datings.py

import csv
import datetime
from abc import ABCMeta, abstractmethod
from collections import namedtuple, defaultdict
from typing import List, Tuple, Optional, Any, Dict

import networkx as nx
import requests
from lxml import etree
from more_itertools import pairwise

import faust
from faust_logging import logging
from uris import Witness, Reference

logger = logging.getLogger(__name__)


def _parse_datestr(datestr: str) -> datetime.date:
    if datestr is None:
        return None

    dt = datetime.datetime.strptime(datestr, '%Y-%m-%d')
    if dt is not None:
        return dt.date()
    else:
        return None


class InvalidDatingError(ValueError):

    def __init__(self, msg, element: Optional[etree._Element] = None):
        if element is not None:
            xml = etree.tostring(element, pretty_print=True, encoding='unicode')
            msg = f"{msg}:\n{xml} at {element.getroottree().docinfo.URL}:{element.sourceline}"
        super().__init__(msg)


BibEntry = namedtuple('BibEntry', ['uri', 'citation', 'reference', 'weight'])


def _parse_bibliography(url):
    db: Dict[str, BibEntry] = {}
    scores = _read_scores()
    et = etree.fromstring(requests.get(url).content)
    for bib in et.xpath('//f:bib', namespaces=faust.namespaces):
        uri = bib.get('uri')
        citation = bib.find('f:citation', namespaces=faust.namespaces).text
        reference = bib.find('f:reference', namespaces=faust.namespaces).text
        db[uri] = BibEntry(uri, citation, reference, scores[uri])
    return db


def _read_scores():
    scores = defaultdict(lambda: 1)
    try:
        with open('bibscores.tsv', encoding='utf-8') as scorefile:
            r = csv.reader(scorefile, delimiter='\t')
            for row in r:
                try:
                    scores[row[0]] = int(row[1])
                except ValueError as e:
                    logger.warning('Skipping row %s: %s', row, e)
    except FileNotFoundError as e:
        logger.warning('Could not read score file: %s. Will use default score', e)
    return scores


_bib_db = _parse_bibliography('https://raw.githubusercontent.com/faustedition/faust-gen-html/master/xslt/bibliography.xml')


class BiblSource:
    """
    A bibliographic source
    """

    def __init__(self, uri, detail=''):
        self.uri = uri
        self.detail = detail
        self.weight = _bib_db[uri].weight if uri in _bib_db else 1

    def __eq__(self, other):
        if isinstance(other, BiblSource):
            return self.uri == other.uri and self.detail == other.detail
        else:
            return super().__eq__(other)

    def __hash__(self):
        return hash(self.uri) ^ hash(self.detail)

    def __str__(self):
        result = self.citation
        if self.detail is not None:
            result += '\n' + self.detail
        return result

    @property
    def filename(self):
        if self.uri.startswith('faust://bibliography'):
            return self.uri.replace('faust://bibliography/', '')
        else:
            return self.uri.replace('faust://', '').replace('/', '-')

    @property
    def citation(self):
        if self.uri in _bib_db:
            return _bib_db[self.uri].citation
        else:
            return self.filename


class _AbstractDating(metaclass=ABCMeta):

    def __init__(self, el: etree._Element):
        self.items: List[Reference] = [Witness.get(uri) for uri in el.xpath('f:item/@uri', namespaces=faust.namespaces)]
        self.sources = tuple(BiblSource(source.get('uri'), source.text)
                             for source in el.xpath('f:source', namespaces=faust.namespaces))
        self.comments = tuple(comment.text for comment in el.xpath('f:comment', namespaces=faust.namespaces))
        self.xmlsource: Tuple[str, int] = (faust.relative_path(el.getroottree().docinfo.URL), el.sourceline)

    @abstractmethod
    def add_to_graph(self, G: nx.MultiDiGraph):
        ...


