import { createHash } from "node:crypto";
import { mkdir, readFile, rm, writeFile } from "node:fs/promises";
import path from "node:path";
import { gunzipSync, gzipSync } from "node:zlib";
import { afterEach, describe, expect, it } from "vitest";
import {
  acquireCorrespondingSources,
  buildCorrespondingSource,
  CorrespondingSourceError,
  type CorrespondingSourceErrorCode,
  hasSourceObligations,
  loadSourceRecipes,
  verifyRedistribution,
} from "../src/corresponding-source.js";
import { contentDigest } from "../src/supplements.js";
import { deterministicTarGz, readTarGz } from "../src/tar.js";
import { cleanupFixtures, scratchDirectory } from "./support/fixture-module.js";

/**
 * Corresponding-source artifacts and the public-distribution gate (ADR 0055), on small synthetic
 * inputs: a fake LGPL native package, its reviewed supplement, its source recipe, and a source
 * cache. The real libvips proof is `corresponding-source-native.test.ts`.
 */

afterEach(cleanupFixtures);

function sha256(data: string | Uint8Array): string {
  return createHash("sha256").update(data).digest("hex");
}

const PACKAGE_FILE = "example-0.1.0-linux-x64-glibc.tar.gz";
const SOURCE_FILE = "example-0.1.0-linux-x64-glibc-corresponding-source.tar.gz";
const METADATA_FILE = "example-0.1.0-linux-x64-glibc.redistribution.json";
const TOP = "example-0.1.0-linux-x64-glibc-corresponding-source";

const SOURCES: Readonly<Record<string, string>> = {
  "sources/fake-build-1.0.tar.gz": "build definitions for libfake\n",
  "sources/fakelib-2.0.tar.gz": "fakelib 2.0 source\n",
  "patches/fakelib-fix.patch": "--- a/x\n+++ b/x\n@@ -1 +1 @@\n-a\n+b\n",
  "sources/helperlib-1.1.tar.gz": "helperlib 1.1 source\n",
  "sources/codegen-0.3.crate": "codegen 0.3 build-only source\n",
};

interface FixtureOptions {
  readonly version?: string;
  readonly libraryBytes?: string;
  readonly license?: string;
  readonly notices?: string;
  readonly recipe?: (recipe: Record<string, unknown>) => void;
  readonly withRecipe?: boolean;
}

interface Fixture {
  readonly root: string;
  readonly packagePath: string;
  readonly cache: string;
  readonly recipesDirectory: string;
  readonly supplementsDirectory: string;
}

function noticeEntry(name: string, version: string, licence: string, uses: string): string {
  const rule = "-".repeat(80);
  return `${rule}\n${name} ${version}\nLicense: ${licence}\nUsed in: ${uses}\n${rule}\n\n[LICENSE]\n\ntext\n`;
}

/** Writes a fake native package into a Module Package archive, its supplement, recipe, and cache. */
async function fixture(options: FixtureOptions = {}): Promise<Fixture> {
  const version = options.version ?? "1.0.0";
  const license = options.license ?? "LGPL-2.1-or-later";
  const root = await scratchDirectory("ekklesia-corresponding-");
  const nativeFiles = new Map<string, Buffer>([
    ["lib/libfake.so.1", Buffer.from(options.libraryBytes ?? `\u007fELF fake library ${version}`)],
    ["package.json", Buffer.from(JSON.stringify({ license, name: "fake-native", version }))],
  ]);
  const digest = contentDigest(nativeFiles);
  const packageFiles = new Map<string, Buffer>([
    [
      "ekklesia.package.json",
      Buffer.from(
        JSON.stringify({
          module: { id: "example", version: "0.1.0" },
          packageFormat: 1,
          target: "linux-x64-glibc",
        }),
      ),
    ],
    [
      "THIRD_PARTY_NOTICES",
      Buffer.from(options.notices ?? noticeEntry("fake-native", version, license, "node_modules")),
    ],
    ...[...nativeFiles].map(([file, data]) => [`node_modules/fake-native/${file}`, data] as const),
  ]);
  const packageDirectory = path.join(root, "package");
  await mkdir(packageDirectory);
  const packagePath = path.join(packageDirectory, PACKAGE_FILE);
  await writeFile(packagePath, deterministicTarGz("example", packageFiles));

