import warnings
from xml.etree import ElementTree
import requests
from django.forms import ValidationError
from urllib.parse import urlsplit, urlunsplit, urlencode
from django.utils.translation import gettext_lazy as _
from common.logger import log
from django.conf import settings


class MediaServerError(Exception):
    '''
        Raised when a back-end error occurs.
    '''
    pass


class MediaServer:

    TIMEOUT = 0
    HELP = ''
    default_headers = {'User-Agent': 'TubeSync'}

    def __init__(self, mediaserver_instance):
        self.object = mediaserver_instance
        self.headers = dict(**self.default_headers)
        self.token = None

    def make_request_args(self, uri='/', token_header=None, headers={}, token_param=None, params={}):
        base_parts = urlsplit(self.object.url)
        if self.token is None:
            self.token = self.object.options['token'] or None
        if token_header and self.token:
            headers.update({token_header: self.token})
        self.headers.update(headers)
        if token_param and self.token:
            params.update({token_param: self.token})
        qs = urlencode(params)
        enable_verify = (
            base_parts.scheme.endswith('s') and
            self.object.verify_https
        )
        url = urlunsplit((base_parts.scheme, base_parts.netloc, uri, qs, ''))
        return (url, dict(
                headers=self.headers,
                verify=enable_verify,
                timeout=self.TIMEOUT,
            ))

    def make_request(self, uri='/', /, *, headers={}, params={}):
        '''
            A very simple implementation is:
                url, kwargs = self.make_request_args(uri=uri, headers=headers, params=params)
                return requests.get(url, **kwargs)
        '''
        raise NotImplementedError('MediaServer.make_request() must be implemented')

    def validate(self):
        '''
            Called to check that the configured media server values are correct.
        '''
        raise NotImplementedError('MediaServer.validate() must be implemented')

    def update(self):
        '''
            Called after the `Media` instance has saved a downloaded file.
        '''
        raise NotImplementedError('MediaServer.update() must be implemented')


class PlexMediaServer(MediaServer):

    TIMEOUT = 5

    HELP = _('<p>To connect your TubeSync sevrer to your Plex Media Server you will '
             'need to enter the details of your Plex server below.</p>'
             '<p>The <strong>host</strong> can be either an IP address or valid hostname.</p>'
             '<p>The <strong>port</strong> number must be between 1 and 65536.</p>'
             '<p>The <strong>token</strong> is a Plex access token to your Plex server. You can find '
             'out how to get a Plex access token <a href="https://support.plex.tv/'
             'articles/204059436-finding-an-authentication-token-x-plex-token/" '
             'target="_blank">here</a>.</p>'
             '<p>The <strong>libraries</strong> is a comma-separated list of Plex '
             'library or section IDs, you can find out how to get your library or '
             'section IDs <a href="https://support.plex.tv/articles/201242707-plex-'
             'media-scanner-via-command-line/#toc-1" target="_blank">here</a> or '
             '<a href="https://www.plexopedia.com/plex-media-server/api/server/libraries/" '
             'target="_blank">here</a></p>.')

    def make_request(self, uri='/', /, *, headers={}, params={}):
        url, kwargs = self.make_request_args(uri=uri, headers=headers, token_param='X-Plex-Token', params=params)
        log.debug(f'[plex media server] Making HTTP GET request to: {url}')
        if self.object.use_https and not kwargs['verify']:
            # If not validating SSL, given this is likely going to be for an internal
            # or private network, that Plex issues certs *.hash.plex.direct and that
            # the warning won't ever been sensibly seen in the HTTPS logs, hide it
            with warnings.catch_warnings():
                warnings.simplefilter("ignore")
                return requests.get(url, **kwargs)
        return requests.get(url, **kwargs)

