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

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

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

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

  if [ "$args" = "--path" ]; then
    mode="path"
    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
    exit 0
    ;;
  "print")
    init_dirs
    print_path
    print_env
    print_completion
    print_shell_function
    exit 0
    ;;
  esac
  # should never get here
  exit 2
}

function help_() {
  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 )
    profile='~/.profile'
    rc='~/.profile'
    ;;
  * )
    profile='your shell'\''s login startup file'
    rc='your shell'\''s interactive startup file'
    ;;
  esac

  {
    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 'command -v pyenv >/dev/null || 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() {
  case "$shell" in
    fish )
      echo 'while set index (contains -i -- '\'"${PYENV_ROOT}/shims"\'' $PATH)'
      echo 'set -eg PATH[$index]; end; set -e index'
      echo 'set -gx PATH '\'"${PYENV_ROOT}/shims"\'' $PATH'
      ;;
    * )
      echo 'PATH="$(bash -ec '\''IFS=:; paths=($PATH); for i in ${!paths[@]}; do if [[ ${paths[i]} == "'\'"${PYENV_ROOT}/shims"\''" ]]; then unset '\'\\\'\''paths[i]'\'\\\'\''; fi; done; echo "${paths[*]}"'\'')"'
      echo 'export PATH="'"${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

  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 )
    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