  // The reviewed supplement for exactly these package bytes.
  const supplementsDirectory = path.join(root, "supplements");
  const supplementDirectory = path.join(supplementsDirectory, "fake-native", version);
  await mkdir(path.join(supplementDirectory, "texts"), { recursive: true });
  const material = async (content: string) => {
    await writeFile(path.join(supplementDirectory, "texts", `${sha256(content)}.txt`), content);
    return `texts/${sha256(content)}.txt`;
  };
  const supplement = {
    supplementFormat: 1,
    package: { name: "fake-native", version, license, contentDigest: digest },
    statement: "Covers the libraries built into lib/libfake.so.1.",
    components: [
      {
        name: "fakelib",
        version: "2.0",
        license: "LGPL-2.1-or-later",
        source: "https://example.org/fakelib-2.0.tar.gz",
        material: [
          { title: "COPYING", text: await material("GNU LESSER GENERAL PUBLIC LICENSE (fake)\n") },
        ],
      },
      {
        name: "helperlib",
        version: "1.1",
        license: "MIT",
        source: "https://example.org/helperlib-1.1.tar.gz",
        material: [{ title: "LICENSE", text: await material("MIT License (fake)\n") }],
      },
    ],
  };
  const supplementJson = `${JSON.stringify(supplement, null, 2)}\n`;
  await writeFile(path.join(supplementDirectory, "supplement.json"), supplementJson);
  await writeFile(path.join(supplementDirectory, "PROVENANCE.md"), "# How this was assembled\n");

  // The recipe, and a cache holding the recorded bytes.
  const recipesDirectory = path.join(root, "recipes");
  const cache = path.join(root, "cache");
  await mkdir(path.join(cache, "sha256"), { recursive: true });
  const file = async (relative: string) => {
    const content = SOURCES[relative] ?? "";
    await writeFile(path.join(cache, "sha256", sha256(content)), content);
    return {
      file: relative,
      origin: `https://example.org/${path.basename(relative)}`,
      sha256: sha256(content),
      size: Buffer.byteLength(content),
    };
  };
  const building = "# Rebuilding libfake\n\nRun `make` in fake-build.\n";
  const recipe: Record<string, unknown> = {
    recipeFormat: 1,
    package: {
      name: "fake-native",
      version,
      license,
      contentDigest: digest,
      target: "linux-x64-glibc",
      binaries: ["lib/libfake.so.1"],
    },
    supplement: { version, sha256: sha256(supplementJson) },
    documents: [
      { path: "BUILDING.md", sha256: sha256(building), size: Buffer.byteLength(building) },
    ],
    components: [
      {
        name: "fake-build",
        version: "1.0",
        role: "build-definition",
        license: "MIT",
        relationship: "The build definitions.",
        licenseMaterial: [],
        sources: [await file("sources/fake-build-1.0.tar.gz")],
        patches: [],
      },
      {
        name: "fakelib",
        version: "2.0",
        role: "compiled",
        license: "LGPL-2.1-or-later",
        relationship: "Compiled into lib/libfake.so.1.",
        licenseMaterial: [{ name: "fakelib", version: "2.0" }],
        sources: [await file("sources/fakelib-2.0.tar.gz")],
        patches: [await file("patches/fakelib-fix.patch")],
      },
      {
        name: "helperlib",
        version: "1.1",
        role: "compiled",
        license: "MIT",
        relationship: "Compiled into lib/libfake.so.1.",
        licenseMaterial: [{ name: "helperlib", version: "1.1" }],
        sources: [await file("sources/helperlib-1.1.tar.gz")],
        patches: [],
      },
      {
        name: "codegen",
        version: "0.3",
        role: "build-input",
        license: "MIT",
        relationship: "Needed only to build.",
        licenseMaterial: [],
        sources: [await file("sources/codegen-0.3.crate")],
        patches: [],
      },
    ],
    exclusions: [{ name: "testlib", reason: "Used only by tests." }],
  };
  options.recipe?.(recipe);
  if (options.withRecipe !== false) {
    const recipeDirectory = path.join(recipesDirectory, "fake-native", version);
    await mkdir(recipeDirectory, { recursive: true });
    await writeFile(
      path.join(recipeDirectory, "recipe.json"),
      `${JSON.stringify(recipe, null, 2)}\n`,
    );
    await writeFile(path.join(recipeDirectory, "BUILDING.md"), building);
  }
  return { cache, packagePath, recipesDirectory, root, supplementsDirectory };
}