    def validate(self):
        '''
            A Plex server requires a host, port, access token and a comma-separated
            list of library IDs.
        '''
        # Check all the required values are present
        if not self.object.host:
            raise ValidationError('Plex Media Server requires a "host"')
        if not self.object.port:
            raise ValidationError('Plex Media Server requires a "port"')
        try:
            port = int(self.object.port)
        except (TypeError, ValueError):
            raise ValidationError('Plex Media Server "port" must be an integer')
        if port < 1 or port > 65535:
            raise ValidationError('Plex Media Server "port" must be between 1 '
                                  'and 65535')
        options = self.object.options
        if 'token' not in options:
            raise ValidationError('Plex Media Server requires a "token"')
        token = options['token'].strip()
        if 'token' not in options:
            raise ValidationError('Plex Media Server requires a "token"')
        if 'libraries' not in options:
            raise ValidationError('Plex Media Server requires a "libraries"')
        libraries = options['libraries'].strip().split(',')
        for position, library in enumerate(libraries):
            library = library.strip()
            try:
                int(library)
            except (TypeError, ValueError):
                raise ValidationError(f'Plex Media Server library ID "{library}" at '
                                      f'position {position+1} must be an integer')
        # Test the details work by requesting a summary page from the Plex server
        try:
            response = self.make_request('/library/sections')
        except Exception as e:
            raise ValidationError(f'Failed to make a test connection to your Plex '
                                  f'Media Server at "{self.object.host}:'
                                  f'{self.object.port}", the error was "{e}". Check '
                                  'your host and port are correct.') from e
        if response.status_code != 200:
            check_token = ''
            if 400 <= response.status_code < 500:
                check_token = (' A 4XX error could mean your access token is being '
                               'rejected. Check your token is correct.')
            raise ValidationError(f'Your Plex Media Server returned an invalid HTTP '
                                  f'status code, expected 200 but received '
                                  f'{response.status_code}.' + check_token)
        try:
            parsed_response = ElementTree.fromstring(response.content)
        except Exception as e:
            raise ValidationError(f'Your Plex Media Server returned unexpected data, '
                                  f'expected valid XML but parsing it as XML caused '
                                  f'the error "{e}"')
        # Seems we have a valid library sections page, get the library IDs
        remote_libraries = {}
        try:
            for parent in parsed_response.iter('MediaContainer'):
                for d in parent:
                    library_id = d.attrib['key']
                    library_name = d.attrib['title']
                    remote_libraries[library_id] = library_name
        except Exception as e:
            raise ValidationError(f'Your Plex Media Server returned unexpected data, '
                                  f'the XML it returned could not be parsed and the '
                                  f'error was "{e}"')
        # Validate the library IDs
        remote_libraries_desc = []
        for remote_library_id, remote_library_name in remote_libraries.items():
            remote_libraries_desc.append(f'"{remote_library_name}" with ID '
                                         f'"{remote_library_id}"')
        remote_libraries_str = ', '.join(remote_libraries_desc)
        for library_id in libraries:
            library_id = library_id.strip()
            if library_id not in remote_libraries:
                raise ValidationError(f'One or more of your specified library IDs do '
                                      f'not exist on your Plex Media Server. Your '
                                      f'valid libraries are: {remote_libraries_str}')
        # All good!
        return True

    def update(self):
        # For each section / library ID pop off a request to refresh it
        libraries = self.object.options.get('libraries', '')
        for library_id in libraries.split(','):
            library_id = library_id.strip()
            uri = f'/library/sections/{library_id}/refresh'
            response = self.make_request(uri)
            if response.status_code != 200:
                raise MediaServerError(f'Failed to refresh library "{library_id}" on '
                                       f'Plex server "{self.object.url}", expected a '
                                       f'200 status code but got '
                                       f'{response.status_code}. Check your media '
                                       f'server details.')
        return True


class JellyfinMediaServer(MediaServer):
    TIMEOUT = 5

    HELP = _('<p>To connect your TubeSync server to your Jellyfin Media Server, please enter the details below.</p>'
             '<p>The <strong>host</strong> can be either an IP address or a valid hostname.</p>'
             '<p>The <strong>port</strong> should be between 1 and 65536.</p>'
             '<p>The "API Key" <strong>token</strong> is required for API access. Your Jellyfin administrator can generate an "API Key" token for use with TubeSync for you.</p>'
             '<p>The <strong>libraries</strong> is a comma-separated list of library IDs in Jellyfin. Leave this blank to see a list.</p>')

    def make_request(self, uri='/', /, *, headers={}, params={}, data={}, json=None, method='GET'):
        assert method in {'GET', 'POST'}, f'Unimplemented method: {method}'
        
