#!/usr/bin/env python3
#
# verify.py - part of the FDroid server tools
# Copyright (C) 2013, Ciaran Gultnieks, ciaran@ciarang.com
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import sys
import os
import glob
import json
import logging
import requests
from argparse import ArgumentParser
from collections import OrderedDict

from . import _
from . import common
from . import net
from .exception import FDroidException

options = None
config = None


def _add_diffoscope_info(d):
    """Add diffoscope setup metadata to provided dict under 'diffoscope' key.

    The imports are broken out at stages since various versions of
    diffoscope support various parts of these.

    """
    try:
        import diffoscope

        d['diffoscope'] = dict()
        d['diffoscope']['VERSION'] = diffoscope.VERSION

        from diffoscope.comparators import ComparatorManager

        ComparatorManager().reload()

        from diffoscope.tools import tool_check_installed, tool_required

        external_tools = sorted(tool_required.all)
        external_tools = [
            tool for tool in external_tools if not tool_check_installed(tool)
        ]
        d['diffoscope']['External-Tools-Required'] = external_tools

        from diffoscope.tools import OS_NAMES, get_current_os
        from diffoscope.external_tools import EXTERNAL_TOOLS

        current_os = get_current_os()
        os_list = [current_os] if (current_os in OS_NAMES) else iter(OS_NAMES)
        for os_ in os_list:
            tools = set()
            for x in external_tools:
                try:
                    tools.add(EXTERNAL_TOOLS[x][os_])
                except KeyError:
                    pass
            tools = sorted(tools)
            d['diffoscope']['Available-in-{}-packages'.format(OS_NAMES[os_])] = tools

        from diffoscope.tools import python_module_missing as pmm

        d['diffoscope']['Missing-Python-Modules'] = sorted(pmm.modules)
    except ImportError:
        pass


def write_json_report(url, remote_apk, unsigned_apk, compare_result):
    """Write out the results of the verify run to JSON.

    This builds up reports on the repeated runs of `fdroid verify` on
    a set of apps.  It uses the timestamps on the compared files to
    ensure that there is only one report per file, even when run
    repeatedly.

    The output is run through JSON to normalize things like tuples vs
    lists.

    """
    jsonfile = unsigned_apk + '.json'
    if os.path.exists(jsonfile):
        with open(jsonfile) as fp:
            data = json.load(fp, object_pairs_hook=OrderedDict)
    else:
        data = OrderedDict()
    output = dict()
    _add_diffoscope_info(output)
    output['url'] = url
    for key, filename in (('local', unsigned_apk), ('remote', remote_apk)):
        d = dict()
        output[key] = d
        d['file'] = filename
        d['sha256'] = common.sha256sum(filename)
        d['timestamp'] = os.stat(filename).st_ctime
        d['packageName'], d['versionCode'], d['versionName'] = common.get_apk_id(
            filename
        )
    if compare_result:
        output['verified'] = False
        output['result'] = compare_result
    else:
        output['verified'] = True
    # str makes better dict keys than float
    data[str(output['local']['timestamp'])] = output
    with open(jsonfile, 'w') as fp:
        json.dump(data, fp, sort_keys=True)

    if output['verified']:
        jsonfile = 'unsigned/verified.json'
        if os.path.exists(jsonfile):
            with open(jsonfile) as fp:
                data = json.load(fp)
        else:
            data = OrderedDict()
            data['packages'] = OrderedDict()
        packageName = output['local']['packageName']

        if packageName not in data['packages']:
            data['packages'][packageName] = []
        found = False
        output_dump = json.dumps(output, sort_keys=True)
        for p in data['packages'][packageName]:
            if output_dump == json.dumps(p, sort_keys=True):
                found = True
                break
        if not found:
            data['packages'][packageName].insert(0, json.loads(output_dump))
        with open(jsonfile, 'w') as fp:
            json.dump(data, fp, cls=common.Encoder, sort_keys=True)


def main():

    global options, config

    # Parse command line...
    parser = ArgumentParser(
        usage="%(prog)s [options] [APPID[:VERCODE] [APPID[:VERCODE] ...]]"
    )
    common.setup_global_opts(parser)
    parser.add_argument(
        "appid",
        nargs='*',
        help=_("application ID with optional versionCode in the form APPID[:VERCODE]"),
    )
    parser.add_argument(
        "--reuse-remote-apk",
        action="store_true",
        default=False,
        help=_("Verify against locally cached copy rather than redownloading."),
    )
    parser.add_argument(
        "--output-json",
        action="store_true",
        default=False,
        help=_("Output JSON report to file named after APK."),
    )
    options = parser.parse_args()

    config = common.read_config(options)

    tmp_dir = 'tmp'
    if not os.path.isdir(tmp_dir):
        logging.info(_("Creating temporary directory"))
        os.makedirs(tmp_dir)

    unsigned_dir = 'unsigned'
    if not os.path.isdir(unsigned_dir):
        logging.error(_("No unsigned directory - nothing to do"))
        sys.exit(0)

    processed = set()
    verified = 0
    notverified = 0

    vercodes = common.read_pkg_args(options.appid, True)

    for apkfile in sorted(glob.glob(os.path.join(unsigned_dir, '*.apk'))):

        apkfilename = os.path.basename(apkfile)
        url = 'https://f-droid.org/repo/' + apkfilename
        appid, vercode = common.publishednameinfo(apkfile)

        if vercodes and appid not in vercodes:
            continue
        if vercodes[appid] and vercode not in vercodes[appid]:
            continue

        processed.add(appid)

        try:

            logging.info("Processing {apkfilename}".format(apkfilename=apkfilename))

            remote_apk = os.path.join(tmp_dir, apkfilename)
            if not options.reuse_remote_apk or not os.path.exists(remote_apk):
                if os.path.exists(remote_apk):
                    os.remove(remote_apk)
                logging.info("...retrieving " + url)
                try:
                    net.download_file(url, dldir=tmp_dir)
                except requests.exceptions.HTTPError:
                    try:
                        net.download_file(
                            url.replace('/repo', '/archive'), dldir=tmp_dir
                        )
                    except requests.exceptions.HTTPError as e:
                        raise FDroidException(
                            _('Downloading {url} failed. {error}').format(
                                url=url, error=e
                            )
                        ) from e

            unsigned_apk = os.path.join(unsigned_dir, apkfilename)
            compare_result = common.verify_apks(remote_apk, unsigned_apk, tmp_dir)
            if options.output_json:
                write_json_report(url, remote_apk, unsigned_apk, compare_result)
            if compare_result:
                raise FDroidException(compare_result)

            logging.info("...successfully verified")
            verified += 1

        except FDroidException as e:
            logging.info("...NOT verified - {0}".format(e))
            notverified += 1

    for appid in options.appid:
        package = appid.split(":")[0]
        if package not in processed:
            logging.critical(_("No APK for package: %s") % package)
            notverified += 1

    if verified > 0:
        logging.info("{0} successfully verified".format(verified))
    if notverified > 0:
        logging.info("{0} NOT verified".format(notverified))
    sys.exit(notverified)


if __name__ == "__main__":
    main()
