# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:

# Copyright 2014-2018 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
#
# This file is part of qutebrowser.
#
# qutebrowser is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# qutebrowser is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.

"""An HTTP client based on QNetworkAccessManager."""

import functools
import urllib.request
import urllib.parse

from PyQt5.QtCore import pyqtSignal, QObject, QTimer
from PyQt5.QtNetwork import (QNetworkAccessManager, QNetworkRequest,
                             QNetworkReply)


class HTTPRequest(QNetworkRequest):
    """A QNetworkRquest that follows (secure) redirects by default."""

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        try:
            self.setAttribute(QNetworkRequest.RedirectPolicyAttribute,
                              QNetworkRequest.NoLessSafeRedirectPolicy)
        except AttributeError:
            # RedirectPolicyAttribute was introduced in 5.9 to replace
            # FollowRedirectsAttribute.
            self.setAttribute(QNetworkRequest.FollowRedirectsAttribute,
                              True)


class HTTPClient(QObject):

    """An HTTP client based on QNetworkAccessManager.

    Intended for APIs, automatically decodes data.

    Attributes:
        _nam: The QNetworkAccessManager used.
        _timers: A {QNetworkReply: QTimer} dict.

    Signals:
        success: Emitted when the operation succeeded.
                 arg: The received data.
        error: Emitted when the request failed.
               arg: The error message, as string.
    """

    success = pyqtSignal(str)
    error = pyqtSignal(str)

    def __init__(self, parent=None):
        super().__init__(parent)
        self._nam = QNetworkAccessManager(self)
        self._timers = {}

    def post(self, url, data=None):
        """Create a new POST request.

        Args:
            url: The URL to post to, as QUrl.
            data: A dict of data to send.
        """
        if data is None:
            data = {}
        encoded_data = urllib.parse.urlencode(data).encode('utf-8')
        request = HTTPRequest(url)
        request.setHeader(QNetworkRequest.ContentTypeHeader,
                          'application/x-www-form-urlencoded;charset=utf-8')
        reply = self._nam.post(request, encoded_data)
        self._handle_reply(reply)

    def get(self, url):
        """Create a new GET request.

        Emits success/error when done.

        Args:
            url: The URL to access, as QUrl.
        """
        request = HTTPRequest(url)
        reply = self._nam.get(request)
        self._handle_reply(reply)

    def _handle_reply(self, reply):
        """Handle a new QNetworkReply."""
        if reply.isFinished():
            self.on_reply_finished(reply)
        else:
            timer = QTimer(self)
            timer.setInterval(10000)
            timer.timeout.connect(reply.abort)
            timer.start()
            self._timers[reply] = timer
            reply.finished.connect(functools.partial(
                self.on_reply_finished, reply))

    def on_reply_finished(self, reply):
        """Read the data and finish when the reply finished.

        Args:
            reply: The QNetworkReply which finished.
        """
        timer = self._timers.pop(reply)
        if timer is not None:
            timer.stop()
            timer.deleteLater()
        if reply.error() != QNetworkReply.NoError:
            self.error.emit(reply.errorString())
            return
        try:
            data = bytes(reply.readAll()).decode('utf-8')
        except UnicodeDecodeError:
            self.error.emit("Invalid UTF-8 data received in reply!")
            return
        self.success.emit(data)
