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

import datetime
from fastapi import FastAPI, Request, Response
from fastapi.responses import FileResponse
from fastapi.staticfiles import StaticFiles
import json
from slixmpp import ClientXMPP
from slixmpp.exceptions import IqError, IqTimeout
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 graphic, script and stylesheet directories
app.mount("/css", StaticFiles(directory="css"), name="css")
app.mount("/data", StaticFiles(directory="data"), name="data")
app.mount("/graphic", StaticFiles(directory="graphic"), name="graphic")
app.mount("/script", StaticFiles(directory="script"), name="script")
app.mount("/xsl", StaticFiles(directory="xsl"), name="xsl")

@app.get('/favicon.ico', include_in_schema=False)
async def favicon():
    return FileResponse('favicon.ico')

@app.get('/opml')
async def view_pubsub_nodes(request: Request):
    global xmpp
    if not xmpp:
        credentials = get_configuration('account')
        xmpp = XmppInstance(credentials['xmpp'], credentials['pass'])
        # xmpp.connect()

    pubsub = request.query_params.get('pubsub', '')
    settings = get_configuration('settings')
    result = None
    if settings['service']:
        if settings['include'] in pubsub or not settings['include']:
            if pubsub:
                iq = await get_nodes(pubsub)
                if iq:
                    link = 'xmpp:{pubsub}'.format(pubsub=pubsub)
                    xml_opml = generate_opml(iq)
                    result = append_stylesheet(xml_opml, 'opml.xsl')
                else:
                    text = 'Please check that PubSub Jabber ID is valid and accessible.'
                    xml_atom = error_message(text)
                    result = append_stylesheet(
                        xml_atom, 'atom.xsl', namespace='http://www.w3.org/2005/Atom')
        else:
            text = 'The given domain {} is not allowed.'.format(pubsub)
            xml_atom = error_message(text)
            result = append_stylesheet(
                xml_atom, 'atom.xsl', namespace='http://www.w3.org/2005/Atom')
    default = get_configuration('default')
    if not result:
        if default['pubsub']:
            if not pubsub:
                pubsub = default['pubsub']
                iq = await get_nodes(pubsub)
                link = 'xmpp:{pubsub}'.format(pubsub=pubsub)
                xml_opml = generate_opml(iq)
                result = append_stylesheet(xml_opml, 'opml.xsl')
            elif not settings['service']:
                pubsub = default['pubsub']
                link = 'xmpp:{pubsub}'.format(pubsub=pubsub)
                xml_opml = generate_opml(iq)
                result = append_stylesheet(xml_opml, 'opml.xsl')
        else:
            text = 'Please contact the administrator and ask him to set default PubSub and Node ID.'
            xml_atom = error_message(text)
            result = append_stylesheet(
                xml_atom, 'atom.xsl', namespace='http://www.w3.org/2005/Atom')
    response = Response(content=result, media_type="application/xml")
    return response

@app.get('/atom')
async def view_node_items(request: Request):
    global xmpp
    if not xmpp:
        credentials = get_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', '')
    settings = get_configuration('settings')
    result = None
    if settings['service']:
        if settings['include'] in pubsub or not settings['include']:
            if pubsub and node and item_id:
                iq = await get_node_item(pubsub, node, item_id)
                if iq:
                    link = form_an_item_link(pubsub, node, item_id)
                    xml_atom = generate_atom(iq, link)
                    iq = await get_node_items(pubsub, node)
                    if iq:
                        generate_json(iq)
                    else:
                        operator = get_configuration('settings')['operator']
                        json_data = [{'title' : 'Error retrieving items list.',
                                      'link' : ('javascript:alert("XJP: XMPP Journal Publisher has experienced an error '
                                                'while attempting to retrieve the list of items for Node {} of PubSub {}.")')
                                                .format(node, pubsub)},
                                     {'title' : 'Contact the operator.',
                                      'link' : ('xmpp:{}?message;subject=XJP: XMPP Journal Publisher;body=Greetings! '
                                                'I am contacting you to inform you that there is an error listing '
                                                'node items for Node {} on PubSub {}.').format(operator, node, pubsub)}]
                        filename = 'data/{}.json'.format(node)
                        with open(filename, 'w', encoding='utf-8') as f:
                            json.dump(json_data, f, ensure_ascii=False, indent=4)
                else:
                    text = 'Please check that PubSub node and item are valid and accessible.'
                    xml_atom = error_message(text)
                result = append_stylesheet(
                    xml_atom, 'atom.xsl', namespace='http://www.w3.org/2005/Atom')
                
