# -*- coding: utf-8 -*-
# Copyright: 2011, Grigoriy Petukhov
# Author: Grigoriy Petukhov (http://lorien.name)
# License: BSD
"""
The core of grab package: the Grab class.
"""
import collections
import email
import itertools
import logging
import os
import threading
import weakref
from copy import copy, deepcopy
from datetime import datetime
from random import randint
from warnings import warn

import six
from six.moves.collections_abc import Callable
from six.moves.urllib.parse import urljoin

from grab import error
from grab.cookie import CookieManager
from grab.deprecated import DeprecatedThings
from grab.document import Document
from grab.proxylist import ProxyList, parse_proxy_line
from grab.unset import UNSET
from grab.util.encoding import make_str
from grab.util.html import find_base_url
from grab.util.http import normalize_http_values

__all__ = ("Grab",)
# This counter will used in enumerating network queries.
# Its value will be displayed in logging messages and also used
# in names of dumps
# I use mutable module variable to allow different
# instances of Grab to maintain single counter
# This could be helpful in debugging when your script
# creates multiple Grab instances - in case of shared counter
# grab instances do not overwrite dump logs
REQUEST_COUNTER = itertools.count(1)
MUTABLE_CONFIG_KEYS = ("post", "multipart_post", "headers", "cookies")
TRANSPORT_CACHE = {}
TRANSPORT_ALIAS = {
    "pycurl": "grab.transport.curl.CurlTransport",
    "urllib3": "grab.transport.urllib3.Urllib3Transport",
}
DEFAULT_TRANSPORT = "pycurl"

# pylint: disable=invalid-name
logger = logging.getLogger("grab.base")
# Logger to handle network activity
# It is done as separate logger to allow you easily
# control network logging separately from other grab logs
logger_network = logging.getLogger("grab.network")
# pylint: enable=invalid-name


def copy_config(config, mutable_config_keys=MUTABLE_CONFIG_KEYS):
    """
    Copy grab config with correct handling of mutable config values.
    """

    cloned_config = copy(config)
    # Apply ``copy`` function to mutable config values
    for key in mutable_config_keys:
        cloned_config[key] = copy(config[key])
    return cloned_config


def default_config():
    # TODO: Maybe config should be splitted into two entities:
    # 1) config which is not changed during request
    # 2) changeable settings
    return dict(
        # Common
        url=None,
        # Debugging
        log_file=None,
        log_dir=False,
        debug_post=False,
        debug_post_limit=150,
        # Only for curl transport
        debug=False,
        verbose_logging=False,
        # Only for selenium transport
        webdriver="firefox",
        selenium_wait=1,  # in seconds
        # Proxy
        proxy=None,
        proxy_type=None,
        proxy_userpwd=None,
        proxy_auto_change=True,
        # Method, Post
        method=None,
        post=None,
        multipart_post=None,
        # Headers, User-Agent, Referer
        headers={},
        common_headers={},
        user_agent=None,
        user_agent_file=None,
        referer=None,
        reuse_referer=True,
        # Cookies
        cookies={},
        reuse_cookies=True,
        cookiefile=None,
        # Timeouts
        timeout=15,
        connect_timeout=3,
        # Connection
        connection_reuse=True,
        # Response processing
        nobody=False,
        body_maxsize=None,
        body_inmemory=True,
        body_storage_dir=None,
        body_storage_filename=None,
        body_storage_create_dir=False,
        reject_file_size=None,
        # Content compression
        encoding="gzip",
        # Network interface
        interface=None,
        # Redirects
        follow_refresh=False,
        follow_location=True,
        redirect_limit=10,
        # Authentication
        userpwd=None,
        # Character set to which any unicode data should be encoded
        # before get placed in request
        # This setting is overwritten after each request with
        # charset of retrieved document
        charset="utf-8",
        # Charset to use for converting content of response
        # into unicode, by default it is detected automatically
        document_charset=None,
        # Content type control how DOM are built
        # For html type HTML DOM builder is used
        # For xml type XML DOM builder is used
        content_type="html",
        # Fix &#X; entities, where X between 128 and 160
        # Such entities are parsed by modern browsers as
        # windows-1251 entities independently of the real charset of
        # the document, If this option is True then such entities
        # will be replaced with correct unicode entities e.g.:
        # &#151; ->  &#8212;
        # THIS SETTING IS DEPRECATED AND IS NOT USED ANYMORE
        fix_special_entities=UNSET,
        # Convert document body to lower case before building LXML tree
        # It does not affect `self.doc.body`
        lowercased_tree=False,
        # Strip null bytes from document body before building lXML tree
        # It does not affect `self.doc.body`
        # THIS SETTING IS DEPREATED AND IS NOT USED ANYMORE
        strip_null_bytes=UNSET,
        # Internal object to store
        state={},
    )


