ghp-import

#! /usr/bin/env python
#
# This file is part of the ghp-import package released under
# the Tumbolia Public License. See the LICENSE file for more
# information.

import optparse as op
import os
import subprocess as sp
import sys
import time

__usage__ = "%prog [OPTIONS] DIRECTORY"


if sys.version_info[0] == 3:
    def enc(text):
        if isinstance(text, bytes):
            return text
        return text.encode()

    def write(pipe, data):
        try:
            pipe.stdin.write(data)
        except IOError as e:
            if e.errno != errno.EPIPE:
                raise
else:
    def enc(text):
        if isinstance(text, unicode):
            return text.encode('utf-8')
        return text

    def write(pipe, data):
        pipe.stdin.write(data)


def is_repo(d):
    if not os.path.isdir(d):
        return False
    if not os.path.isdir(os.path.join(d, 'objects')):
        return False
    if not os.path.isdir(os.path.join(d, 'refs')):
        return False

    headref = os.path.join(d, 'HEAD')
    if os.path.isfile(headref):
        return True
    if os.path.islink(headref) and os.readlink(headref).startswith("refs"):
        return True
    return False


def find_repo(path):
    if is_repo(path):
        return True
    if is_repo(os.path.join(path, '.git')):
        return True
    (parent, ignore) = os.path.split(path)
    if parent == path:
        return False
    return find_repo(parent)


def try_rebase(remote, branch):
    cmd = ['git', 'rev-list', '--max-count=1', 'origin/%s' % branch]
    p = sp.Popen(cmd, stdin=sp.PIPE, stdout=sp.PIPE, stderr=sp.PIPE)
    (rev, ignore) = p.communicate()
    if p.wait() != 0:
        return True
    cmd = ['git', 'update-ref', 'refs/heads/%s' % branch, rev.strip()]
    if sp.call(cmd) != 0:
        return False
    return True


def get_config(key):
    p = sp.Popen(['git', 'config', key], stdin=sp.PIPE, stdout=sp.PIPE)
    (value, stderr) = p.communicate()
    return value.strip()


def get_prev_commit(branch):
    cmd = ['git', 'rev-list', '--max-count=1', branch]
    p = sp.Popen(cmd, stdin=sp.PIPE, stdout=sp.PIPE, stderr=sp.PIPE)
    (rev, ignore) = p.communicate()
    if p.wait() != 0:
        return None
    return rev.decode('utf-8').strip()


def mk_when(timestamp=None):
    if timestamp is None:
        timestamp = int(time.time())
    currtz = "%+05d" % (time.timezone / 36) # / 3600 * 100
    return "%s %s" % (timestamp, currtz)


def start_commit(pipe, branch, message):
    uname = get_config("user.name")
    email = get_config("user.email")
    write(pipe, enc('commit refs/heads/%s\n' % branch))
    write(pipe, enc('committer %s <%s> %s\n' % (uname, email, mk_when())))
    write(pipe, enc('data %d\n%s\n' % (len(message), message)))
    head = get_prev_commit(branch)
    if head:
        write(pipe, enc('from %s\n' % head))
    write(pipe, enc('deleteall\n'))


def add_file(pipe, srcpath, tgtpath):
    write(pipe, enc('M 100644 inline %s\n' % tgtpath))
    with open(srcpath) as handle:
        data = handle.read()
        write(pipe, enc('data %d\n' % len(data)))
        write(pipe, enc(data))
        write(pipe, enc('\n'))


def run_import(srcdir, branch, message):
    cmd = ['git', 'fast-import', '--date-format=raw', '--quiet']
    kwargs = {"stdin": sp.PIPE}
    if sys.version_info >= (3, 2, 0):
        kwargs["universal_newlines"] = False
    pipe = sp.Popen(cmd, **kwargs)
    start_commit(pipe, branch, message)
    for path, dnames, fnames in os.walk(srcdir):
        for fn in fnames:
            fpath = os.path.join(path, fn)
            add_file(pipe, fpath, os.path.relpath(fpath, start=srcdir))
    write(pipe, enc('\n'))
    pipe.stdin.close()
    if pipe.wait() != 0:
        sys.stdout.write(enc("Failed to process commit.\n"))


def options():
    return [
        op.make_option('-m', dest='mesg', default='Update documentation',
            help='The commit message to use on the target branch.'),
        op.make_option('-p', dest='push', default=False, action='store_true',
            help='Push the branch to origin/{branch} after committing.'),
        op.make_option('-f', dest='force', default=False, action='store_true',
            help='Force push the branch.'),
        op.make_option('-r', dest='remote', default='origin',
            help='The name of the remote to push to. [%default]'),
        op.make_option('-b', dest='branch', default='gh-pages',
            help='Name of the branch to write to. [%default]'),
    ]


def main():
    parser = op.OptionParser(usage=__usage__, option_list=options())
    opts, args = parser.parse_args()

    if len(args) == 0:
        parser.error("No import directory specified.")

    if len(args) > 1:
        parser.error("Unknown arguments specified: %s" % ', '.join(args[1:]))

    if not os.path.isdir(args[0]):
        parser.error("Not a directory: %s" % args[0])

    if not find_repo(os.getcwd()):
        parser.error("No Git repository found.")

    if not try_rebase(opts.remote, opts.branch):
        parser.error("Failed to rebase %s branch." % opts.branch)

    run_import(args[0], opts.branch, opts.mesg)

    if opts.push:
        if opts.force:
            sp.check_call(['git', 'push', '--force', opts.remote, opts.branch])
        else:
            sp.check_call(['git', 'push', opts.remote, opts.branch])


if __name__ == '__main__':
    main()