import os
import json
from contextlib import asynccontextmanager

# ─── Load environment FIRST — before any local imports that read env vars ─────
# Routes instantiate Groq/Firebase clients at module level, so env vars must
# be present before those modules are imported.
from dotenv import load_dotenv
load_dotenv()

from fastapi import FastAPI, Request
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
import firebase_admin
from firebase_admin import credentials

from routes import bff, chat, transcribe, documents, consultation, planning, admin, account, help as help_routes, news, bsa as bsa_routes, bff_form


# ─── Firebase Admin SDK initialisation ───────────────────────────────────────
def _init_firebase():
    if firebase_admin._apps:
        return  # already initialised (e.g. during hot-reload)

    sa_json = os.environ.get("FIREBASE_SERVICE_ACCOUNT")
    if sa_json:
        try:
            cred_dict = json.loads(sa_json)
            cred = credentials.Certificate(cred_dict)
        except json.JSONDecodeError as e:
            raise RuntimeError(f"FIREBASE_SERVICE_ACCOUNT is not valid JSON: {e}")
    else:
        # Fall back to application default credentials (GCP environment)
        cred = credentials.ApplicationDefault()

    firebase_admin.initialize_app(cred)


_init_firebase()


# ─── App lifecycle ────────────────────────────────────────────────────────────
@asynccontextmanager
async def lifespan(app: FastAPI):
    print("VenThrive API starting up...")
    yield
    print("VenThrive API shutting down.")


# ─── FastAPI app ──────────────────────────────────────────────────────────────
app = FastAPI(
    title="VenThrive API",
    version="1.0.0",
    description="AI backend for VenThrive — Nigerian business operating system",
    # Disable auto-generated docs in production
    docs_url="/docs" if os.environ.get("ENV") != "production" else None,
    redoc_url=None,
    lifespan=lifespan,
)


# ─── CORS ─────────────────────────────────────────────────────────────────────
allowed_origins_str = os.environ.get("ALLOWED_ORIGINS", "http://localhost:3000")
allowed_origins = [o.strip() for o in allowed_origins_str.split(",")]

app.add_middleware(
    CORSMiddleware,
    allow_origins=allowed_origins,
    allow_credentials=True,
    allow_methods=["GET", "POST"],
    allow_headers=["Authorization", "Content-Type"],
)


# ─── Global error handler ─────────────────────────────────────────────────────
@app.exception_handler(Exception)
async def global_exception_handler(request: Request, exc: Exception):
    # Never expose internal error details to the client in production
    return JSONResponse(
        status_code=500,
        content={"detail": "An unexpected error occurred. Please try again."},
    )


# ─── Routes ───────────────────────────────────────────────────────────────────
app.include_router(bff.router,        prefix="/api/bff",       tags=["BFF"])
app.include_router(chat.router,       prefix="/api/chat",      tags=["Chat"])
app.include_router(transcribe.router, prefix="/api",           tags=["Transcribe"])
app.include_router(documents.router,     prefix="/api/documents",    tags=["Documents"])
app.include_router(consultation.router, prefix="/api/consultation", tags=["Consultation"])
app.include_router(planning.router,     prefix="/api/planning",     tags=["Planning"])
app.include_router(admin.router,        prefix="/api/admin",        tags=["Admin"])
app.include_router(account.router,      prefix="/api/account",      tags=["Account"])
app.include_router(help_routes.router,  prefix="/api/help",         tags=["Help"])
app.include_router(news.router,         prefix="/api/news",         tags=["News"])
app.include_router(bsa_routes.router,   prefix="/api/bsa",          tags=["BSA"])
app.include_router(bff_form.router,     prefix="/api/bff-form",     tags=["BFF form"])


# ─── Health check (unauthenticated) ──────────────────────────────────────────
@app.get("/health", tags=["System"])
def health_check():
    return {"status": "ok", "service": "venthrive-api"}