import { beforeEach, describe, expect, it, vi } from "vitest";
import { createHash, generateKeyPairSync, randomBytes } from "node:crypto";

const s3Calls = vi.hoisted(() => ({
  sent: [] as string[],
  ranges: [] as string[],
  sealed: null as Buffer | null,
}));

vi.mock("@aws-sdk/client-s3", () => {
  class FakeCommand {
    constructor(readonly input: unknown, readonly marker: string) {}
  }
  class S3ServiceException extends Error {
    readonly $metadata: { httpStatusCode?: number };
    constructor(message: string, status: number, name: string) {
      super(message);
      this.name = name;
      this.$metadata = { httpStatusCode: status };
    }
  }
  return {
    CreateBucketCommand: class extends FakeCommand { constructor(input: unknown) { super(input, "Create"); } },
    HeadObjectCommand: class extends FakeCommand { constructor(input: unknown) { super(input, "Head"); } },
    PutObjectCommand: class extends FakeCommand { constructor(input: unknown) { super(input, "Put"); } },
    GetObjectCommand: class extends FakeCommand { constructor(input: unknown) { super(input, "Get"); } },
    S3ServiceException,
    S3Client: class {
      constructor(readonly config: unknown) {}
      async send(cmd: FakeCommand): Promise<unknown> {
        s3Calls.sent.push(cmd.marker);
        if (cmd.marker === "Create") throw new S3ServiceException("Access Denied", 403, "AccessDenied");
        if (cmd.marker === "Head") throw new S3ServiceException("Not Found", 404, "NotFound");
        if (cmd.marker === "Get" && s3Calls.sealed !== null) {
          const range = (cmd.input as { Range: string }).Range;
          s3Calls.ranges.push(range);
          const match = /^bytes=(\d+)-(\d+)$/.exec(range)!;
          const body = s3Calls.sealed.subarray(Number(match[1]), Number(match[2]) + 1);
          return { Body: { transformToByteArray: async () => body } };
        }
        return {};
      }
    },
  };
});

import { DIRECT_SEGMENT_BYTES, S3Storage, directSealedSize, directPlaintextSize, extensionFor, keyForHash, open, seal, sealForDirect, sha256 } from "./storage.js";

const TEST_KEK = createHash("sha256").update("test-kek").digest();

describe("SPENC2 sealed size", () => {
  it.each([
    [1, 168],
    [DIRECT_SEGMENT_BYTES - 1, 135 + DIRECT_SEGMENT_BYTES - 1 + 32],
    [DIRECT_SEGMENT_BYTES, 135 + DIRECT_SEGMENT_BYTES + 32],
    [DIRECT_SEGMENT_BYTES + 1, 135 + DIRECT_SEGMENT_BYTES + 1 + 64],
    [2 * 1024 ** 3, 135 + 2 * 1024 ** 3 + 205 * 32],
  ])("computes exact size for %i plaintext bytes", (plain, sealed) => {
    expect(directSealedSize(plain)).toBe(sealed);
    expect(directPlaintextSize(sealed)).toBe(plain);
  });

  it.each([0, -1, 1.5, NaN, Infinity, Number.MAX_SAFE_INTEGER])("rejects invalid plaintext size %s", (size) => {
    expect(() => directSealedSize(size)).toThrow(RangeError);
  });
});

describe("storage key scheme (pure)", () => {
  it("maps content types to extensions, unknown -> bin", () => {
    expect(extensionFor("image/png")).toBe("png");
    expect(extensionFor("video/mp4")).toBe("mp4");
    expect(extensionFor("application/x-weird")).toBe("bin");
  });

  it("keys are content-addressed and deterministic", () => {
    const hash = sha256(Buffer.from("same bytes"));
    expect(keyForHash(hash, "image/png")).toBe(`sha256/${hash}.png`);
    expect(keyForHash(hash, "video/mp4")).toBe(`sha256/${hash}.mp4`);
    expect(keyForHash(sha256(Buffer.from("same bytes")), "image/png")).toBe(keyForHash(hash, "image/png"));
    expect(keyForHash(sha256(Buffer.from("other")), "image/png")).not.toBe(keyForHash(hash, "image/png"));
  });

  it("hash is stable across buffer instances", () => {
    expect(sha256(Buffer.from("abc"))).toBe(sha256(Buffer.from("abc")));
    expect(sha256(Buffer.from("abc"))).toHaveLength(64);
  });
});

describe("client-side encryption (pure)", () => {
  it("seal → open roundtrips arbitrary bytes", () => {
    const plaintext = randomBytes(1024 * 64);
    const sealed = seal(plaintext, TEST_KEK);
    expect(open(sealed, TEST_KEK).equals(plaintext)).toBe(true);
  });

  it("ciphertext never contains plaintext (endpoint sees only sealed frame)", () => {
    const plaintext = Buffer.from("TOPSECRET-media-bytes-123");
    const sealed = seal(plaintext, TEST_KEK);
    expect(sealed.includes(plaintext)).toBe(false);
  });

  it("fresh CEK per seal → identical plaintext, different ciphertexts (dedup still by key)", () => {
    const plaintext = Buffer.from("identical");
    const a = seal(plaintext, TEST_KEK);
    const b = seal(plaintext, TEST_KEK);
    expect(a.equals(b)).toBe(false);
    expect(open(a, TEST_KEK).equals(open(b, TEST_KEK))).toBe(true);
  });

  it("tampered ciphertext fails GCM authentication", () => {
    const sealed = seal(Buffer.from("authentic"), TEST_KEK);
    const last = sealed.length - 1;
    sealed[last] = (sealed[last] ?? 0) ^ 0xff;
    expect(() => open(sealed, TEST_KEK)).toThrow();
  });

