# Copyright (c) 2026 Krzysztof Rudnicki. MIT licence.
"""Answering a specific message rather than the room.

The container advertises this: /v1/about reports
``capabilities: {"v2/send": ["quotes", "mentions"]}`` and /v2/send accepts
``quote_timestamp``, ``quote_author`` and ``quote_message``.

A quote needs the *sent timestamp of the message being answered*, which is why
``IncomingMessage`` had to start carrying one -- parse_envelope threw it away,
so until now nothing downstream could have built a quote even in principle.
"""

from __future__ import annotations

from dataclasses import dataclass
from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from signal_bot.models import IncomingMessage


@dataclass(frozen=True, slots=True)
class Quote:
    """The message a reply points at."""

    timestamp: int
    author: str
    text: str

    def payload(self) -> dict[str, str | int]:
        """The three keys /v2/send wants for a quoted reply."""
        return {
            "quote_timestamp": self.timestamp,
            "quote_author": self.author,
            "quote_message": self.text,
        }


def quote_of(message: IncomingMessage) -> Quote | None:
    """Return the quote that answers this message, or None if it has none.

    Both fields are required by the API, and an envelope missing either is a
    shape this bot has not seen -- worth replying without a quote rather than
    sending something the container will reject.
    """
    if not message.timestamp or not message.source_uuid:
        return None
    return Quote(message.timestamp, message.source_uuid, message.text or "")