#!/usr/bin/python
# -*- coding: utf-8 -*-

#import datetime
from fastapi import FastAPI, Request, Response
from fastapi.staticfiles import StaticFiles
import feedgenerator
from slixmpp import ClientXMPP
import xml.etree.ElementTree as ET
#import importlib.resources

try:
    import tomllib
except:
    import tomli as tomllib

app = FastAPI()

class XmppInstance(ClientXMPP):
    def __init__(self, jid, password):
        super().__init__(jid, password)
        self.register_plugin('xep_0060')
        self.connect()
        # self.process(forever=False)

xmpp = None

# Mount static scripts and stylesheet directories
app.mount("/css", StaticFiles(directory="css"), name="css")
app.mount("/script", StaticFiles(directory="script"), name="script")
app.mount("/xsl", StaticFiles(directory="xsl"), name="xsl")


@app.get('/atom')
async def view_pubsub(request: Request):
    global xmpp
    if not xmpp:
        with open('configuration.toml', mode="rb") as configuration:
            credentials = tomllib.load(configuration)['account']
        xmpp = XmppInstance(credentials['xmpp'], credentials['pass'])
        # xmpp.connect()

    pubsub = request.query_params.get('pubsub', '')
    node = request.query_params.get('node', '')
    item_id = request.query_params.get('item', '')
    if pubsub and node and item_id:
        iq = await xmpp.plugin['xep_0060'].get_item(pubsub, node, item_id)
        link = 'xmpp:{pubsub}?;node={node};item={item}'.format(
            pubsub=pubsub, node=node, item=item_id)
        xml_atom = pubsub_to_atom(iq, link)
        result = append_stylesheet(xml_atom)
    elif pubsub and node:
        iq = await xmpp.plugin['xep_0060'].get_items(pubsub, node)
        link = 'xmpp:{pubsub}?;node={node}'.format(pubsub=pubsub, node=node)
        xml_atom = pubsub_to_atom(iq, link)
        result = append_stylesheet(xml_atom)
    elif pubsub:
        iq = await xmpp.plugin['xep_0060'].get_nodes(pubsub)
        link = 'xmpp:{pubsub}'.format(pubsub=pubsub)
        result = pubsub_to_opml(iq)
    elif node:
        result = 'PubSub parameter is missing.'
    else:
        result = ('Mandatory parameter PubSub and '
                  'optional parameter Node are missing.')
    return Response(content=result, media_type="application/xml")

def pubsub_to_atom(iq,link):
    """Convert XEP-0060: Publish-Subscribe to RFC 4287: The Atom Syndication Format."""
    feed = feedgenerator.Atom1Feed(
        description = ('This is a syndication feed generated with PubSub to '
                       'Atom, which conveys XEP-0060: Publish-Subscribe nodes '
                       'to standard RFC 4287: The Atom Syndication Format.'),
        language = iq['pubsub']['items']['lang'],
        link = link,
        subtitle = 'XMPP PubSub Syndication Feed',
        title = iq['pubsub']['items']['node'])
    # See also iq['pubsub']['items']['substanzas']
    entries = iq['pubsub']['items']
    for entry in entries:
        item = entry['payload']
        namespace = '{http://www.w3.org/2005/Atom}'
        title = item.find(namespace + 'title')
        title = None if title == None else title.text
        feed_url = 'sch'
        updated = item.find(namespace + 'updated')
        updated = None if updated == None else updated.text
        # if updated: updated = datetime.datetime.fromisoformat(updated)
        content = item.find(namespace + 'content')
        content = 'No content' if content == None else content.text
        link = item.find(namespace + 'link')
        link = '' if link == None else link.attrib['href']
        author = item.find(namespace + 'author')
        if author and author.attrib: print(author.attrib)
        author = 'None' if author == None else author.text
        # create entry
        feed.add_item(
            description = content,
            # enclosure = feedgenerator.Enclosure(enclosure, enclosure_size, enclosure_type) if args.entry_enclosure else None,
            link = link,
            # pubdate = updated,
            title = title,
            unique_id = link)
    xml_atom = feed.writeString('utf-8')
    xml_atom_extended = append_element(
        xml_atom,
        'generator',
        'XPTA: XMPP PubSub To Atom')
    return xml_atom_extended

"""Patch function to append elements which are not provided by feedgenerator"""
def append_element(xml_data, element, text):
  root = ET.fromstring(xml_data)

  # Create the generator element
  generator_element = ET.Element(element)
  generator_element.text = text

  # Append the generator element to the root
  root.append(generator_element)

  # Return the modified XML as a string
  return ET.tostring(root, encoding='unicode')

"""Patch function to append XSLT reference to XML"""
"""Why is not this a built-in function of ElementTree or LXML"""
def append_stylesheet(xml_data):
    # Register namespace in order to avoide ns0:
    ET.register_namespace("", "http://www.w3.org/2005/Atom")
    # Load XML from string
    tree = ET.fromstring(xml_data)
    # The following direction removes the XML declaration
    xml_data_no_declaration = ET.tostring(tree, encoding='unicode')
    # Add XML declaration and stylesheet
    xml_data_declaration = ('<?xml version="1.0" encoding="utf-8"?>'
                            '<?xml-stylesheet type="text/xsl" href="xsl/stylesheet.xsl"?>' +
                            xml_data_no_declaration)
    return xml_data_declaration