async function build(fx: Fixture, out = path.join(fx.root, "out")) {
  return buildCorrespondingSource({
    cacheDirectory: fx.cache,
    outDirectory: out,
    packageArchivePath: fx.packagePath,
    recipesDirectory: fx.recipesDirectory,
    supplementsDirectory: fx.supplementsDirectory,
  });
}

function verify(fx: Fixture, source?: string, metadata?: string) {
  return verifyRedistribution({
    packageArchivePath: fx.packagePath,
    recipesDirectory: fx.recipesDirectory,
    supplementsDirectory: fx.supplementsDirectory,
    ...(source === undefined ? {} : { sourceArchivePath: source }),
    ...(metadata === undefined ? {} : { metadataPath: metadata }),
  });
}

async function rejects(promise: Promise<unknown>, code: CorrespondingSourceErrorCode) {
  const error = await promise.then(
    () => undefined,
    (caught: unknown) => caught,
  );
  expect(error).toBeInstanceOf(CorrespondingSourceError);
  expect((error as CorrespondingSourceError).code).toBe(code);
  return error as CorrespondingSourceError;
}

/** A built release, ready to tamper with: its source archive's files, and a way to write a changed
 * archive (and metadata naming it) where the gate will look. */
async function release() {
  const fx = await fixture();
  const out = path.join(fx.root, "out");
  await build(fx, out);
  const sourcePath = path.join(out, SOURCE_FILE);
  const metadataPath = path.join(out, METADATA_FILE);
  const files = new Map<string, Buffer>();
  for (const entry of readTarGz(await readFile(sourcePath))) {
    if (!entry.directory) files.set(entry.path.slice(TOP.length + 1), entry.data);
  }
  /** Writes `changed` as the archive and keeps the metadata consistent with its bytes, so only the
   * change itself can fail the gate. */
  const write = async (changed: Map<string, Buffer>, archive?: Buffer) => {
    const bytes = archive ?? deterministicTarGz(TOP, changed);
    await writeFile(sourcePath, bytes);
    const metadata = JSON.parse(await readFile(metadataPath, "utf8"));
    const digest = sha256(bytes);
    metadata.correspondingSource.sha256 = digest;
    metadata.correspondingSource.size = bytes.length;
    metadata.correspondingSource.manifestSha256 = sha256(
      changed.get("corresponding-source.json") ?? "",
    );
    metadata.notice = metadata.notice.replace(/SHA-256 [0-9a-f]{64}/u, `SHA-256 ${digest}`);
    await writeFile(metadataPath, `${JSON.stringify(metadata, null, 2)}\n`);
  };
  /** Rewrites the manifest's file list to match `changed`, as a careful forger would. */
  const relist = (changed: Map<string, Buffer>) => {
    const manifest = JSON.parse(changed.get("corresponding-source.json")?.toString("utf8") ?? "{}");
    manifest.files = [...changed]
      .filter(([file]) => file !== "corresponding-source.json")
      .map(([file, data]) => ({ path: file, size: data.length, sha256: sha256(data) }))
      .sort((left: { path: string }, right: { path: string }) => (left.path < right.path ? -1 : 1));
    changed.set("corresponding-source.json", Buffer.from(`${JSON.stringify(manifest, null, 2)}\n`));
    return manifest;
  };
  return { files, fx, metadataPath, out, relist, sourcePath, write };
}

describe("building the corresponding-source artifact", () => {
  it("writes a deterministic archive, its digest, the redistribution metadata, and the release notice", async () => {
    const fx = await fixture();
    const first = await build(fx, path.join(fx.root, "out-a"));
    // A second build into an unrelated directory, from a moved cache and package copy.
    const second = await build(
      fx,
      path.join(await scratchDirectory("ekklesia-elsewhere-"), "out-b"),
    );
    expect(first.required).toBe(true);
    expect(first.sourceSha256).toBe(second.sourceSha256);
    expect(await readFile(first.sourceArchivePath ?? "")).toEqual(
      await readFile(second.sourceArchivePath ?? ""),
    );
    expect(await readFile(`${first.sourceArchivePath}.sha256`, "utf8")).toBe(
      `${first.sourceSha256}  ${SOURCE_FILE}\n`,
    );

