const crypto = require("node:crypto");

const sharp = require("sharp");

const {
  PURCHASE_ATTACHMENT_MAX_FILE_NAME_CODE_POINTS,
  PURCHASE_ATTACHMENT_MAX_IMAGE_PIXELS,
  PurchaseAttachmentPolicyError,
  buildAttachmentContentDisposition,
  buildAttachmentStorageKey,
  validateAndNormalizePurchaseAttachment,
} = require("../../../src/services/purchaseAttachmentPolicy");

const MAX_BYTES = 2 * 1024 * 1024;

function buildPdf(body = "1 0 obj\n<<>>\nendobj") {
  return Buffer.from(`%PDF-1.7\n${body}\n%%EOF\n`, "ascii");
}

function expectPolicyError(error, reasonCode) {
  expect(error).toBeInstanceOf(PurchaseAttachmentPolicyError);
  expect(error).toMatchObject({
    code: "PURCHASE_ATTACHMENT_POLICY_ERROR",
    reasonCode,
    details: { file: reasonCode },
  });
}

async function capturePolicyError(input) {
  try {
    await validateAndNormalizePurchaseAttachment(input);
  } catch (error) {
    return error;
  }
  throw new Error("expected purchase attachment policy rejection");
}

function crc32(buffer) {
  let crc = 0xffffffff;
  for (const byte of buffer) {
    crc ^= byte;
    for (let bit = 0; bit < 8; bit += 1) {
      crc = (crc >>> 1) ^ (crc & 1 ? 0xedb88320 : 0);
    }
  }
  return (crc ^ 0xffffffff) >>> 0;
}

function patchPngDimensions(buffer, width, height) {
  const patched = Buffer.from(buffer);
  patched.writeUInt32BE(width, 16);
  patched.writeUInt32BE(height, 20);
  patched.writeUInt32BE(crc32(patched.subarray(12, 29)), 29);
  return patched;
}

function buildPngChunk(type, data) {
  const typeBuffer = Buffer.from(type, "ascii");
  const chunk = Buffer.alloc(12 + data.length);
  chunk.writeUInt32BE(data.length, 0);
  typeBuffer.copy(chunk, 4);
  data.copy(chunk, 8);
  chunk.writeUInt32BE(crc32(Buffer.concat([typeBuffer, data])), 8 + data.length);
  return chunk;
}

function parsePngChunks(buffer) {
  const chunks = [];
  let offset = 8;
  while (offset < buffer.length) {
    const dataLength = buffer.readUInt32BE(offset);
    const type = buffer.toString("ascii", offset + 4, offset + 8);
    chunks.push({
      type,
      data: buffer.subarray(offset + 8, offset + 8 + dataLength),
    });
    offset += 12 + dataLength;
  }
  return chunks;
}

function buildAnimatedPng(firstFrame, secondFrame) {
  const firstChunks = parsePngChunks(firstFrame);
  const secondChunks = parsePngChunks(secondFrame);
  const ihdr = firstChunks.find((chunk) => chunk.type === "IHDR").data;
  const width = ihdr.readUInt32BE(0);
  const height = ihdr.readUInt32BE(4);
  let sequence = 0;

  const animationControl = Buffer.alloc(8);
  animationControl.writeUInt32BE(2, 0);
  animationControl.writeUInt32BE(0, 4);

  const frameControl = () => {
    const data = Buffer.alloc(26);
    data.writeUInt32BE(sequence, 0);
    sequence += 1;
    data.writeUInt32BE(width, 4);
    data.writeUInt32BE(height, 8);
    data.writeUInt16BE(1, 20);
    data.writeUInt16BE(10, 22);
    return buildPngChunk("fcTL", data);
  };

  const parts = [
    firstFrame.subarray(0, 8),
    buildPngChunk("IHDR", ihdr),
    buildPngChunk("acTL", animationControl),
    frameControl(),
    ...firstChunks
      .filter((chunk) => chunk.type === "IDAT")
      .map((chunk) => buildPngChunk("IDAT", chunk.data)),
    frameControl(),
  ];
  for (const chunk of secondChunks.filter((candidate) => candidate.type === "IDAT")) {
    const frameData = Buffer.alloc(4 + chunk.data.length);
    frameData.writeUInt32BE(sequence, 0);
    sequence += 1;
    chunk.data.copy(frameData, 4);
    parts.push(buildPngChunk("fdAT", frameData));
  }
  parts.push(buildPngChunk("IEND", Buffer.alloc(0)));
  return Buffer.concat(parts);
}

