Problem

At AcmeQA, automated UI tests fail because element IDs change on every page load. Implement a function that finds the best matching element using stable properties instead of relying on the full id value.

Task

Given a list of element records and a target specification, return the index of the first element that matches all required stable fields. A field matches if:

1. tag must match exactly when provided.
2. text must match exactly when provided.
3. Every key-value pair in attributes must exist in the element's attributes.
4. If id_prefix is provided, the element's id must start with that prefix.

If no element matches, return -1.

Input/Output

• Input: elements is a list of dictionaries. Each element has keys: tag (string), id (string), text (string), and attributes (dictionary of strings).
• Input: target is a dictionary with optional keys: tag, text, id_prefix, and attributes.
• Output: Integer index of the first matching element, or -1.

Examples

Example 1 Input: elements = [{"tag":"button","id":"login_4831","text":"Login","attributes":{"data-testid":"login-btn","role":"primary"}}], target = {"tag":"button","text":"Login","attributes":{"data-testid":"login-btn"},"id_prefix":"login_"} Output: 0 Explanation: The button matches the tag, text, required attribute, and its ID starts with login_.

Example 2 Input: elements = [{"tag":"input","id":"user_91","text":"","attributes":{"name":"email"}}], target = {"tag":"input","attributes":{"name":"password"}} Output: -1 Explanation: The required attribute does not match.

Constraints

• 1 <= len(elements) <= 10^4
• Each attributes dictionary contains at most 20 key-value pairs
• All keys and values are strings
• Return the first valid match by index