from __future__ import annotations

from pathlib import Path

from fastapi import FastAPI, HTTPException
from fastapi.responses import FileResponse
from fastapi.staticfiles import StaticFiles
from pydantic import BaseModel, Field

from .config_loader import business_config
from .scheme_engine import create_session, handle_message
from .settings import settings

STATIC_DIR = Path(__file__).resolve().parent / "static"

app = FastAPI(title=settings.app_name, version="0.1.0")
app.mount("/static", StaticFiles(directory=STATIC_DIR), name="static")


class ChatRequest(BaseModel):
    message: str = Field(..., min_length=1)
    session_id: str | None = None


class SessionResponse(BaseModel):
    session_id: str


@app.get("/")
def index() -> FileResponse:
    return FileResponse(STATIC_DIR / "index.html")


@app.get("/api/health")
def health() -> dict:
    return {
        "ok": True,
        "app": settings.app_name,
        "retrieval_backend": settings.retrieval_backend,
        "slots": len(business_config.slots),
        "rules": len(business_config.rules),
    }


@app.get("/api/config/slots")
def get_slots() -> dict:
    return business_config.slots_doc


@app.get("/api/config/decision-tree")
def get_tree() -> dict:
    return business_config.tree_doc


@app.post("/api/admin/reload-config")
def reload_config() -> dict:
    business_config.reload()
    return {"reloaded": True, "slots": len(business_config.slots), "rules": len(business_config.rules)}


@app.post("/api/sessions", response_model=SessionResponse)
def api_create_session() -> SessionResponse:
    session = create_session()
    return SessionResponse(session_id=session.id)


@app.post("/api/chat")
def api_chat(body: ChatRequest) -> dict:
    session_id = body.session_id
    if not session_id:
        session_id = create_session().id
    try:
        return handle_message(session_id, body.message)
    except KeyError:
        raise HTTPException(status_code=404, detail="session_not_found") from None