describe("purchase attachment content policy", () => {
  let jpegBuffer;
  let pngBuffer;
  let webpBuffer;

  beforeAll(async () => {
    const source = {
      create: {
        width: 4,
        height: 3,
        channels: 4,
        background: { r: 30, g: 120, b: 210, alpha: 1 },
      },
    };
    [jpegBuffer, pngBuffer, webpBuffer] = await Promise.all([
      sharp(source).jpeg().toBuffer(),
      sharp(source).png().toBuffer(),
      sharp(source).webp().toBuffer(),
    ]);
  });

  it("accepts a strict PDF boundary and preserves its bytes", async () => {
    const buffer = buildPdf();
    const result = await validateAndNormalizePurchaseAttachment({
      buffer,
      fileName: "报价.v2.PDF",
      declaredMimeType: "application/pdf",
      maxBytes: MAX_BYTES,
    });

    expect(result).toEqual({
      buffer,
      originalName: "报价.v2.pdf",
      extension: ".pdf",
      mimeType: "application/pdf",
      fileSize: buffer.length,
      fileSha256: crypto.createHash("sha256").update(buffer).digest("hex"),
    });
  });

  it.each([
    ["photo.jpeg", "image/jpg", "jpeg", ".jpg", "image/jpeg"],
    ["evidence.png", "image/png", "png", ".png", "image/png"],
    ["evidence.webp", "image/webp", "webp", ".webp", "image/webp"],
  ])("decodes and normalizes an allowed %s image", async (fileName, declaredMimeType, fixture, extension, mimeType) => {
    const source = { jpeg: jpegBuffer, png: pngBuffer, webp: webpBuffer }[fixture];
    const result = await validateAndNormalizePurchaseAttachment({
      buffer: source,
      fileName,
      declaredMimeType,
      maxBytes: MAX_BYTES,
    });

    expect(result.originalName).toBe(`${fileName.slice(0, fileName.lastIndexOf("."))}${extension}`);
    expect(result.extension).toBe(extension);
    expect(result.mimeType).toBe(mimeType);
    expect(result.fileSize).toBe(result.buffer.length);
    expect(result.fileSha256).toBe(
      crypto.createHash("sha256").update(result.buffer).digest("hex"),
    );
    const metadata = await sharp(result.buffer).metadata();
    expect(metadata.format).toBe(fixture);
    expect(metadata.pages ?? 1).toBe(1);
  });

  it("fully validates but does not rewrite historical image bytes when normalization is disabled", async () => {
    const result = await validateAndNormalizePurchaseAttachment({
      buffer: pngBuffer,
      fileName: "历史附件.png",
      declaredMimeType: "application/octet-stream",
      maxBytes: MAX_BYTES,
      normalizeImages: false,
    });

    expect(result.buffer).toBe(pngBuffer);
    expect(result.fileSize).toBe(pngBuffer.length);
    expect(result.mimeType).toBe("image/png");
    expect(result.fileSha256).toBe(
      crypto.createHash("sha256").update(pngBuffer).digest("hex"),
    );
  });

  it("applies the normalized-output size limit only when storing a normalized upload", async () => {
    const compactPng = Buffer.from(
      "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNk+A8AAQUBAScY42YAAAAASUVORK5CYII=",
      "base64",
    );
    const historical = await validateAndNormalizePurchaseAttachment({
      buffer: compactPng,
      fileName: "历史附件.png",
      declaredMimeType: "image/png",
      maxBytes: compactPng.length,
      normalizeImages: false,
    });

    expect(historical.buffer).toBe(compactPng);
    expect(historical.fileSize).toBe(compactPng.length);

    const uploadError = await capturePolicyError({
      buffer: compactPng,
      fileName: "新附件.png",
      declaredMimeType: "image/png",
      maxBytes: compactPng.length,
      normalizeImages: true,
    });
    expectPolicyError(uploadError, "size_limit");
  });

