#!/bin/bash

if [ "$#" -eq 0 ] || [ "$1" == "help" ] || [ "$1" == "--help" ] || [ "$1" == "-h" ]; then
  cat <<EOF
  curl-wrapper utilizing CAS-authentication for hsadmin-ng
  usage: $0 [--trace] <<command>> [parameters]

  commands:
EOF
  grep '") ''# ' $0
  exit
fi

if [ "$1" == "--trace" ]; then
  function trace() {
    echo "$*" >&2
  }
  function doCurl() {
    set -x
    curl --fail-with-body --header "Authorization: $HSADMINNG_CAS_TICKET" "$@"
    set +x
  }
  shift
else
  function trace() {
    : # noop
  }
  function doCurl() {
    curl --fail-with-body --header "Authorization: $HSADMINNG_CAS_TICKET" "$@"
  }
fi

if [ -z "$HSADMINNG_CAS_LOGIN" ] || [ -z "$HSADMINNG_CAS_VALIDATE" ] || \
   [ -z "$HSADMINNG_CAS_SERVICE_ID" ]; then
  cat >&2 <<EOF
  ERROR: environment incomplete

  please set the following environment variables:
  export HSADMINNG_CAS_LOGIN=https://login.hostsharing.net/cas/v1/tickets
  export HSADMINNG_CAS_VALIDATE=https://login.hostsharing.net/cas/proxyValidate
  export HSADMINNG_CAS_USERNAME=<<optionally, your username, or leave empty after '='>>
  export HSADMINNG_CAS_PASSWORD=<<optionally, your password, or leave empty after '='>>
  export HSADMINNG_CAS_SERVICE_ID=https://hsadminng.hostsharing.net:443/
EOF
  exit 1
fi

function casLogout() {
  rm -f ~/.cas-login-tgt
}

function casLogin() {
  # ticket granting ticket exists and not expired?
  if find ~/.cas-login-tgt -type f -size +0c -mmin -60 2>/dev/null | grep -q .; then
    return
  fi

  if [ -z "$HSADMINNG_CAS_USERNAME" ]; then
    read -e -p "Username: " HSADMINNG_CAS_USERNAME
  fi

  if [ -z "$HSADMINNG_CAS_PASSWORD" ]; then
    read -s -e -p "Password: " HSADMINNG_CAS_PASSWORD
  fi

  # Do NOT use doCurl here! We do neither want to print the password nor pass a CAS service ticket.
  trace "+ curl --fail-with-body -s -i -X POST \
        -H 'Content-Type: application/x-www-form-urlencoded' \
        -d \"username=$HSADMINNG_CAS_USERNAME&password=<<PASSWORD OMITTED>>\" \
        $HSADMINNG_CAS_LOGIN -o ~/.cas-login-tgt.response -D -"
  HSADMINNG_CAS_TGT=`curl --fail-with-body -s -i -X POST \
        -H 'Content-Type: application/x-www-form-urlencoded' \
        -d "username=$HSADMINNG_CAS_USERNAME&password=$HSADMINNG_CAS_PASSWORD" \
        $HSADMINNG_CAS_LOGIN -o ~/.cas-login-tgt.response -D - \
        | grep -i "^Location: " |  sed -e 's/^Location: //' -e 's/\\r//'`
  if [ -z "$HSADMINNG_CAS_TGT" ]; then
    echo "ERROR: could not get ticket granting ticket" >&2
    cat ~/.cas-login-tgt.response >&2
  fi
  echo "$HSADMINNG_CAS_TGT" >~/.cas-login-tgt
  trace "$HSADMINNG_CAS_TGT"
}

function casTicket() {
  HSADMINNG_CAS_TGT=$(<~/.cas-login-tgt)
  if [[ -z "$HSADMINNG_CAS_TGT" ]]; then
    echo "ERROR: cannot get CAS ticket granting ticket for $HSADMINNG_CAS_USERNAME" >&2
    exit 1
  fi
  trace "CAS-TGT: $HSADMINNG_CAS_TGT"

  trace "fetching CAS service ticket"
  trace "curl -s -d \"service=$HSADMINNG_CAS_SERVICE_ID\" $HSADMINNG_CAS_TGT"
  HSADMINNG_CAS_TICKET=$(curl -s -d "service=$HSADMINNG_CAS_SERVICE_ID" $HSADMINNG_CAS_TGT)
  if [[ -z "$HSADMINNG_CAS_TICKET" ]]; then
    echo "ERROR: cannot get CAS service ticket" >&2
    exit 1
  fi

  echo $HSADMINNG_CAS_TICKET
}

function casValidate() {
  HSADMINNG_CAS_TICKET=`casTicket`

  trace "validating CAS-TICKET: $HSADMINNG_CAS_TICKET"
  # Do NOT use doCurl here! We do not pass a CAS service ticket.
  trace curl -i -s $HSADMINNG_CAS_VALIDATE?ticket=${HSADMINNG_CAS_TICKET}\&service=${HSADMINNG_CAS_SERVICE_ID}
  HSADMINNG_CAS_USER=`curl -i -s $HSADMINNG_CAS_VALIDATE?ticket=${HSADMINNG_CAS_TICKET}\&service=${HSADMINNG_CAS_SERVICE_ID} | grep -oPm1 "(?<=<cas:user>)[^<]+"`
  if [ -z "$HSADMINNG_CAS_USER" ]; then
    echo "validation failed" >&2
    exit 1
  fi
  echo "CAS-User: $HSADMINNG_CAS_USER"
}

case "${1,,}" in
  "login") # reads username+password and fetches ticket granting ticket (bypasses HSADMINNG_CAS_USERNAME+HSADMINNG_CAS_PASSWORD)
    casLogout
    export HSADMINNG_CAS_USERNAME=
    export HSADMINNG_CAS_PASSWORD=
    casLogin
    ;;
  "logout") # logout, deleting ticket granting ticket
    casLogout
    ;;
  "validate") # validates ticket granting ticket and prints currently logged in user
    casValidate
    ;;
  "get") # HTTP GET, add URL as parameter
    shift
    casLogin
    HSADMINNG_CAS_TICKET=`casTicket`
    doCurl "$*"
    ;;
  "post") # HTTP POST, add curl options to specify the request body and the URL as last parameter
    shift
    casLogin
    HSADMINNG_CAS_TICKET=`casTicket`
    doCurl --header "Content-Type: application/json" -X POST "$@"
    ;;
  "patch") # HTTP PATCH, add curl options to specify the request body and the URL as last parameter
    shift
    casLogin
    HSADMINNG_CAS_TICKET=`casTicket`
    doCurl --header "Content-Type: application/json" -X POST "$*"
    ;;
  "delete") # HTTP DELETE, add curl options to specify the request body and the URL as last parameter
    shift
    casLogin
    HSADMINNG_CAS_TICKET=`casTicket`
    curl -X POST "$@"
    ;;
  *)
    cat >&2 <<EOF
    unknown command: '$1'
    valid commands: help, login, logout, validate, get, post, patch, delete
EOF
    exit 1
    ;;
esac