feat: timeline e2e tests (#23895)

* feat: timeline e2e tests

* Fix flakiness, mock all apis, allow parallel tests

* Upload playwright reports

* wrong report path

* Add CI=true, disable flaky/failing tests

* Re-enable tests, fix worker thread config

* fix maintance e2e test

* increase retries

e2e/src/generators/timeline/utils.ts

@@ -0,0 +1,186 @@
+import { DateTime } from 'luxon';
+import { GENERATION_CONSTANTS, MockTimelineAsset } from 'src/generators/timeline/timeline-config';
+
+/**
+ * Linear Congruential Generator for deterministic pseudo-random numbers
+ */
+export class SeededRandom {
+  private seed: number;
+
+  constructor(seed: number) {
+    this.seed = seed;
+  }
+
+  /**
+   * Generate next random number in range [0, 1)
+   */
+  next(): number {
+    // LCG parameters from Numerical Recipes
+    this.seed = (this.seed * 1_664_525 + 1_013_904_223) % 2_147_483_647;
+    return this.seed / 2_147_483_647;
+  }
+
+  /**
+   * Generate random integer in range [min, max)
+   */
+  nextInt(min: number, max: number): number {
+    return Math.floor(this.next() * (max - min)) + min;
+  }
+
+  /**
+   * Generate random boolean with given probability
+   */
+  nextBoolean(probability = 0.5): boolean {
+    return this.next() < probability;
+  }
+}
+
+/**
+ * Select random days using seed variation to avoid collisions.
+ *
+ * @param daysInMonth - Total number of days in the month
+ * @param numDays - Number of days to select
+ * @param rng - Random number generator instance
+ * @returns Array of selected day numbers, sorted in descending order
+ */
+export function selectRandomDays(daysInMonth: number, numDays: number, rng: SeededRandom): number[] {
+  const selectedDays = new Set<number>();
+  const maxAttempts = numDays * GENERATION_CONSTANTS.MAX_SELECT_ATTEMPTS; // Safety limit
+  let attempts = 0;
+
+  while (selectedDays.size < numDays && attempts < maxAttempts) {
+    const day = rng.nextInt(1, daysInMonth + 1);
+    selectedDays.add(day);
+    attempts++;
+  }
+
+  // Fallback: if we couldn't select enough random days, fill with sequential days
+  if (selectedDays.size < numDays) {
+    for (let day = 1; day <= daysInMonth && selectedDays.size < numDays; day++) {
+      selectedDays.add(day);
+    }
+  }
+
+  return [...selectedDays].sort((a, b) => b - a);
+}
+
+/**
+ * Select item from array using seeded random
+ */
+export function selectRandom<T>(arr: T[], rng: SeededRandom): T {
+  if (arr.length === 0) {
+    throw new Error('Cannot select from empty array');
+  }
+  const index = rng.nextInt(0, arr.length);
+  return arr[index];
+}
+
+/**
+ * Select multiple random items from array using seeded random without duplicates
+ */
+export function selectRandomMultiple<T>(arr: T[], count: number, rng: SeededRandom): T[] {
+  if (arr.length === 0) {
+    throw new Error('Cannot select from empty array');
+  }
+  if (count < 0) {
+    throw new Error('Count must be non-negative');
+  }
+  if (count > arr.length) {
+    throw new Error('Count cannot exceed array length');
+  }
+
+  const result: T[] = [];
+  const selectedIndices = new Set<number>();
+
+  while (result.length < count) {
+    const index = rng.nextInt(0, arr.length);
+    if (!selectedIndices.has(index)) {
+      selectedIndices.add(index);
+      result.push(arr[index]);
+    }
+  }
+
+  return result;
+}
+
+/**
+ * Parse timeBucket parameter to extract year-month key
+ * Handles both formats:
+ * - ISO timestamp: "2024-12-01T00:00:00.000Z" -> "2024-12-01"
+ * - Simple format: "2024-12-01" -> "2024-12-01"
+ */
+export function parseTimeBucketKey(timeBucket: string): string {
+  if (!timeBucket) {
+    throw new Error('timeBucket parameter cannot be empty');
+  }
+
+  const dt = DateTime.fromISO(timeBucket, { zone: 'utc' });
+
+  if (!dt.isValid) {
+    // Fallback to regex if not a valid ISO string
+    const match = timeBucket.match(/^(\d{4}-\d{2}-\d{2})/);
+    return match ? match[1] : timeBucket;
+  }
+
+  // Format as YYYY-MM-01 (first day of month)
+  return `${dt.year}-${String(dt.month).padStart(2, '0')}-01`;
+}
+
+export function getMockAsset(
+  asset: MockTimelineAsset,
+  sortedDescendingAssets: MockTimelineAsset[],
+  direction: 'next' | 'previous',
+  unit: 'day' | 'month' | 'year' = 'day',
+): MockTimelineAsset | null {
+  const currentDateTime = DateTime.fromISO(asset.localDateTime, { zone: 'utc' });
+
+  const currentIndex = sortedDescendingAssets.findIndex((a) => a.id === asset.id);
+
+  if (currentIndex === -1) {
+    return null;
+  }
+
+  const step = direction === 'next' ? 1 : -1;
+  const startIndex = currentIndex + step;
+
+  if (direction === 'next' && currentIndex >= sortedDescendingAssets.length - 1) {
+    return null;
+  }
+  if (direction === 'previous' && currentIndex <= 0) {
+    return null;
+  }
+
+  const isInDifferentPeriod = (date1: DateTime, date2: DateTime): boolean => {
+    if (unit === 'day') {
+      return !date1.startOf('day').equals(date2.startOf('day'));
+    } else if (unit === 'month') {
+      return date1.year !== date2.year || date1.month !== date2.month;
+    } else {
+      return date1.year !== date2.year;
+    }
+  };
+
+  if (direction === 'next') {
+    // Search forward in array (backwards in time)
+    for (let i = startIndex; i < sortedDescendingAssets.length; i++) {
+      const nextAsset = sortedDescendingAssets[i];
+      const nextDate = DateTime.fromISO(nextAsset.localDateTime, { zone: 'utc' });
+
+      if (isInDifferentPeriod(nextDate, currentDateTime)) {
+        return nextAsset;
+      }
+    }
+  } else {
+    // Search backward in array (forwards in time)
+    for (let i = startIndex; i >= 0; i--) {
+      const prevAsset = sortedDescendingAssets[i];
+      const prevDate = DateTime.fromISO(prevAsset.localDateTime, { zone: 'utc' });
+
+      if (isInDifferentPeriod(prevDate, currentDateTime)) {
+        return prevAsset;
+      }
+    }
+  }
+
+  return null;
+}