#!/usr/bin/env bash
# Summary: Configure the shell environment for pyenv
# Usage: eval "$(pyenv init [-|--path] [--no-push-path] [--detect-shell] [--no-rehash] [<shell>])"

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

# Provide pyenv completions
if [ "$1" = "--complete" ]; then
  echo -
  echo --path
  echo --no-push-path
  echo --no-rehash
  echo --detect-shell
  echo bash
  echo fish
  echo ksh
  echo zsh
  exit
fi

mode="help"
no_rehash=""
no_push_path=""
for args in "$@"
do
  if [ "$args" = "-" ]; then
    mode="print"
    shift
  fi

  if [ "$args" = "--path" ]; then
    mode="path"
    shift
  fi

  if [ "$args" = "--detect-shell" ]; then
    mode="detect-shell"
    shift
  fi

  if [ "$args" = "--no-push-path" ]; then
    no_push_path=1
    shift
  fi
  
  if [ "$args" = "--no-rehash" ]; then
    no_rehash=1
    shift
  fi
done

shell="$1"
if [ -z "$shell" ]; then
  shell="$(ps -p "$PPID" -o 'args=' 2>/dev/null || true)"
  shell="${shell%% *}"
  shell="${shell##-}"
  shell="${shell:-$SHELL}"
  shell="${shell##*/}"
  shell="${shell%%-*}"
fi

root="${0%/*}/.."

function main() {
  case "$mode" in
  "help")
    help_
    exit 1
    ;;
  "path")
    print_path
    print_rehash
    exit 0
    ;;
  "print")
    init_dirs
    print_path
    print_env
    print_completion
    print_rehash
    print_shell_function
    exit 0
    ;;
  "detect-shell")
    detect_profile 1
    print_detect_shell
    exit 0
    ;;
  esac
  # should never get here
  exit 2
}

function detect_profile() {
  local detect_for_detect_shell="$1"

  case "$shell" in
  bash )
    if [ -e '~/.bash_profile' ]; then
      profile='~/.bash_profile'
    else
      profile='~/.profile'
    fi
    profile_explain="~/.bash_profile if it exists, otherwise ~/.profile"
    rc='~/.bashrc'
    ;;
  zsh )
    profile='~/.zprofile'
    rc='~/.zshrc'
    ;;
  ksh | ksh93 | mksh )
    # There are two implementations of Korn shell: AT&T (ksh93) and Mir (mksh).
    # Systems may have them installed under those names, or as ksh, so those
    # are recognized here. The obsolete ksh88 (subsumed by ksh93) and pdksh
    # (subsumed by mksh) are not included, since they are unlikely to still
    # be in use as interactive shells anywhere.
    profile='~/.profile'
    rc='~/.profile'
    ;;
  * )
    if [ -n "$detect_for_detect_shell" ]; then
      profile=
      rc=
    else
      profile='your shell'\''s login startup file'
      rc='your shell'\''s interactive startup file'
    fi
    ;;
  esac
}

function print_detect_shell() {
  echo "PYENV_SHELL_DETECT=$shell"
  echo "PYENV_PROFILE_DETECT=$profile"
  echo "PYENV_RC_DETECT=$rc"
}

function help_() {
  detect_profile
  {
    case "$shell" in
    fish )
      echo "# Add pyenv executable to PATH by running"
      echo "# the following interactively:"
      echo
      echo 'set -Ux PYENV_ROOT $HOME/.pyenv'
      echo 'set -U fish_user_paths $PYENV_ROOT/bin $fish_user_paths'
      echo
      echo "# Load pyenv automatically by appending"
      echo "# the following to ~/.config/fish/config.fish:"
      echo
      echo 'pyenv init - | source'
      echo
      ;;
    * )
      echo '# Load pyenv automatically by appending'
      echo -n "# the following to "
      if [ "$profile" == "$rc" ]; then
        echo "$profile :"
      else
        echo
        echo "# ${profile_explain:-$profile} (for login shells)"
        echo "# and $rc (for interactive shells) :"
      fi
      echo
      echo 'export PYENV_ROOT="$HOME/.pyenv"'
      echo '[[ -d $PYENV_ROOT/bin ]] && export PATH="$PYENV_ROOT/bin:$PATH"'
      echo 'eval "$(pyenv init -)"'
      ;;
    esac
    echo
    echo '# Restart your shell for the changes to take effect.'
    echo
  } >&2
}

