#!/usr/bin/env bash
set -e

VERSION=0.1
LOGIN_PAGE=https://www.humblebundle.com/login
HOME_PAGE=https://www.humblebundle.com/home
COOKIE_JAR=

FILE=
DESTINATION=
DOWNLOAD=1
LISTING_PAGES=()
USERNAME=
PASSWORD=
KEYS=()

login() {
  /usr/bin/curl -s --cookie-jar "$COOKIE_JAR" \
    --data "username=$USERNAME" --data "password=$PASSWORD" "$LOGIN_PAGE"
}

discover_url() {
  local LISTING_PAGE="$1"
  /usr/bin/curl -s --cookie "$COOKIE_JAR" "$LISTING_PAGE" | grep "/$FILE?" | \
    sed -e "s/.* data-web='\([^']*\)'.*/\1/" | head -n 1
}

usage() {
  echo "hib-dlagent $VERSION"
  echo "Tool to download Humble Indie Bundle binaries by file name"
  echo
  echo "Usage: $0 [OPTIONS] FILE"
  echo "Options:"
  echo " -h         This help"
  echo " -k <key>   Search key's files. Use multiple times for multiple keys"
  echo " -o <file>  Name to use when saving file"
  echo " -p <pass>  Use pass to login. If specified multiple times, the last is"
  echo "            used"
  echo " -s         Print URL to stdout instead of downloading"
  echo " -u <user>  Use user to login. Search account's files. If specified"
  echo "            multiple times, the last is used"
  echo
  echo "If you specify -u, then all of that account's bundles are searched. If"
  echo "a key is associated with a HIB account then you must use -u/-p, since"
  echo "that key only works when logged into that account. It is not helpful to"
  echo "specify -k for bundles associated with an account."
}

main() {
  if [ $# -eq 0 ]; then
    usage
    exit 1
  fi

  while getopts "hk:o:p:su:" opt; do
    case $opt in
      \?)
        exit 1
      ;;
      h)
        usage
        exit 1
      ;;
      k)
        KEYS+=("$OPTARG")
      ;;
      o)
        DESTINATION="$OPTARG"
      ;;
      p)
        PASSWORD="$OPTARG"
      ;;
      s)
        DOWNLOAD=0
      ;;
      u)
        USERNAME="$OPTARG"
      ;;
    esac
  done

  shift $(($OPTIND - 1))

  if [ $# == 0 ]; then
    echo "Missing argument FILE" >&2
    exit 1
  fi

  if [ $# != 1 ]; then
    echo "Unexpected argument: $2" >&2
    exit 1
  fi

  COOKIE_JAR=$(mktemp)
  FILE="$1"

  if [ -z "$DESTINATION" ]; then
    DESTINATION="${FILE##*/}"
  fi

  if [ -n "$USERNAME" ]; then
    login;
    LISTING_PAGES+=("$HOME_PAGE")
  fi

  for KEY in "${KEYS[@]}"; do
    LISTING_PAGES+=("https://www.humblebundle.com/downloads?key=$KEY")
  done

  if [ -z "$LISTING_PAGES" ]; then
    echo "You must specify at least one of -u and -k" >&1
    exit 1
  fi

  for LISTING_PAGE in "${LISTING_PAGES[@]}"; do
    URL=$(discover_url "$LISTING_PAGE")
    if [ -n "$URL" ]; then break; fi
  done

  # Cookie no longer necessary.
  rm "$COOKIE_JAR"

  if [ ! -n "$URL" ]; then
    echo "Could not find URL for file: $FILE" >&2
    exit 2
  fi

  if [ $DOWNLOAD -eq 0 ]; then
    echo "$URL"
  else
    /usr/bin/curl -C - --retry 3 --retry-delay 3 -o "$DESTINATION" "$URL"
  fi
}

main "$@"