# pushover 1.0
#
# Copyright (C) 2013-2018  Thibaut Horel <thibaut.horel@gmail.com>

# This program 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.

# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
import time
from ConfigParser import RawConfigParser, NoSectionError, NoOptionError
from argparse import ArgumentParser, RawDescriptionHelpFormatter
import os

import requests

__all__ = ["Pushover", "MessageRequest", "ApiTokenError", "RequestError",
        "read_config"]

BASE_URL = "https://api.pushover.net/1/"
MESSAGE_URL = BASE_URL + "messages.json"
USER_URL = BASE_URL + "users/validate.json"
SOUND_URL = BASE_URL + "sounds.json"
RECEIPT_URL = BASE_URL + "receipts/"
GLANCE_URL = BASE_URL + "glances.json"


class ApiTokenError(Exception):
    """Exception which is raised when trying to send a message before
    initializing the module.
    """

    def __str__(self):
        return "No api_token provided."


class RequestError(Exception):
    """Exception which is raised when Pushover's API returns an error code.

    The list of errors is stored in the :attr:`errors` attribute.
    """

    def __init__(self, errors):
        Exception.__init__(self)
        self.errors = errors

    def __str__(self):
        return "\n==> " + "\n==> ".join(self.errors)


class Request:
    """Base class to send a request to the Pushover server and check the return
    status code. The request is sent on instantiation and raises
    a :class:`RequestError` exception when the request is rejected.
    """

    def __init__(self, request_type, url, payload, files={}):
        request = getattr(requests, request_type)(url, params=payload, files=files)
        self.answer = request.json()
        if 400 <= request.status_code < 500:
            raise RequestError(self.answer["errors"])

    def __str__(self):
        return str(self.answer)


class MessageRequest(Request):
    """Class representing a message request to the Pushover API. You do not
    need to create them yourself, but the :func:`Client.send_message` function
    returns :class:`MessageRequest` objects if you need to inspect the requests
    after they have been answered by the Pushover server.

    The :attr:`answer` attribute contains a JSON representation of the answer
    made by the Pushover API. In the case where you have sent a message with
    a priority of 2, you can poll the status of the notification with the
    :func:`poll` function.
    """

    def __init__(self, payload, files):
        Request.__init__(self, "post", MESSAGE_URL, payload, files)
        self.token = payload["token"]
        self.receipt = None
        if payload.get("priority", 0) == 2:
            self.receipt = self.answer["receipt"]
        self.parameters = {"expired": "expires_at",
                           "called_back": "called_back_at",
                           "acknowledged": "acknowledged_at"}
        for param, when in self.parameters.iteritems():
            setattr(self, param, False)
            setattr(self, when, 0)

    def poll(self):
        """If the message request has a priority of 2, Pushover will keep
        sending the same notification until the client acknowledges it. Calling
        the :func:`poll` function will update the status of the
        :class:`MessageRequest` object until the notifications either expires,
        is acknowledged by the client, or the callback url is reached. The
        attributes of interest are: ``expired, called_back, acknowledged`` and
        their *_at* variants as explained in the API documentation.

        This function returns ``None`` when the request has expired or been
        acknowledged, so that a typical handling of a priority-2 notification
        can look like this::

            request = client.send_message("Urgent notification", priority=2,
                                          expire=120, retry=60)
            while request.poll():
                # do something
                time.sleep(5)

            print request.acknowledged_at, request.acknowledged_by
        """
        if (self.receipt and not any(getattr(self, parameter)
                                     for parameter in self.parameters)):
            request = Request("get", RECEIPT_URL + self.receipt + ".json", {
                "token": self.token
                })
            for param, when in self.parameters.iteritems():
                setattr(self, param, bool(request.answer[param]))
                setattr(self, when, request.answer[when])
            for param in ["last_delivered_at", "acknowledged_by",
                          "acknowledged_by_device"]:
                setattr(self, param, request.answer[param])
            return request

    def cancel(self):
        """If the message request has a priority of 2, Pushover will keep
        sending the same notification until it either reaches its ``expire``
        value or is aknowledged by the client. Calling the :func:`cancel`
        function will cancel the notification early.
        """
        if (self.receipt and not any(getattr(self, parameter)
                                     for parameter in self.parameters)):
            request = Request("post", RECEIPT_URL + self.receipt
                              + "/cancel.json", {
                                  "token": self.token
                                  })
            return request


class GlanceRequest(Request):
    """Class representing a glance request to the Pushover API. This is
    a heavily simplified version of the MessageRequest class, with all
    polling-related features removed.
    """

    def __init__(self, payload):
        Request.__init__(self, "post", GLANCE_URL, payload)


class Pushover:
    """This is the main class of the module. It represents a Pushover app, i.e.
    it is tied to an API token.

    * ``token``: Pushover API token
    """

    _SOUNDS = None

    def __init__(self, token):
        self.token = token

    @property
    def sounds(self):
        """Return a list of sounds (as a list of strings) recognized
        by Pushover and that can be used in a notification message.