function init_dirs() {
  mkdir -p "${PYENV_ROOT}/"{shims,versions}
}

function print_path() {
  # if no_push_path is set, guard the PATH manipulation with a check on whether
  # the shim is already in the PATH.
  if [ -n "$no_push_path" ]; then
    case "$shell" in
      fish )
          echo 'if not contains -- "'"${PYENV_ROOT}/shims"'" $PATH'
          print_path_prepend_shims
          echo 'end'
          ;;
      * )
          echo 'if [[ ":$PATH:" != *'\':"${PYENV_ROOT}"/shims:\''* ]]; then'
          print_path_prepend_shims
          echo 'fi'
          ;;
    esac
  else
    case "$shell" in
      fish )
        echo 'while set pyenv_index (contains -i -- "'"${PYENV_ROOT}/shims"'" $PATH)'
        echo 'set -eg PATH[$pyenv_index]; end; set -e pyenv_index'
        print_path_prepend_shims
        ;;
      * )
        # Some distros (notably Debian-based) set Bash's SSH_SOURCE_BASHRC compilation option
        # that makes it source `bashrc` under SSH even when not interactive.
        # This is inhibited by a guard in Debian's stock `bashrc` but some people remove it
        # in order to get proper environment for noninteractive remote commands
        # (SSH provides /etc/ssh/sshrc and ~/.ssh/rc for that but no-one seems to use them for some reason).
        # This has caused an infinite `bashrc` execution loop for those people in the below nested Bash invocation (#2367).
        # --norc negates this behavior of such a customized Bash.
        echo 'PATH="$(bash --norc -ec '\''IFS=:; paths=($PATH); '
        echo 'for i in ${!paths[@]}; do '
        echo 'if [[ ${paths[i]} == "'\'\'"${PYENV_ROOT}/shims"\'\''" ]]; then unset '\'\\\'\''paths[i]'\'\\\'\''; '
        echo 'fi; done; '
        echo 'echo "${paths[*]}"'\'')"'
        print_path_prepend_shims
        ;;
    esac
  fi
}

function print_path_prepend_shims() {
    case "$shell" in
      fish )
          echo 'set -gx PATH '\'"${PYENV_ROOT}/shims"\'' $PATH'
          ;;
      * )
          echo 'export PATH="'"${PYENV_ROOT}"'/shims:${PATH}"'
          ;;
    esac
}

function print_env() {
  case "$shell" in
  fish )
    echo "set -gx PYENV_SHELL $shell"
    ;;
  * )
    echo "export PYENV_SHELL=$shell"
    ;;
  esac
}

function print_completion() {
  completion="${root}/completions/pyenv.${shell}"
  if [ -r "$completion" ]; then
    echo "source '$completion'"
  fi
}

function print_rehash() {
  if [ -z "$no_rehash" ]; then
    echo 'command pyenv rehash 2>/dev/null'
  fi
}

function print_shell_function() {
  commands=(`pyenv-commands --sh`)
  case "$shell" in
  fish )
    cat <<EOS
function pyenv
  set command \$argv[1]
  set -e argv[1]

  switch "\$command"
  case ${commands[*]}
    source (pyenv "sh-\$command" \$argv|psub)
  case '*'
    command pyenv "\$command" \$argv
  end
end
EOS
    ;;
  ksh | ksh93 | mksh )
    cat <<EOS
function pyenv {
  typeset command
EOS
    ;;
  * )
    cat <<EOS
pyenv() {
  local command
EOS
    ;;
  esac

  if [ "$shell" != "fish" ]; then
    IFS="|"
    cat <<EOS
  command="\${1:-}"
  if [ "\$#" -gt 0 ]; then
    shift
  fi

  case "\$command" in
  ${commands[*]:-/})
    eval "\$(pyenv "sh-\$command" "\$@")"
    ;;
  *)
    command pyenv "\$command" "\$@"
    ;;
  esac
}
EOS
  fi
}

main