def _firstattr(object, *args: Tuple[str]) -> Optional[Tuple[str, Any]]:
    for attribute in args:
        value = getattr(object, attribute, None)
        if value is not None:
            return attribute, value
    return None, None


class AbsoluteDating(_AbstractDating):

    def __init__(self, el: etree._Element):
        super().__init__(el)
        self.from_ = _parse_datestr(el.get('from', None))
        self.to = _parse_datestr(el.get('to', None))
        self.not_before = _parse_datestr(el.get('notBefore', None))
        self.not_after = _parse_datestr(el.get('notAfter', None))
        self.when = _parse_datestr(el.get('when', None))
        self.normalized = el.get('type', '') == 'normalized'

        if self.start is None and self.end is None:
            raise InvalidDatingError('Absolute dating without a date', el)
        elif self.date_before is not None and self.date_after is not None and not self.date_before < self.date_after:
            raise InvalidDatingError('Backwards dating (%s), this would have caused a conflict' % self, el)

    @property
    def start_attr(self):
        return _firstattr(self, 'from_', 'when', 'not_before')

    @property
    def end_attr(self):
        return _firstattr(self, 'to', 'when', 'not_after')

    @property
    def start(self) -> Optional[datetime.date]:
        return self.start_attr[1]

    @property
    def end(self) -> Optional[datetime.date]:
        return self.end_attr[1]

    @property
    def date_before(self) -> Optional[datetime.date]:
        return self.start - datetime.timedelta(days=1) if self.start is not None else None

    @property
    def date_after(self) -> Optional[datetime.date]:
        return self.end + datetime.timedelta(days=1) if self.end is not None else None

    def __str__(self):
        if self.when is not None:
            result = self.when.isoformat()
        else:
            result = ''
            if self.start is not None: result += self.start.isoformat()
            result += ' .. '
            if self.end is not None: result += self.end.isoformat()
        return result

    def add_to_graph(self, G: nx.MultiDiGraph):
        for item in self.items:
            for source in self.sources:
                if self.start is not None:
                    G.add_edge(self.date_before, item, kind=self.start_attr[0], source=source, dating=self, xml=self.xmlsource)
                if self.end is not None:
                    G.add_edge(item, self.date_after, kind=self.end_attr[0], source=source, dating=self, xml=self.xmlsource)


class RelativeDating(_AbstractDating):

    def __init__(self, el: etree._Element):
        super().__init__(el)
        self.kind = el.get('name')

    def add_to_graph(self, G: nx.MultiDiGraph) -> None:
        """
        Adds nodes for the given relative dating to the graph.

        Args:
            G: the graph to work on
        """
        G.add_nodes_from(self.items)
        for source in self.sources:
            G.add_edges_from(pairwise(self.items),
                             kind=self.kind,
                             source=source,
                             comments=self.comments,
                             dating=self,
                             xml=self.xmlsource)


def _parse_file(filename: str):
    tree = etree.parse(filename)
    for element in tree.xpath('//f:relation', namespaces=faust.namespaces):
        yield RelativeDating(element)
    for element in tree.xpath('//f:date', namespaces=faust.namespaces):
        try:
            yield AbsoluteDating(element)
        except InvalidDatingError as e:
            logger.error(str(e))


def _parse_files():
    for file in faust.macrogenesis_files():
        yield from _parse_file(file)


def add_timeline_edges(graph):
    date_nodes = sorted(node for node in graph.nodes if isinstance(node, datetime.date))
    for earlier, later in pairwise(date_nodes):
        if earlier != later and (earlier, later) not in graph.edges:
            graph.add_edge(earlier, later, kind='timeline')


def base_graph():
    graph = nx.MultiDiGraph()
    logger.info('Reading data to build base graph ...')
    for dating in _parse_files():
        dating.add_to_graph(graph)
    add_timeline_edges(graph)
    return graph


def cycle_subgraphs(graph: nx.Graph):
    """
    Extracts the strongly connected components of the given graph. Those components
    that consist of more than one nodes are then returned, sorted by size (in nodes,
    descending)

    Args:
        graph: a graph

    Returns:
        list of subgraphs
    """
    cycles = [cycle for cycle in nx.strongly_connected_components(graph) if len(cycle) > 1]
    sorted_cycles = sorted(cycles, key=len, reverse=True)
    return [graph.subgraph(cycle) for cycle in sorted_cycles]