import { mkdtempSync, readFileSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { ffmpegAvailable } from "@snapotter/media-engine";
import { afterEach, describe, expect, it, vi } from "vitest";
import { fixtureRoot } from "../../fixtures/index.js";

/**
 * A container missing ffmpeg is an operator problem, not a bad upload.
 *
 * media-input caught every probe failure and reported "may be corrupt or in an
 * unsupported format", so an operator whose image lacks ffprobe was told their
 * perfectly good MP4 was broken, with nothing pointing at the real cause. The
 * CI integration shards ship without ffmpeg by design, which is where this
 * surfaced: every media tool failed there for a reason no caller could see.
 *
 * These run without the ffmpegAvailable() gate the sibling media specs use,
 * because the whole point is the behaviour when the binary is gone.
 */
const MP4 = readFileSync(join(fixtureRoot, "video", "formats", "tiny.mp4"));

function scratch(): { scratchDir: string } {
  return { scratchDir: mkdtempSync(join(tmpdir(), "media-unavailable-")) };
}

const originalFfprobe = process.env.FFPROBE_PATH;

afterEach(() => {
  if (originalFfprobe === undefined) delete process.env.FFPROBE_PATH;
  else process.env.FFPROBE_PATH = originalFfprobe;
  vi.resetModules();
});

/**
 * media-engine resolves the binary once and caches it in a module variable, so
 * changing FFPROBE_PATH after any earlier call has no effect. Re-import through
 * a fresh module graph so each case actually gets the environment it sets.
 */
async function freshHandler(kind: "video") {
  vi.resetModules();
  const { MediaInputHandler } = await import("../../../apps/api/src/modality/media-input.js");
  return new MediaInputHandler(kind);
}

describe("media validation when the engine is unavailable", () => {
  it("reports the missing engine instead of blaming the upload", async () => {
    process.env.FFPROBE_PATH = join(tmpdir(), "definitely-not-ffprobe");
    const handler = await freshHandler("video");

    const error = await handler.prepare(MP4, "clip.mp4", scratch()).then(
      () => null,
      (caught: unknown) => caught,
    );

    // Shape, not instanceof: vi.resetModules() gives the handler a different
    // copy of the error class than a static import here would hold.
    const failure = error as { name?: string; message: string; statusCode?: number };
    expect(failure.name, "a missing engine must still reject the request").toBe(
      "InputValidationError",
    );

    // The upload is fine. Saying otherwise sends the operator looking at their
    // file instead of their container.
    expect(failure.message).not.toMatch(/corrupt/i);
    expect(failure.message).toMatch(/ffprobe|ffmpeg|unavailable|not installed/i);

    // 400 tells the caller to fix their request, which cannot help here. This
    // is the server missing a dependency, so it belongs in the 5xx range.
    expect(failure.statusCode).toBeGreaterThanOrEqual(500);
  });

  // Needs a working ffprobe to reach the parse failure at all. CI shards ship
  // without ffmpeg, where every media input is an engine gap instead.
  it.skipIf(!ffmpegAvailable())(
    "still rejects a genuinely corrupt upload as a client error",
    async () => {
      delete process.env.FFPROBE_PATH;
      const handler = await freshHandler("video");
      const notMedia = Buffer.from("this is not a video file, it is prose");

      const error = await handler.prepare(notMedia, "clip.mp4", scratch()).then(
        () => null,
        (caught: unknown) => caught,
      );

      const failure = error as { name?: string; message: string; statusCode?: number };
      expect(failure.name).toBe("InputValidationError");
      expect(failure.statusCode).toBe(400);
      expect(failure.message).toMatch(/corrupt|unsupported/i);
    },
  );
});