        The result is cached: a request is made to the Pushover server only
        the first time this function is called.
        """
        if not Pushover._SOUNDS:
            request = Request("get", SOUND_URL, {"token": self.token})
            Pushover._SOUNDS = request.answer["sounds"].keys()
        return Pushover._SOUNDS

    def verify(self, user_key, device=None):
        """Verify that the `user_key` and optional `device` exist. Returns
        `None` when the user/device does not exist or a list of the user's
        devices otherwise.
        """
        payload = {"user": self.user_key, "token": self.token}
        if device:
            payload["device"] = device
        try:
            request = Request("post", USER_URL, payload)
        except RequestError:
            return None

        return request.answer["devices"]

    def send_message(self, user_key, message, **kwords):
        """Send `message` to the user specified by `user_key`. It is possible
        to specify additional properties of the message by passing keyword
        arguments. The list of valid keywords is ``title, priority, sound,
        callback, timestamp, url, url_title, device, retry, expire and html``
        which are described in the Pushover API documentation.
        
        For convenience, you can simply set ``timestamp=True`` to set the
        timestamp to the current timestamp.

        An image can be attached to a message by passing a file-like object
        to the `attachment` keyword argument.

        This method returns a :class:`MessageRequest` object.
        """
        valid_keywords = ["title", "priority", "sound", "callback",
                          "timestamp", "url", "url_title", "device",
                          "retry", "expire", "html", "attachment"]

        payload = {"message": message, "user": user_key, "token": self.token}
        files = {}
        for key, value in kwords.iteritems():
            if key not in valid_keywords:
                raise ValueError("{0}: invalid message parameter".format(key))

            if key == "timestamp" and value is True:
                payload[key] = int(time.time())
            elif key == "sound":
                if value not in self.sounds:
                    raise ValueError("{0}: invalid sound".format(value))
                else:
                    payload[key] = value
            elif key == "attachment":
                files["attachment"] = value
            elif value:
                payload[key] = value

        return MessageRequest(payload, files)

    def send_glance(self, user_key, **kwords):
        """Send a glance to the user. The default property is ``text``,
        as this is used on most glances, however a valid glance does not
        need to require text and can be constructed using any combination
        of valid keyword properties. The list of valid keywords is ``title,
        text, subtext, count and percent`` which are  described in the
        Pushover Glance API documentation.

        This method returns a :class:`GlanceRequest` object.
        """
        valid_keywords = ["title", "text", "subtext", "count", "percent",
                "device"]

        payload = {"user": user_key, "token": self.token}

        for key, value in kwords.iteritems():
            if key not in valid_keywords:
                raise ValueError("{0}: invalid message parameter".format(key))
            payload[key] = value

        return GlanceRequest(payload)


def read_config(config_path):
    config_path = os.path.expanduser(config_path)
    config = RawConfigParser()
    params = {"users": {}}
    files = config.read(config_path)
    if not files:
        return params
    params["token"] = config.get("main", "token")
    for name in config.sections():
        if name != "main":
            user = {}
            user["user_key"] = config.get(name, "user_key")
            try:
                user["device"] = config.get(name, "device")
            except NoOptionError:
                user["device"] = None
            params["users"][name] = user
    return params


def main():
    parser = ArgumentParser(description="Send a message to pushover.",
                            formatter_class=RawDescriptionHelpFormatter,
                            epilog="""
For more details and bug reports, see: https://github.com/Thibauth/python-pushover""")
    parser.add_argument("--token", help="API token")
    parser.add_argument("--user", "-u", help="User key or section name in the configuration", required=True)
    parser.add_argument("-c", "--config", help="configuration file\
                        (default: ~/.pushoverrc)", default="~/.pushoverrc")
    parser.add_argument("message", help="message to send")
    parser.add_argument("--url", help="additional url")
    parser.add_argument("--url-title", help="url title")
    parser.add_argument("--title", "-t", help="message title")
    parser.add_argument("--priority", "-p", help="notification priority (-1, 0, 1 or 2)", type=int)
    parser.add_argument("--retry", "-r", help="resend interval in seconds (required for priority 2)", type=int)
    parser.add_argument("--expire", "-e", help="expiration time in seconds (required for priority 2)", type=int)
    parser.add_argument("--version", "-v", action="version",
                        help="output version information and exit",
                        version="""
%(prog)s 1.0
Copyright (C) 2013-2018 Thibaut Horel <thibaut.horel@gmail.com>
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.""")

    args = parser.parse_args()
    params = read_config(args.config)
    if args.priority==2 and (args.retry is None or args.expire is None):
        parser.error("priority of 2 requires expire and retry")
    if args.user in params["users"]:
        user_key = params["users"][args.user]["user_key"]
        device = params["users"][args.user]["device"]
    else:
        user_key = args.user
        device = None
    try:
        token = args.token or params["token"]
    except KeyError:
        raise ApiTokenError()

    Pushover(token).send_message(user_key, args.message, device=device,
            title=args.title, priority=args.priority, url=args.url,
            url_title=args.url_title, timestamp=True, retry=args.retry,
            expire=args.expire)

if __name__ == "__main__":
    main()