"""AI Chat: a plain scratchpad for talking to a model directly. Power users reach it, which means the `AIDND_POWER_USERS` email allowlist. It is deliberately thin. It adds no story context, no scripts, and no world state, and it persists nothing. The conversation lives in the browser and is posted in full on each turn. It exists for testing models, prompts, and endpoints without starting an adventure. Model choice is free when the user brought their own API key. On the shared demo key the model stays pinned to the `AIDND_DEMO_MODELS` allowlist, exactly as it is for turns. The server funds that key, so this page must not let it reach paid models. """ from fastapi import APIRouter, Depends, HTTPException, Request from fastapi.responses import StreamingResponse from sqlalchemy.orm import Session from .. import auth, limits, models, schemas from ..database import get_db from ..providers import OpenAICompatibleProvider, ProviderError from .adventures import SSE_HEADERS, sse from .settings import get_settings, list_endpoint_models router = APIRouter(prefix="/api/chat", tags=["chat"]) def power_user( db: Session = Depends(get_db), user: models.User = Depends(auth.get_current_user), ) -> models.User: """Gate for the whole router. 404 rather than 403 so the feature simply doesn't appear to exist for everyone else.""" if not auth.is_power_user(user): raise HTTPException(404, "Not found") return user PowerUser = Depends(power_user) def _resolve_model( settings: models.Settings, requested: str | None ) -> tuple[auth.ProviderConfig, str | None]: """Returns the provider config for this chat, plus a note when the requested model was not used. The pinning rule lives in `resolve_provider_config`. This function only reports the substitution that call made, so one place decides what the demo key may talk to. """ cfg = auth.resolve_provider_config(settings, model_override=requested) wanted = (requested or "").strip() if wanted and wanted != cfg.model: return cfg, ( f"'{wanted}' isn't available on the shared demo key — using " f"{cfg.model}. Add your own API key in Settings to use any model." ) return cfg, None @router.get("/config") async def chat_config( db: Session = Depends(get_db), user: models.User = PowerUser, ): """Returns what this page can talk to. The response holds the resolved endpoint and model, whether model choice is pinned to the demo allowlist, and the endpoint's model listing. The listing is best effort, and an unreachable endpoint returns an empty list. """ settings = get_settings(db, user) cfg = auth.resolve_provider_config(settings) listing = await list_endpoint_models(cfg) return { "endpoint_url": cfg.endpoint_url, "model": cfg.model, "using_demo": cfg.using_demo, "api_mode": settings.api_mode, "temperature": settings.temperature, "max_tokens": settings.max_output_tokens, # On the demo key the whitelist IS the list of choices; otherwise it's # whatever the endpoint advertises (suggestions, not a restriction). "models": auth.DEMO_MODELS if cfg.using_demo else listing.get("models", []), "models_error": None if listing.get("ok") else listing.get("detail"), } async def run_chat(cfg: auth.ProviderConfig, settings: models.Settings, payload: schemas.ChatRequest, note: str | None, db: Session, user: models.User): """Streams the reply as SSE, using the turn stream's event shape. The generator emits `reasoning` and `chunk` events while generating and then a `done` event, so the frontend reuses the same code. """ if note: yield sse({"type": "note", "detail": note}) provider = OpenAICompatibleProvider( cfg.endpoint_url, cfg.api_key, cfg.model, settings.api_mode, settings.reasoning_max_tokens, ) messages = [m.model_dump() for m in payload.messages] chunks: list[str] = [] reasoning_chunks: list[str] = [] try: async for kind, chunk in provider.chat( messages, temperature=payload.temperature if payload.temperature is not None else settings.temperature, max_tokens=payload.max_tokens or settings.max_output_tokens, ): if kind == "reasoning": reasoning_chunks.append(chunk) yield sse({"type": "reasoning", "text": chunk}) else: chunks.append(chunk) yield sse({"type": "chunk", "text": chunk}) except ProviderError as exc: yield sse({"type": "error", "detail": str(exc)}) return text = "".join(chunks).strip() if not text: detail = ( "The model used its entire token budget on reasoning and returned no " "reply — raise max tokens, cap the reasoning budget in Settings, or " "use a non-reasoning model." if reasoning_chunks else "The AI returned an empty response." ) yield sse({"type": "error", "detail": detail}) return if cfg.using_demo: # Unmetered for power users (count_demo_turn is a no-op for them), but # keep the call so the accounting stays right if the gate ever widens. auth.count_demo_turn(user) db.commit() yield sse({ "type": "done", "text": text, "reasoning": "".join(reasoning_chunks).strip() or None, "model": cfg.model, }) @router.post("/stream") def chat_stream( payload: schemas.ChatRequest, request: Request, db: Session = Depends(get_db), user: models.User = PowerUser, ): total = sum(len(m.content) for m in payload.messages) if total > schemas.CHAT_TOTAL_MAX: raise HTTPException( 413, f"This conversation is too long to send ({total:,} characters) — " "clear it or start a new one." ) limits.rate_limit("chat", request, user) settings = get_settings(db, user) cfg, note = _resolve_model(settings, payload.model) if not cfg.model: raise HTTPException(400, "No model configured — set one in Settings or pick one here.") return StreamingResponse( run_chat(cfg, settings, payload, note, db, user), media_type="text/event-stream", headers=SSE_HEADERS, )