#!/usr/bin/env bash
# Detects which OS and if it is Linux then it will detect which Linux Distribution.

OS=`uname -s`
REV=`uname -r`
MACH=`uname -m`

if [ "${OS}" = "SunOS" ] ; then
  OS=Solaris
  ARCH=`uname -p`
  OSSTR="${OS} ${REV}(${ARCH} `uname -v`)"

elif [ "${OS}" = "AIX" ] ; then
  OSSTR="${OS} `oslevel` (`oslevel -r`)"

elif [ "${OS}" = "Linux" ] ; then
  KERNEL=`uname -r`

  if [ -f /etc/fedora-release ]; then
    DIST=$(cat /etc/fedora-release | awk '{print $1}')
    REV=`cat /etc/fedora-release | sed s/.*release\ // | sed s/\ .*//`
        
  elif [ -f /etc/redhat-release ] ; then
    DIST=$(cat /etc/redhat-release | awk '{print $1}')
    if [ "${DIST}" = "CentOS" ]; then
      DIST="CentOS"
      IGNORE_OS_RELEASE=1 # https://bugs.centos.org/view.php?id=8359
    elif [ "${DIST}" = "CloudLinux" ]; then
      DIST="CloudLinux"
    elif [ "${DIST}" = "Mandriva" ]; then
      DIST="Mandriva"
      PSEUDONAME=`cat /etc/mandriva-release | sed s/.*\(// | sed s/\)//`
      REV=`cat /etc/mandriva-release | sed s/.*release\ // | sed s/\ .*//`
    elif [ -f /etc/oracle-release ]; then
      DIST="Oracle"
    elif [ -f /etc/rockstor-release ]; then
      DIST="Rockstor"
    else
      DIST="RedHat"
    fi

    PSEUDONAME=`cat /etc/redhat-release | sed s/.*\(// | sed s/\)//`
    REV=`cat /etc/redhat-release | sed s/.*release\ // | sed s/\ .*//`

  elif [ -f /etc/mandrake-release ] ; then
    DIST='Mandrake'
    PSEUDONAME=`cat /etc/mandrake-release | sed s/.*\(// | sed s/\)//`
    REV=`cat /etc/mandrake-release | sed s/.*release\ // | sed s/\ .*//`

  elif [ -f /etc/devuan_version ] ; then
    DIST="Devuan `cat /etc/devuan_version`"
    REV=""

  elif [ -f /etc/debian_version ] ; then
    DIST="Debian `cat /etc/debian_version`"
    REV=""
    if [ -f /usr/bin/lsb_release ] ; then
      ID=`lsb_release -i | awk -F ':' '{print $2}' | sed 's/	//g'`
    fi
    if [ "${ID}" = "Raspbian" ] ; then
      DIST="Raspbian `cat /etc/debian_version`"
    fi
    if [ -f /usr/bin/pveversion ]; then
      DIST="${DIST}/PVE `/usr/bin/pveversion | cut -d '/' -f 2`"
    fi
    
  elif [ -f /etc/gentoo-release ] ; then
    DIST="Gentoo"
    REV=$(tr -d '[[:alpha:]]' </etc/gentoo-release | tr -d " ")

  elif [ -f /etc/arch-release ] ; then
    DIST="Arch Linux"
    REV="" # Omit version since Arch Linux uses rolling releases
    IGNORE_LSB=1 # /etc/lsb-release would overwrite $REV with "rolling"
    
  elif [ -f /etc/photon-release ] ; then
    DIST=$(head -1 < /etc/photon-release)
    REV=$(sed -n -e 's/^.*PHOTON_BUILD_NUMBER=//p' /etc/photon-release)
    IGNORE_LSB=1 # photon os does not have /etc/lsb-release nor lsb_release

  elif [ -f /etc/openwrt_version ] ; then
    DIST="OpenWrt"
    REV=$(cat /etc/openwrt_version)

  elif [ -f /etc/pld-release ] ; then
    DIST=$(cat /etc/pld-release)
    REV=""

  elif [ -f /etc/SuSE-release ] ; then
    DIST=$(echo SLES $(grep VERSION /etc/SuSE-release | cut -d = -f 2 | tr -d " "))
    REV=$(echo SP$(grep PATCHLEVEL /etc/SuSE-release | cut -d = -f 2 | tr -d " "))
  fi

  if [ -x "$(command -v  awk)" ];  then # some distros do not ship with awk
    if [ "`uname -a | awk '{print $(NF)}'`" = "DD-WRT" ] ; then
      DIST="dd-wrt"
    fi
    if [ "`uname -a | awk '{print $(NF)}'`" = "ASUSWRT-Merlin" ] ; then
      DIST="ASUSWRT-Merlin"
      REV=`nvram show | grep buildno= | egrep -o '[0-9].[0-9].[0-9]'` > /dev/null 2>&1
    fi
  fi

  # try standardized os version methods
  if [ -f /etc/os-release -a "${IGNORE_OS_RELEASE}" != 1 ] ; then
    source /etc/os-release
    STD_DIST="$NAME"
    STD_REV="$VERSION_ID"
  elif [ -f /etc/lsb-release -a "${IGNORE_LSB}" != 1 ] ; then
    STD_DIST=$(lsb_release -si)
    STD_REV=$(lsb_release -sr)
  fi
  if [ -n "${STD_DIST}" ]; then
    DIST="${STD_DIST}"
  fi
  if [ -n "${STD_REV}" ]; then
    REV="${STD_REV}"
  fi

  if [ -n "${REV}" ]; then
    OSSTR="${DIST} ${REV}"
  else
    OSSTR="${DIST}"
  fi

elif [ "${OS}" = "Darwin" ] ; then
  if [ -f /usr/bin/sw_vers ] ; then
    OSSTR=`/usr/bin/sw_vers|grep -v Build|sed 's/^.*:.//'| tr "\n" ' '`
  fi

elif [ "${OS}" = "FreeBSD" ] ; then
  DIST=$(cat /etc/version | cut -d'-' -f 1)
  if [ "${DIST}" = "FreeNAS" ]; then
    OSSTR=`cat /etc/version | cut -d' ' -f 1`
  else
    OSSTR=`/usr/bin/uname -mior`
  fi
fi

echo ${OSSTR}