"""
FILE: app/main.py
DESCRIPTION: Bootstrap der FastAPI Anwendung für WP-25 (Agentic RAG).
             Orchestriert Lifespan-Events, globale Fehlerbehandlung und Routing.
VERSION: 1.0.0 (WP-25 Release)
STATUS: Active
DEPENDENCIES: app.config, app.routers.*, app.services.llm_service
"""

from __future__ import annotations
import logging
import os
from contextlib import asynccontextmanager
from fastapi import FastAPI, Request
from fastapi.responses import JSONResponse

from .config import get_settings
from .services.llm_service import LLMService

# Import der Router
from .routers.query import router as query_router
from .routers.graph import router as graph_router
from .routers.tools import router as tools_router
from .routers.feedback import router as feedback_router
from .routers.chat import router as chat_router
from .routers.ingest import router as ingest_router

try:
    from .routers.admin import router as admin_router
except Exception:
    admin_router = None

from .core.logging_setup import setup_logging

# Initialisierung noch VOR create_app()
setup_logging()

logger = logging.getLogger(__name__)

# --- WP-25: Lifespan Management ---

@asynccontextmanager
async def lifespan(app: FastAPI):
    """
    Verwaltet den Lebenszyklus der Anwendung.
    Führt Startup-Prüfungen durch und bereinigt Ressourcen beim Shutdown.
    """
    settings = get_settings()
    logger.info("🚀 mindnet API: Starting up (WP-25 Agentic RAG Mode)...")
    
    # 1. Startup: Integritäts-Check der WP-25 Konfiguration
    # Wir prüfen, ob die für die DecisionEngine kritischen Dateien vorhanden sind.
    decision_cfg = os.getenv("MINDNET_DECISION_CONFIG", "config/decision_engine.yaml")
    prompts_cfg = settings.PROMPTS_PATH
    
    if not os.path.exists(decision_cfg):
        logger.error(f"❌ CRITICAL: Decision Engine config missing at {decision_cfg}")
    if not os.path.exists(prompts_cfg):
        logger.error(f"❌ CRITICAL: Prompts config missing at {prompts_cfg}")
        
    yield
    
    # 2. Shutdown: Ressourcen bereinigen
    logger.info("🛑 mindnet API: Shutting down...")
    llm = LLMService()
    await llm.close()
    logger.info("✨ Cleanup complete. Goodbye.")

# --- App Factory ---

def create_app() -> FastAPI:
    """Initialisiert die FastAPI App mit WP-25 Erweiterungen."""
    app = FastAPI(
        title="mindnet API", 
        version="1.0.0", # WP-25 Milestone
        lifespan=lifespan,
        description="Digital Twin Knowledge Engine mit Agentic Multi-Stream RAG."
    )
    
    s = get_settings()

    # --- Globale Fehlerbehandlung (WP-25 Resilienz) ---
    
    @app.exception_handler(Exception)
    async def global_exception_handler(request: Request, exc: Exception):
        """Fängt unerwartete Fehler in der Multi-Stream Kette ab."""
        logger.error(f"❌ Unhandled Engine Error: {exc}", exc_info=True)
        return JSONResponse(
            status_code=500,
            content={
                "detail": "Ein interner Fehler ist aufgetreten. Die DecisionEngine konnte die Anfrage nicht finalisieren.",
                "error_type": type(exc).__name__
            }
        )

    # Healthcheck
    @app.get("/healthz")
    def healthz():
        return {
            "status": "ok", 
            "version": "1.0.0",
            "qdrant": s.QDRANT_URL, 
            "prefix": s.COLLECTION_PREFIX,
            "agentic_mode": True
        }

    # Inkludieren der Router (100% Kompatibilität erhalten)
    app.include_router(query_router, prefix="/query", tags=["query"])
    app.include_router(graph_router, prefix="/graph", tags=["graph"])
    app.include_router(tools_router, prefix="/tools", tags=["tools"])
    app.include_router(feedback_router, prefix="/feedback", tags=["feedback"])
    app.include_router(chat_router, prefix="/chat", tags=["chat"]) # Nutzt nun WP-25 DecisionEngine
    app.include_router(ingest_router, prefix="/ingest", tags=["ingest"])

    if admin_router:
        app.include_router(admin_router, prefix="/admin", tags=["admin"])

    return app

# Instanziierung der App
app = create_app()