#!/usr/bin/env bash
#
# Summary: Link a Python environment as a pyenv version
#
# Usage: pyenv link version [--dry] [--quiet] <path> [<name>]
#
# Link a virtual python environment to pyenvs version directory
# so that the venv can be used like one created with *pyenv-virtualenv*.
#
# <path> should be a path to a Python installation or virtual environment.
# <name> should be string used as a version name it may not be present
#        in the pyenv version directory yet.
#        If not specified a matching name is guessed from pyvenv.cfg
#        or directory name of the venv.
set -e
[ -n "$PYENV_DEBUG" ] && set -x

# functions

if ! {
    enable -f "${BASH_SOURCE%/*}"/../../../libexec/pyenv-realpath.dylib realpath ||
        type realpath # realpath available?
} >/dev/null 2>&1; then
    # realpath requires GNU coreutils to be installed. That's why its bundled with pyenv
    echo realpath not available >&2

    # work-around when realpath is unavailable
    realpath() {
        (cd "$1" && pwd)
    }
fi

guess_name() {
    local venv_dir=$1
    local name

    # guess venv name from pyvenv.cfg
    local pyvenv_cfg_path=$venv_dir/pyvenv.cfg
    if [ -f "$pyvenv_cfg_path" ]; then
        # if `prompt` key wasn't found the var remains empty
        name=$(cut -b 1-1024 "$pyvenv_cfg_path" | sed -n '/^ *prompt *= */s///p')
        case "$name" in
        \"*\" | \'*\')
            name=${name:1:${#name}-2}
            ;;
        esac
    fi

    # guess venv name from name of venv directory
    local venv_dir_name=${venv_dir##*/}
    if [ -z "$name" ]; then
        case "$venv_dir_name" in
        venv | env | .venv | .env | ENV | VENV) ;;
        *) name=$venv_dir_name ;;
        esac
    fi

    # guess venv name from name of the parent directory of the venv directory
    local venv_dir_parent=${venv_dir%/*}
    local venv_dir_parent_name=${venv_dir_parent##*/}
    if [ -z "$name" ]; then
        name=$venv_dir_parent_name
    fi

    echo "$name"
}

# process args
POSARGS=()
# Provide pyenv completions
if [ "$1" = "--complete" ]; then
    echo --dry
    echo --quiet
    exit
fi

for arg in "$@"; do
    case $arg in
    --dry)
        dry=true # any value
        ;;
    --quiet)
        quiet=true # any value
        ;;
    -*)
        pyenv-help --usage link-version >&2
        exit 1
        ;;
    *)
        POSARGS+=("$arg")
        ;;
    esac
done

if [ ! ${#POSARGS[@]} -le 2 ] || [ ! ${#POSARGS[@]} -ge 1 ]; then
    pyenv-help --usage link-version >&2
    exit 1
fi

venv_dir=${POSARGS[0]%/}
venv_name=${POSARGS[1]}

# Check venv exists
if [ ! -d "$venv_dir" ]; then
    echo "The virtual env you specified doesn't exist"
    exit 2
fi

# make venv dir absolute
venv_dir=$(realpath "$venv_dir")

# determine venv name
if [ -z "$venv_name" ]; then
    venv_name=$(guess_name "$venv_dir")
fi

case "$venv_name" in
"" | */* | . | .. | *:* | system | *[[:cntrl:]]* )
    echo "pyenv-link: invalid version name \`${venv_name}'" >&2
    exit 1
    ;;
esac

versions_dir="$PYENV_ROOT/versions"
pyenv_prefix_path="$versions_dir/$venv_name"

if [ -e "$pyenv_prefix_path" ] || [ -L "$pyenv_prefix_path" ]; then
    echo Version "$venv_name" already exists >&2
    exit 3
fi

case "$venv_dir" in
"$versions_dir"/*)
    link_target=${venv_dir#"$versions_dir"/}
    ;;
*)
    link_target=$venv_dir
    ;;
esac

# link to pyenv version directory
if [ -z "$dry" ]; then
    mkdir -p "$versions_dir"
    ln -s "$link_target" "$pyenv_prefix_path"
fi

# output
if [ -z "$quiet" ]; then
    echo "Linked new version named $venv_name"
fi