}"

OUTPUT_FILE=\$(mktemp)
TIME_FILE=\$(mktemp)
START_TIME=\$(date)
EOF

if [ -e "${ENV_FILE}" ] ; then
    cat "${ENV_FILE}" >> "${RUN_SCRIPT}"
fi

cat <<EOF >> "${RUN_SCRIPT}"

env time -o \${TIME_FILE} $@ 2>&1 | tee \${OUTPUT_FILE}

cat \${TIME_FILE}

END_TIME=\$(date)

EOF

if [ ! -z "${MAIL_NOTIFICATION}" ] ; then
    cat <<EOF >> "${RUN_SCRIPT}"

MESSAGE_FILE=\$(mktemp)

cat <<EOM > "\${MESSAGE_FILE}"
Job \${JOB_NAME} has completed.  The output is attached.

Start time: \${START_TIME}
End time  : \${END_TIME}

Process Time/Usage Statistics:
EOM

cat "\${TIME_FILE}" >> "\${MESSAGE_FILE}"

cat <<EOM >> "\${MESSAGE_FILE}"

FN="${RUN_SCRIPT}"
JOB_NAME="${NAME}"
MAIL_NOTIFICATION="${MAIL_NOTIFICATION}"
ENV_FILE="${ENV_FILE}"
EOM

mail -s "Job \${JOB_NAME} complete" -a "\${OUTPUT_FILE}" "\${MAIL_NOTIFICATION}" < "\${MESSAGE_FILE}"

rm "\${MESSAGE_FILE}"
EOF
fi

cat <<EOF >> "${RUN_SCRIPT}"
rm "\${OUTPUT_FILE}"
rm "\${TIME_FILE}"
rm "\${FN}"
EOF

chmod +x ${RUN_SCRIPT}
screen -d -S "job-${NAME}" -m ${RUN_SCRIPT}