#!/bin/bash
# mjk235 [at] nyu [dot] edu --2018.17.2018
# v.0.1

# auto-magically install Office 2016 in OS X

LOCAL_WEB="128.122.112.23"

OFFICE=(
Office2016
"www.cns.nyu.edu/mac/.local/office2016.tgz"
)

#######################
#### Sanity Checks ####
#######################

# Is current UID 0? If not, exit.

root_check () {
  if [ "$EUID" -ne "0" ] ; then
    printf "%s\\n" "ERROR: ROOT PRIVILEGES ARE REQUIRED TO CONTINUE. EXITING." >&2
    exit 1
fi
}

# Is there adequate disk space in "/Applications"? If not, exit.

check_disk_space () {
  if [ $(df -lk /Applications |awk 'FNR == 2 {print $4}' |sed 's/G//') -le "77175193" ]; then
    printf "%s\\n" "ERROR: NOT ENOUGH FREE DISK SPACE. EXITING." >&2
    exit 1
fi
}

# Is curl installed? If not, exit. (Curl ships with OS X, but let's check).

curl_check () {
  if ! [ -x "$(command -v curl 2>/dev/null)" ]; then
    printf "%s\\n" "ERROR: CURL IS NOT INSTALLED. EXITING."  >&2
    exit 1
fi
}

# Is CNS local web available? If not, exit.

ping_local_web() {
  printf "%s\\n" "PINGING CNS LOCAL WEB..."

  if ping -c 1 "$LOCAL_WEB" &> /dev/null; then
    printf "%s\\n" "CNS LOCAL WEB IS REACHABLE. CONTINUING..."
  else
    printf "%s\\n" "ERROR: CNS LOCAL WEB IS NOT REACHABLE. EXITING." >&2
    exit 1
fi
}

sanity_checks() {
  root_check
  check_disk_space
  curl_check
  ping_local_web
}

sanity_checks

##########################
#### Office Install-r ####
##########################

# Download tarball to /Applications.

get_office () {
  printf "%s\\n" "RETRIEVING ${OFFICE[0]} INSTALLER..."

  curl --progress-bar --retry 3 --retry-delay 5 --keepalive-time 60 --continue-at - "${OFFICE[1]}" --output /Applications/office.app.tgz
}

# Unpack tarball to /Applications, which installs Office.

untar_office () {
  printf "%s\\n" "UNTARRING ${OFFIE[0]} PACKAGE TO /Applications..."

  tar --extract --gzip -v --file=/Applications/office.app.tgz --directory=/Applications
}

# Remove tarball from /Applications.

remove_office_tar () {
  printf "%s\\n" "REMOVING ${OFFICE[0]} TARBALL..."

  rm -rv /Applications/office.app.tgz
}

office_installer () {
  get_office
  untar_office
  remove_office_tar
}

##############
#### Main ####
##############

main () {
  sanity_checks
  office_installer
}

main "$@"