  it("still fully decodes corrupt historical image bytes when normalization is disabled", async () => {
    const boundaryOnlyJpeg = Buffer.from([0xff, 0xd8, 0xff, 0x00, 0x00, 0xff, 0xd9]);
    const error = await capturePolicyError({
      buffer: boundaryOnlyJpeg,
      fileName: "历史损坏附件.jpg",
      declaredMimeType: "image/jpeg",
      maxBytes: MAX_BYTES,
      normalizeImages: false,
    });

    expectPolicyError(error, "corrupt_content");
  });

  it("rejects warning-only corrupt historical JPEG bytes when normalization is disabled", async () => {
    const validJpeg = await sharp({
      create: {
        width: 64,
        height: 64,
        channels: 3,
        background: { r: 30, g: 120, b: 210 },
      },
    }).jpeg().toBuffer();
    expect(validJpeg.subarray(-2)).toEqual(Buffer.from([0xff, 0xd9]));

    const warningOnlyCorruptJpeg = Buffer.concat([
      validJpeg.subarray(0, validJpeg.length - 3),
      Buffer.from([0xff, 0xd9]),
    ]);
    const error = await capturePolicyError({
      buffer: warningOnlyCorruptJpeg,
      fileName: "历史损坏附件.jpg",
      declaredMimeType: "image/jpeg",
      maxBytes: MAX_BYTES,
      normalizeImages: false,
    });

    expectPolicyError(error, "corrupt_content");
  });

  it("accepts an empty historical MIME only when extension and bytes agree", async () => {
    const result = await validateAndNormalizePurchaseAttachment({
      buffer: jpegBuffer,
      fileName: "历史照片.jpg",
      declaredMimeType: "  ",
      maxBytes: MAX_BYTES,
      normalizeImages: false,
    });

    expect(result.extension).toBe(".jpg");
    expect(result.mimeType).toBe("image/jpeg");
  });

  it("strips image metadata when normalizing", async () => {
    const withMetadata = await sharp({
      create: {
        width: 3,
        height: 2,
        channels: 3,
        background: { r: 200, g: 20, b: 10 },
      },
    }).withMetadata({ orientation: 6 }).jpeg().toBuffer();

    const result = await validateAndNormalizePurchaseAttachment({
      buffer: withMetadata,
      fileName: "orientation.jpg",
      declaredMimeType: "image/jpeg",
      maxBytes: MAX_BYTES,
    });

    const metadata = await sharp(result.buffer).metadata();
    expect(metadata.orientation).toBeUndefined();
    expect(metadata.exif).toBeUndefined();
  });

  it.each([
    ["quote.html.pdf", "dangerous_filename"],
    ["quote.svg.png", "dangerous_filename"],
    ["../quote.pdf", "dangerous_filename"],
    ["folder\\quote.pdf", "dangerous_filename"],
    ["quote\r\nname.pdf", "dangerous_filename"],
    ["quote\u202Efdp.pdf", "dangerous_filename"],
    ["quote.pdf.html", "unsupported_type"],
    ["quote.txt", "unsupported_type"],
  ])("rejects unsafe or unsupported filename %s", async (fileName, reasonCode) => {
    const error = await capturePolicyError({
      buffer: buildPdf(),
      fileName,
      declaredMimeType: "application/pdf",
      maxBytes: MAX_BYTES,
    });
    expectPolicyError(error, reasonCode);
  });

  it("truncates a long safe display name while preserving its canonical extension", async () => {
    const result = await validateAndNormalizePurchaseAttachment({
      buffer: buildPdf(),
      fileName: `${"报".repeat(300)}.pdf`,
      declaredMimeType: "application/pdf",
      maxBytes: MAX_BYTES,
    });

    expect(Array.from(result.originalName)).toHaveLength(
      PURCHASE_ATTACHMENT_MAX_FILE_NAME_CODE_POINTS,
    );
    expect(result.originalName.endsWith(".pdf")).toBe(true);
  });

