# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.
import ipaddress
import platform
import socket
import subprocess

# Networks that must never be reached via user-supplied hostnames.
# Includes loopback, RFC-1918 private ranges, link-local (covers cloud
# metadata endpoints such as 169.254.169.254), shared address space
# (RFC 6598, 100.64.0.0/10), multicast (ip.is_global returns True for
# multicast addresses in Python, so explicit blocking is required), and
# IPv6 equivalents.
_SSRF_UNSAFE_NETWORKS = (
    ipaddress.ip_network("0.0.0.0/8"),
    ipaddress.ip_network("10.0.0.0/8"),
    ipaddress.ip_network("100.64.0.0/10"),
    ipaddress.ip_network("127.0.0.0/8"),
    ipaddress.ip_network("169.254.0.0/16"),
    ipaddress.ip_network("172.16.0.0/12"),
    ipaddress.ip_network("192.168.0.0/16"),
    ipaddress.ip_network("224.0.0.0/4"),  # IPv4 multicast — is_global is True in Python
    ipaddress.ip_network("::1/128"),
    ipaddress.ip_network("fc00::/7"),
    ipaddress.ip_network("fe80::/10"),
    ipaddress.ip_network("ff00::/8"),  # IPv6 multicast
)

PORT_TIMEOUT = 5
PING_TIMEOUT = 5


def is_safe_host(host: str) -> bool:
    """
    Return True if ``host`` resolves exclusively to public, globally-routable
    IP addresses.

    Returns False if any resolved address falls within a private, loopback,
    link-local, or otherwise non-routable range.  An unresolvable host also
    returns False.
    """
    try:
        results = socket.getaddrinfo(host, None)
    except socket.gaierror:
        return False
    if not results:
        return False
    for _, _, _, _, sockaddr in results:
        try:
            ip = ipaddress.ip_address(sockaddr[0])
        except ValueError:
            return False
        # Unwrap IPv4-mapped IPv6 addresses (e.g. ::ffff:127.0.0.1) so they
        # are checked against the IPv4 unsafe networks rather than bypassing.
        if isinstance(ip, ipaddress.IPv6Address) and ip.ipv4_mapped:
            ip = ip.ipv4_mapped
        if not ip.is_global or any(ip in net for net in _SSRF_UNSAFE_NETWORKS):
            return False
    return True


def is_port_open(host: str, port: int) -> bool:
    """
    Test if a given port in a host is open.
    """
    # pylint: disable=invalid-name
    for res in socket.getaddrinfo(host, port, 0, socket.SOCK_STREAM):
        af, _, _, _, sockaddr = res
        s = socket.socket(af, socket.SOCK_STREAM)
        try:
            s.settimeout(PORT_TIMEOUT)
            s.connect(sockaddr)
            s.shutdown(socket.SHUT_RDWR)
            return True
        except OSError as _:
            continue
        finally:
            s.close()
    return False


def is_hostname_valid(host: str) -> bool:
    """
    Test if a given hostname can be resolved.
    """
    try:
        socket.getaddrinfo(host, None)
        return True
    except socket.gaierror:
        return False


def is_host_up(host: str) -> bool:
    """
    Ping a host to see if it's up.

    Note that if we don't get a response the host might still be up,
    since many firewalls block ICMP packets.
    """
    param = "-n" if platform.system().lower() == "windows" else "-c"
    command = ["ping", param, "1", host]
    try:
        output = subprocess.call(command, timeout=PING_TIMEOUT)  # noqa: S603
    except subprocess.TimeoutExpired:
        return False

    return output == 0