import json
import logging
import os
import time
from abc import ABCMeta, abstractmethod
from collections import namedtuple
from threading import Lock, Thread
from typing import Dict

import geoip2.database
import geoip2.errors
import requests
from cachetools.func import lru_cache, ttl_cache
from netaddr import AddrFormatError, IPAddress, IPNetwork, IPSet
from six import add_metaclass

from util.abchelpers import nooper

ResolvedLocation = namedtuple(
    "ResolvedLocation",
    ["provider", "service", "sync_token", "country_iso_code", "aws_region", "continent"],
)

AWS_SERVICES = {"EC2", "CODEBUILD"}

# https://support.maxmind.com/hc/en-us/articles/4414877149467-IP-Geolocation-Data#h_01FRRGRYTGZB29ERDBZCX3MR8Q
GEOIP_CONTINENT_CODES = ["AF", "AN", "AS", "EU", "NA", "OC", "SA"]

logger = logging.getLogger(__name__)


def _get_aws_ip_ranges():
    try:
        # resolve absolute path to file
        path = os.path.dirname(os.path.abspath(__file__))
        file_path = os.path.join(path, "aws-ip-ranges.json")
        with open(file_path, "r") as f:
            return json.loads(f.read())
    except IOError:
        logger.exception("Could not load AWS IP Ranges")
        return None
    except ValueError:
        logger.exception("Could not load AWS IP Ranges")
        return None
    except TypeError:
        logger.exception("Could not load AWS IP Ranges")
        return None


@add_metaclass(ABCMeta)
class IPResolverInterface(object):
    """
    Helper class for resolving information about an IP address.
    """

    @abstractmethod
    def resolve_ip(self, ip_address):
        """
        Attempts to return resolved information about the specified IP Address.

        If such an attempt fails, returns None.
        """
        pass

    @abstractmethod
    def is_ip_possible_threat(self, ip_address):
        """
        Attempts to return whether the given IP address is a possible abuser or spammer.

        Returns False if the IP address information could not be looked up.
        """
        pass


@nooper
class NoopIPResolver(IPResolverInterface):
    """
    No-op version of the security scanner API.
    """

    pass


class IPResolver(IPResolverInterface):
    def __init__(self, app):
        self.app = app

        # resolve absolute path to file
        path = os.path.dirname(os.path.abspath(__file__))
        file_path = os.path.join(path, "GeoLite2-Country.mmdb")
        self.geoip_db = geoip2.database.Reader(file_path)

        self.amazon_ranges: Dict[str, IPSet] = None
        self.sync_token = None

        logger.info("Loading AWS IP ranges from disk")
        aws_ip_ranges_data = _get_aws_ip_ranges()
        if aws_ip_ranges_data is not None and aws_ip_ranges_data.get("syncToken"):
            logger.debug("Building AWS IP ranges")
            self.amazon_ranges = IPResolver._parse_amazon_ranges(aws_ip_ranges_data)
            self.sync_token = aws_ip_ranges_data["syncToken"]
            logger.debug("Finished building AWS IP ranges")

    @ttl_cache(maxsize=100, ttl=600)
    def is_ip_possible_threat(self, ip_address):
        if self.app.config.get("THREAT_NAMESPACE_MAXIMUM_BUILD_COUNT") is None:
            return False

        if self.app.config.get("IP_DATA_API_KEY") is None:
            return False

        if not ip_address:
            return False

        api_key = self.app.config["IP_DATA_API_KEY"]

        try:
            logger.debug("Requesting IP data for IP %s", ip_address)
            r = requests.get(
                "https://api.ipdata.co/%s/threat?api-key=%s" % (ip_address, api_key), timeout=1
            )
            if r.status_code != 200:
                logger.debug("Got non-200 response for IP %s: %s", ip_address, r.status_code)
                return False

            logger.debug("Got IP data for IP %s: %s => %s", ip_address, r.status_code, r.json())
            threat_data = r.json()
            return threat_data.get("is_threat", False) or threat_data.get("is_bogon", False)
        except requests.RequestException:
            logger.exception("Got exception when trying to lookup IP Address")
        except ValueError:
            logger.exception("Got exception when trying to lookup IP Address")
        except Exception:
            logger.exception("Got exception when trying to lookup IP Address")

        return False

    def resolve_ip(self, ip_address):
        """
        Attempts to return resolved information about the specified IP Address.

        If such an attempt fails, returns None.
        """
        if not ip_address:
            return None

        try:
            parsed_ip = IPAddress(ip_address)
        except AddrFormatError:
            return ResolvedLocation("invalid_ip", None, self.sync_token, None, None, None)

        # Try geoip classification
        try:
            geoinfo = self.geoip_db.country(ip_address)
        except geoip2.errors.AddressNotFoundError:
            geoinfo = None

        aws_region = self.get_aws_ip_region(parsed_ip)

        # Not an AWS IP
        if not aws_region:
            if geoinfo:
                return ResolvedLocation(
                    "internet",
                    geoinfo.country.iso_code,
                    self.sync_token,
                    geoinfo.country.iso_code,
                    None,
                    geoinfo.continent.code,
                )

            return ResolvedLocation("internet", None, self.sync_token, None, None, None)

        return ResolvedLocation(
            "aws",
            None,
            self.sync_token,
            geoinfo.country.iso_code if geoinfo else None,
            aws_region,
            geoinfo.continent.code if geoinfo else None,
        )

    def get_aws_ip_region(self, ip_address: IPAddress):
        if not self.amazon_ranges:
            return None

        for region in self.amazon_ranges:
            ipset = self.amazon_ranges[region]
            if ip_address in ipset:
                return region
        return None

    @staticmethod
    def _parse_amazon_ranges(ranges):
        all_amazon = {}
        for service_description in ranges["prefixes"]:
            region = service_description["region"]
            service = service_description["service"]

            if region not in all_amazon:
                all_amazon[region] = IPSet()

            if service in AWS_SERVICES:
                all_amazon[region].add(IPNetwork(service_description["ip_prefix"]))

        return all_amazon