#!/bin/bash

# EXAMPLES
usage() {
  echo "usage: " \
  "NAME=app " \
  "DESCRIPTION=Testapp " \
  "EXEPATH=testapp " \
  "[USERNAMEGROUP=appuser " \
  "EXEARGUMENTS=-v " \
  "RUNNER=/bin/dotnet " \
  "ENVIROMENTVARS=test HOME " \
  "LOGOUTPUT=syslog] " \
  "sh service-build.sh"
  exit 1
}

echo "DEB Builder service-file: https://git.blubbfish.net/vs_utils/CI-Scripts/src/branch/master/deb/service-build.sh"

if [[ -z "${DESCRIPTION}" ]]; then
  usage
fi

if [[ -z "${NAME}" ]]; then
  usage  
fi

if [ -z "${USERNAMEGROUP}" ]; then
  USERNAMEGROUP="${NAME}bot"
fi

if [[ -z "${EXEPATH}" ]]; then
  usage  
fi

if [[ -z "${EXEARGUMENTS}" ]]; then
  EXEARGUMENTS=" "
fi

INSTLOCAL="/usr/local/bin/${NAME}"
BINARY="$INSTLOCAL/${EXEPATH}"

if [[ -z "${RUNNER}" ]]; then
  RUNNER="${BINARY}"
else 
  EXEARGUMENTS="${BINARY} ${EXEARGUMENTS}"
fi

echo "[Unit]"                                                    > service-${NAME}
echo "Description=${DESCRIPTION}"                               >> service-${NAME}
echo "After=network-online.target"                              >> service-${NAME}
echo "Wants=network-online.target"                              >> service-${NAME}
echo ""                                                         >> service-${NAME}
echo "[Service]"                                                >> service-${NAME}
echo "User=${USERNAMEGROUP}"                                    >> service-${NAME}
echo "Group=${USERNAMEGROUP}"                                   >> service-${NAME}
echo "WorkingDirectory=${INSTLOCAL}"                            >> service-${NAME}
if [[ -n "${ENVIROMENTVARS}" ]]; then
  for enviromentvar in ${ENVIROMENTVARS}
  do
    echo "Environment=\"${enviromentvar}\""                     >> service-${NAME}
  done
fi
echo "PermissionsStartOnly=true"                                >> service-${NAME}
echo "ExecStartPre=setcap 'cap_net_bind_service=+ep' ${RUNNER}" >> service-${NAME}
echo "ExecStart=${RUNNER} ${EXEARGUMENTS}"                      >> service-${NAME}
echo "KillMode=control-group"                                   >> service-${NAME}
echo "KillSignal=SIGINT"                                        >> service-${NAME}
echo "TimeoutStopSec=30"                                        >> service-${NAME}
echo "Restart=on-failure"                                       >> service-${NAME}
if [[ -n "${LOGOUTPUT}" ]]; then
  echo "StandardOutput=${LOGOUTPUT}"                            >> service-${NAME}
else
  echo "StandardOutput=null"                                    >> service-${NAME}
fi
echo "StandardError=journal"                                    >> service-${NAME}
echo ""                                                         >> service-${NAME}
echo "[Install]"                                                >> service-${NAME}
echo "WantedBy=multi-user.target"                               >> service-${NAME}
echo "Alias=${NAME}.service"                                    >> service-${NAME}