#!/usr/bin/env bash
# Summary: List all Python versions available to pyenv
# Usage: pyenv versions [--bare] [--skip-aliases] [--skip-envs] [--executables]
#
# Lists all Python versions found in `$PYENV_ROOT/versions/*'.
#
#   --bare            List just the names, omit `system'
#   --skip-aliases    Skip symlinks to other versions and to virtual environments
#   --skip-envs       Skip virtual environments (under <version>/envs)
#   --executables     Internal. Overrides other options.
#                     Optimally get a deduplicated list of all executable names in Pyenv-managed
#                     versions and environments for `pyenv rehash'
#

set -euo pipefail
[ -n "${PYENV_DEBUG:-}" ] && set -x

bare=
skip_aliases=
skip_envs=
executables=

# Provide pyenv completions
for arg; do
  case "$arg" in
  --complete )
    echo --bare
    echo --skip-aliases
    echo --skip-envs
    exit ;;
  --executables ) executables=1; break ;;
  --bare ) bare=1 ;;
  --skip-aliases ) skip_aliases=1 ;;
  --skip-envs ) skip_envs=1 ;;
  * )
    pyenv-help --usage versions >&2
    exit 1
    ;;
  esac
done


versions_dir="${PYENV_ROOT}/versions"

# Fast path for rehash: skip filtering and link resolution
if [[ -n "$executables" ]]; then
  if [ -d "$versions_dir" ]; then
    shopt -s dotglob nullglob
    # MacOS 12+ and FreeBSD 15 support `xargs -r -0' and `basename -a'
    # `sort -u` is simpler and a bit faster than `awk '!seen[$0]++'`, with the same result for rehash purposes
    printf '%s\0' "$versions_dir"/*/bin/* "$versions_dir"/*/envs/*/bin/* | xargs -0 -r basename -a | sort -u
    shopt -u dotglob nullglob
  fi
  exit 0
fi

if ! enable -f "${BASH_SOURCE%/*}"/pyenv-realpath.dylib realpath 2>/dev/null; then
  if [ -n "${PYENV_NATIVE_EXT:-}" ]; then
    echo "pyenv: failed to load \`realpath' builtin" >&2
    exit 1
  fi

  READLINK="$(type -P readlink || true)"
  if [ -z "${READLINK}" ]; then
    echo "pyenv: cannot find readlink - are you missing GNU coreutils?" >&2
    exit 1
  fi

  resolve_link() {
    "$READLINK" "$1"
  }

  realpath() {
    local path="$1"
    local name

    # Use a subshell to avoid changing the current path
    (
    while [ -n "$path" ]; do
      name="${path##*/}"
      [ "$name" = "$path" ] || cd "${path%/*}"
      path="$(resolve_link "$name" || true)"
    done

    echo "${PWD}/$name"
    )
  }
fi

if [ -d "$versions_dir" ]; then
  versions_dir="$(realpath "$versions_dir")"
fi

if ((${BASH_VERSINFO[0]} > 3)); then
  declare -A current_versions=()
else
  current_versions=()
fi
if [[ -n $bare ]]; then
  include_system=
else
  hit_prefix="* "
  miss_prefix="  "
  OLDIFS="$IFS"
  IFS=:
  # VAR=() of unquoted value does glob expansion (against the current dir's contents) after IFS-splitting
  # which is undesired
  set -f
  if ((${BASH_VERSINFO[0]} > 3)); then
    for i in $(pyenv-version-name || true); do
      current_versions["$i"]="1"
    done
  else
    current_versions=($(pyenv-version-name || true))
  fi
  set +f
  IFS="$OLDIFS"
  include_system="1"
fi

num_versions=0

exists() {
  local car="$1"
  local cdar
  shift
  for cdar in "$@"; do
    if [ "${car}" == "${cdar}" ]; then
      return 0
    fi
  done
  return 1
}

print_version() {
  local version="${1:?}"
  if [[ -n $bare ]]; then
    echo "$version"
    return
  fi
  local path="${2:?}"
  if [[ -L "$path" ]]; then
    # Only resolve the link itself for printing, do not resolve further.
    # Doing otherwise would misinform the user of what the link contains.
    version_repr="$version --> $(readlink "$path")"
  else
    version_repr="$version"
  fi
  if ((${BASH_VERSINFO[0]} > 3)) && [[ -n ${current_versions["$1"]:-} ]]; then
    echo "${hit_prefix}${version_repr} (set by $(pyenv-version-origin))"
  elif (( ${BASH_VERSINFO[0]} <= 3 )) && exists "$1" "${current_versions[@]+"${current_versions[@]}"}"; then
    echo "${hit_prefix}${version_repr} (set by $(pyenv-version-origin))"
  else
    echo "${miss_prefix}${version_repr}"
  fi
  num_versions=$((num_versions + 1))
}

# Include "system" in the non-bare output, if it exists
if [[ -n $include_system ]] && \
    (PYENV_VERSION=system pyenv-which python --skip-advice >/dev/null 2>&1 || \
     PYENV_VERSION=system pyenv-which python3 --skip-advice >/dev/null 2>&1 || \
     PYENV_VERSION=system pyenv-which python2 --skip-advice >/dev/null 2>&1) ; then
  print_version system "/"
fi

shopt -s dotglob nullglob
versions_dir_entries=("$versions_dir"/*)
if sort --version-sort </dev/null >/dev/null 2>&1; then
    # system sort supports version sorting
    OLDIFS="$IFS"
    # VAR=() of unquoted value does glob expansion (against the current dir's contents) after IFS-splitting
    # which is undesired
    set -f
    IFS=$'\n'
    versions_dir_entries=($(
        printf "%s\n" "${versions_dir_entries[@]:-}" |
        sort --version-sort
    ))
    set +f
    IFS="$OLDIFS"
fi

for path in ${versions_dir_entries[@]+"${versions_dir_entries[@]}"}; do
  if [ -d "$path" ]; then
    if [[ -n $skip_aliases && -L $path ]]; then
      target="$(realpath "$path")"
      [ "${target%/*}" == "$versions_dir" ] && continue
      [ "${target%/*/envs/*}" == "$versions_dir" ] && continue
    fi
    print_version "${path##*/}" "$path"
    # virtual environments created by anaconda/miniconda/pyenv-virtualenv
    if [[ -z $skip_envs ]]; then
      for env_path in "${path}/envs/"*; do
        if [ -d "${env_path}" ]; then
          print_version "${env_path#${PYENV_ROOT}/versions/}" "${env_path}"
        fi
      done
    fi
  fi
done
shopt -u dotglob nullglob

if [[ $num_versions -eq 0 && -n $include_system ]]; then
  echo "Warning: no Python detected on the system" >&2
  exit 1
fi