        headers.update({'Content-Type': 'application/json'})
        url, kwargs = self.make_request_args(uri=uri, token_header='X-Emby-Token', headers=headers, params=params)
        # From the Emby source code;
        #   this is the order in which the headers are tried:
        # X-Emby-Authorization: ('MediaBrowser'|'Emby') 'Token'=<token_value>, 'Client'=<client_value>, 'Version'=<version_value>
        # X-Emby-Token: <token_value>
        # X-MediaBrowser-Token: <token_value>
        # Jellyfin uses 'Authorization' first,
        # then optionally falls back to the 'X-Emby-Authorization' header.
        # Jellyfin uses (") around values, but not keys in that header.
        token = kwargs['headers'].get('X-Emby-Token', None)
        if token:
            kwargs['headers'].update({
                'X-MediaBrowser-Token': token,
                'X-Emby-Authorization': f'Emby Token={token}, Client=TubeSync, Version={settings.VERSION}',
                'Authorization': f'MediaBrowser Token="{token}", Client="TubeSync", Version="{settings.VERSION}"',
            })

        log.debug(f'[jellyfin media server] Making HTTP {method} request to: {url}')
        if self.object.use_https and not kwargs['verify']:
            # not verifying certificates
            with warnings.catch_warnings():
                warnings.simplefilter("ignore")
                return requests.request(
                    method, url,
                    data=data,
                    json=json,
                    **kwargs,
                )
        return requests.request(
            method, url,
            data=data,
            json=json,
            **kwargs,
        )

    def validate(self):
        if not self.object.host:
            raise ValidationError('Jellyfin Media Server requires a "host"')
        if not self.object.port:
            raise ValidationError('Jellyfin Media Server requires a "port"')

        try:
            port = int(self.object.port)
            if port < 1 or port > 65535:
                raise ValidationError('Jellyfin Media Server "port" must be between 1 and 65535')
        except (TypeError, ValueError):
            raise ValidationError('Jellyfin Media Server "port" must be an integer')

        options = self.object.options
        if 'token' not in options:
            raise ValidationError('Jellyfin Media Server requires a "token"')
        if 'libraries' not in options:
            raise ValidationError('Jellyfin Media Server requires a "libraries"')

        # Test connection and fetch libraries
        try:
            response = self.make_request('/Library/MediaFolders', params={'Recursive': 'true', 'IncludeItemTypes': 'CollectionFolder'})
            if response.status_code != 200:
                raise ValidationError(f'Failed to connect to Jellyfin server: {response.status_code}')
            data = response.json()
            if 'Items' not in data:
                raise ValidationError('Jellyfin Media Server returned unexpected data.')
        except Exception as e:
            raise ValidationError(f'Connection error: {e}')

        # Seems we have a valid library sections page, get the library IDs
        remote_libraries = {}
        try:
            for d in data['Items']:
                library_id = d['Id']
                library_name = d['Name']
                remote_libraries[library_id] = library_name
        except Exception as e:
            raise ValidationError(f'Jellyfin Media Server returned unexpected data, '
                                  f'the JSON it returned could not be parsed and the '
                                  f'error was "{e}"')
        # Validate the library IDs
        remote_libraries_desc = []
        for remote_library_id, remote_library_name in remote_libraries.items():
            remote_libraries_desc.append(f'"{remote_library_name}" with ID '
                                         f'"{remote_library_id}"')
        remote_libraries_str = ', '.join(remote_libraries_desc)
        libraries = options.get('libraries', '').split(',')
        for library_id in map(str.strip, libraries):
            if library_id not in remote_libraries:
                raise ValidationError(f'One or more of your specified library IDs do '
                                      f'not exist on your Jellyfin Media Server. Your '
                                      f'valid libraries are: {remote_libraries_str}')

        return True

    def update(self):
        libraries = self.object.options.get('libraries', '').split(',')
        for library_id in map(str.strip, libraries):
            uri = f'/Items/{library_id}/Refresh'
            response = self.make_request(uri, method='POST')
            if response.status_code != 204:  # 204 No Content is expected for successful refresh
                raise MediaServerError(f'Failed to refresh Jellyfin library "{library_id}", status code: {response.status_code}')
        return True