import { describe, expect, test } from "bun:test";
import { deflateSync } from "node:zlib";
import {
  compressionRatio,
  DEFAULT_FALLBACK,
  needsFallback,
} from "../src/worker/longform/quality";

describe("compressionRatio (faster-whisper get_compression_ratio)", () => {
  test("matches zlib.compress on the same bytes", async () => {
    const text = "The problem I find with AI is that it is probably a bit overhyped.";
    const bytes = new TextEncoder().encode(text);
    expect(await compressionRatio(text)).toBeCloseTo(
      bytes.length / deflateSync(bytes).length,
      5,
    );
  });

  test("a repetition loop compresses far above 2.4, normal speech below", async () => {
    expect(await compressionRatio("the main clar, ".repeat(40))).toBeGreaterThan(2.4);
    expect(
      await compressionRatio(
        "På Aarhus Festuges sekretariat har vi løbet rigtig stærkt de sidste måneder.",
      ),
    ).toBeLessThan(2.4);
  });

  test("empty text is not a loop", async () => {
    expect(await compressionRatio("")).toBe(0);
  });
});

describe("needsFallback", () => {
  test("uses the spec thresholds by default", () => {
    expect(DEFAULT_FALLBACK.compressionRatioThreshold).toBe(2.4);
    expect(DEFAULT_FALLBACK.logProbThreshold).toBe(-1.0);
    expect(DEFAULT_FALLBACK.temperatures).toEqual([0, 0.2, 0.4, 0.6, 0.8, 1.0]);
  });

  test("rejects a high compression ratio or a low average log-prob", () => {
    expect(needsFallback({ compressionRatio: 3.1, avgLogProb: -0.2 })).toBe(true);
    expect(needsFallback({ compressionRatio: 1.5, avgLogProb: -1.5 })).toBe(true);
    expect(needsFallback({ compressionRatio: 1.5, avgLogProb: -0.3 })).toBe(false);
    expect(needsFallback({ compressionRatio: 1.5, avgLogProb: null })).toBe(false);
  });
});