    const entries = readTarGz(await readFile(first.sourceArchivePath ?? ""));
    const files = entries
      .filter((entry) => !entry.directory)
      .map((entry) => entry.path.slice(TOP.length + 1));
    expect(files).toEqual([
      "README.md",
      "SHA256SUMS",
      "corresponding-source.json",
      "dependencies/fake-native/1.0.0/BUILDING.md",
      "dependencies/fake-native/1.0.0/PROVENANCE.md",
      "dependencies/fake-native/1.0.0/licenses/supplement.json",
      expect.stringMatching(
        /^dependencies\/fake-native\/1\.0\.0\/licenses\/texts\/[0-9a-f]{64}\.txt$/u,
      ),
      expect.stringMatching(
        /^dependencies\/fake-native\/1\.0\.0\/licenses\/texts\/[0-9a-f]{64}\.txt$/u,
      ),
      "dependencies/fake-native/1.0.0/patches/fakelib-fix.patch",
      "dependencies/fake-native/1.0.0/recipe.json",
      "dependencies/fake-native/1.0.0/sources/codegen-0.3.crate",
      "dependencies/fake-native/1.0.0/sources/fake-build-1.0.tar.gz",
      "dependencies/fake-native/1.0.0/sources/fakelib-2.0.tar.gz",
      "dependencies/fake-native/1.0.0/sources/helperlib-1.1.tar.gz",
    ]);
    // The actual bytes, not references to them.
    const patch = entries.find((entry) => entry.path.endsWith("patches/fakelib-fix.patch"));
    expect(patch?.data.toString("utf8")).toBe(SOURCES["patches/fakelib-fix.patch"]);

    const manifest = JSON.parse(
      entries
        .find((entry) => entry.path.endsWith("/corresponding-source.json"))
        ?.data.toString("utf8") ?? "{}",
    );
    expect(manifest.module).toEqual({ id: "example", target: "linux-x64-glibc", version: "0.1.0" });
    expect(manifest.dependencies[0]).toMatchObject({
      binaries: ["lib/libfake.so.1"],
      exclusions: [{ name: "testlib", reason: "Used only by tests." }],
      name: "fake-native",
      version: "1.0.0",
    });
    expect(
      manifest.dependencies[0].components.map((component: { role: string }) => component.role),
    ).toEqual(["build-definition", "compiled", "compiled", "build-input"]);

    const metadata = JSON.parse(await readFile(first.metadataPath ?? "", "utf8"));
    expect(metadata).toMatchObject({
      correspondingSource: {
        file: SOURCE_FILE,
        sha256: first.sourceSha256,
        manifestSha256: first.manifestSha256,
      },
      covered: [{ name: "fake-native", version: "1.0.0" }],
      package: { file: PACKAGE_FILE, sha256: sha256(await readFile(fx.packagePath)) },
    });
    const notice = await readFile(first.noticePath ?? "", "utf8");
    expect(notice).toBe(metadata.notice);
    expect(notice).toContain(
      "This release includes third-party software covered by licenses including the GNU LGPL",
    );
    expect(notice).toContain(
      "Corresponding source and build/relink materials for the covered native dependencies",
    );
    expect(notice).toContain(SOURCE_FILE);
    expect(notice).toContain(`SHA-256 ${first.sourceSha256}`);
    // Nothing machine-specific in what the build generated.
    for (const generated of ["README.md", "SHA256SUMS", "corresponding-source.json"]) {
      const content =
        entries.find((entry) => entry.path === `${TOP}/${generated}`)?.data.toString("utf8") ?? "";
      expect(content).not.toContain(fx.root);
      expect(content).not.toContain(fx.cache);
    }
    expect(JSON.stringify(metadata)).not.toContain(fx.root);
  });

  it("is approved by the gate exactly as built", async () => {
    const { fx, metadataPath, sourcePath } = await release();
    await expect(verify(fx, sourcePath, metadataPath)).resolves.toMatchObject({
      approved: true,
      correspondingSource: { file: SOURCE_FILE },
      covered: [{ name: "fake-native", version: "1.0.0" }],
    });
  });

  it("refuses to build from cached bytes that differ from the recipe, and writes nothing", async () => {
    const fx = await fixture();
    await writeFile(
      path.join(fx.cache, "sha256", sha256(SOURCES["patches/fakelib-fix.patch"] ?? "")),
      "changed patch\n",
    );
    await rejects(build(fx), "CORRESPONDING_SOURCE_SOURCE_MISMATCH");
    await rm(path.join(fx.cache, "sha256", sha256(SOURCES["sources/fakelib-2.0.tar.gz"] ?? "")));
    await expect(readFile(path.join(fx.root, "out", SOURCE_FILE))).rejects.toThrow();
  });

