import json
import chromadb
import firebase_admin
from firebase_admin import credentials, firestore
from encoder import SentenceEncoder

def initialize_firebase_with_file():
    """Initializes Firebase using a local serviceAccountKey.json file."""
    try:
        # Use the service account key file
        cred = credentials.Certificate("serviceAccountKey.json")
        
        if not firebase_admin._apps:
            firebase_admin.initialize_app(cred)
            
        db = firestore.client()
        print("✅ Firebase connection initialized from file.")
        return db
    except Exception as e:
        print(f"❌ Could not initialize Firebase from file. Error: {e}")
        print("   - Make sure 'serviceAccountKey.json' has been uploaded to the terminal.")
        return None

def populate_vector_db():
    """
    Reads internships from Firestore, generates embeddings, and populates ChromaDB.
    """
    db = initialize_firebase_with_file()
    if db is None:
        return

    # 1. Initialize other clients
    encoder = SentenceEncoder()
    chroma_client = chromadb.PersistentClient(path="/data/chroma_db")
    collection = chroma_client.get_or_create_collection(name="internships")

    # 2. Clear existing data
    if collection.count() > 0:
        print(f"ℹ️ Clearing {collection.count()} existing items from ChromaDB.")
        collection.delete(ids=collection.get()['ids'])

    # 3. Fetch data from Firestore
    print("📚 Reading internship data from Firestore...")
    internships_ref = db.collection('internships').stream()
    internships = [doc.to_dict() for doc in internships_ref]
    
    if not internships:
        print("❌ No internship data found in Firestore.")
        return

    # 4. Generate embeddings
    print(f"🧠 Generating embeddings for {len(internships)} internships...")
    texts = [f"{i['title']}. {i['description']}. Skills: {', '.join(i['skills'])}" for i in internships]
    embeddings = encoder.encode(texts, show_progress_bar=True).tolist()
    ids = [i['id'] for i in internships]
    
    metadatas = []
    for i in internships:
        i['skills'] = json.dumps(i['skills'])
        metadatas.append(i)
        
    # 5. Add to ChromaDB
    print("➕ Adding data to ChromaDB...")
    collection.add(ids=ids, embeddings=embeddings, metadatas=metadatas)
    print(f"✅ Successfully populated ChromaDB with {collection.count()} items.")

if __name__ == "__main__":
    populate_vector_db()