"""POST /api/chat — placeholder (phase 01).

Phase 03 replaces this with the real RAG pipeline and SSE streaming
(PLAN §4 contract: ``delta`` events + final ``done``). The placeholder
keeps the same JSON shape the frontend already consumes, so the UI round-trip
is exercised end-to-end from day one.
"""
from __future__ import annotations

from fastapi import APIRouter

from app.schemas import ChatRequest

router = APIRouter()


@router.post("/chat")
async def chat(request: ChatRequest) -> dict[str, object]:
    """Placeholder answer — no LLM, no DB."""
    return {
        "ok": True,
        "answer": (
            "Hey! My neurons are still wiring up — the real Brain "
            "(RAG over your docs, powered by aipi) lands in the next "
            "phases. Try me again soon! 🧠"
        ),
        "deflected": False,
        "sources": [],
    }