#!/usr/bin/env python3

import argparse
import os
import pwd
import re
import sys
import tempfile
import urllib
import warnings

from jinja2 import Template


def get_full_name():
    full_name = os.getenv("DEBFULLNAME")
    if full_name:
        return full_name
    return pwd.getpwuid(os.getuid()).pw_gecos.split(",")[0]


try:
    import rdflib
except ImportError:
    warnings.warn("python-rdflib not installed; will fall back to PTS email address")

    def get_maintainers(pkg):
        return u"{}@packages.debian.org".format(pkg)
else:
    def get_maintainers(pkg):

        # RDF object and predicate references used on PTS
        project = rdflib.term.URIRef(
            u"http://packages.qa.debian.org/{}#project".format(pkg)
        )
        has_contributor = rdflib.term.URIRef(u"http://schema.org/contributor")
        is_named = rdflib.term.URIRef(u"http://xmlns.com/foaf/0.1/name")
        is_same_as = rdflib.term.URIRef(u"http://www.w3.org/2002/07/owl#sameAs")

        maint = []

        graph = rdflib.Graph()
        try:
            graph.parse(
                "https://packages.qa.debian.org/{}/{}.rdf".format(
                    re.match("((?:lib)?.)", pkg).group(1), pkg
                )
            )
        except urllib.error.HTTPError as exc:
            if exc.code == 404:
                raise ValueError("unknown package '{}'".format(pkg))
            raise
        for contrib in graph[project:has_contributor]:
            names = [n for n in graph[contrib:is_named]]
            addresses = [
                urllib.parse.unquote(m.group(1))
                for m in map(
                    re.compile(
                        r"http://webid\.debian\.net/maintainers/(.*)#agent$"
                    ).match,
                    graph[contrib:is_same_as],
                )
                if m
            ]
            if not names or not addresses:
                warnings.warn("found contributor missing name and/or address")
                continue
            address = addresses[0]
            if "@" not in address:
                address += "@debian.org"
            maint.append(u'"{}" <{}>'.format(names[0], address))

        return u", ".join(maint)

# Parse command line
parser = argparse.ArgumentParser(description="Get in touch with package maintainers")
parser.add_argument("--force", action="store_true", help="Ignore safety checks")
parser.add_argument(
    "--lts", action="store_true", help="Act as a member of the LTS team"
)
parser.add_argument(
    "--no-dsa",
    dest="no_dsa",
    action="store_true",
    help="Say that issues are low severity (no need for DSA/DLA)",
)
parser.add_argument(
    "--minor",
    dest="minor_issues",
    action="store_true",
    help="Say that issues are low severity and someone will work on them (LTS team only)",
)
parser.add_argument(
    "--mailer",
    action="store",
    default="mutt -H {}",
    help="Command executed. Must contain {} to be replaced "
    "by the filename of the draft contact mail",
)
parser.add_argument("package")
parser.add_argument("cve", nargs="*")
args = parser.parse_args()

cc = "debian-lts@lists.debian.org" if args.lts else "team@security.debian.org"
team = "lts" if args.lts else "sec"
model = "no-dsa" if args.no_dsa else "update-planned"
minor = "-minor" if args.minor_issues and args.lts else ""
template_file = "templates/{}-{}{}.txt".format(team, model, minor)

# Basic check
instructions = "packages/{}.txt".format(args.package)
if os.path.exists(instructions) and not args.force:
    print("Have a look at {}".format(instructions))
    print("If you still want to run this script, run it with --force.")
    sys.exit(1)

# Check if we should contact maintainers
dontcall = "data/packages/lts-do-not-call"
if args.lts and not args.force:
    with open(dontcall) as f:
        for line in f:
            if line[0] == "#":
                continue
            if not line.strip():
                continue
            if line.split()[0] == args.package:
                print("Maintainer(s) may not be contacted for LTS issues.")
                print("Reason: {}".format(" ".join(line.split()[1:])))
                print("If you still want to run this script, run it with --force.")
                sys.exit(1)

# Generate the context

# XXX: Once that 761859 is fixed, improve the logic here to:
# - retrieve the current list of CVE dynamically
# - check whether we should use the no-dsa variant of the template
# - check whether we have an open bug report, in which case we should
#   include it in the recipients of the mail

context = {
    "package": args.package,
    "sender": get_full_name(),
    "cve": args.cve,
    "to": get_maintainers(args.package),
    "cc": cc,
    "uploaders": "",
}

# Generate the mail
with open(template_file) as f:
    template = Template(f.read())

fd, filename = tempfile.mkstemp(prefix="contact-maintainers", suffix=".txt")
draft = os.fdopen(fd, "wb")
draft.write(template.render(context).encode("utf-8"))
draft.close()

os.system(args.mailer.format(filename))
os.unlink(filename)