#!/bin/bash

set -eu

source $(dirname "$0")/activate


# Prefer python 3 over python 2
TOX_BASE_PYTHON=${PYTHON:-$(which python3 || which python)}
TOX_VIRTUAL_ENV=$(realpath "${TOX_VIRTUAL_ENV:-.tox/tox}")


function tox {
    tox_setup
    "${TOX_VIRTUAL_ENV}/bin/tox" "$@"
}


function tox_python {
    "${TOX_VIRTUAL_ENV}/bin/python" "$@"
}


function tox_pip {
    "${TOX_VIRTUAL_ENV}/bin/pip" "$@"
}


function tox_setup {
    if ! tox_activate; then
        tox_install_deps

        # Cleanup and create virtualenv directory
        rm -fR "${TOX_VIRTUAL_ENV}"
        mkdir -p $(dirname "${TOX_VIRTUAL_ENV}")
        "${TOX_BASE_PYTHON}" -m virtualenv "${TOX_VIRTUAL_ENV}"

        # Activate virtualenv
        if tox_activate; then
            # Install/upgrade the last Python packages into the new virutalenv
            curl https://bootstrap.pypa.io/get-pip.py | tox_python
            tox_pip install --upgrade setuptools wheel virtualenv tox
        fi
    fi
}


function tox_install_deps {
    if ! "${TOX_BASE_PYTHON}" -m pip --version; then
        curl https://bootstrap.pypa.io/get-pip.py --user | "${TOX_BASE_PYTHON}"
    fi
    if ! "${TOX_BASE_PYTHON}" -m virtualenv --version; then
        "${TOX_BASE_PYTHON}" -m pip install --user virtualenv
    fi
}


function tox_activate {
    local venv_script=${TOX_VIRTUAL_ENV}/bin/activate
    if ! [ -r "${venv_script}" ]; then
        return 1
    fi

    if ! tox_is_active; then
        # Activate only once
        set +eu
        source "${venv_script}"
        set -eu
        tox_is_active
    fi
}


function tox_is_active {
    [ "$(python_prefix)" == "${TOX_VIRTUAL_ENV}" ]
}


if [ $(basename "$0") == tox ]; then
    tox "$@"
fi