#!/bin/bash

set -e

home=$(pwd)

INIT_SYSTEM="unknown"
SERVICE_NAME="<Имя сервиса>" # Имя твоего сервиса, например mydotnetserver
SERVICE_DESCRIPTION="<Описание твоего сервиса>"
PROJECT_PATH="$home/" # Путь к папке с файлом Server.dll
PROJECT_BIN="<Имя файла DLL>" # Например Server.dll

if [[ `/sbin/init --version` =~ upstart ]]; then INIT_SYSTEM="upstart";
elif [[ `systemctl` =~ -\.mount ]]; then INIT_SYSTEM="systemd";
elif [[ -f /etc/init.d/cron && ! -h /etc/init.d/cron ]]; then INIT_SYSTEM="sysv-init";
else INIT_SYSTEM="unknown"; fi

if [[ "$INIT_SYSTEM" = "unknown" ]]; then
    echo "Unknown init system. Nothing done"
    exit 1
fi

if [[ "$INIT_SYSTEM" = "upstart" ]]; then
    echo "Detected UPSTART init system"

    echo "Creating $SERVICE_NAME service entry..."

    UPSTART_SERVICE_TEMPLATE=$(cat <<EOF
description "$SERVICE_DESCRIPTION"

start on (started networking)
stop on shutdown

script
    echo $$ > /var/run/$SERVICE_NAME.pid
    cd "$PROJECT_PATH"
    exec /usr/bin/dotnet "$PROJECT_BIN"
end script

respawn

pre-stop script
    rm -f /var/run/$SERVICE_NAME.pid
end script
EOF
)

    echo "$UPSTART_SERVICE_TEMPLATE" > "/etc/init/$SERVICE_NAME.conf"

    echo "Starting the service..."
    initctl start "$SERVICE_NAME"
fi

if [[ "$INIT_SYSTEM" = "systemd" ]]; then
    echo "Detected SYSTEMD init system"

    echo "Creating $SERVICE_NAME service entry..."

    SYSTEMD_SERVICE_TEMPLATE=$(cat <<EOF
[Unit]
Description=$SERVICE_DESCRIPTION
Wants=network.target
After=network.target

[Service]
WorkingDirectory=$PROJECT_PATH
ExecStart=/usr/bin/dotnet "$PROJECT_BIN"
Restart=on-failure

[Install]
WantedBy=multi-user.target
EOF
)

    echo "$SYSTEMD_SERVICE_TEMPLATE" > "/etc/systemd/system/$SERVICE_NAME.service"

    echo "Realoading services..."
    systemctl daemon-reload

    echo "Enabling the service..."
    systemctl enable "$SERVICE_NAME"

    echo "Starting the service..."
    systemctl start "$SERVICE_NAME"
fi

if [[ "$INIT_SYSTEM" = "sysv-init" ]]; then
    echo "Detected SYSV init system"

    echo "Creating $SERVICE_NAME service entry..."

    SCRIPT="/usr/bin/dotnet \\\"$PROJECT_PATH$PROJECT_BIN\\\""

    PIDFILE="/var/run/$SERVICE_NAME.pid"
    LOGFILE="/var/log/$SERVICE_NAME.log"

    SYSV_SERVICE_TEMPLATE=$(cat <<EOF
#!/bin/sh
### BEGIN INIT INFO
# Provides:          $SERVICE_NAME
# Required-Start:    \$local_fs \$network \$named \$time \$syslog
# Required-Stop:     \$local_fs \$network \$named \$time \$syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Description:       $SERVICE_DESCRIPTION
### END INIT INFO

start() {
  if [ -f "$PIDFILE" ] && kill -0 \$(cat "$PIDFILE") 2> /dev/null; then
    echo "Service already running" >&2
    return 1
  fi
  echo "Starting service..." >&2
  local CMD="($SCRIPT > \"$LOGFILE\") &"
  eval \$CMD
  echo \$! > "$PIDFILE"
  echo "Service started" >&2
}

stop() {
  if [ ! -f "$PIDFILE" ] || ! kill -0 \$(cat "$PIDFILE") 2> /dev/null; then
    echo 'Service not running' >&2
    return 1
  fi
  echo 'Stopping service...' >&2
  kill -15 \$(cat "$PIDFILE") && rm -f "$PIDFILE"
  echo 'Service stopped' >&2
}

uninstall() {
  FD=0
  INTERACTIVE=0
  if [ -t "\$FD" -o -p /dev/stdin ]; then
    INTERACTIVE=1
  fi

  SURE="no"
  if [ "\$INTERACTIVE" -eq 1 ]; then
    echo -n "Are you really sure you want to uninstall this service? That cannot be undone. [yes|No]: "
    read SURE
    echo
  fi

  if [ "\$INTERACTIVE" -eq 0 -o "\$SURE" = "yes" ]; then
    stop
    rm -f "$PIDFILE"
    echo "Notice: log file is not be removed: '$LOGFILE'" >&2
    update-rc.d -f $SERVICE_NAME remove
    rm -fv "\$0"
  fi
}

case "\$1" in
  start)
    start
    ;;
  stop)
    stop
    ;;
  uninstall)
    uninstall
    ;;
  retart)
    stop
    start
    ;;
  *)
    echo "Usage: \$0 {start|stop|restart|uninstall}"
esac

EOF
)

    echo "$SYSV_SERVICE_TEMPLATE" > "/etc/init.d/$SERVICE_NAME"
    chmod +x "/etc/init.d/$SERVICE_NAME"

    echo "Starting the service..."
    service "$SERVICE_NAME" start

    echo "Updating the service..."
    update-rc.d $SERVICE_NAME defaults
fi

echo "Service successfully installed"