#!/usr/bin/env python
#
# Copyright 2011-2014 The Rust Project Developers. See the COPYRIGHT
# file at the top-level directory of this distribution and at
# http://rust-lang.org/COPYRIGHT.
#
# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
# option. This file may not be copied, modified, or distributed
# except according to those terms.

import os
import tarfile
import shutil
import sys
from snapshot import *


def unpack_snapshot(triple, dl_path):
    print("opening snapshot " + dl_path)
    tar = tarfile.open(dl_path)
    kernel = get_kernel(triple)

    stagep = os.path.join(triple, "stage0")

    # Remove files from prior unpackings, since snapshot rustc may not
    # be able to disambiguate between multiple candidate libraries.
    # (Leave dirs in place since extracting step still needs them.)
    for root, _, files in os.walk(stagep):
        for f in files:
            print("removing " + os.path.join(root, f))
            os.unlink(os.path.join(root, f))

    for p in tar.getnames():
        name = p.replace("rust-stage0/", "", 1)

        fp = os.path.join(stagep, name)
        print("extracting " + p)
        tar.extract(p, download_unpack_base)
        tp = os.path.join(download_unpack_base, p)
        if os.path.isdir(tp) and os.path.exists(fp):
            continue
        shutil.move(tp, fp)
    tar.close()
    shutil.rmtree(download_unpack_base)


# Main

# this gets called with one or two arguments:
# The first is the O/S triple.
# The second is an optional path to the snapshot to use.

def main(argv):
    triple = argv[1]
    if len(argv) == 3:
        dl_path = argv[2]
    else:
        snap = determine_curr_snapshot(triple)
        dl = os.path.join(download_dir_base, snap)
        url = download_url_base + "/" + snap
        print("determined most recent snapshot: " + snap)

        if (not os.path.exists(dl)):
            get_url_to_file(url, dl)

        if (snap_filename_hash_part(snap) == hash_file(dl)):
            print("got download with ok hash")
        else:
            raise Exception("bad hash on download")

        dl_path = os.path.join(download_dir_base, snap)

    unpack_snapshot(triple, dl_path)

if __name__ == '__main__':
    main(sys.argv)