  it("refuses a missing cached file, and never overwrites an existing release", async () => {
    const fx = await fixture();
    await rm(path.join(fx.cache, "sha256", sha256(SOURCES["sources/helperlib-1.1.tar.gz"] ?? "")));
    await rejects(build(fx), "CORRESPONDING_SOURCE_SOURCE_MISSING");
    const fresh = await fixture();
    await build(fresh);
    await rejects(build(fresh), "CORRESPONDING_SOURCE_OUTPUT_EXISTS");
  });

  it("builds nothing for a package with no covered native code, and the gate approves it without an artifact", async () => {
    const fx = await fixture({ license: "MIT", withRecipe: false });
    // The fixture's supplement records an LGPL component, so remove it: a package whose own files and
    // licence carry no source obligation needs no corresponding source.
    await rm(fx.supplementsDirectory, { force: true, recursive: true });
    await expect(build(fx)).resolves.toEqual({ required: false });
    await expect(verify(fx)).resolves.toMatchObject({ approved: true, covered: [] });
  });

  it("treats a dependency as covered when its reviewed supplement records a copyleft component", async () => {
    // Declared MIT, but the supplement says an LGPL library is built into it.
    const fx = await fixture({ license: "MIT", withRecipe: false });
    // The supplement's declared licence must match the package's for the supplement to apply.
    const supplementPath = path.join(
      fx.supplementsDirectory,
      "fake-native",
      "1.0.0",
      "supplement.json",
    );
    const supplement = JSON.parse(await readFile(supplementPath, "utf8"));
    expect(supplement.package.license).toBe("MIT");
    await rejects(build(fx), "CORRESPONDING_SOURCE_RECIPE_MISSING");
  });
});

describe("the public-distribution gate fails closed", () => {
  it("without the corresponding-source archive, or without the redistribution metadata", async () => {
    const { fx, metadataPath, sourcePath } = await release();
    await rejects(verify(fx), "CORRESPONDING_SOURCE_ARTIFACT_MISSING");
    await rm(sourcePath);
    await rejects(verify(fx, sourcePath, metadataPath), "CORRESPONDING_SOURCE_ARTIFACT_MISSING");
    const second = await release();
    await rejects(verify(second.fx, second.sourcePath), "CORRESPONDING_SOURCE_METADATA_MISMATCH");
  });

  it("when the metadata names a different source digest, or the archive's bytes are corrupted", async () => {
    const { fx, metadataPath, sourcePath } = await release();
    const metadata = JSON.parse(await readFile(metadataPath, "utf8"));
    metadata.correspondingSource.sha256 = "0".repeat(64);
    await writeFile(metadataPath, JSON.stringify(metadata));
    await rejects(verify(fx, sourcePath, metadataPath), "CORRESPONDING_SOURCE_METADATA_MISMATCH");

    const corrupt = await release();
    const bytes = await readFile(corrupt.sourcePath);
    const middle = Math.floor(bytes.length / 2);
    bytes[middle] = (bytes[middle] ?? 0) ^ 0xff;
    await writeFile(corrupt.sourcePath, bytes);
    await rejects(
      verify(corrupt.fx, corrupt.sourcePath, corrupt.metadataPath),
      "CORRESPONDING_SOURCE_ARTIFACT_INVALID",
    );
  });

  it("when the release notice does not name the exact artifact", async () => {
    const { fx, metadataPath, sourcePath } = await release();
    const metadata = JSON.parse(await readFile(metadataPath, "utf8"));
    metadata.notice = metadata.notice.replace(SOURCE_FILE, "some-other-source.tar.gz");
    await writeFile(metadataPath, JSON.stringify(metadata));
    await rejects(verify(fx, sourcePath, metadataPath), "CORRESPONDING_SOURCE_METADATA_MISMATCH");
  });

  it("when the native package's bytes are not those the recipe was prepared for", async () => {
    const built = await release();
    // The same name and version, different library bytes: a different content digest.
    const other = await fixture({ libraryBytes: "\u007fELF a different build" });
    await writeFile(built.fx.packagePath, await readFile(other.packagePath));
    await rejects(
      verify(built.fx, built.sourcePath, built.metadataPath),
      "CORRESPONDING_SOURCE_RECIPE_MISMATCH",
    );
  });

