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import { describe, expect, test } from "bun:test";
import {
buildThumbnailTileKey,
FILMSTRIP_MAX_INTERVAL_SECONDS,
FILMSTRIP_MIN_INTERVAL_SECONDS,
getFilmstripInterval,
getFilmstripSlotCount,
getFilmstripSlotSourceTime,
getVisibleSlotRange,
MEDIA_TILE_ASPECT_RATIO,
} from "../tiling";
const TRACK_HEIGHT_PX = 65;
const MIN_TILE_WIDTH_PX = TRACK_HEIGHT_PX * MEDIA_TILE_ASPECT_RATIO;
describe("getFilmstripInterval", () => {
test("snaps to the nearest power of two seconds", () => {
expect(
getFilmstripInterval({
pixelsPerSecond: 100,
minTileWidthPx: MIN_TILE_WIDTH_PX,
}),
).toBe(1);
expect(
getFilmstripInterval({
pixelsPerSecond: 50,
minTileWidthPx: MIN_TILE_WIDTH_PX,
}),
).toBe(2);
expect(
getFilmstripInterval({
pixelsPerSecond: 200,
minTileWidthPx: MIN_TILE_WIDTH_PX,
}),
).toBe(0.5);
});
test("keeps tile width near the minimum across zoom levels", () => {
for (const pixelsPerSecond of [5, 12, 25, 40, 80, 160, 320, 640]) {
const interval = getFilmstripInterval({
pixelsPerSecond,
minTileWidthPx: MIN_TILE_WIDTH_PX,
});
const tileWidthPx = interval * pixelsPerSecond;
expect(tileWidthPx).toBeGreaterThanOrEqual(MIN_TILE_WIDTH_PX * 0.7);
expect(tileWidthPx).toBeLessThanOrEqual(MIN_TILE_WIDTH_PX * 1.45);
}
});
test("is stable under tiny zoom changes", () => {
const coarse = getFilmstripInterval({
pixelsPerSecond: 100,
minTileWidthPx: MIN_TILE_WIDTH_PX,
});
const nudged = getFilmstripInterval({
pixelsPerSecond: 110,
minTileWidthPx: MIN_TILE_WIDTH_PX,
});
expect(nudged).toBe(coarse);
});
test("clamps the interval at extreme zoom levels", () => {
const zoomedIn = getFilmstripInterval({
pixelsPerSecond: 5000,
minTileWidthPx: MIN_TILE_WIDTH_PX,
});
expect(zoomedIn).toBeGreaterThanOrEqual(FILMSTRIP_MIN_INTERVAL_SECONDS);
const zoomedOut = getFilmstripInterval({
pixelsPerSecond: 5,
minTileWidthPx: MIN_TILE_WIDTH_PX,
});
expect(zoomedOut).toBeLessThanOrEqual(FILMSTRIP_MAX_INTERVAL_SECONDS);
});
test("falls back to the max interval for invalid zoom", () => {
expect(
getFilmstripInterval({
pixelsPerSecond: 0,
minTileWidthPx: MIN_TILE_WIDTH_PX,
}),
).toBe(FILMSTRIP_MAX_INTERVAL_SECONDS);
expect(
getFilmstripInterval({
pixelsPerSecond: Number.NaN,
minTileWidthPx: MIN_TILE_WIDTH_PX,
}),
).toBe(FILMSTRIP_MAX_INTERVAL_SECONDS);
});
});
describe("getFilmstripSlotCount", () => {
test("covers the clip duration with exact tiles", () => {
expect(getFilmstripSlotCount({ clipDurationSec: 10, interval: 2 })).toBe(5);
expect(getFilmstripSlotCount({ clipDurationSec: 10.5, interval: 2 })).toBe(
6,
);
});
test("does not add a trailing tile on exact multiples", () => {
expect(getFilmstripSlotCount({ clipDurationSec: 4, interval: 2 })).toBe(2);
});
test("returns zero for empty clips", () => {
expect(getFilmstripSlotCount({ clipDurationSec: 0, interval: 2 })).toBe(0);
expect(getFilmstripSlotCount({ clipDurationSec: -3, interval: 2 })).toBe(0);
});
});
describe("getVisibleSlotRange", () => {
test("returns the slots intersecting the visible window plus overscan", () => {
const range = getVisibleSlotRange({
slotCount: 100,
tileWidthPx: 100,
visibleLeftPx: 500,
visibleRightPx: 1000,
overscanSlots: 2,
});
expect(range).toEqual({ firstSlot: 3, lastSlot: 11 });
});
test("clamps to the slot bounds", () => {
const range = getVisibleSlotRange({
slotCount: 8,
tileWidthPx: 100,
visibleLeftPx: 0,
visibleRightPx: 1000,
overscanSlots: 2,
});
expect(range).toEqual({ firstSlot: 0, lastSlot: 7 });
});
test("returns an empty range when nothing is visible", () => {
const range = getVisibleSlotRange({
slotCount: 10,
tileWidthPx: 100,
visibleLeftPx: 500,
visibleRightPx: 500,
overscanSlots: 2,
});
expect(range.lastSlot).toBeLessThan(range.firstSlot);
});
});
describe("getFilmstripSlotSourceTime", () => {
test("offsets by the trim start", () => {
expect(
getFilmstripSlotSourceTime({
slot: 2,
interval: 1,
trimStartSec: 5,
rate: 1,
}),
).toBe(7);
});
test("scales clip time by the retime rate", () => {
expect(
getFilmstripSlotSourceTime({
slot: 2,
interval: 1,
trimStartSec: 5,
rate: 2,
}),
).toBe(9);
});
test("clamps to the end of the asset", () => {
const clamped = getFilmstripSlotSourceTime({
slot: 100,
interval: 1,
trimStartSec: 0,
rate: 1,
assetDurationSec: 10,
});
expect(clamped).toBeLessThan(10);
expect(clamped).toBeGreaterThan(9);
});
test("never returns negative times", () => {
expect(
getFilmstripSlotSourceTime({
slot: 0,
interval: 1,
trimStartSec: -4,
rate: 1,
}),
).toBe(0);
});
});
describe("buildThumbnailTileKey", () => {
test("changes per media, size, and quantized time", () => {
const base = buildThumbnailTileKey({
mediaId: "media-1",
time: 1,
width: 232,
height: 130,
});
expect(base).not.toBe(
buildThumbnailTileKey({
mediaId: "media-2",
time: 1,
width: 232,
height: 130,
}),
);
expect(base).not.toBe(
buildThumbnailTileKey({
mediaId: "media-1",
time: 2,
width: 232,
height: 130,
}),
);
expect(base).not.toBe(
buildThumbnailTileKey({
mediaId: "media-1",
time: 1,
width: 464,
height: 260,
}),
);
});
test("shares keys for times within one quantum", () => {
const quantum = 1 / 4096;
const first = buildThumbnailTileKey({
mediaId: "media-1",
time: 1,
width: 232,
height: 130,
});
const second = buildThumbnailTileKey({
mediaId: "media-1",
time: 1 + quantum / 4,
width: 232,
height: 130,
});
expect(second).toBe(first);
});
test("splits keys across quantum boundaries", () => {
const first = buildThumbnailTileKey({
mediaId: "media-1",
time: 1,
width: 232,
height: 130,
});
const second = buildThumbnailTileKey({
mediaId: "media-1",
time: 1 + 1 / 4096,
width: 232,
height: 130,
});
expect(second).not.toBe(first);
});
});
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