#!/bin/bash

# @author: <sylvain.herledan@hrafnagud.info>
# @date: 2017-06-06

set -o nounset
set -o errexit
set -o pipefail

readonly PROGNAME="$(basename "${0}")";
readonly PROGDIR="$(readlink -f "$(dirname "${0}")")";
readonly ARGS="${@}";

install_virtualenv()
{
  local python="${1}"; shift;
  local env_dir="${1}"; shift;
  local install_script_path="$(mktemp)";

  wget 'https://bootstrap.pypa.io/get-pip.py' -O "${install_script_path}"

  mkdir -p "${env_dir}"

  PYTHONUSERBASE="${env_dir}" \
  "${python}" "${install_script_path}" --user --ignore-installed --no-cache
  rm -f "${install_script_path}"

  PYTHONUSERBASE="${env_dir}" \
  "${env_dir}/bin/pip" install --user --ignore-installed --no-cache virtualenv

  local virtualenv_path="$(find "${env_dir}/lib" -name 'virtualenv.py')";
  local python_pkg_dir="$(readlink -f "$(dirname "${virtualenv_path}")")";

  mkdir -p "${env_dir}/cache"

  PIP_CACHE_DIR="${env_dir}/cache" \
  PIP_IGNORE_INSTALLED=true \
  PYTHONPATH="${python_pkg_dir}" \
  "${python}" -m virtualenv "${env_dir}"

  cat > "${env_dir}/pip.conf" << EOF
[global]
cache-dir=${env_dir}/cache
EOF

  echo 'Environment ready'
}

main()
{
  local python="${1}"; shift;
  local _install_dir="${1}"; shift;
  local install_dir="$(readlink -f "${_install_dir}")";
  local env_dir="${install_dir}/env";

  install_virtualenv "${python}" "${env_dir}"
}

main ${ARGS}
exit 0