/**
 * @module api
 * Data layer module for fetching Drift-Matrix data.
 *
 * Provides a function to retrieve matrix data from the backend.
 */

/**
 * Fetches Drift-Matrix data from the API for a given run.
 *
 * @async
 * @function fetchMatrixData
 * @param {string|number} run_id - The identifier of the run for which drift data should be retrieved.
 * @returns {Promise<Array<{quadrant: string, warn_reasons: string[], counts: number[]}>>} - The matrix data as JSON array.
 * @throws {Error} Throws if the fetch fails or response is invalid.
 */
export async function fetchMatrixData(run_id) {
  if (!run_id) {
    throw new Error('fetchMatrixData: Missing required parameter run_id');
  }

  const url = new URL('/drift-matrix', window.location.origin);
  url.searchParams.append('run_id', run_id);

  try {
    const response = await fetch(url.toString(), {
      method: 'GET',
      headers: {
        'Accept': 'application/json'
      }
    });

    if (!response.ok) {
      throw new Error(`API request failed with status ${response.status}`);
    }

    const data = await response.json();

    if (!Array.isArray(data)) {
      throw new Error('Invalid API response format: expected an array');
    }

    return data;
  } catch (error) {
    console.error('Error fetching drift matrix data:', error);
    throw error;
  }
}