import { describe, expect, it } from "vitest";
import {
compareDocuments,
convertFrameRate,
insertCue,
mergeCueWithNext,
parseSubtitle,
removeCue,
serializeSubtitle,
snapCuesToFrames,
splitCue,
transformCueText,
transformTiming,
validateDocument,
} from "../../src/subtitle/model";
const SRT = `1\r\n00:00:01,000 --> 00:00:02,500\r\nHello world\r\n\r\n2\r\n00:00:02,400 --> 00:00:04,000\r\nSecond cue\r\n`;
describe("subtitle model", () => {
it("parses SRT and reports overlap", () => {
const document = parseSubtitle(SRT);
expect(document.format).toBe("srt");
expect(document.cues).toHaveLength(2);
expect(document.cues[0]).toMatchObject({
startMs: 1000,
endMs: 2500,
text: "Hello world",
});
expect(
validateDocument(document).some((issue) => issue.code === "overlap"),
).toBe(true);
});
it("round-trips WebVTT identifiers, settings and notes", () => {
const source = `WEBVTT - sample\n\nNOTE inert note\nline two\n\nc1\n00:00:01.000 --> 00:00:02.000 align:start\nHello\n`;
const document = parseSubtitle(source);
expect(document).toMatchObject({ format: "vtt" });
expect(document.cues[0]).toMatchObject({
id: "c1",
settings: "align:start",
});
const serialized = serializeSubtitle(document, "vtt");
expect(serialized).toContain("NOTE inert note");
expect(serialized).toContain("align:start");
expect(parseSubtitle(serialized).cues[0]?.text).toBe("Hello");
});
it("parses ASS dialogue fields containing commas and preserves styles", () => {
const source = `[Script Info]\nScriptType: v4.00+\n\n[V4+ Styles]\nFormat: Name, Fontname\nStyle: Loud,Arial\n\n[Events]\nFormat: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text\nDialogue: 0,0:00:01.00,0:00:03.25,Loud,Ada,0,0,0,,Hello, world\\Nagain\n`;
const document = parseSubtitle(source);
expect(document.format).toBe("ass");
expect(document.cues[0]).toMatchObject({
startMs: 1000,
endMs: 3250,
text: "Hello, world\nagain",
});
const serialized = serializeSubtitle(document, "ass");
expect(serialized).toContain("Dialogue: 0,0:00:01.00,0:00:03.25,Loud");
expect(serialized).toContain("Hello, world\\Nagain");
});
it("writes an Events format even when only a style format was supplied", () => {
const source = `[Script Info]\nScriptType: v4.00+\n\n[V4+ Styles]\nFormat: Name, Fontname\nStyle: Default,Arial\n\n[Events]\nDialogue: 0,0:00:01.00,0:00:02.00,Default,,0,0,0,,Hello\n`;
const serialized = serializeSubtitle(parseSubtitle(source), "ass");
expect(serialized).toMatch(
/\[Events\]\nFormat: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text/u,
);
expect(parseSubtitle(serialized).cues).toHaveLength(1);
});
it("converts formats and timing without silently creating negatives", () => {
const document = parseSubtitle(SRT);
expect(() => transformTiming(document, { shiftMs: -2000 })).toThrow(
/negative/u,
);
const clamped = transformTiming(document, {
shiftMs: -2000,
clampToZero: true,
});
expect(clamped.cues[0]?.startMs).toBe(0);
const converted = convertFrameRate(document, 25, 50);
expect(converted.cues[0]).toMatchObject({ startMs: 500, endMs: 1250 });
expect(serializeSubtitle(converted, "vtt")).toMatch(/^WEBVTT/u);
});
it("compares revisions deterministically", () => {
const before = parseSubtitle(SRT);
const after = parseSubtitle(SRT.replace("Hello world", "Hello again"));
expect(compareDocuments(before, after)).toMatchObject([
{ index: 0, kind: "text" },
]);
});
it("imports and exports a bounded flat TTML profile", () => {
const source = ``;
const document = parseSubtitle(source);
expect(document.format).toBe("ttml");
expect(document.cues).toMatchObject([
{ id: "one", startMs: 1000, endMs: 2500, text: "Hello\nworld" },
{ startMs: 3000, endMs: 4000, text: "Frames" },
]);
const exported = serializeSubtitle(document, "ttml");
expect(exported).toContain('xml:id="one"');
expect(exported).toContain("Hello
world");
expect(parseSubtitle(exported).cues).toHaveLength(2);
expect(() =>
parseSubtitle(
']>',
"ttml",
),
).toThrow(/entities/iu);
});
it("edits cue structure, text and frame timing without mutating input", () => {
const original = parseSubtitle(SRT);
const inserted = insertCue(original, 1, {
startMs: 2600,
endMs: 3000,
text: " New ",
});
expect(original.cues).toHaveLength(2);
expect(inserted.cues).toHaveLength(3);
const cleaned = transformCueText(inserted, "trim", [1]);
expect(cleaned.cues[1]?.text).toBe("New");
const split = splitCue(cleaned, 0, 1500);
expect(split.cues).toHaveLength(4);
const merged = mergeCueWithNext(split, 0);
expect(merged.cues).toHaveLength(3);
const removed = removeCue(merged, 1);
expect(removed.cues).toHaveLength(2);
const snapped = snapCuesToFrames(removed, 25);
expect(snapped.cues.every((cue) => cue.startMs % 40 === 0)).toBe(true);
});
it("rejects pathological input bounds", () => {
expect(() => parseSubtitle("x".repeat(4_000_001))).toThrow(/4,000,000/u);
expect(() =>
parseSubtitle(`1\n00:61:00,000 --> 00:61:01,000\nBad`),
).not.toThrow();
expect(
parseSubtitle(`1\n00:61:00,000 --> 00:61:01,000\nBad`).cues,
).toHaveLength(0);
});
});