  it.each([
    ["text/html", "unsupported_type"],
    ["image/png", "type_mismatch"],
  ])("rejects invalid declared MIME %s", async (declaredMimeType, reasonCode) => {
    const error = await capturePolicyError({
      buffer: buildPdf(),
      fileName: "quote.pdf",
      declaredMimeType,
      maxBytes: MAX_BYTES,
    });
    expectPolicyError(error, reasonCode);
  });

  it("rejects allowed bytes whose extension declares another allowed type", async () => {
    const error = await capturePolicyError({
      buffer: pngBuffer,
      fileName: "quote.jpg",
      declaredMimeType: "application/octet-stream",
      maxBytes: MAX_BYTES,
    });
    expectPolicyError(error, "type_mismatch");
  });

  it.each([
    [Buffer.from("<!doctype html><title>marker</title>", "utf8"), "quote.pdf"],
    [Buffer.from("<svg xmlns=\"http://www.w3.org/2000/svg\"></svg>", "utf8"), "quote.png"],
    [Buffer.from("plain marker", "utf8"), "quote.webp"],
  ])("rejects active or unknown content before Sharp", async (buffer, fileName) => {
    const error = await capturePolicyError({
      buffer,
      fileName,
      declaredMimeType: "application/octet-stream",
      maxBytes: MAX_BYTES,
    });
    expectPolicyError(error, "unsupported_type");
  });

  it.each([
    [Buffer.from("%PDF-1.7\ntruncated", "ascii"), "truncated.pdf", "application/pdf"],
    [Buffer.from("%PDF-1.9\nmarker\n%%EOF\n", "ascii"), "version.pdf", "application/pdf"],
    [Buffer.concat([buildPdf(), Buffer.from("<html>tail</html>", "ascii")]), "tail.pdf", "application/pdf"],
  ])("rejects truncated or trailing PDF content", async (buffer, fileName, declaredMimeType) => {
    const error = await capturePolicyError({
      buffer,
      fileName,
      declaredMimeType,
      maxBytes: MAX_BYTES,
    });
    expectPolicyError(error, "corrupt_content");
  });

  it.each([
    ["jpeg", "truncated.jpg", "image/jpeg", 2],
    ["png", "truncated.png", "image/png", 4],
  ])("rejects truncated %s content", async (fixture, fileName, declaredMimeType, bytesToRemove) => {
    const source = { jpeg: jpegBuffer, png: pngBuffer }[fixture];
    const error = await capturePolicyError({
      buffer: source.subarray(0, source.length - bytesToRemove),
      fileName,
      declaredMimeType,
      maxBytes: MAX_BYTES,
    });
    expectPolicyError(error, "corrupt_content");
  });

  it("rejects a WEBP whose RIFF length does not match the actual bytes", async () => {
    const corrupted = Buffer.from(webpBuffer);
    corrupted.writeUInt32LE(corrupted.readUInt32LE(4) - 1, 4);
    const error = await capturePolicyError({
      buffer: corrupted,
      fileName: "corrupted.webp",
      declaredMimeType: "image/webp",
      maxBytes: MAX_BYTES,
    });
    expectPolicyError(error, "corrupt_content");
  });

  it("rejects an animated WEBP as multiple pages", async () => {
    const [firstFrame, secondFrame] = await Promise.all([
      sharp({
        create: {
          width: 2,
          height: 2,
          channels: 4,
          background: { r: 10, g: 200, b: 100, alpha: 1 },
        },
      }).png().toBuffer(),
      sharp({
        create: {
          width: 2,
          height: 2,
          channels: 4,
          background: { r: 200, g: 10, b: 100, alpha: 1 },
        },
      }).png().toBuffer(),
    ]);
    const animated = await sharp(
      [firstFrame, secondFrame],
      { join: { animated: true } },
    ).webp({ loop: 0, delay: [100, 100] }).toBuffer();

    const error = await capturePolicyError({
      buffer: animated,
      fileName: "animated.webp",
      declaredMimeType: "image/webp",
      maxBytes: MAX_BYTES,
    });
    expectPolicyError(error, "multiple_pages");
  });

  it("rejects an APNG animation control stream as multiple pages", async () => {
    const secondFrame = await sharp({
      create: {
        width: 4,
        height: 3,
        channels: 4,
        background: { r: 210, g: 30, b: 120, alpha: 1 },
      },
    }).png().toBuffer();
    const animatedPng = buildAnimatedPng(pngBuffer, secondFrame);

