import os
import pickle
from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from fastapi.staticfiles import StaticFiles
from pydantic import BaseModel
import numpy as np

# Filenames (local, already in repo)
MOVIES_PKL = "movies.pkl"
SIM_PKL = "similarity.pkl"

movies = None
similarity = None


def load_artifacts():
    global movies, similarity

    if not os.path.exists(MOVIES_PKL) or not os.path.exists(SIM_PKL):
        raise FileNotFoundError("Pickle files not found in project directory.")

    with open(MOVIES_PKL, "rb") as f:
        movies = pickle.load(f)

    with open(SIM_PKL, "rb") as f:
        similarity = pickle.load(f)

    print("✅ Artifacts loaded successfully")


# FastAPI app
app = FastAPI()

# CORS for frontend / external calls
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


class RecommendRequest(BaseModel):
    title: str
    top_n: int = 5


# Root route
@app.get("/")
def home():
    return {"message": "🎬 Movie Recommendation API is running!"}


@app.get("/health")
def health():
    return {"status": "ok", "movies_loaded": movies is not None}


@app.post("/recommend")
def recommend(request: RecommendRequest):
    if movies is None or similarity is None:
        raise HTTPException(status_code=500, detail="Model not loaded.")

    if request.title not in movies["title"].values:
        raise HTTPException(
            status_code=404,
            detail=f"Movie '{request.title}' not found in dataset",
        )

    idx = movies[movies["title"] == request.title].index[0]

    sim_scores = sorted(
        enumerate(similarity[idx]), key=lambda x: x[1], reverse=True
    )[1 : request.top_n + 1]

    recommendations = [
        {"title": movies.iloc[i].title, "score": float(score)}
        for i, score in sim_scores
    ]

    return {"input": request.title, "recommendations": recommendations}


# Optional: mount frontend if you add HTML files
FRONTEND_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)), "frontend")
if os.path.exists(FRONTEND_DIR):
    app.mount("/", StaticFiles(directory=FRONTEND_DIR, html=True), name="frontend")


@app.on_event("startup")
def startup_event():
    load_artifacts()