class Grab(DeprecatedThings):
    __slots__ = (
        "request_head",
        "request_body",
        #'request_log',
        "proxylist",
        "config",
        "transport",
        "transport_param",
        "request_method",
        "request_counter",
        "__weakref__",
        "cookies",
        "meta",
        "exception",
        # Dirty hack to make it possible to inherit Grab from
        # multiple base classes with __slots__
        "_doc",
    )

    # Attributes which should be processed when clone
    # of Grab instance is creating
    clonable_attributes = (
        "request_head",
        "request_body",
        #'request_log',
        "proxylist",
    )

    # Complex config items which points to mutable objects
    mutable_config_keys = copy(MUTABLE_CONFIG_KEYS)

    #
    # Public methods
    #

    def __init__(self, document_body=None, transport=None, **kwargs):
        """
        Create Grab instance
        """

        self.meta = {}
        self._doc = None
        self.config = default_config()
        self.config["common_headers"] = self.common_headers()
        self.cookies = CookieManager()
        self.proxylist = ProxyList()
        self.exception = None

        # makes pylint happy
        self.request_counter = None
        self.request_head = None
        self.request_body = None
        self.request_method = None
        self.transport_param = transport
        self.transport = None

        self.reset()
        if kwargs:
            self.setup(**kwargs)
        if document_body is not None:
            self.setup_document(document_body)

    def _get_doc(self):
        if self._doc is None:
            self._doc = Document(self)
        return self._doc

    def _set_doc(self, obj):
        self._doc = obj

    doc = property(_get_doc, _set_doc)

    def setup_transport(self, transport_param, reset=False):
        if self.transport is not None and not reset:
            raise error.GrabMisuseError(
                "Transport is already set up. Use"
                " setup_transport(..., reset=True) to explicitly setup"
                " new transport"
            )
        if transport_param is None:
            transport_param = DEFAULT_TRANSPORT
        if isinstance(transport_param, six.string_types):
            if transport_param in TRANSPORT_ALIAS:
                transport_param = TRANSPORT_ALIAS[transport_param]
            if "." not in transport_param:
                raise error.GrabMisuseError("Unknown transport: %s" % transport_param)
            else:
                mod_path, cls_name = transport_param.rsplit(".", 1)
                try:
                    cls = TRANSPORT_CACHE[(mod_path, cls_name)]
                except KeyError:
                    mod = __import__(mod_path, globals(), locals(), ["foo"])
                    cls = getattr(mod, cls_name)
                    TRANSPORT_CACHE[(mod_path, cls_name)] = cls
                self.transport = cls()
        elif isinstance(transport_param, Callable):
            self.transport = transport_param()
        else:
            raise error.GrabMisuseError(
                "Option `transport` should be string "
                "or class or callable. Got %s" % type(transport_param)
            )

    def reset(self):
        """
        Reset all attributes which could be modified during previous request
        or which is not initialized yet if this is the new Grab instance.

        This methods is automatically called before each network request.
        """

        self.request_head = None
        # self.request_log = None
        self.request_body = None
        self.request_method = None
        self.request_counter = None
        self.exception = None
        if self.transport:
            self.transport.reset()

    def clone(self, **kwargs):
        """
        Create clone of Grab instance.

        Cloned instance will have the same state: cookies, referrer, response
        document data

        :param **kwargs: overrides settings of cloned grab instance
        """

        grab = Grab(transport=self.transport_param)
        grab.config = self.dump_config()

        grab.doc = self.doc.copy()
        # grab.doc.grab = weakref.proxy(grab)

        for key in self.clonable_attributes:
            setattr(grab, key, getattr(self, key))
        grab.cookies = deepcopy(self.cookies)

        if kwargs:
            grab.setup(**kwargs)

        return grab

    def adopt(self, grab):
        """
        Copy the state of another `Grab` instance.

