Experimentations with Data Classes (PEP 557 – https://www.python.org/dev/peps/pep-0557/)

dataclasses.py

from dataclasses import dataclass
from itertools import groupby
from operator import countOf
from typing import Callable, Dict, Iterable, List, Tuple


@dataclass
class Document:
    url: str
    title: str
    thumbnail: str
    caption: str
    description: str
    issued: str
    tenant_id: str
    publisher: str
    live_now: bool
    is_live: bool

    def __post_init__(self) -> None:
        self.id = self.url


def live_doc(doc: Document) -> bool:
    return doc.live_now or doc.is_live


class Roster:
    def __init__(self) -> None:
        self.docs_list: List[Document] = []
        self.docs_dict: Dict[str, Document] = {}

    def add(self, doc: Document):
        if doc.id in self.docs_dict:
            raise ValueError(f'Duplicated doc {doc.id}')
        self.docs_list.append(doc)
        self.docs_dict[doc.id] = doc
        return self

    def _projection(
                self, attr: str, filter: Callable[[Document], bool]
            ) -> Iterable[str]:
        return (getattr(doc, attr) for doc in self.docs_list if filter(doc))

    @property
    def tenant_id(self) -> Iterable[Tuple[str, Iterable[str]]]:
        return groupby(self._projection('tenant_id', live_doc))

    @property
    def count_tenant_id(self) -> Iterable[Tuple[str, int]]:
        return [
            (tenant_id, len(list(docs)))
            for tenant_id, docs in self.tenant_id
        ]

    @property
    def num_docs(self) -> int:
        return len(self.docs_list)

    @property
    def live_docs(self) -> int:
        return countOf(list(map(live_doc, self.docs_list)), True)

    def __repr__(self):
        return (
            f'Roster Numdocs {{{self.num_docs}}} '
            f'Live docs {{{self.live_docs}: {self.count_tenant_id}}}.'
        )


if __name__ == '__main__':
    doc1 = Document(
        'https://g1.globo.com/foo.ghtml',
        'Sint laborum ex tempor incididunt',
        'https://s2.glbimg.com/foo.jpg',
        'Velit labore dolor amet',
        'Occaecat ea duis mollit nisi et occaecat cupidatat ullamco. Nisi '
        'ex elit. Magna eu duis magna occaecat officia ex officia et. '
        'Deserunt fugiat quis nulla elit duis ex cupidatat qui aute. Et '
        'cupidatat laboris voluptate ullamco.',
        '2017-12-17T19:48:29Z',
        'g1',
        'G1',
        True,
        False,
    )
    print(doc1)
    doc2 = Document(
        'http://gshow.globo.com/bar.html',
        'Eu id elit officia velit commodo',
        'https://s2.glbimg.com/bar.jpg',
        'Quis in culpa dolor quis',
        'Esse adipisicing elit amet anim minim enim eiusmod laborum nisi '
        'laborum exercitation. Labore adipisicing anim deserunt veniam id '
        'minim fugiat voluptate. Eiusmod voluptate consequat esse anim '
        'reprehenderit nostrud.',
        '2017-12-17T19:48:29Z',
        'gshow',
        'Gshow',
        False,
        True,
    )
    print(doc2)

    roster = Roster()
    roster.add(doc1).add(doc2)

    print(roster)

    doc1.live_now = False

    print(roster)