from __future__ import absolute_import
import os
from .. import utils, platform
from netlib import http_auth, certutils
from .primitives import ConstUpstreamServerResolver, TransparentUpstreamServerResolver

TRANSPARENT_SSL_PORTS = [443, 8443]
CONF_BASENAME = "mitmproxy"
CONF_DIR = "~/.mitmproxy"


class ProxyConfig:
    def __init__(self, confdir=CONF_DIR, clientcerts=None,
                 no_upstream_cert=False, body_size_limit=None,
                 mode=None, upstream_server=None, http_form_in=None, http_form_out=None,
                 authenticator=None,
                 ciphers=None, certs=[], certforward=False):
        self.ciphers = ciphers
        self.clientcerts = clientcerts
        self.no_upstream_cert = no_upstream_cert
        self.body_size_limit = body_size_limit

        if mode == "transparent":
            get_upstream_server = TransparentUpstreamServerResolver(platform.resolver(), TRANSPARENT_SSL_PORTS)
            http_form_in_default, http_form_out_default = "relative", "relative"
        elif mode == "reverse":
            get_upstream_server = ConstUpstreamServerResolver(upstream_server)
            http_form_in_default, http_form_out_default = "relative", "relative"
        elif mode == "upstream":
            get_upstream_server = ConstUpstreamServerResolver(upstream_server)
            http_form_in_default, http_form_out_default = "absolute", "absolute"
        elif upstream_server:
            get_upstream_server = ConstUpstreamServerResolver(upstream_server)
            http_form_in_default, http_form_out_default = "absolute", "relative"
        else:
            get_upstream_server, http_form_in_default, http_form_out_default = None, "absolute", "relative"
        http_form_in = http_form_in or http_form_in_default
        http_form_out = http_form_out or http_form_out_default

        self.get_upstream_server = get_upstream_server
        self.http_form_in = http_form_in
        self.http_form_out = http_form_out
        self.authenticator = authenticator
        self.confdir = os.path.expanduser(confdir)
        self.ca_file = os.path.join(self.confdir, CONF_BASENAME + "-ca.pem")
        self.certstore = certutils.CertStore.from_store(self.confdir, CONF_BASENAME)
        for spec, cert in certs:
            self.certstore.add_cert_file(spec, cert)
        self.certforward = certforward


def process_proxy_options(parser, options):
    body_size_limit = utils.parse_size(options.body_size_limit)

    c = 0
    mode, upstream_server = None, None
    if options.transparent_proxy:
        c += 1
        if not platform.resolver:
            return parser.error("Transparent mode not supported on this platform.")
        mode = "transparent"
    if options.reverse_proxy:
        c += 1
        mode = "reverse"
        upstream_server = options.reverse_proxy
    if options.upstream_proxy:
        c += 1
        mode = "upstream"
        upstream_server = options.upstream_proxy
    if options.manual_destination_server:
        c += 1
        mode = "manual"
        upstream_server = options.manual_destination_server
    if c > 1:
        return parser.error("Transparent mode, reverse mode, upstream proxy mode and "
                            "specification of an upstream server are mutually exclusive.")

    if options.clientcerts:
        options.clientcerts = os.path.expanduser(options.clientcerts)
        if not os.path.exists(options.clientcerts) or not os.path.isdir(options.clientcerts):
            return parser.error(
                "Client certificate directory does not exist or is not a directory: %s" % options.clientcerts
            )

    if (options.auth_nonanonymous or options.auth_singleuser or options.auth_htpasswd):
        if options.auth_singleuser:
            if len(options.auth_singleuser.split(':')) != 2:
                return parser.error("Invalid single-user specification. Please use the format username:password")
            username, password = options.auth_singleuser.split(':')
            password_manager = http_auth.PassManSingleUser(username, password)
        elif options.auth_nonanonymous:
            password_manager = http_auth.PassManNonAnon()
        elif options.auth_htpasswd:
            try:
                password_manager = http_auth.PassManHtpasswd(options.auth_htpasswd)
            except ValueError, v:
                return parser.error(v.message)
        authenticator = http_auth.BasicProxyAuth(password_manager, "mitmproxy")
    else:
        authenticator = http_auth.NullProxyAuth(None)

    certs = []
    for i in options.certs:
        parts = i.split("=", 1)
        if len(parts) == 1:
            parts = ["*", parts[0]]
        parts[1] = os.path.expanduser(parts[1])
        if not os.path.exists(parts[1]):
            parser.error("Certificate file does not exist: %s" % parts[1])
        certs.append(parts)

    return ProxyConfig(
        confdir=options.confdir,
        clientcerts=options.clientcerts,
        no_upstream_cert=options.no_upstream_cert,
        body_size_limit=body_size_limit,
        mode=mode,
        upstream_server=upstream_server,
        http_form_in=options.http_form_in,
        http_form_out=options.http_form_out,
        authenticator=authenticator,
        ciphers=options.ciphers,
        certs=certs,
        certforward=options.certforward,
    )


def ssl_option_group(parser):
    group = parser.add_argument_group("SSL")
    group.add_argument(
        "--cert", dest='certs', default=[], type=str,
        metavar="SPEC", action="append",
        help='Add an SSL certificate. SPEC is of the form "[domain=]path". ' \
             'The domain may include a wildcard, and is equal to "*" if not specified. ' \
             'The file at path is a certificate in PEM format. If a private key is included in the PEM, ' \
             'it is used, else the default key in the conf dir is used. Can be passed multiple times.'
    )
    group.add_argument(
        "--client-certs", action="store",
        type=str, dest="clientcerts", default=None,
        help="Client certificate directory."
    )
    group.add_argument(
        "--ciphers", action="store",
        type=str, dest="ciphers", default=None,
        help="SSL cipher specification."
    )
    group.add_argument(
        "--cert-forward", action="store_true",
        dest="certforward", default=False,
        help="Simply forward SSL certificates from upstream."
    )
    group.add_argument(
        "--no-upstream-cert", default=False,
        action="store_true", dest="no_upstream_cert",
        help="Don't connect to upstream server to look up certificate details."
    )