        Use case: create backup of current state to the cloned instance and
        then restore the state from it.
        """

        self.load_config(grab.config)

        self.doc = grab.doc.copy(new_grab=self)

        for key in self.clonable_attributes:
            setattr(self, key, getattr(grab, key))
        self.cookies = deepcopy(grab.cookies)

    def dump_config(self):
        """
        Make clone of current config.
        """

        conf = copy_config(self.config, self.mutable_config_keys)
        conf["state"] = {
            "cookiejar_cookies": list(self.cookies.cookiejar),
        }
        return conf

    def load_config(self, config):
        """
        Configure grab instance with external config object.
        """

        self.config = copy_config(config, self.mutable_config_keys)
        if "cookiejar_cookies" in config["state"]:
            self.cookies = CookieManager.from_cookie_list(
                config["state"]["cookiejar_cookies"]
            )

    def setup(self, **kwargs):
        """
        Setting up Grab instance configuration.
        """

        for key in kwargs:
            if key not in self.config.keys():
                raise error.GrabMisuseError("Unknown option: %s" % key)
        for key in ["fix_special_entities", "strip_null_bytes"]:
            if key in kwargs:
                warn(
                    "Option {} is deprecated and does not affect anything".format(key),
                    category=DeprecationWarning,
                )
                del kwargs[key]

        if "url" in kwargs:
            if self.config.get("url"):
                kwargs["url"] = self.make_url_absolute(kwargs["url"])
        self.config.update(kwargs)

    def go(self, url, **kwargs):  # pylint: disable=invalid-name
        """
        Go to ``url``

        Args:
            :url: could be absolute or relative. If relative then t will be
            appended to the absolute URL of previous request.
        """

        return self.request(url=url, **kwargs)

    def download(self, url, location, **kwargs):
        """
        Fetch document located at ``url`` and save to to ``location``.
        """

        doc = self.go(url, **kwargs)
        with open(location, "wb") as out:
            out.write(doc.body)
        return len(doc.body)

    def init_transport(self):
        """
        Create transport object if it is not crated yet.
        """

        if self.transport is None:
            self.setup_transport(self.transport_param)

    def prepare_request(self, **kwargs):
        """
        Configure all things to make real network request.
        This method is called before doing real request via
        transport extension.
        """

        self.init_transport()
        self.reset()
        self.request_counter = next(REQUEST_COUNTER)
        if kwargs:
            self.setup(**kwargs)
        if self.proxylist.size() and self.config["proxy_auto_change"]:
            self.change_proxy()
        self.request_method = self.detect_request_method()
        self.transport.process_config(self)

    def log_request(self, extra=""):
        """
        Send request details to logging system.
        """

        # pylint: disable=no-member
        thread_name = threading.currentThread().getName().lower()
        # pylint: enable=no-member
        if thread_name == "mainthread":
            thread_name = ""
        else:
            thread_name = "-%s" % thread_name

        if self.config["proxy"]:
            if self.config["proxy_userpwd"]:
                auth = " with authorization"
            else:
                auth = ""
            proxy_info = " via %s proxy of type %s%s" % (
                self.config["proxy"],
                self.config["proxy_type"],
                auth,
            )
        else:
            proxy_info = ""
        if extra:
            extra = "[%s] " % extra
        logger_network.debug(
            "[%s%s] %s%s %s%s",
            (
                "%02d" % self.request_counter
                if self.request_counter is not None
                else "NA"
            ),
            thread_name,
            extra,
            self.request_method or "GET",
            self.config["url"],
            proxy_info,
        )

    def request(self, **kwargs):
        """
        Perform network request.

        You can specify grab settings in ``**kwargs``.
        Any keyword argument will be passed to ``self.config``.

        Returns: ``Document`` objects.
        """

        self.prepare_request(**kwargs)
        refresh_count = 0

        while True:
            self.log_request()

            try:
                self.transport.request()
            except error.GrabError as ex:
                self.exception = ex
                self.reset_temporary_options()
                if self.config["log_dir"]:
                    self.save_failed_dump()
                raise
            else:
                doc = self.process_request_result()

                if self.config["follow_location"]:
                    if doc.code in (301, 302, 303, 307, 308):
                        if doc.headers.get("Location"):
                            refresh_count += 1
                            if refresh_count > self.config["redirect_limit"]:
                                raise error.GrabTooManyRedirectsError()
                            else:
                                url = doc.headers.get("Location")
                                self.prepare_request(
                                    url=self.make_url_absolute(url), referer=None
                                )
                                continue

                if self.config["follow_refresh"]:
                    refresh_url = self.doc.get_meta_refresh_url()
                    if refresh_url is not None:
                        refresh_count += 1
                        if refresh_count > self.config["redirect_limit"]:
                            raise error.GrabTooManyRedirectsError()
                        else:
                            self.prepare_request(
                                url=self.make_url_absolute(refresh_url), referer=None
                            )
                            continue
                return doc

    def submit(self, make_request=True, **kwargs):
        """
        Submit current form.