  it("when a source component's version differs from the recipe", async () => {
    const { files, fx, metadataPath, relist, sourcePath, write } = await release();
    const manifest = JSON.parse(files.get("corresponding-source.json")?.toString("utf8") ?? "{}");
    manifest.dependencies[0].components[1].version = "2.1";
    files.set("corresponding-source.json", Buffer.from(`${JSON.stringify(manifest, null, 2)}\n`));
    relist(files);
    await write(files);
    const error = await rejects(
      verify(fx, sourcePath, metadataPath),
      "CORRESPONDING_SOURCE_MANIFEST_MISMATCH",
    );
    expect(error.subject).toBe("fake-native@1.0.0");
  });

  it("when a required source component is missing", async () => {
    const { files, fx, metadataPath, relist, sourcePath, write } = await release();
    const manifest = JSON.parse(files.get("corresponding-source.json")?.toString("utf8") ?? "{}");
    manifest.dependencies[0].components.splice(2, 1);
    files.set("corresponding-source.json", Buffer.from(`${JSON.stringify(manifest, null, 2)}\n`));
    files.delete("dependencies/fake-native/1.0.0/sources/helperlib-1.1.tar.gz");
    relist(files);
    await write(files);
    await rejects(verify(fx, sourcePath, metadataPath), "CORRESPONDING_SOURCE_MANIFEST_MISMATCH");
  });

  it("when a patch's bytes changed, even with the file list rewritten to match", async () => {
    const { files, fx, metadataPath, relist, sourcePath, write } = await release();
    files.set(
      "dependencies/fake-native/1.0.0/patches/fakelib-fix.patch",
      Buffer.from("a different patch\n"),
    );
    relist(files);
    await write(files);
    await rejects(verify(fx, sourcePath, metadataPath), "CORRESPONDING_SOURCE_MANIFEST_MISMATCH");
  });

  it("when the manifest records a file the archive does not hold", async () => {
    const { files, fx, metadataPath, sourcePath, write } = await release();
    files.delete("dependencies/fake-native/1.0.0/sources/fakelib-2.0.tar.gz");
    await write(files);
    const error = await rejects(
      verify(fx, sourcePath, metadataPath),
      "CORRESPONDING_SOURCE_MANIFEST_MISMATCH",
    );
    expect(error.subject).toBe("dependencies/fake-native/1.0.0/sources/fakelib-2.0.tar.gz");
  });

  it("when the archive holds source material its manifest does not record", async () => {
    const { files, fx, metadataPath, sourcePath, write } = await release();
    files.set(
      "dependencies/fake-native/1.0.0/sources/unreviewed.tar.gz",
      Buffer.from("not recorded\n"),
    );
    await write(files);
    const error = await rejects(
      verify(fx, sourcePath, metadataPath),
      "CORRESPONDING_SOURCE_UNRECORDED_FILE",
    );
    expect(error.subject).toBe("dependencies/fake-native/1.0.0/sources/unreviewed.tar.gz");
  });

  it("when a generated file names a machine-specific path", async () => {
    const { files, fx, metadataPath, relist, sourcePath, write } = await release();
    files.set("README.md", Buffer.from("Built from /home/builder/cache/sha256.\n"));
    relist(files);
    await write(files);
    await rejects(verify(fx, sourcePath, metadataPath), "CORRESPONDING_SOURCE_LOCAL_PATH");
  });

  it("when the archive's entries are not in the deterministic order", async () => {
    const { files, fx, metadataPath, sourcePath, write } = await release();
    // The same entries and bytes, with the last two file entries swapped.
    const raw = gunzipSync(await readFile(sourcePath));
    const chunks: Buffer[] = [];
    let offset = 0;
    while (offset < raw.length && !raw.subarray(offset, offset + 512).every((byte) => byte === 0)) {
      const size = Number.parseInt(
        raw
          .subarray(offset + 124, offset + 136)
          .toString("latin1")
          .replace(/\0.*$/u, "")
          .trim() || "0",
        8,
      );
      const length = 512 + Math.ceil(size / 512) * 512;
      chunks.push(raw.subarray(offset, offset + length));
      offset += length;
    }
    const last = chunks.length - 1;
    [chunks[last - 1], chunks[last]] = [chunks[last] as Buffer, chunks[last - 1] as Buffer];
    await write(files, gzipSync(Buffer.concat([...chunks, Buffer.alloc(1024)]), { level: 9 }));
    await rejects(verify(fx, sourcePath, metadataPath), "CORRESPONDING_SOURCE_ARTIFACT_INVALID");
  });

