# Copyright (C) 2016 Red Hat, Inc., Michal Srb <michal@redhat.com>

# This file is part of the sos project: https://github.com/sosreport/sos
#
# This copyrighted material is made available to anyone wishing to use,
# modify, copy, or redistribute it subject to the terms and conditions of
# version 2 of the GNU General Public License.
#
# See the LICENSE file in the source distribution for further information.

import hashlib
import json
import os
import re
import zipfile
from functools import partial
from sos.plugins import Plugin, RedHatPlugin


class Jars(Plugin, RedHatPlugin):
    """Collect information about available Java archives."""

    plugin_name = "jars"
    version = "1.0.0"
    profiles = ("java",)
    option_list = [
        ("append_locations", "colon-separated list of additional JAR paths",
         "fast", ""),
        ("all_known_locations", "scan all known paths", "slow", False)
    ]

    # There is no standard location for JAR files and scanning
    # the whole filesystem could be very slow. Therefore we only
    # scan directories in which JARs can be typically found.
    jar_locations = (
        "/usr/share/java",  # common location for JARs
        "/usr/lib/java"     # common location for JARs containing native code
    )

    # Following paths can be optionally scanned as well. Note the scan can take
    # *very* long time.
    extra_jar_locations = (
        "/opt",             # location for RHSCL and 3rd party software
        "/usr/local",       # used by sysadmins when installing SW locally
        "/var/lib"          # Java services commonly explode WARs there
    )

    def setup(self):
        results = {"jars": []}
        jar_paths = []

        locations = list(Jars.jar_locations)
        if self.get_option("all_known_locations"):
            locations += list(Jars.extra_jar_locations)

        # append also user-defined locations, if any
        user_locations = self.get_option("append_locations")
        if user_locations:
            locations += user_locations.split(":")

        # find all JARs in given locations
        for location in locations:
            for dirpath, _, filenames in os.walk(location):
                for filename in filenames:
                    path = os.path.join(dirpath, filename)
                    if Jars.is_jar(path):
                        jar_paths.append(path)

        # try to extract information about found JARs
        for jar_path in jar_paths:
            maven_id = Jars.get_maven_id(jar_path)
            jar_id = Jars.get_jar_id(jar_path)
            if maven_id or jar_id:
                record = {"path": jar_path,
                          "sha1": jar_id,
                          "maven_id": maven_id
                          }
                results["jars"].append(record)

        results_str = json.dumps(results, indent=4, separators=(",", ": "))
        self.add_string_as_file(results_str, "jars.json")

    @staticmethod
    def is_jar(path):
        """Check whether given file is a JAR file.

        JARs are ZIP files which usually include a manifest
        at the canonical location 'META-INF/MANIFEST.MF'.
        """
        if os.path.isfile(path) and zipfile.is_zipfile(path):
            try:
                with zipfile.ZipFile(path) as f:
                    if "META-INF/MANIFEST.MF" in f.namelist():
                        return True
            except (IOError, zipfile.BadZipfile):
                pass
        return False

    @staticmethod
    def get_maven_id(jar_path):
        """Extract Maven coordinates from a given JAR file, if possible.

        JARs build by Maven (most popular Java build system) contain
        'pom.properties' file. We can extract Maven coordinates
         from there.
        """
        props = {}
        try:
            with zipfile.ZipFile(jar_path) as f:
                r = re.compile("META-INF/maven/[^/]+/[^/]+/pom.properties$")
                result = [x for x in f.namelist() if r.match(x)]
                if len(result) != 1:
                    return None
                with f.open(result[0]) as props_f:
                    for line in props_f.readlines():
                        line = line.strip()
                        if not line.startswith(b"#"):
                            try:
                                (key, value) = line.split(b"=")
                                key = key.decode('utf8').strip()
                                value = value.decode('utf8').strip()
                                props[key] = value
                            except ValueError:
                                return None
        except IOError:
            pass
        return props

    @staticmethod
    def get_jar_id(jar_path):
        """Compute JAR id.

        Returns sha1 hash of a given JAR file.
        """
        jar_id = ""
        try:
            with open(jar_path, mode="rb") as f:
                m = hashlib.sha1()
                for buf in iter(partial(f.read, 4096), b''):
                    m.update(buf)
            jar_id = m.hexdigest()
        except IOError:
            pass
        return jar_id