        :param make_request: if `False` then grab instance will be
            configured with form post data but request will not be
            performed

        For details see `Document.submit()` method

        Example::

            # Assume that we going to some page with some form
            g.go('some url')
            # Fill some fields
            g.doc.set_input('username', 'bob')
            g.doc.set_input('pwd', '123')
            # Submit the form
            g.submit()

            # or we can just fill the form
            # and do manual submission
            g.doc.set_input('foo', 'bar')
            g.submit(make_request=False)
            g.request()

            # for multipart forms we can specify files
            from grab import UploadFile
            g.doc.set_input('img', UploadFile('/path/to/image.png'))
            g.submit()
        """
        result = self.doc.get_form_request(**kwargs)
        if result["multipart_post"]:
            self.setup(multipart_post=result["multipart_post"])
        if result["post"]:
            self.setup(post=result["post"])
        if result["url"]:
            self.setup(url=result["url"])
        if make_request:
            return self.request()
        else:
            return None

    def process_request_result(self, prepare_response_func=None):
        """
        Process result of real request performed via transport extension.
        """

        now = datetime.utcnow()
        # TODO: move into separate method
        if self.config["debug_post"]:
            post = self.config["post"] or self.config["multipart_post"]
            if isinstance(post, dict):
                post = list(post.items())
            if post:
                if isinstance(post, six.string_types):
                    post = (
                        make_str(
                            post[: self.config["debug_post_limit"]], errors="ignore"
                        )
                        + b"..."
                    )
                else:
                    items = normalize_http_values(post, charset=self.config["charset"])
                    new_items = []
                    for key, value in items:
                        if len(value) > self.config["debug_post_limit"]:
                            value = value[: self.config["debug_post_limit"]] + b"..."
                        else:
                            value = value
                        new_items.append((key, value))
                    post = "\n".join("%-25s: %s" % x for x in new_items)
            if post:
                logger_network.debug(
                    "[%02d] POST request:\n%s\n", self.request_counter, post
                )

        # It's important to delete old POST data after request is performed.
        # If POST data is not cleared then next request will try to use them
        # again!
        self.reset_temporary_options()

        if prepare_response_func:
            self.doc = prepare_response_func(self.transport, self)
        else:
            self.doc = self.transport.prepare_response(self)

        self.doc.process_grab(self)

        if self.config["reuse_cookies"]:
            self.cookies.update(self.doc.cookies)

        self.doc.timestamp = now

        self.config["charset"] = self.doc.charset

        if self.config["log_file"]:
            with open(self.config["log_file"], "wb") as out:
                out.write(self.doc.body)

        if self.config["cookiefile"]:
            self.cookies.save_to_file(self.config["cookiefile"])

        if self.config["reuse_referer"]:
            self.config["referer"] = self.doc.url

        self.copy_request_data()

        # Should be called after `copy_request_data`
        if self.config["log_dir"]:
            self.save_dumps()

        return self.doc

    def reset_temporary_options(self):
        self.config["post"] = None
        self.config["multipart_post"] = None
        self.config["method"] = None
        self.config["body_storage_filename"] = None

    def save_failed_dump(self):
        """
        Save dump of failed request for debugging.

        This method is called then fatal network exception is raised.
        The saved dump could be used for debugging the reason of the failure.
        """

        # try/except for safety, to not break live spiders
        try:
            # FIXME
            if self.transport.__class__.__name__ == "Urllib3Transport" and not getattr(
                self.transport, "_response", None
            ):
                self.doc = None
            else:
                self.doc = self.transport.prepare_response(self)
            self.copy_request_data()
            self.save_dumps()
        except Exception as ex:  # pylint: disable=broad-except
            logger.error("", exc_info=ex)

    def copy_request_data(self):
        # TODO: Maybe request object?
        self.request_head = self.transport.request_head
        self.request_body = self.transport.request_body
        # self.request_log = self.transport.request_log

    def setup_document(self, content, **kwargs):
        """
        Setup `response` object without real network requests.

        Useful for testing and debuging.

