#!/usr/bin/env sh

# This is a wrapper script, that automatically download mill from GitHub release pages
# You can give the required mill version with --mill-version parameter
# If no version is given, it falls back to the value of DEFAULT_MILL_VERSION

DEFAULT_MILL_VERSION=0.4.1

set -e

if [ -f ".mill-version" ] ; then
  MILL_VERSION="$(head -n 1 .mill-version 2> /dev/null)"
fi

if [ "x$1" = "x--mill-version" ] ; then
  shift
  if [ "x$1" != "x" ] ; then
    MILL_VERSION="$1"
    shift
  else
    echo "You specified --mill-version without a version."
    echo "Please provide a version that matches one provided on"
    echo "https://github.com/lihaoyi/mill/releases"
    false
  fi
fi

MILL_DOWNLOAD_PATH="${HOME}/.mill/download"

if [ "x${MILL_VERSION}" = "x" ] ; then
  # TODO: try to load latest version from release page
  echo -n "Retrieving latest mill version..."
  if [ -e "${MILL_DOWNLOAD_PATH}/.latest" ] ; then

    MILL_VERSION="$(head -n 1 \"${MILL_DOWNLOAD_PATH}/.latest\" 2> /dev/null)"
  fi

  # Last resort
  if [ "x${MILL_VERSION}" = "x" ] ; then
    MILL_VERSION="${DEFAULT_MILL_VERSION}"
  fi
fi

MILL="${MILL_DOWNLOAD_PATH}/${MILL_VERSION}"

if [ ! -x "${MILL}" ] ; then
  DOWNLOAD_FILE=$(mktemp mill.XXXX)
  # TODO: handle command not found
  curl -L -o "${DOWNLOAD_FILE}" "https://github.com/lihaoyi/mill/releases/download/${MILL_VERSION%%-*}/${MILL_VERSION}"
  chmod +x "${DOWNLOAD_FILE}"
  mkdir -p "${MILL_DOWNLOAD_PATH}"
  mv "${DOWNLOAD_FILE}" "${MILL}"
  unset DOWNLOAD_FILE
fi

unset MILL_DOWNLOAD_PATH
unset MILL_VERSION

exec $MILL "$@"