#!/usr/bin/env python2

"""
Release script for botan (https://botan.randombit.net/)

(C) 2011,2012,2013,2015,2016,2017 Jack Lloyd

Botan is released under the Simplified BSD License (see license.txt)
"""

import time
import errno
import logging
import optparse
import os
import shutil
import subprocess
import sys
import datetime
import hashlib
import re
import tarfile

# This is horrible, but there is no way to override tarfile's use of time.time
# in setting the gzip header timestamp, which breaks deterministic archives

def null_time():
    return 0
time.time = null_time


def check_subprocess_results(subproc, name):
    (stdout, stderr) = subproc.communicate()

    if subproc.returncode != 0:
        if stdout != '':
            logging.error(stdout)
        if stderr != '':
            logging.error(stderr)
        raise Exception('Running %s failed' % (name))
    else:
        if stderr != '':
            logging.debug(stderr)

    return stdout

def run_git(args):
    cmd = ['git'] + args
    logging.debug('Running %s' % (' '.join(cmd)))
    proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    return check_subprocess_results(proc, 'git')

def maybe_gpg(val):
    val = val.decode('ascii')
    if 'BEGIN PGP SIGNATURE' in val:
        return val.split('\n')[-2]
    else:
        return val.strip()

def datestamp(tag):
    ts = maybe_gpg(run_git(['show', '--no-patch', '--format=%ai', tag]))

    ts_matcher = re.compile(r'^(\d{4})-(\d{2})-(\d{2}) \d{2}:\d{2}:\d{2} .*')

    logging.debug('Git returned timestamp of %s for tag %s' % (ts, tag))
    match = ts_matcher.match(ts)

    if match is None:
        logging.error('Failed parsing timestamp "%s" of tag %s' % (ts, tag))
        return 0

    return int(match.group(1) + match.group(2) + match.group(3))

def revision_of(tag):
    return maybe_gpg(run_git(['show', '--no-patch', '--format=%H', tag]))

def extract_revision(revision, to):
    tar_val = run_git(['archive', '--format=tar', '--prefix=%s/' % (to), revision])

    if sys.version_info.major == 3:
        import io
        tar_f = tarfile.open(fileobj=io.BytesIO(tar_val))
        tar_f.extractall()
    else:
        import StringIO
        tar_f = tarfile.open(fileobj=StringIO.StringIO(tar_val))
        tar_f.extractall()


def gpg_sign(keyid, passphrase_file, files, detached=True):

    options = ['--armor', '--detach-sign'] if detached else ['--clearsign']

    gpg_cmd = ['gpg', '--batch'] + options + ['--local-user', keyid]
    if passphrase_file != None:
        gpg_cmd[1:1] = ['--passphrase-file', passphrase_file]

    for filename in files:
        logging.info('Signing %s using PGP id %s' % (filename, keyid))

        cmd = gpg_cmd + [filename]

        logging.debug('Running %s' % (' '.join(cmd)))

        gpg = subprocess.Popen(cmd,
                               stdout=subprocess.PIPE,
                               stderr=subprocess.PIPE)

        check_subprocess_results(gpg, 'gpg')

    return [filename + '.asc' for filename in files]

def parse_args(args):
    parser = optparse.OptionParser(
        "usage: %prog [options] <version tag>\n" +
        "       %prog [options] snapshot <branch>"
        )

    parser.add_option('--verbose', action='store_true',
                      default=False, help='Extra debug output')

    parser.add_option('--quiet', action='store_true',
                      default=False, help='Only show errors')

    parser.add_option('--output-dir', metavar='DIR', default='.',
                      help='Where to place output (default %default)')

    parser.add_option('--print-output-names', action='store_true',
                      help='Print output archive filenames to stdout')

    parser.add_option('--archive-types', metavar='LIST', default='tgz',
                      help='Set archive types to generate (default %default)')

    parser.add_option('--pgp-key-id', metavar='KEYID',
                      default='EFBADFBC',
                      help='PGP signing key (default %default, "none" to disable)')

    parser.add_option('--pgp-passphrase-file', metavar='FILE',
                      default=None,
                      help='PGP signing key passphrase file')