    expect(animatedPng.includes(Buffer.from("acTL", "ascii"))).toBe(true);
    expect(animatedPng.includes(Buffer.from("fdAT", "ascii"))).toBe(true);
    const error = await capturePolicyError({
      buffer: animatedPng,
      fileName: "animated.png",
      declaredMimeType: "image/png",
      maxBytes: MAX_BYTES,
    });
    expectPolicyError(error, "multiple_pages");
  });

  it("rejects image metadata above the 40MP hard limit", async () => {
    const oversizedHeader = patchPngDimensions(pngBuffer, 10_000, 4_001);
    expect(10_000 * 4_001).toBeGreaterThan(PURCHASE_ATTACHMENT_MAX_IMAGE_PIXELS);

    const error = await capturePolicyError({
      buffer: oversizedHeader,
      fileName: "oversized.png",
      declaredMimeType: "image/png",
      maxBytes: MAX_BYTES,
    });
    expectPolicyError(error, "pixel_limit");
  });

  it("rejects empty and oversized buffers with stable reasons", async () => {
    const emptyError = await capturePolicyError({
      buffer: Buffer.alloc(0),
      fileName: "empty.pdf",
      declaredMimeType: "application/pdf",
      maxBytes: 10,
    });
    expectPolicyError(emptyError, "empty_file");

    const sizeError = await capturePolicyError({
      buffer: buildPdf(),
      fileName: "large.pdf",
      declaredMimeType: "application/pdf",
      maxBytes: 4,
    });
    expectPolicyError(sizeError, "size_limit");
  });
});

describe("purchase attachment storage and response helpers", () => {
  it("builds a random canonical storage key without an original basename", () => {
    const purchaseRequestId = "aaaaaaaa-aaaa-4aaa-8aaa-aaaaaaaaaaaa";
    const first = buildAttachmentStorageKey(purchaseRequestId, ".pdf");
    const second = buildAttachmentStorageKey(purchaseRequestId, ".pdf");

    expect(first).toMatch(
      /^purchase-requests\/aaaaaaaa-aaaa-4aaa-8aaa-aaaaaaaaaaaa\/[0-9a-f-]{36}\.pdf$/u,
    );
    expect(second).not.toBe(first);
    expect(first).not.toContain("quote");
  });

  it("rejects invalid storage key inputs", () => {
    expect(() => buildAttachmentStorageKey("not-an-id", ".pdf")).toThrow(TypeError);
    try {
      buildAttachmentStorageKey("aaaaaaaa-aaaa-4aaa-8aaa-aaaaaaaaaaaa", ".html");
      throw new Error("expected invalid extension rejection");
    } catch (error) {
      expectPolicyError(error, "unsupported_type");
    }
  });

  it("builds RFC 5987 Content-Disposition with a safe ASCII fallback", () => {
    const header = buildAttachmentContentDisposition("采购报价.pdf");

    expect(header).toBe(
      "attachment; filename=\"attachment.pdf\"; filename*=UTF-8''%E9%87%87%E8%B4%AD%E6%8A%A5%E4%BB%B7.pdf",
    );
  });

  it("removes header injection and path syntax from Content-Disposition", () => {
    const header = buildAttachmentContentDisposition("folder/evil\"\r\nX-Test: marker\\quote.pdf");

    expect(header.startsWith("attachment; filename=\"")).toBe(true);
    expect(header).not.toMatch(/[\r\n]/u);
    expect(header).not.toContain("/evil");
    expect(header).not.toContain("\\quote");
    expect(header).toContain("filename*=UTF-8''");
  });

  it("supports safe inline Content-Disposition without changing the default", () => {
    const header = buildAttachmentContentDisposition("铁路电子客票.pdf", { disposition: "inline" });

    expect(header).toBe(
      "inline; filename=\"attachment.pdf\"; filename*=UTF-8''%E9%93%81%E8%B7%AF%E7%94%B5%E5%AD%90%E5%AE%A2%E7%A5%A8.pdf",
    );
    expect(() => buildAttachmentContentDisposition("file.pdf", { disposition: "preview" })).toThrow(TypeError);
  });
});