  it("wrong KEK cannot open", () => {
    const otherKek = createHash("sha256").update("other-kek").digest();
    const sealed = seal(Buffer.from("private"), TEST_KEK);
    expect(() => open(sealed, otherKek)).toThrow();
  });

  it("plaintext hash addressing + seal preserves dedup semantics", () => {
    const a = Buffer.from("media");
    const b = Buffer.from("media");
    expect(sha256(a)).toBe(sha256(b));
    expect(keyForHash(sha256(a), "video/mp4")).toBe(keyForHash(sha256(b), "video/mp4"));
  });
});

describe("S3Storage with object-scoped credentials", () => {
  beforeEach(() => { s3Calls.sent.length = 0; });

  it("stores despite 403 on bucket create (pre-provisioned bucket, least-privilege token)", async () => {
    const storage = new S3Storage({
      endpoint: "https://s3.example.invalid",
      accessKeyId: "scoped-key",
      secretAccessKey: "scoped-secret",
      bucket: "pre-provisioned",
      mediaKek: TEST_KEK,
    });
    const stored = await storage.putContent(Buffer.from("scoped-token-probe"), "text/plain");
    expect(stored.deduplicated).toBe(false);
    expect(s3Calls.sent).toEqual(["Create", "Head", "Put"]);
  });
});


describe("SPENC2 range reads", () => {
  beforeEach(() => {
    s3Calls.sent.length = 0;
    s3Calls.ranges.length = 0;
    s3Calls.sealed = null;
  });

  async function fixture(plaintext: Buffer): Promise<S3Storage> {
    const { privateKey } = generateKeyPairSync("ec", { namedCurve: "P-256" });
    const storage = new S3Storage({ mediaKek: TEST_KEK, directPrivateKey: privateKey });
    const jwk = (await storage.directPublicJwk())!;
    s3Calls.sealed = sealForDirect(plaintext, jwk);
    expect(directPlaintextSize(s3Calls.sealed.length)).toBe(plaintext.length);
    return storage;
  }

  it("recovers plaintext size at full-segment boundaries", () => {
    for (const size of [1, DIRECT_SEGMENT_BYTES - 1, DIRECT_SEGMENT_BYTES, DIRECT_SEGMENT_BYTES + 1]) {
      const sealedSize = 135 + size + Math.ceil(size / DIRECT_SEGMENT_BYTES) * 32;
      expect(directPlaintextSize(sealedSize)).toBe(size);
    }
    expect(() => directPlaintextSize(167)).toThrow("invalid SPENC2 sealed size");
    expect(() => directPlaintextSize(135 + DIRECT_SEGMENT_BYTES + 33)).toThrow("invalid SPENC2 sealed size");
  });

  it("slices mid-segment bounds across three segments without fetching earlier segments", async () => {
    const plaintext = randomBytes(4 * DIRECT_SEGMENT_BYTES);
    const storage = await fixture(plaintext);
    const start = DIRECT_SEGMENT_BYTES + 321;
    const end = 3 * DIRECT_SEGMENT_BYTES + 789;
    const bytes = await storage.readDirectRange("direct/clip.enc", start, end - start);
    expect(bytes.equals(plaintext.subarray(start, end))).toBe(true);
    const stride = DIRECT_SEGMENT_BYTES + 32;
    expect(s3Calls.ranges).toEqual(["bytes=0-134", `bytes=${135 + stride}-${135 + 4 * stride - 1}`]);
    expect(s3Calls.sent).toEqual(["Get", "Get"]);
  });

  it("clips the sealed fetch at EOF and slices a final partial segment", async () => {
    const plaintext = randomBytes(2 * DIRECT_SEGMENT_BYTES + 1234);
    const storage = await fixture(plaintext);
    const start = DIRECT_SEGMENT_BYTES + 17;
    expect((await storage.readDirectRange("direct/clip.enc", start, plaintext.length - start))
      .equals(plaintext.subarray(start))).toBe(true);
    expect(s3Calls.ranges).toEqual(["bytes=0-134",
      `bytes=${135 + DIRECT_SEGMENT_BYTES + 32}-${135 + 3 * (DIRECT_SEGMENT_BYTES + 32) - 1}`]);
  });

  it("validates the magic on every read before fetching any segments", async () => {
    const storage = await fixture(Buffer.from("video payload"));
    await storage.readDirectRange("direct/clip.enc", 0, 3);
    s3Calls.sealed![0] = 0;
    await expect(storage.readDirectRange("direct/clip.enc", 0, 3)).rejects.toThrow("magic mismatch");
    expect(s3Calls.ranges).toEqual(["bytes=0-134", `bytes=135-${135 + DIRECT_SEGMENT_BYTES + 32 - 1}`, "bytes=0-134"]);
  });

  it("refuses tampered ciphertext and truncated segments", async () => {
    const storage = await fixture(Buffer.from("authenticated payload"));
    const last = s3Calls.sealed!.length - 1;
    s3Calls.sealed![last] = (s3Calls.sealed![last] ?? 0) ^ 1;
    await expect(storage.readDirectRange("direct/clip.enc", 0, 3)).rejects.toThrow();
    s3Calls.sealed = s3Calls.sealed!.subarray(0, 140);
    await expect(storage.readDirectRange("direct/clip.enc", 0, 3)).rejects.toThrow("truncated");
  });

  it("rejects ranges beyond the segment count or final plaintext length", async () => {
    const storage = await fixture(Buffer.from("short"));
    await expect(storage.readDirectRange("direct/clip.enc", DIRECT_SEGMENT_BYTES, 1)).rejects.toThrow(RangeError);
    expect(s3Calls.ranges).toEqual(["bytes=0-134"]);
    await expect(storage.readDirectRange("direct/clip.enc", 4, 5)).rejects.toThrow("object length");
  });
});