MementoSet

memento_set.py

import dataclasses
from datetime import datetime
from typing import Optional, Dict, Iterable


@dataclasses.dataclass(frozen=True)
class Memento:
    original_url: str
    time: datetime
    archived_headers_cid: str
    archived_body_cid: str

    data: Optional[Dict[str, str]] = None


@dataclasses.dataclass(frozen=True)
class MementoCursor:
    first: Optional[Memento]
    previous: Optional[Memento]
    closest: Optional[Memento]
    next: Optional[Memento]
    last: Optional[Memento]


@dataclasses.dataclass(frozen=True)
class MementoSet:
    original_uri: Optional[str] = None

    def all(self) -> Iterable[Memento]:
        ...

    def by_original_uri(self, uri: Optional[str]) -> 'MementoSet':
        return dataclasses.replace(
            self,
            original_uri=uri,
        )

    def first(self) -> Optional[Memento]:
        ...

    def last(self) -> Optional[Memento]:
        ...

    def closest_to(self, time: datetime) -> Optional[Memento]:
        ...

    def before(self, memento: Memento) -> Optional[Memento]:
        ...

    def after(self, memento: Memento) -> Optional[Memento]:
        ...

    def cursor(self, time: datetime) -> MementoCursor:
        closest = self.closest_to(time)
        return MementoCursor(
            first=self.first(),
            previous=self.before(closest) if closest is not None else None,
            closest=closest,
            next=self.after(closest) if closest is not None else None,
            last=self.last()
        )