    parser.add_option('--write-hash-file', metavar='FILE', default=None,
                      help='Write a file with checksums')

    return parser.parse_args(args)

def remove_file_if_exists(fspath):
    try:
        os.unlink(fspath)
    except OSError as e:
        if e.errno != errno.ENOENT:
            raise

def rewrite_version_file(version_file, target_version, snapshot_branch, rev_id, rel_date):

    if snapshot_branch:
        assert target_version == snapshot_branch

    version_file_name = os.path.basename(version_file)

    contents = open(version_file).readlines()

    version_re = re.compile('release_(major|minor|patch) = ([0-9]+)')

    def content_rewriter():
        for line in contents:

            if not snapshot_branch:
                # Verify the version set in the source matches the tag
                match = version_re.match(line)
                if match:
                    name_to_idx = {
                        'major': 0,
                        'minor': 1,
                        'patch': 2
                    }
                    version_parts = target_version.split('.')
                    assert len(version_parts) == 3
                    in_tag = int(version_parts[name_to_idx[match.group(1)]])
                    in_file = int(match.group(2))

                    if in_tag != in_file:
                        raise Exception('Version number part "%s" in %s does not match tag %s' %
                                        (match.group(1), version_file_name, target_version))

            if line == 'release_vc_rev = None\n':
                yield 'release_vc_rev = \'git:%s\'\n' % (rev_id)
            elif line == 'release_datestamp = 0\n':
                yield 'release_datestamp = %d\n' % (rel_date)
            elif line == "release_type = \'unreleased\'\n":
                if target_version == snapshot_branch:
                    yield "release_type = 'snapshot:%s'\n" % (snapshot_branch)
                else:
                    yield "release_type = 'release'\n"
            else:
                yield line

    open(version_file, 'w').write(''.join(list(content_rewriter())))

def rel_date_to_epoch(rel_date):
    rel_str = str(rel_date)
    year = int(rel_str[0:4])
    month = int(rel_str[5:6])
    day = int(rel_str[7:8])

    dt = datetime.datetime(year, month, day, 6, 0, 0)
    return (dt - datetime.datetime(1970, 1, 1)).total_seconds()

def write_archive(output_basename, archive_type, rel_epoch, all_files, hash_file):
    output_archive = output_basename + '.' + archive_type
    logging.info('Writing archive "%s"' % (output_archive))

    remove_file_if_exists(output_archive)
    remove_file_if_exists(output_archive + '.asc')

    def write_mode(archive_type):
        if archive_type == 'tgz':
            return 'w:gz'
        elif archive_type == 'tbz':
            return 'w:bz2'
        elif archive_type == 'tar':
            return 'w'

    # gzip format embeds the original filename, tarfile.py does the wrong
    # thing unless the output name ends in .gz. So pass an explicit
    # fileobj in that case, and supply a name in the form tarfile expects.
    if archive_type == 'tgz':
        archive = tarfile.open(output_basename + '.tar.gz',
                               write_mode(archive_type),
                               fileobj=open(output_archive, 'wb'))
    else:
        archive = tarfile.open(output_basename + '.tar',
                               write_mode(archive_type))

    for f in all_files:
        tarinfo = archive.gettarinfo(f)
        tarinfo.uid = 500
        tarinfo.gid = 500
        tarinfo.uname = "botan"
        tarinfo.gname = "botan"
        tarinfo.mtime = rel_epoch
        archive.addfile(tarinfo, open(f))
    archive.close()

    sha256 = hashlib.new('sha256')
    sha256.update(open(output_archive).read())
    archive_hash = sha256.hexdigest().upper()

    logging.info('SHA-256(%s) = %s' % (output_archive, archive_hash))
    if hash_file != None:
        hash_file.write("%s  %s\n" % (archive_hash, output_archive))

    return output_archive

def main(args=None):
    if args is None:
        args = sys.argv[1:]