                # try:
                #     iq = await get_node_items(pubsub, node)
                #     generate_json(iq, node)
                # except:
                #     operator = get_configuration('settings')['operator']
                #     json_data = [{'title' : 'Timeout retrieving node items from {}'.format(node),
                #                   'link' : 'xmpp:{}?message'.format(operator)}]
                #     filename = 'data/{}.json'.format(node)
                #     with open(filename, 'w', encoding='utf-8') as f:
                #         json.dump(json_data, f, ensure_ascii=False, indent=4)
            elif pubsub and node:
                iq = await get_node_items(pubsub, node)
                if iq:
                    link = form_a_node_link(pubsub, node)
                    xml_atom = generate_atom(iq, link)
                else:
                    text = 'Please check that PubSub node is valid and accessible.'
                    xml_atom = error_message(text)
                result = append_stylesheet(
                    xml_atom, 'atom.xsl', namespace='http://www.w3.org/2005/Atom')
            elif pubsub:
                text = 'Node parameter is missing.'
                xml_atom = error_message(text)
                result = append_stylesheet(
                    xml_atom, 'atom.xsl', namespace='http://www.w3.org/2005/Atom')
            elif node:
                text = 'PubSub parameter is missing.'
                xml_atom = error_message(text)
                result = append_stylesheet(
                    xml_atom, 'atom.xsl', namespace='http://www.w3.org/2005/Atom')
            # else:
            #     result = ('Mandatory parameter PubSub and '
            #               'optional parameter Node are missing.')
        else:
            text = 'The given domain {} is not allowed.'.format(pubsub)
            xml_atom = error_message(text)
            result = append_stylesheet(
                xml_atom, 'atom.xsl', namespace='http://www.w3.org/2005/Atom')
    default = get_configuration('default')
    if not result:
        if default['pubsub'] and default['nodeid']:
            if not pubsub and not node:
                pubsub = default['pubsub']
                node = default['nodeid']
                iq = await get_node_items(pubsub, node)
                link = form_a_node_link(pubsub, node)
                xml_atom = generate_atom(iq, link)
                result = append_stylesheet(
                    xml_atom, 'atom.xsl', namespace='http://www.w3.org/2005/Atom')
            elif not settings['service']:
                pubsub = default['pubsub']
                node = default['nodeid']
                iq = await get_node_items(pubsub, node)
                link = form_a_node_link(pubsub, node)
                xml_atom = generate_atom(iq, link)
                result = append_stylesheet(
                    xml_atom, 'atom.xsl', namespace='http://www.w3.org/2005/Atom')
        else:
            text = 'Please contact the administrator and ask him to set default PubSub and Node ID.'
            xml_atom = error_message(text)
            result = append_stylesheet(
                xml_atom, 'atom.xsl', namespace='http://www.w3.org/2005/Atom')
    response = Response(content=result, media_type="application/xml")
    return response

def get_configuration(section):
    with open('configuration.toml', mode="rb") as configuration:
        result = tomllib.load(configuration)[section]
    return result

