#!/usr/bin/env bash
#
# Summary: Run an executable with the selected Python version
#
# Usage: pyenv exec [-N|--environment] <command> [arg1 arg2...]
#
#    -N  Set PYTHONHOME and LD_LIBRARY_PATH envvars for the running command.
#        This allows to run programs that embed Python without using rpath or
#        exact library path.
#        WARNING! For the running command and its child processes, this will
#        break linkage for programs that expect to be linked to system libpython!
#        This option is Linux only.
#
# Runs an executable by first preparing PATH so that the selected Python
# version's `bin' directory is at the front.
#
# For example, if the currently selected Python version is 2.7.6:
#   pyenv exec pip install -r requirements.txt
#
# is equivalent to:
#   PATH="$PYENV_ROOT/versions/2.7.6/bin:$PATH" pip install -r requirements.txt

set -e
[ -n "$PYENV_DEBUG" ] && set -x

# Provide pyenv completions
if [ "$1" = "--complete" ]; then
  echo --environment
  exec pyenv-shims --short
fi

unset MODIFY_ENV
if [ "$1" = "-N" ] || [ "$1" = "--environment" ]; then
  MODIFY_ENV=true
  shift
fi

PYENV_VERSION="$(pyenv-version-name -f)"
PYENV_COMMAND="$1"

if [ -z "$PYENV_COMMAND" ]; then
  pyenv-help --usage exec >&2
  exit 1
fi

if [[ -n $_PYENV_SHIM_PATH ]]; then
  PROGRAM="$(echo "$PYENV_COMMAND" | tr a-z- A-Z_ | sed 's/[^A-Z0-9_]/_/g')"
  NR_PYENV_SHIM_PATHS_PROGRAM="_PYENV_SHIM_PATHS_${PROGRAM}"
  export -- "$NR_PYENV_SHIM_PATHS_PROGRAM=$_PYENV_SHIM_PATH${!NR_PYENV_SHIM_PATHS_PROGRAM:+:${!NR_PYENV_SHIM_PATHS_PROGRAM}}"
  unset PROGRAM NR_PYENV_SHIM_PATHS_PROGRAM
  unset _PYENV_SHIM_PATH
fi

PYENV_COMMAND_PATH="$(pyenv-which "$PYENV_COMMAND")"
PYENV_BIN_PATH="${PYENV_COMMAND_PATH%/*}"

export PYENV_VERSION

OLDIFS="$IFS"
IFS=$'\n' scripts=(`pyenv-hooks exec`)
IFS="$OLDIFS"
for script in "${scripts[@]}"; do
  source "$script"
done

shift 1
if [ "${PYENV_BIN_PATH#${PYENV_ROOT}}" != "${PYENV_BIN_PATH}" ]; then
  # Only add to $PATH for non-system version.
  export PATH="${PYENV_BIN_PATH}:${PATH}"
fi
if [ -n "$MODIFY_ENV" ] && [ "$(uname -s)" = Linux ]; then
  # Check if multiple Python versions are selected
  VERSIONS=$(pyenv-prefix)
  if [[ "$VERSIONS" == *:* ]]; then
    echo 'Warning: multiple Python versions are selected' >&2
    VERSION="${VERSIONS%%:*}"
    echo "Using the first one available (${VERSION##*/})" >&2
  else
    VERSION="$VERSIONS"
  fi

  # Assign the correct version of PYTHONHOME
  export PYTHONHOME="$VERSION"
  export LD_LIBRARY_PATH="${PYTHONHOME}/lib${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}"
fi
exec "$PYENV_COMMAND_PATH" "$@"