"""Updates the Emby Library whenever the beets library is changed.

    emby:
        host: localhost
        port: 8096
        username: user
        apikey: apikey
        password: password
"""

import hashlib
from urllib.parse import parse_qs, urlencode, urljoin, urlsplit, urlunsplit

import requests

from beets import config
from beets.plugins import BeetsPlugin


def api_url(host, port, endpoint):
    """Returns a joined url.

    Takes host, port and endpoint and generates a valid emby API url.

    :param host: Hostname of the emby server
    :param port: Portnumber of the emby server
    :param endpoint: API endpoint
    :type host: str
    :type port: int
    :type endpoint: str
    :returns: Full API url
    :rtype: str
    """
    # check if http or https is defined as host and create hostname
    hostname_list = [host]
    if host.startswith("http://") or host.startswith("https://"):
        hostname = "".join(hostname_list)
    else:
        hostname_list.insert(0, "http://")
        hostname = "".join(hostname_list)

    joined = urljoin(
        "{hostname}:{port}".format(hostname=hostname, port=port), endpoint
    )

    scheme, netloc, path, query_string, fragment = urlsplit(joined)
    query_params = parse_qs(query_string)

    query_params["format"] = ["json"]
    new_query_string = urlencode(query_params, doseq=True)

    return urlunsplit((scheme, netloc, path, new_query_string, fragment))


def password_data(username, password):
    """Returns a dict with username and its encoded password.

    :param username: Emby username
    :param password: Emby password
    :type username: str
    :type password: str
    :returns: Dictionary with username and encoded password
    :rtype: dict
    """
    return {
        "username": username,
        "password": hashlib.sha1(password.encode("utf-8")).hexdigest(),
        "passwordMd5": hashlib.md5(password.encode("utf-8")).hexdigest(),
    }


def create_headers(user_id, token=None):
    """Return header dict that is needed to talk to the Emby API.

    :param user_id: Emby user ID
    :param token: Authentication token for Emby
    :type user_id: str
    :type token: str
    :returns: Headers for requests
    :rtype: dict
    """
    headers = {}

    authorization = (
        'MediaBrowser UserId="{user_id}", '
        'Client="other", '
        'Device="beets", '
        'DeviceId="beets", '
        'Version="0.0.0"'
    ).format(user_id=user_id)

    headers["x-emby-authorization"] = authorization

    if token:
        headers["x-mediabrowser-token"] = token

    return headers


def get_token(host, port, headers, auth_data):
    """Return token for a user.

    :param host: Emby host
    :param port: Emby port
    :param headers: Headers for requests
    :param auth_data: Username and encoded password for authentication
    :type host: str
    :type port: int
    :type headers: dict
    :type auth_data: dict
    :returns: Access Token
    :rtype: str
    """
    url = api_url(host, port, "/Users/AuthenticateByName")
    r = requests.post(url, headers=headers, data=auth_data)

    return r.json().get("AccessToken")


def get_user(host, port, username):
    """Return user dict from server or None if there is no user.

    :param host: Emby host
    :param port: Emby port
    :username: Username
    :type host: str
    :type port: int
    :type username: str
    :returns: Matched Users
    :rtype: list
    """
    url = api_url(host, port, "/Users/Public")
    r = requests.get(url)
    user = [i for i in r.json() if i["Name"] == username]

    return user


class EmbyUpdate(BeetsPlugin):
    def __init__(self):
        super().__init__()

        # Adding defaults.
        config["emby"].add(
            {
                "host": "http://localhost",
                "port": 8096,
                "apikey": None,
                "password": None,
            }
        )

        self.register_listener("database_change", self.listen_for_db_change)

    def listen_for_db_change(self, lib, model):
        """Listens for beets db change and register the update for the end."""
        self.register_listener("cli_exit", self.update)

    def update(self, lib):
        """When the client exists try to send refresh request to Emby."""
        self._log.info("Updating Emby library...")

        host = config["emby"]["host"].get()
        port = config["emby"]["port"].get()
        username = config["emby"]["username"].get()
        password = config["emby"]["password"].get()
        userid = config["emby"]["userid"].get()
        token = config["emby"]["apikey"].get()

        # Check if at least a apikey or password is given.
        if not any([password, token]):
            self._log.warning("Provide at least Emby password or apikey.")
            return

        if not userid:
            # Get user information from the Emby API.
            user = get_user(host, port, username)
            if not user:
                self._log.warning(f"User {username} could not be found.")
                return
            userid = user[0]["Id"]

        if not token:
            # Create Authentication data and headers.
            auth_data = password_data(username, password)
            headers = create_headers(userid)

            # Get authentication token.
            token = get_token(host, port, headers, auth_data)
            if not token:
                self._log.warning("Could not get token for user {0}", username)
                return

        # Recreate headers with a token.
        headers = create_headers(userid, token=token)

        # Trigger the Update.
        url = api_url(host, port, "/Library/Refresh")
        r = requests.post(url, headers=headers)
        if r.status_code != 204:
            self._log.warning("Update could not be triggered")
        else:
            self._log.info("Update triggered.")