#@timeout(5)
async def get_node_item(pubsub, node, item_id):
    try:
      iq = await xmpp.plugin['xep_0060'].get_item(pubsub, node, item_id, timeout=5)
      return iq
    except (IqError, IqTimeout) as e:
      print(e)

async def get_node_items(pubsub, node):
    try:
      iq = await xmpp.plugin['xep_0060'].get_items(pubsub, node, timeout=5)
      return iq
    except (IqError, IqTimeout) as e:
      print(e)

async def get_nodes(pubsub):
    try:
      iq = await xmpp.plugin['xep_0060'].get_nodes(pubsub, timeout=5)
      return iq
    except (IqError, IqTimeout) as e:
      print(e)

def form_a_node_link(pubsub, node):
    link = 'xmpp:{pubsub}?;node={node}'.format(pubsub=pubsub, node=node)
    return link

def form_an_item_link(pubsub, node, item_id):
    link = 'xmpp:{pubsub}?;node={node};item={item}'.format(
        pubsub=pubsub, node=node, item=item_id)
    return link

def error_message(text):
    """Error message in RFC 4287: The Atom Syndication Format."""
    title = 'StreamBurner'
    subtitle = 'XMPP Journal Publisher'
    description = ('This is a syndication feed generated with XMPP Journal '
                   'Publisher, which conveys XEP-0060: Publish-Subscribe '
                   'nodes to standard RFC 4287: The Atom Syndication Format.')
    language = 'en'
    feed = ET.Element("feed")
    feed.set('xmlns', 'http://www.w3.org/2005/Atom')
    ET.SubElement(feed, 'title', {'type': 'text'}).text = title
    ET.SubElement(feed, 'subtitle', {'type': 'text'}).text = subtitle
    ET.SubElement(feed, 'author', {'name':'XMPP Journal Publisher','email':'xjp@schimon.i2p'})
    ET.SubElement(feed, 'generator', {
        'uri': 'https://git.xmpp-it.net/sch/XJP',
        'version': '0.1'}).text = 'XMPP Journal Publisher (XJP)'
    ET.SubElement(feed, 'updated').text = datetime.datetime.now(datetime.UTC).isoformat()
    entry = ET.SubElement(feed, 'entry')
    ET.SubElement(entry, 'title').text = 'Error'
    ET.SubElement(entry, 'id').text = 'xjp-error'
    ET.SubElement(entry, 'updated').text = datetime.datetime.now(datetime.UTC).isoformat()
    ET.SubElement(entry, 'published').text = datetime.datetime.now(datetime.UTC).isoformat()
    # ET.SubElement(entry, 'summary', {'type': summary_type_text}).text = summary_text
    ET.SubElement(entry, 'content', {'type': 'text'}).text = text
    return ET.tostring(feed, encoding='unicode')

# generate_rfc_4287
def generate_atom(iq, link):
    """Generate an Atom Syndication Format (RFC 4287) from a Publish-Subscribe (XEP-0060) node items."""
    pubsub = iq['from'].bare
    node = iq['pubsub']['items']['node']
    title = node
    link = link
    # link = form_a_node_link(pubsub, node)
    # subtitle = 'XMPP PubSub Syndication Feed'
    subtitle = pubsub
    description = ('This is a syndication feed generated with XMPP Journal '
                   'Publisher, which conveys XEP-0060: Publish-Subscribe '
                   'nodes to standard RFC 4287: The Atom Syndication Format.')
    language = iq['pubsub']['items']['lang']
    items = iq['pubsub']['items']
    feed = ET.Element("feed")
    feed.set('xmlns', 'http://www.w3.org/2005/Atom')
    ET.SubElement(feed, 'title', {'type': 'text'}).text = title
    ET.SubElement(feed, 'subtitle', {'type': 'text'}).text = subtitle
    ET.SubElement(feed, 'link', {'rel': 'self', 'href': link})
    ET.SubElement(feed, 'generator', {
        'uri': 'https://git.xmpp-it.net/sch/XJP',
        'version': '0.1'}).text = 'XMPP Journal Publisher (XJP)'
    ET.SubElement(feed, 'updated').text = datetime.datetime.now(datetime.UTC).isoformat()
    for item in items:
        item_id = item['id']
        item_payload = item['payload']
        namespace = '{http://www.w3.org/2005/Atom}'
        title = item_payload.find(namespace + 'title')
        title_text = None if title == None else title.text
        # link = item_payload.find(namespace + 'link')
        # link_href = '' if link == None else link.attrib['href']
        link_href = form_an_item_link(pubsub, node, item_id)
        if not title_text or not link_href: continue
        content = item_payload.find(namespace + 'content')
        content_text = 'No content' if content == None else content.text
        if content:
            content_type = content.attrib['type'] if 'type' in content.attrib else 'text'
            content_type_text = 'html' if 'html' in content_type else 'text'
        else:
            content_type_text = 'html'
        published = item_payload.find(namespace + 'published')
        published_text = None if published == None else published.text
        updated = item_payload.find(namespace + 'updated')
        updated_text = None if updated == None else updated.text
        author = item_payload.find(namespace + 'author')
        if author and author.attrib: print(author.attrib)
        identifier = item_payload.find(namespace + 'id')
        if identifier and identifier.attrib: print(identifier.attrib)
        identifier_text = 'None' if identifier == None else identifier.text
        entry = ET.SubElement(feed, 'entry')
        ET.SubElement(entry, 'title').text = title_text
        ET.SubElement(entry, 'link', {'href': link_href})
        ET.SubElement(entry, 'id').text = identifier_text
        ET.SubElement(entry, 'updated').text = updated_text
        ET.SubElement(entry, 'published').text = published_text
        # ET.SubElement(entry, 'summary', {'type': summary_type_text}).text = summary_text
        ET.SubElement(entry, 'content', {'type': content_type_text}).text = content_text
    return ET.tostring(feed, encoding='unicode')