    (options, args) = parse_args(args)

    def log_level():
        if options.verbose:
            return logging.DEBUG
        if options.quiet:
            return logging.ERROR
        return logging.INFO

    logging.basicConfig(stream=sys.stderr,
                        format='%(levelname) 7s: %(message)s',
                        level=log_level())

    if len(args) != 1 and len(args) != 2:
        logging.error('Usage: %s [options] <version tag>' % (sys.argv[0]))
        logging.error('Try --help')
        return 1

    snapshot_branch = None
    target_version = None

    archives = options.archive_types.split(',') if options.archive_types != '' else []
    for archive_type in archives:
        if archive_type not in ['tar', 'tgz', 'tbz']:
            logging.error('Unknown archive type "%s"' % (archive_type))
            return 1

    if args[0] == 'snapshot':
        if len(args) != 2:
            logging.error('Missing branch name for snapshot command')
            return 1
        snapshot_branch = args[1]
    else:
        if len(args) != 1:
            logging.error('Usage error, try --help')
            return 1
        target_version = args[0]

    if snapshot_branch:
        logging.info('Creating snapshot release from branch %s', snapshot_branch)
        target_version = snapshot_branch
    elif len(args) == 1:
        try:
            logging.info('Creating release for version %s' % (target_version))

            (major, minor, patch) = map(int, target_version.split('.'))

            assert target_version == '%d.%d.%d' % (major, minor, patch)
            target_version = target_version
        except ValueError as e:
            logging.error('Invalid version number %s' % (target_version))
            return 1

    rev_id = revision_of(target_version)

    if rev_id == '':
        logging.error('No tag matching %s found' % (target_version))
        return 2

    rel_date = datestamp(target_version)
    if rel_date == 0:
        logging.error('No date found for version')
        return 2

    rel_epoch = rel_date_to_epoch(rel_date)

    logging.info('Found %s at revision id %s released %d' % (target_version, rev_id, rel_date))

    def output_name():
        if snapshot_branch:
            if snapshot_branch == 'master':
                return 'Botan-snapshot-%s' % (rel_date)
            else:
                return 'Botan-snapshot-%s-%s' % (snapshot_branch, rel_date)
        else:
            return 'Botan-' + target_version

    output_basename = output_name()

    logging.debug('Output basename %s' % (output_basename))

    if os.access(output_basename, os.X_OK):
        logging.info('Removing existing output dir %s' % (output_basename))
        shutil.rmtree(output_basename)

    extract_revision(rev_id, output_basename)

    all_files = []
    for (curdir, _, files) in os.walk(output_basename):
        all_files += [os.path.join(curdir, f) for f in files]
    all_files.sort(key=lambda f: (os.path.dirname(f), os.path.basename(f)))

    version_file = None

    for possible_version_file in ['version.txt', 'botan_version.py']:
        full_path = os.path.join(output_basename, possible_version_file)
        if os.access(full_path, os.R_OK):
            version_file = full_path
            break

    if not os.access(version_file, os.R_OK):
        logging.error('Cannot read %s' % (version_file))
        return 2

    rewrite_version_file(version_file, target_version, snapshot_branch, rev_id, rel_date)

    try:
        os.makedirs(options.output_dir)
    except OSError as e:
        if e.errno != errno.EEXIST:
            logging.error('Creating dir %s failed %s' % (options.output_dir, e))
            return 2

    output_files = []

    hash_file = None
    if options.write_hash_file != None:
        hash_file = open(options.write_hash_file, 'w')

    for archive_type in archives:
        output_files.append(write_archive(output_basename, archive_type, rel_epoch, all_files, hash_file))

    if hash_file != None:
        hash_file.close()

    shutil.rmtree(output_basename)

    if options.pgp_key_id != 'none':
        if options.write_hash_file != None:
            output_files += gpg_sign(options.pgp_key_id, options.pgp_passphrase_file,
                                     [options.write_hash_file], False)
        else:
            output_files += gpg_sign(options.pgp_key_id, options.pgp_passphrase_file,
                                     output_files, True)

    if options.output_dir != '.':
        for output_file in output_files:
            logging.debug('Moving %s to %s' % (output_file, options.output_dir))
            shutil.move(output_file, os.path.join(options.output_dir, output_file))

    if options.print_output_names:
        for output_file in output_files:
            print(output_file)

    return 0

if __name__ == '__main__':
    try:
        sys.exit(main())
    except Exception as e:
        logging.error(e)
        import traceback
        logging.error(traceback.format_exc())
        sys.exit(1)