# utils/export.py (new file)
import csv
import json
import base64
from io import BytesIO, StringIO

def export_to_csv(explanation_data, filename="attributions.csv"):
    """Export explanation data to CSV"""
    output = StringIO()
    writer = csv.writer(output)
    
    if explanation_data and isinstance(explanation_data[0], dict):
        # SHAP/Captum format
        writer.writerow(['Token', 'Value', 'Position'])
        for item in explanation_data:
            writer.writerow([item.get('token', ''), item.get('value', 0), item.get('position', 0)])
    else:
        # LIME format
        writer.writerow(['Feature', 'Weight'])
        for feature, weight in explanation_data:
            writer.writerow([feature, weight])
    
    csv_string = output.getvalue()
    output.close()
    
    # Create downloadable link
    b64 = base64.b64encode(csv_string.encode()).decode()
    return f'<a href="data:file/csv;base64,{b64}" download="{filename}">Download CSV</a>'

def export_to_json(explanation_data, filename="attributions.json"):
    """Export explanation data to JSON"""
    json_string = json.dumps(explanation_data, indent=2)
    b64 = base64.b64encode(json_string.encode()).decode()
    return f'<a href="data:application/json;base64,{b64}" download="{filename}">Download JSON</a>'

def export_plot_as_png(plot_html, filename="attribution_plot.png"):
    """Extract PNG from plot HTML and create download link"""
    try:
        # Extract base64 data from HTML
        import re
        match = re.search(r'base64,([^"]+)', plot_html)
        if match:
            b64_data = match.group(1)
            return f'<a href="data:image/png;base64,{b64_data}" download="{filename}">Download PNG</a>'
        return "Download not available"
    except Exception as e:
        print(f"Export error: {e}")
        return "Download failed"