/* js/dataProcessor.js
 * Verantwortlich für Transformierung der eBPF Analyse-Rohdaten
 * in darstellungsfähige Strukturen (Diagramme & Tabellen)
 */

/**
 * Verknüpft write_pre und write_post Events anhand derselben corr_id.
 * @param {Array<{corr_id: string, type: string, timestamp: number, details: object}>} rawData
 * @returns {Array<{corr_id: string, pre: object|null, post: object|null, duration: number|null}>}
 */
export function aggregatePrePostPairs(rawData) {
  if (!Array.isArray(rawData)) return [];

  const grouped = new Map();
  for (const event of rawData) {
    if (!event?.corr_id || !event?.type) continue;

    const group = grouped.get(event.corr_id) ?? { corr_id: event.corr_id, pre: null, post: null, duration: null };

    if (event.type === 'write_pre') {
      group.pre = event;
    } else if (event.type === 'write_post') {
      group.post = event;
    }

    grouped.set(event.corr_id, group);
  }

  const pairs = [];
  for (const [, pair] of grouped) {
    if (pair.pre && pair.post) {
      pair.duration = pair.post.timestamp - pair.pre.timestamp;
    }
    pairs.push(pair);
  }

  return pairs;
}

/**
 * Berechnet Kennzahlen wie mittlere Dauer, Eventanzahl pro Typ.
 * @param {Array<{corr_id: string, pre: object|null, post: object|null, duration: number|null}>} aggregatedEvents
 * @returns {{totalEvents: number, counts: Record<string, number>, meanDuration: number|null}}
 */
export function computeStats(aggregatedEvents) {
  if (!Array.isArray(aggregatedEvents)) return { totalEvents: 0, counts: {}, meanDuration: null };

  const counts = { write_pre: 0, write_post: 0, read: 0 };
  let totalDuration = 0;
  let validDurations = 0;
  let totalEvents = 0;

  aggregatedEvents.forEach(entry => {
    if (entry.pre) counts.write_pre++;
    if (entry.post) counts.write_post++;
    totalEvents++;

    if (typeof entry.duration === 'number' && !isNaN(entry.duration)) {
      totalDuration += entry.duration;
      validDurations++;
    }
  });

  const meanDuration = validDurations > 0 ? totalDuration / validDurations : null;

  return {
    totalEvents,
    counts,
    meanDuration
  };
}