import { describe, expect, test } from 'bun:test';

import { shouldAutoLoadEarlierForUnderfilledPinnedViewport } from './useChatTimelineController';

const baseInput = {
    sessionId: 'ses_1',
    isPinned: true,
    canLoadEarlier: true,
    isLoadingOlder: false,
    pendingRevealWork: false,
    scrollHeight: 799,
    clientHeight: 800,
};

describe('shouldAutoLoadEarlierForUnderfilledPinnedViewport', () => {
    test('loads when pinned content does not fill the viewport', () => {
        expect(shouldAutoLoadEarlierForUnderfilledPinnedViewport(baseInput)).toBe(true);
    });

    test('does not load when content already overflows', () => {
        expect(shouldAutoLoadEarlierForUnderfilledPinnedViewport({
            ...baseInput,
            scrollHeight: 802,
        })).toBe(false);
    });

    test('does not load while user is away from bottom or history work is active', () => {
        expect(shouldAutoLoadEarlierForUnderfilledPinnedViewport({
            ...baseInput,
            isPinned: false,
        })).toBe(false);
        expect(shouldAutoLoadEarlierForUnderfilledPinnedViewport({
            ...baseInput,
            isLoadingOlder: true,
        })).toBe(false);
        expect(shouldAutoLoadEarlierForUnderfilledPinnedViewport({
            ...baseInput,
            pendingRevealWork: true,
        })).toBe(false);
    });
});