"""Rows to API shapes.

A conversation has no title column: the first message is the title, derived
here so the list and the detail can never disagree about what a conversation
is called.
"""

from app.api.conversations.schemas import MessageOut, MessageSource
from app.models import Message
from app.modes.query import excerpt as clean_excerpt

TITLE_LENGTH = 80


def title(first_message: str | None) -> str | None:
    if not first_message:
        return None
    flattened = " ".join(first_message.split())
    if len(flattened) <= TITLE_LENGTH:
        return flattened
    return flattened[: TITLE_LENGTH - 1] + "…"


def message_out(message: Message) -> MessageOut:
    """Message + its citation snapshot from `meta` (assistant turns only).

    The excerpt is re-cleaned on the way out, not just on the way in. It is
    a presentation detail frozen at answer time, so an improvement to the
    cleaning would otherwise only reach conversations created afterwards,
    and every existing citation would keep showing raw Markdown forever.
    Cleaning is idempotent, so text stored by a newer backend passes
    through untouched.
    """
    meta = message.meta or {}
    sources = [
        MessageSource.model_validate(item).model_copy(
            update={"excerpt": clean_excerpt(item.get("excerpt", ""))}
        )
        for item in meta.get("sources", [])
    ]
    return MessageOut.model_validate(message).model_copy(
        update={"sources": sources, "fallback": meta.get("fallback")}
    )