def generate_json(iq):
    """Create a JSON file from node items."""
    json_data = []
    pubsub = iq['from'].bare
    node = iq['pubsub']['items']['node']
    entries = iq['pubsub']['items']
    for entry in entries:
        item_id = entry['id']
        item_payload = entry['payload']
        namespace = '{http://www.w3.org/2005/Atom}'
        title = item_payload.find(namespace + 'title')
        title_text = '*** No Title ***' if title == None else title.text
        # updated = item.find(namespace + 'updated')
        # updated = None if updated == None else updated.text
        # if updated: updated = datetime.datetime.fromisoformat(updated)
        link_href = form_an_item_link(pubsub, node, item_id)
        # link = item.find(namespace + 'link')
        # link_href = '' if link == None else link.attrib['href']
        json_data_entry = {'title' : title_text,
                           'link' : link_href}
        json_data.append(json_data_entry)
        if len(json_data) > 6: break
    filename = 'data/{}.json'.format(node)
    with open(filename, 'w', encoding='utf-8') as f:
        json.dump(json_data, f, ensure_ascii=False, indent=4)

"""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, filename, namespace=None):
    # Register namespace in order to avoide ns0:
    if namespace: ET.register_namespace("", namespace)
    # Load XML from string
    tree = ET.fromstring(xml_data)
    # The following direction removes the XML declaration
    xml_data_without_a_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/{}"?>'.format(filename) +
        xml_data_without_a_declaration)
    return xml_data_declaration

def generate_opml(iq):
    pubsub = iq['from'].bare
    items = iq['disco_items']['items']
    opml = ET.Element("opml")
    opml.set("version", "1.0")
    head = ET.SubElement(opml, "head")
    ET.SubElement(head, "title").text = pubsub
    ET.SubElement(head, "description").text = (
        "PubSub Nodes of {}").format(pubsub)
    ET.SubElement(head, "generator").text = 'XMPP Journal Publisher (XJP)'
    ET.SubElement(head, "urlPublic").text = 'https://git.xmpp-it.net/sch/XJP'
    time_stamp = datetime.datetime.now(datetime.UTC).isoformat()
    ET.SubElement(head, "dateCreated").text = time_stamp
    ET.SubElement(head, "dateModified").text = time_stamp
    body = ET.SubElement(opml, "body")
    for item in items:
        pubsub, node, title = item
        uri = form_a_node_link(pubsub, node)
        outline = ET.SubElement(body, "outline")
        outline.set("text", title or node)
        outline.set("xmlUrl", uri)
    return ET.tostring(opml, encoding='unicode')