import pandas as pd
from typing import List, Tuple, Dict, Any
from langchain_community.vectorstores import faiss


def multi_column(db: faiss.FAISS, df: pd.DataFrame, qc_pairs: Dict[str, str], threshold: float) -> List[Tuple[int, float, Dict[str, Any]]]:
    """Perform semantic search across multiple columns and return aggregated results.
    
    Args:
        db: FAISS vector database for search
        df: Original DataFrame containing the data
        qc_pairs: Dictionary mapping columns to query fragments
        threshold: Minimum similarity threshold to include a result
        
    Returns:
        List[Tuple[int, float, Dict[str, Any]]]: List of tuples (row_id, avg_score, row_dict)
    """
    per_column_scores = []
    for column, query in qc_pairs.items():
        hits = db.similarity_search_with_score(
            query,
            k=db.index.ntotal,
            filter={'column': column},
            distance_strategy=faiss.DistanceStrategy.COSINE
        )
        score_map = {
            doc.metadata['row']: score
            for doc, score in hits
            if score >= threshold
        }
        per_column_scores.append(score_map)

    all_rows = set()
    for score_map in per_column_scores:
        all_rows.update(score_map.keys())

    results = []
    for rid in all_rows:
        scores = [score_map[rid] for score_map in per_column_scores if rid in score_map]
        if scores:
            avg_score = sum(scores) / len(scores)
            row_dict = df.loc[rid].to_dict()
            results.append((rid, avg_score, row_dict))

    results.sort(key=lambda x: x[1], reverse=True)
    return results