from flask import Blueprint, request, jsonify, make_response, render_template
from app.core.models import Subnet, Server, App
from app.core.extensions import db
import csv
import io
import datetime

bp = Blueprint('importexport', __name__, url_prefix='/import-export')

MODEL_MAP = {
    'subnet': Subnet,
    'server': Server,
    'app': App
}

@bp.route('/export/<model_name>', methods=['GET'])
def export_model(model_name):
    if model_name not in MODEL_MAP:
        return jsonify({'error': 'Invalid model name'}), 400
        
    model = MODEL_MAP[model_name]
    instances = model.query.all()
    
    # Create a CSV file in memory
    output = io.StringIO()
    writer = csv.writer(output)
    
    # Get column names from model
    columns = [column.name for column in model.__table__.columns]
    writer.writerow(columns)
    
    # Write data
    for instance in instances:
        row = [getattr(instance, column) for column in columns]
        writer.writerow(row)
    
    # Create response
    timestamp = datetime.datetime.now().strftime('%Y%m%d_%H%M%S')
    filename = f"{model_name}_{timestamp}.csv"
    
    response = make_response(output.getvalue())
    response.headers['Content-Disposition'] = f'attachment; filename={filename}'
    response.headers['Content-type'] = 'text/csv'
    
    return response

@bp.route('/import/<model_name>', methods=['GET', 'POST'])
def import_model(model_name):
    if model_name not in MODEL_MAP:
        return jsonify({'error': 'Invalid model name'}), 400
    
    model = MODEL_MAP[model_name]
    
    if request.method == 'GET':
        # Show import form
        return render_template('import_form.html', model_name=model_name)
    
    # Process CSV upload
    if 'file' not in request.files:
        return jsonify({'error': 'No file part'}), 400
    
    file = request.files['file']
    if file.filename == '':
        return jsonify({'error': 'No selected file'}), 400
    
    if not file.filename.endswith('.csv'):
        return jsonify({'error': 'File must be CSV format'}), 400
    
    try:
        # Read CSV
        stream = io.StringIO(file.stream.read().decode("UTF8"), newline=None)
        csv_reader = csv.reader(stream)
        
        # Get headers
        headers = next(csv_reader)
        
        # Validate required columns
        required_columns = [col.name for col in model.__table__.columns 
                            if not col.nullable and col.name != 'id']
        
        for col in required_columns:
            if col not in headers:
                return jsonify({'error': f'Required column {col} missing'}), 400
        
        # Process rows
        imported = 0
        for row in csv_reader:
            data = dict(zip(headers, row))
            
            # Remove id to create new record
            if 'id' in data:
                del data['id']
                
            # Create new instance
            instance = model(**data)
            db.session.add(instance)
            imported += 1
        
        db.session.commit()
        return jsonify({'success': f'Imported {imported} records successfully'})
    
    except Exception as e:
        db.session.rollback()
        return jsonify({'error': str(e)}), 500