import pandas as pd
import logging

logger = logging.getLogger(__name__)

def load_logs(uploaded_files):
    """Load and concatenate logs from uploaded CSV files."""
    logger.info("Loading logs from uploaded files...")
    try:
        dfs = []
        for file in uploaded_files:
            df = pd.read_csv(file)
            logger.info(f"Loaded {len(df)} records from {file.name}")
            dfs.append(df)
        combined_df = pd.concat(dfs, ignore_index=True)
        logger.info(f"Combined {len(combined_df)} total records.")
        return combined_df
    except Exception as e:
        logger.error(f"Failed to load logs: {e}")
        raise