#!/bin/bash

DISTNAME=unknown
DISTVER=

function resetDistVer {
  DISTNAME=unknown
  DISTVER=
}

if [ -f /etc/centos-release ]; then
  . /etc/os-release
  if [ "$VERSION_ID" == "7" ]; then
    DISTNAME=centos
    DISTVER=7
  else
    resetDistVer
  fi
elif [ -f /etc/fedora-release ]; then
  . /etc/os-release
  if [ "$VERSION_ID" == "29" ]; then
    DISTNAME=fedora
    DISTVER=29
  elif [ "$VERSION_ID" == "28" ]; then
    DISTNAME=fedora
    DISTVER=28
  else
    resetDistVer
  fi
elif [ -f /etc/solus-release ]; then
  DISTNAME=solus
elif [ -f /etc/lsb-release ]; then
  . /etc/lsb-release
  DISTNAME=$(echo ${DISTRIB_ID} | awk '{print tolower($0)}')
  DISTVER=${DISTRIB_RELEASE}
  if [ "$DISTNAME" != "ubuntu" ]; then
    if [ "$DISTNAME" = "linuxmint" ]; then
      if [ "$DISTVER" = "19" ] || [ "$DISTVER" = "19.1" ]; then
        DISTNAME=ubuntu
        DISTVER=18.04
      else
        resetDistVer
      fi
    elif [ "$DISTNAME" = "elementary" ]; then
      if [ "$DISTVER" = "5.0" ]; then
        DISTNAME=ubuntu
        DISTVER=18.04
      else
        resetDistVer
      fi
    else
      resetDistVer
    fi
  else
    resetDistVer
  fi
elif [ -f /etc/debian_version ]; then
  DISTNAME=debian
  DISTVER=$(head -1 /etc/debian_version|awk -F. '{print $1}')
  if [ "$DISTVER" != "9" ]; then
    resetDistVer
  fi
elif [ -f /etc/os-release ]; then
  . /etc/os-release
  if [ "$ID" == "arch" ]; then
    DISTNAME=arch
  else
    resetDistVer
  fi
else
  resetDistVer
fi

echo ${DISTNAME}${DISTVER}