import { describe, expect, test } from "bun:test";
import { enqueueUnseenJobs, extractErrorSummary, shouldSendLiveUpdate, yieldAfterChunk } from "../execute";

describe("extractErrorSummary", () => {
	test("pulls the real error line out of ffmpeg's banner", () => {
		const lines = [
			"[stderr] ffmpeg version 7.1.3 ...",
			"[stderr]   built with gcc 14",
			"[stderr]   Stream #0:2(eng): Subtitle: dvd_subtitle (dvdsub), 1280x720",
			"[stderr] Stream mapping:",
			"[stderr]   Stream #0:2 -> #0:0 (copy)",
			"[stderr] [srt @ 0x55] Unsupported subtitles codec: dvd_subtitle",
			"[stderr] [out#0/srt @ 0x55] Could not write header (incorrect codec parameters ?): Invalid argument",
			"[stderr] Conversion failed!",
		];
		const summary = extractErrorSummary(lines, new Error("FFmpeg exited with code 234"));
		expect(summary).toContain("Unsupported subtitles codec: dvd_subtitle");
		expect(summary).toContain("Invalid argument");
		expect(summary).toContain("Conversion failed!");
		// Should NOT include the banner lines.
		expect(summary).not.toContain("ffmpeg version");
		expect(summary).not.toContain("Stream #0:2");
	});

	test("dedupes identical fatal lines (e.g. repeated warnings)", () => {
		const lines = ["[stderr] Conversion failed!", "[stderr] Conversion failed!", "[stderr] Conversion failed!"];
		const summary = extractErrorSummary(lines);
		expect(summary?.split("\n").length).toBe(1);
	});

	test("falls back to the thrown error when no fatal line is found", () => {
		const lines = ["[stderr] ffmpeg version 7", "[stderr]   Duration: 00:10:00"];
		const summary = extractErrorSummary(lines, new Error("FFmpeg exited with code 1"));
		expect(summary).toBe("Error: FFmpeg exited with code 1");
	});

	test("returns null when neither a fatal line nor a thrown error is available", () => {
		expect(extractErrorSummary([])).toBe(null);
		expect(extractErrorSummary(["[stderr] ffmpeg version 7"])).toBe(null);
	});

	test("only scans the tail — a banner from a prior run doesn't leak through", () => {
		// 70 filler lines, real error at the very end; scan window is 60.
		const filler = Array.from({ length: 70 }, (_, i) => `[stderr] banner line ${i}`);
		const lines = [...filler, "[stderr] Error: no space left on device"];
		const summary = extractErrorSummary(lines);
		expect(summary).toBe("Error: no space left on device");
	});
});

describe("shouldSendLiveUpdate", () => {
	test("throttles updates until interval passes", () => {
		expect(shouldSendLiveUpdate(1_000, 800, 500)).toBe(false);
		expect(shouldSendLiveUpdate(1_301, 800, 500)).toBe(true);
	});
});

describe("yieldAfterChunk", () => {
	test("yields once threshold is reached, resets chunk counter", async () => {
		let yieldCalls = 0;
		const sleep = async (_ms: number) => {
			yieldCalls += 1;
		};
		let chunks = 0;
		chunks = await yieldAfterChunk(chunks, 3, sleep);
		expect(chunks).toBe(1);
		chunks = await yieldAfterChunk(chunks, 3, sleep);
		expect(chunks).toBe(2);
		chunks = await yieldAfterChunk(chunks, 3, sleep);
		expect(chunks).toBe(0);
		expect(yieldCalls).toBe(1);
	});
});

describe("enqueueUnseenJobs", () => {
	test("appends only unseen job ids to the active queue", () => {
		const queue = [{ id: 1 }, { id: 2 }] as { id: number }[];
		const seen = new Set([1, 2]);
		const added = enqueueUnseenJobs(queue, seen, [{ id: 2 }, { id: 3 }, { id: 4 }] as { id: number }[]);
		expect(added).toBe(2);
		expect(queue.map((j) => j.id)).toEqual([1, 2, 3, 4]);
		expect(seen.has(3)).toBeTrue();
		expect(seen.has(4)).toBeTrue();
	});
});