#!/usr/bin/env python3
"""Check the docs/THIRDPARTY file against the DEP-5 copyright format.

https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/

Disclaimer: This script is not a lawyer.  It cannot validate that the
claimed licenses are correct.  It can only check for basic syntactic
issues.
"""

# Copyright © 2020 Kandra Labs, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.

import difflib
import io
import os
import subprocess
import sys

from debian import copyright

COPYRIGHT_FILENAME = "docs/THIRDPARTY"
os.chdir(os.path.join(os.path.dirname(__file__), ".."))
status = 0

*files, empty = subprocess.check_output(
    ["git", "ls-files", "-z"],
    encoding="utf-8",
).split("\0")
assert empty == ""
files += [
    "static/generated/emoji/images/emoji/unicode/ignore-this-path",
]

with open(COPYRIGHT_FILENAME) as f:
    lines = list(f)
c = copyright.Copyright(lines)

if not c.header.known_format():
    print(f"{COPYRIGHT_FILENAME}: Unknown header format {c.header.format}")
    status = 1

defined_licenses = {
    p.license.to_str().split("\n", 1)[0]
    for p in c.all_license_paragraphs()
    if "\n" in p.license.to_str()
}

for p in c.all_files_paragraphs():
    for g in p.files:
        if not any(map(copyright.globs_to_re([g]).fullmatch, files)):
            print(f"{COPYRIGHT_FILENAME}: No such file {g}")
            status = 1

    if "\n" not in p.license.to_str() and p.license.to_str() not in defined_licenses:
        print(f"{COPYRIGHT_FILENAME}: Missing license text for {p.license.to_str()}")
        status = 1

dumped = c.dump()
if dumped != "".join(lines):
    print(f"{COPYRIGHT_FILENAME}: Changes expected:")
    sys.stdout.writelines(
        difflib.unified_diff(
            lines,
            io.StringIO(dumped).readlines(),
            COPYRIGHT_FILENAME,
            COPYRIGHT_FILENAME,
        ),
    )
    status = 1

sys.exit(status)