        All ``**kwargs`` will be passed to `Document` constructor.
        """

        self.reset()
        if isinstance(content, six.text_type):
            raise error.GrabMisuseError(
                "Method `setup_document` accepts only "
                "byte string in `content` argument."
            )

        # Configure Document instance
        doc = Document(grab=self)
        doc.body = content
        doc.status = ""
        doc.head = b"HTTP/1.1 200 OK\r\n\r\n"
        doc.parse(charset=kwargs.get("document_charset"))
        doc.code = 200
        doc.total_time = 0
        doc.connect_time = 0
        doc.name_lookup_time = 0
        doc.url = ""

        for key, value in kwargs.items():
            setattr(doc, key, value)

        self.doc = doc

    def change_proxy(self, random=True):
        """
        Set random proxy from proxylist.
        """

        if self.proxylist.size():
            if random:
                proxy = self.proxylist.get_random_proxy()
            else:
                proxy = self.proxylist.get_next_proxy()
            self.setup(
                proxy=proxy.get_address(),
                proxy_userpwd=proxy.get_userpwd(),
                proxy_type=proxy.proxy_type,
            )
        else:
            logger.debug("Proxy list is empty")

    #
    # Private methods
    #

    @classmethod
    def common_headers(cls):
        """
        Build headers which sends typical browser.
        """

        return {
            "Accept": "text/xml,application/xml,application/xhtml+xml"
            ",text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.%d" % randint(2, 5),
            "Accept-Language": "en-us,en;q=0.%d" % (randint(5, 9)),
            "Accept-Charset": "utf-8,windows-1251;q=0.7,*;q=0.%d" % randint(5, 7),
            "Keep-Alive": "300",
        }

    def save_dumps(self):
        # pylint: disable=no-member
        thread_name = threading.currentThread().getName().lower()
        # pylint: enable=no-member
        if thread_name == "mainthread":
            thread_name = ""
        else:
            thread_name = "-%s" % thread_name
        file_name = os.path.join(
            self.config["log_dir"], "%02d%s.log" % (self.request_counter, thread_name)
        )
        with open(file_name, "wb") as out:
            out.write(b"Request headers:\n")
            out.write(self.request_head)
            out.write(b"\n")
            out.write(b"Request body:\n")
            out.write(self.request_body)
            out.write(b"\n\n")
            out.write(b"Response headers:\n")
            out.write(self.doc.head if (self.doc and self.doc.head) else b"")

        file_extension = "html"
        file_name = os.path.join(
            self.config["log_dir"],
            "%02d%s.%s" % (self.request_counter, thread_name, file_extension),
        )
        self.doc.save(file_name)

    def make_url_absolute(self, url, resolve_base=False):
        """
        Make url absolute using previous request url as base url.
        """

        if self.config["url"]:
            if resolve_base:
                ubody = self.doc.unicode_body()
                base_url = find_base_url(ubody)
                if base_url:
                    return urljoin(base_url, url)
            return urljoin(self.config["url"], url)
        else:
            return url

    def detect_request_method(self):
        """
        Analyze request config and find which
        request method will be used.

        Returns request method in upper case

        This method needs simetime when `process_config` method
        was not called yet.
        """

        method = self.config["method"]
        if method:
            method = method.upper()
        else:
            if self.config["post"] or self.config["multipart_post"]:
                method = "POST"
            else:
                method = "GET"
        return method

    def clear_cookies(self):
        """
        Clear all remembered cookies.
        """

        self.config["cookies"] = {}
        self.cookies.clear()

    def setup_with_proxyline(self, line, proxy_type="http"):
        # TODO: remove from base class
        # maybe to proxylist?
        host, port, user, pwd = parse_proxy_line(line)
        server_port = "%s:%s" % (host, port)
        self.setup(proxy=server_port, proxy_type=proxy_type)
        if user:
            userpwd = "%s:%s" % (user, pwd)
            self.setup(proxy_userpwd=userpwd)

    def __getstate__(self):
        """
        Reset cached lxml objects which could not be pickled.
        """
        state = {}
        for cls in type(self).mro():
            cls_slots = getattr(cls, "__slots__", ())
            for slot in cls_slots:
                if slot != "__weakref__":
                    if hasattr(self, slot):
                        state[slot] = getattr(self, slot)

        if state["_doc"]:
            state["_doc"].grab = weakref.proxy(self)

        return state

    def __setstate__(self, state):
        for slot, value in state.items():
            setattr(self, slot, value)

    @property
    def request_headers(self):
        first_head = self.request_head.decode("utf-8").split("\r\n\r\n")[0]
        lines = first_head.split("\r\n")
        lines = [x for x in lines if ":" in x]
        return email.message_from_string("\n".join(lines))


# For backward compatibility
# WTF???
BaseGrab = Grab
