import pandas as pd
from datetime import timedelta

def predict_timeline(df):
    # Dummy logic for testing
    df['Start'] = pd.Timestamp.now()
    df['Finish'] = df['Start'] + pd.to_timedelta(7, unit='D')
    df['Task'] = df.iloc[:, 0]  # Assume first column is task name
    df['Risk'] = ['Low'] * len(df)
    
    summary = "Timeline generated for {} tasks.".format(len(df))
    risks = [{"text": task, "start": 0, "end": len(task), "entity": risk}
             for task, risk in zip(df['Task'], df['Risk'])]

    return df[['Task', 'Start', 'Finish', 'Risk']], risks, summary