  it("when the artifact was built for another version of the native dependency", async () => {
    // The 1.3.3-for-1.3.4 case: an artifact for fake-native 1.0.0 beside a package with 1.0.1.
    const old = await release();
    const current = await fixture({ version: "1.0.1" });
    await mkdir(path.join(current.recipesDirectory, "fake-native", "1.0.0"), { recursive: true });
    for (const file of ["recipe.json", "BUILDING.md"]) {
      await writeFile(
        path.join(current.recipesDirectory, "fake-native", "1.0.0", file),
        await readFile(path.join(old.fx.recipesDirectory, "fake-native", "1.0.0", file)),
      );
    }
    await rejects(
      verify(current, old.sourcePath, old.metadataPath),
      "CORRESPONDING_SOURCE_MANIFEST_MISMATCH",
    );
  });

  it("when the package bundles copyleft code, which this mechanism does not cover", async () => {
    const notices =
      noticeEntry("fake-native", "1.0.0", "LGPL-2.1-or-later", "node_modules") +
      noticeEntry("bundled-lgpl", "3.0.0", "LGPL-3.0-only", "backend");
    const fx = await fixture({ notices });
    await rejects(build(fx), "CORRESPONDING_SOURCE_BUNDLED_COPYLEFT");
    await rejects(verify(fx), "CORRESPONDING_SOURCE_BUNDLED_COPYLEFT");
  });

  it("when a covered dependency has no recipe, or its recipe was prepared against another supplement", async () => {
    await rejects(
      build(await fixture({ withRecipe: false })),
      "CORRESPONDING_SOURCE_RECIPE_MISSING",
    );
    const fx = await fixture({
      recipe: (recipe) => {
        (recipe.supplement as { sha256: string }).sha256 = "f".repeat(64);
      },
    });
    await rejects(build(fx), "CORRESPONDING_SOURCE_RECIPE_MISMATCH");
    const unknownMaterial = await fixture({
      recipe: (recipe) => {
        const components = recipe.components as {
          licenseMaterial: { name: string; version: string }[];
        }[];
        (components[1] as { licenseMaterial: unknown[] }).licenseMaterial = [
          { name: "fakelib", version: "9.9" },
        ];
      },
    });
    await rejects(build(unknownMaterial), "CORRESPONDING_SOURCE_RECIPE_MISMATCH");
  });
});

describe("source recipes are reviewed inputs", () => {
  async function loadWith(change: (recipe: Record<string, unknown>) => void) {
    const fx = await fixture({ recipe: change });
    return loadSourceRecipes(fx.recipesDirectory);
  }

  it("refuses an absolute or climbing source path, a non-https origin, or a compiled component without licence material", async () => {
    const component = (recipe: Record<string, unknown>, index: number) =>
      (recipe.components as Record<string, unknown>[])[index] as Record<string, unknown>;
    const first = (recipe: Record<string, unknown>) =>
      (component(recipe, 1).sources as Record<string, unknown>[])[0] as Record<string, unknown>;
    for (const change of [
      (recipe: Record<string, unknown>) => {
        first(recipe).file = "/home/builder/fakelib-2.0.tar.gz";
      },
      (recipe: Record<string, unknown>) => {
        first(recipe).file = "sources/../../fakelib-2.0.tar.gz";
      },
      (recipe: Record<string, unknown>) => {
        first(recipe).origin = "http://example.org/fakelib-2.0.tar.gz";
      },
      (recipe: Record<string, unknown>) => {
        component(recipe, 1).licenseMaterial = [];
      },
      (recipe: Record<string, unknown>) => {
        component(recipe, 2).version = "2.0";
        component(recipe, 2).name = "fakelib";
      },
    ]) {
      await rejects(loadWith(change), "CORRESPONDING_SOURCE_RECIPE_INVALID");
    }
  });

