# -*- coding: utf-8 -*-

"""
requests.adapters
~~~~~~~~~~~~~~~~~

This module contains the transport adapters that Requests uses to define
and maintain connections.
"""

import socket

from .models import Response
from .packages.urllib3.poolmanager import PoolManager, ProxyManager
from .packages.urllib3.response import HTTPResponse
from .compat import urlparse, basestring, urldefrag
from .utils import (DEFAULT_CA_BUNDLE_PATH, get_encoding_from_headers,
                    prepend_scheme_if_needed, get_auth_from_url)
from .structures import CaseInsensitiveDict
from .packages.urllib3.exceptions import MaxRetryError
from .packages.urllib3.exceptions import TimeoutError
from .packages.urllib3.exceptions import SSLError as _SSLError
from .packages.urllib3.exceptions import HTTPError as _HTTPError
from .cookies import extract_cookies_to_jar
from .exceptions import ConnectionError, Timeout, SSLError
from .auth import _basic_auth_str

DEFAULT_POOLSIZE = 10
DEFAULT_RETRIES = 0


class BaseAdapter(object):
    """The Base Transport Adapter"""

    def __init__(self):
        super(BaseAdapter, self).__init__()

    def send(self):
        raise NotImplementedError

    def close(self):
        raise NotImplementedError


class HTTPAdapter(BaseAdapter):
    """Built-In HTTP Adapter for Urllib3."""
    def __init__(self, pool_connections=DEFAULT_POOLSIZE, pool_maxsize=DEFAULT_POOLSIZE):
        self.max_retries = DEFAULT_RETRIES
        self.config = {}

        super(HTTPAdapter, self).__init__()

        self.init_poolmanager(pool_connections, pool_maxsize)

    def init_poolmanager(self, connections, maxsize):
        self.poolmanager = PoolManager(num_pools=connections, maxsize=maxsize)

    def cert_verify(self, conn, url, verify, cert):
        if url.startswith('https') and verify:

            cert_loc = None

            # Allow self-specified cert location.
            if verify is not True:
                cert_loc = verify

            if not cert_loc:
                cert_loc = DEFAULT_CA_BUNDLE_PATH

            if not cert_loc:
                raise Exception("Could not find a suitable SSL CA certificate bundle.")

            conn.cert_reqs = 'CERT_REQUIRED'
            conn.ca_certs = cert_loc
        else:
            conn.cert_reqs = 'CERT_NONE'
            conn.ca_certs = None

        if cert:
            if not isinstance(cert, basestring):
                conn.cert_file = cert[0]
                conn.key_file = cert[1]
            else:
                conn.cert_file = cert

    def build_response(self, req, resp):
        response = Response()

        # Fallback to None if there's no status_code, for whatever reason.
        response.status_code = getattr(resp, 'status', None)

        # Make headers case-insensitive.
        response.headers = CaseInsensitiveDict(getattr(resp, 'headers', {}))

        # Set encoding.
        response.encoding = get_encoding_from_headers(response.headers)
        response.raw = resp
        response.reason = response.raw.reason

        if isinstance(req.url, bytes):
            response.url = req.url.decode('utf-8')
        else:
            response.url = req.url

        # Add new cookies from the server.
        extract_cookies_to_jar(response.cookies, req, resp)

        # Give the Response some context.
        response.request = req
        response.connection = self

        return response

    def get_connection(self, url, proxies=None):
        """Returns a connection for the given URL."""
        proxies = proxies or {}
        proxy = proxies.get(urlparse(url).scheme)

        if proxy:
            proxy = prepend_scheme_if_needed(proxy, urlparse(url).scheme)
            conn = ProxyManager(self.poolmanager.connection_from_url(proxy))
        else:
            conn = self.poolmanager.connection_from_url(url)

        return conn

    def close(self):
        """Dispose of any internal state.

        Currently, this just closes the PoolManager, which closes pooled
        connections.
        """
        self.poolmanager.clear()

    def request_url(self, request, proxies):
        """Obtain the url to use when making the final request.

        If the message is being sent through a proxy, the full URL has to be
        used. Otherwise, we should only use the path portion of the URL."""
        proxies = proxies or {}
        proxy = proxies.get(urlparse(request.url).scheme)

        if proxy:
            url, _ = urldefrag(request.url)
        else:
            url = request.path_url

        return url

    def add_headers(self, request, **kwargs):
        """Add any headers needed by the connection. Currently this only adds a
        Host: header if a proxy is being used."""
        proxies = kwargs.get('proxies', {})

        if proxies is None:
            proxies = {}

        proxy = proxies.get(urlparse(request.url).scheme)
        username, password = get_auth_from_url(proxy)

        if username and password:
            request.headers['Proxy-Authorization'] = _basic_auth_str(username,
                                                                     password)

    def send(self, request, stream=False, timeout=None, verify=True, cert=None, proxies=None):
        """Sends PreparedRequest object. Returns Response object."""

        conn = self.get_connection(request.url, proxies)

        self.cert_verify(conn, request.url, verify, cert)
        url = self.request_url(request, proxies)
        self.add_headers(request, proxies=proxies)

        chunked = not (request.body is None or 'Content-Length' in request.headers)

        try:
            if not chunked:
                resp = conn.urlopen(
                    method=request.method,
                    url=url,
                    body=request.body,
                    headers=request.headers,
                    redirect=False,
                    assert_same_host=False,
                    preload_content=False,
                    decode_content=False,
                    retries=self.max_retries,
                    timeout=timeout
                )

            # Send the request.
            else:
                if hasattr(conn, 'proxy_pool'):
                    conn = conn.proxy_pool

                low_conn = conn._get_conn(timeout=timeout)
                low_conn.putrequest(request.method, url, skip_accept_encoding=True)

                for header, value in request.headers.items():
                    low_conn.putheader(header, value)

                low_conn.endheaders()

                for i in request.body:
                    low_conn.send(hex(len(i))[2:].encode('utf-8'))
                    low_conn.send(b'\r\n')
                    low_conn.send(i)
                    low_conn.send(b'\r\n')
                low_conn.send(b'0\r\n\r\n')

                r = low_conn.getresponse()
                resp = HTTPResponse.from_httplib(r,
                    pool=conn,
                    connection=low_conn,
                    preload_content=False,
                    decode_content=False
                )

        except socket.error as sockerr:
            raise ConnectionError(sockerr)

        except MaxRetryError as e:
            raise ConnectionError(e)

        except (_SSLError, _HTTPError) as e:
            if isinstance(e, _SSLError):
                raise SSLError(e)
            elif isinstance(e, TimeoutError):
                raise Timeout(e)
            else:
                raise Timeout('Request timed out.')

        r = self.build_response(request, resp)

        if not stream:
            r.content

        return r
