#!/bin/bash

if [ "$#" -eq 0 ]; then
  cat <<EOF
  curl-wrapper utilizing CAS-authentification 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 "$@"
    set +x
  }
  shift
else
  function trace() {
    :
  }
  function doCurl() {
    curl "$@"
  }
fi

if [ -z "$HSADMINNG_CAS_LOGIN" ] || [ -z "$HSADMINNG_CAS_VALIDATE" ] || \
   [ -z "$HSADMINNG_CAS_USERNAME" ] || [ -z "$HSADMINNG_CAS_PASSWORD" ] || \
   [ -z "$HSADMINNG_CAS_SERVICE" ]; 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=<<your username>>
  export HSADMINNG_CAS_PASSWORD=<<your password>>
  export HSADMINNG_CAS_SERVICE=https://hsadminng.hostsharing.net:443/
EOF
  exit 1
fi

function casLogin() {
  HSADMINNG_CAS_TGT=`doCurl -s -i -X POST \
        -H 'Content-Type: application/x-www-form-urlencoded' \
        -d "username=$HSADMINNG_CAS_USERNAME&password=$HSADMINNG_CAS_PASSWORD" \
        $HSADMINNG_CAS_LOGIN -o /dev/null -D - \
        | grep -i "^Location: " |  sed -e 's/^Location: //' -e 's/\\r//'`
      echo "$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\" $HSADMINNG_CAS_TGT"
  HSADMINNG_CAS_TICKET=$(curl -s -d "service=$HSADMINNG_CAS_SERVICE" $HSADMINNG_CAS_TGT)
  if [[ -z "$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"
  trace curl -i -s $HSADMINNG_CAS_VALIDATE?ticket=${HSADMINNG_CAS_TICKET}\&service=${HSADMINNG_CAS_SERVICE}
  HSADMINNG_CAS_USER=`curl -i -s $HSADMINNG_CAS_VALIDATE?ticket=${HSADMINNG_CAS_TICKET}\&service=${HSADMINNG_CAS_SERVICE} | grep -oPm1 "(?<=<cas:user>)[^<]+"`
  if [ -z "$HSADMINNG_CAS_USER" ]; then
    echo "validation failed" >&2
    exit 1
  fi
  echo "CAS-User: $HSADMINNG_CAS_USER"
}

if ! find ~/.cas-login-tgt -type f -size +0c -mmin -60 2>/dev/null | grep -q .; then
    casLogin
fi

case "$1" in
  "login") # explicitly login using CAS-server and credentials in HSADMINNG_CAS_..., fetches ticket granting ticket
    casLogin
    ;;
  "logout") # logout, deleting ticket granting ticket
    rm ~/.cas-login-tgt
    ;;
  "validate") # validate user login and print currently logged in user
    casValidate
    ;;
  "get") # HTTP GET, add URL as parameter
    shift
    HSADMINNG_CAS_TICKET=`casTicket`
    #trace "curl -f -s --header \"Authorization: $HSADMINNG_CAS_TICKET\" " "$@"
    doCurl -f -H "Authorization: $HSADMINNG_CAS_TICKET" "$*"
    ;;
  "post") # HTTP POST, add curl options to specify the request body and the URL as last parameter
    shift
    HSADMINNG_CAS_TICKET=`casTicket`
    trace "curl -f --header \"Authorization: $HSADMINNG_CAS_TICKET\" --header \"Content-Type: application/json\" -X POST " "$@"
    curl -f -H "Authorization: $HSADMINNG_CAS_TICKET" --header "Content-Type: application/json" -X POST "$@"
    ;;
  "patch") # HTTP PATCH, add curl options to specify the request body and the URL as last parameter
    shift
    HSADMINNG_CAS_TICKET=`casTicket`
    trace "curl -f --header \"Authorization: $HSADMINNG_CAS_TICKET\" --header \"Content-Type: application/json\" -X PATCH " "$@"
    curl -f -H "Authorization: $HSADMINNG_CAS_TICKET" --header "Content-Type: application/json" -X POST "$*"
    ;;
  "delete") # HTTP DELETE, add curl options to specify the request body and the URL as last parameter
    shift
    HSADMINNG_CAS_TICKET=`casTicket`
    trace "curl -f --header \"Authorization: $HSADMINNG_CAS_TICKET\" -X DELETE " "$@"
    curl -f -H "Authorization: $HSADMINNG_CAS_TICKET" -X POST "$@"
    ;;
  *)
    cat >&2 <<EOF
    unknown command: '$1'
    valid commands: login, validate, curl
EOF
    exit 1
    ;;
esac