from wsgiref.simple_server import make_server
import json
import pyodbc


response_headers = [
    ('Content-Type', 'application/json'),
    ('Access-Control-Allow-Origin', '*'),
    ('Access-Control-Allow-Methods', 'POST, GET, OPTIONS, DELETE'),
    ('Access-Control-Allow-Headers', 'Content-Type')
]

# Database connection
conn = pyodbc.connect(
    'DRIVER={ODBC Driver 17 for SQL Server};'
    'SERVER=mssql-2017.labs.wmi.amu.edu.pl;'
    'DATABASE=dbad_s490122;' 
    'UID=dbad_s490122;'        
    'PWD=c1Dp8y8iWJ'           
)
cursor = conn.cursor()


def get_request_body(environ):
    request_body_size = int(environ.get('CONTENT_LENGTH', 0))
    request_body = environ['wsgi.input'].read(request_body_size)
    return json.loads(request_body)

def parse_task_id_from_path(path):
    try:
        return int(path.split('/')[-1])
    except (IndexError, ValueError):
        return None

def create_response(start_response, status, response_body):
    start_response(status, response_headers)
    return [json.dumps(response_body).encode('utf-8')]


def add_task(environ, start_response):
    data = get_request_body(environ)
    task_description = data.get('task_description', '')
    
    format_description = lambda desc: desc.upper()
    
    if task_description:
        formatted_description = format_description(task_description)
        cursor.execute("INSERT INTO Tasks (task_description) OUTPUT INSERTED.id VALUES (?)", (formatted_description,))
        task_id = cursor.fetchone()[0]
        conn.commit()
        response_body = {'message': 'Task added successfully', 'id': task_id}
        return create_response(start_response, '200 OK', response_body)
    else:
        response_body = {'message': 'Task description is required'}
        return create_response(start_response, '400 Bad Request', response_body)

def get_tasks(environ, start_response):
    cursor.execute("SELECT id, task_description FROM Tasks")
    tasks = cursor.fetchall()
    tasks_list = [{'id': task[0], 'task_description': task[1]} for task in tasks]
    return create_response(start_response, '200 OK', tasks_list)

def delete_task(environ, start_response, task_id):
    cursor.execute("DELETE FROM Tasks WHERE id = ?", (task_id,))
    conn.commit()
    response_body = {'message': 'Task deleted successfully'}
    return create_response(start_response, '200 OK', response_body)


def handle_request(environ, start_response):
    path = environ.get('PATH_INFO', '')
    method = environ.get('REQUEST_METHOD', '')

    if method == 'OPTIONS':
        start_response('200 OK', response_headers)
        return [b'']

    if method == 'POST' and path == '/add_task':
        return add_task(environ, start_response)
    elif method == 'GET' and path == '/get_tasks':
        return get_tasks(environ, start_response)
    elif method == 'DELETE' and path.startswith('/delete_task/'):
        task_id = parse_task_id_from_path(path)
        if task_id is not None:
            return delete_task(environ, start_response, task_id)
        else:
            response_body = {'message': 'Invalid task ID'}
            return create_response(start_response, '400 Bad Request', response_body)
    else:
        response_body = {'message': 'Not Found'}
        return create_response(start_response, '404 Not Found', response_body)


def application(environ, start_response):
    try:
        return handle_request(environ, start_response)
    except Exception as e:
        response_body = {'message': str(e)}
        return create_response(start_response, '500 Internal Server Error', response_body)

if __name__ == "__main__":
    httpd = make_server('', 8000, application)
    print("Serving on port 8000...")
    httpd.serve_forever()