  it("refuses a document whose bytes changed, and an unlisted file beside the recipe", async () => {
    const fx = await fixture();
    const directory = path.join(fx.recipesDirectory, "fake-native", "1.0.0");
    await writeFile(path.join(directory, "BUILDING.md"), "edited without review\n");
    await rejects(loadSourceRecipes(fx.recipesDirectory), "CORRESPONDING_SOURCE_RECIPE_INVALID");
    const second = await fixture();
    await writeFile(
      path.join(second.recipesDirectory, "fake-native", "1.0.0", "notes.txt"),
      "stray\n",
    );
    await rejects(
      loadSourceRecipes(second.recipesDirectory),
      "CORRESPONDING_SOURCE_RECIPE_INVALID",
    );
  });

  it("recognizes licences with source obligations, by SPDX identifier or by upstream name", () => {
    for (const licence of [
      "LGPL-3.0-or-later",
      "MPL-2.0",
      "GPL-2.0-only",
      "Mozilla Public License 1.1",
      "MIT AND LGPL-2.1-or-later",
      "EPL-2.0",
    ]) {
      expect(hasSourceObligations(licence), licence).toBe(true);
    }
    for (const licence of [
      "MIT",
      "Apache-2.0",
      "BSD-3-Clause",
      "ISC",
      "Zlib",
      "MIT OR Apache-2.0",
    ]) {
      expect(hasSourceObligations(licence), licence).toBe(false);
    }
  });
});

describe("acquisition is separate, verified, and the only network step", () => {
  it("fetches each recorded file once, verifies it, and refuses a response that differs", async () => {
    const fx = await fixture();
    const fetched: string[] = [];
    const served = new Map(
      Object.entries(SOURCES).map(([file, content]) => [
        `https://example.org/${path.basename(file)}`,
        content,
      ]),
    );
    const empty = path.join(fx.root, "fresh-cache");
    const result = await acquireCorrespondingSources({
      cacheDirectory: empty,
      fetch: async (url) => {
        fetched.push(url);
        return Buffer.from(served.get(url) ?? "");
      },
      packageArchivePath: fx.packagePath,
      recipesDirectory: fx.recipesDirectory,
      supplementsDirectory: fx.supplementsDirectory,
    });
    expect(result).toMatchObject({ fetched: 5, files: 5 });
    // A second run finds everything verified and fetches nothing.
    const again = await acquireCorrespondingSources({
      cacheDirectory: empty,
      fetch: async () => {
        throw new Error("no network expected");
      },
      recipes: [{ name: "fake-native", version: "1.0.0" }],
      recipesDirectory: fx.recipesDirectory,
    });
    expect(again).toMatchObject({ fetched: 0, files: 5 });
    // The built artifact from the acquired cache is identical to one built from the original cache.
    const fromAcquired = await buildCorrespondingSource({
      cacheDirectory: empty,
      outDirectory: path.join(fx.root, "acquired-out"),
      packageArchivePath: fx.packagePath,
      recipesDirectory: fx.recipesDirectory,
      supplementsDirectory: fx.supplementsDirectory,
    });
    expect(fromAcquired.sourceSha256).toBe((await build(fx)).sourceSha256);

    // A transient upstream failure is retried; only the recorded bytes are ever stored.
    const flaky = path.join(fx.root, "flaky-cache");
    const attempts = new Map<string, number>();
    await expect(
      acquireCorrespondingSources({
        cacheDirectory: flaky,
        fetch: async (url) => {
          const count = (attempts.get(url) ?? 0) + 1;
          attempts.set(url, count);
          if (count === 1) {
            throw new Error("connection reset");
          }
          return Buffer.from(served.get(url) ?? "");
        },
        recipes: [{ name: "fake-native", version: "1.0.0" }],
        recipesDirectory: fx.recipesDirectory,
      }),
    ).resolves.toMatchObject({ fetched: 5 });

    const tampered = path.join(fx.root, "tampered-cache");
    await rejects(
      acquireCorrespondingSources({
        cacheDirectory: tampered,
        fetch: async (url) => Buffer.from(`${served.get(url) ?? ""}upstream changed\n`),
        recipes: [{ name: "fake-native", version: "1.0.0" }],
        recipesDirectory: fx.recipesDirectory,
      }),
      "CORRESPONDING_SOURCE_ACQUISITION_FAILED",
    );
    const { readdir } = await import("node:fs/promises");
    expect(await readdir(path.join(tampered, "sha256"))).toEqual([]);
  });
});