"""utilities for fetching build dependencies."""

#
#  Copyright (C) PyZMQ Developers
#  Distributed under the terms of the Modified BSD License.
#
#  This bundling code is largely adapted from pyzmq-static's get.sh by
#  Brandon Craig-Rhodes, which is itself BSD licensed.
#
# Adapted for use in pycapnp from pyzmq. See https://github.com/zeromq/pyzmq
# for original project.

import os
import shutil
import tarfile

from urllib.request import urlopen

pjoin = os.path.join


#
# Constants
#


bundled_version = (1, 4, 0)
libcapnp_name = "capnproto-c++-%i.%i.%i.tar.gz" % (bundled_version)
libcapnp_url = "https://capnproto.org/" + libcapnp_name


def fetch_archive(savedir, url):
    """download an archive to a specific location"""
    req = urlopen(url)
    # Lookup filename
    fname = req.info().get_filename()
    if not fname:
        fname = os.path.basename(url)
    dest = pjoin(savedir, fname)
    if os.path.exists(dest):
        print("already have %s" % fname)
        return dest
    print("fetching %s into %s" % (url, savedir))
    if not os.path.exists(savedir):
        os.makedirs(savedir)
    with open(dest, "wb") as f:
        f.write(req.read())
    return dest


#
# libcapnp
#


def fetch_libcapnp(savedir, url=None):
    """download and extract libcapnp"""
    is_preconfigured = False
    if url is None:
        url = libcapnp_url
        is_preconfigured = True
    dest = pjoin(savedir, "capnproto-c++")
    if os.path.exists(dest):
        print("already have %s" % dest)
        return
    fname = fetch_archive(savedir, url)
    tf = tarfile.open(fname)
    with_version = pjoin(savedir, tf.firstmember.path)
    tf.extractall(savedir)
    tf.close()
    # remove version suffix:
    if is_preconfigured:
        shutil.move(with_version, dest)
    else:
        cpp_dir = os.path.join(with_version, "c++")
        shutil.move(cpp_dir, dest)