import assert from "node:assert/strict";
import test from "node:test";

import { inspectNativeWaterDxt1Dds } from "./native-water-dds.mjs";

function ddsFixture({ width = 8, height = 8, mipCount = 3, trailingBytes = 0, fourCC = "DXT1" } = {}) {
  const mipSizes = [];
  let mipWidth = width;
  let mipHeight = height;
  for (let level = 0; level < mipCount; level += 1) {
    mipSizes.push(Math.ceil(mipWidth / 4) * Math.ceil(mipHeight / 4) * 8);
    mipWidth = Math.max(1, Math.floor(mipWidth / 2));
    mipHeight = Math.max(1, Math.floor(mipHeight / 2));
  }
  const bytes = Buffer.alloc(128 + mipSizes.reduce((sum, size) => sum + size, 0) + trailingBytes);
  bytes.write("DDS ", 0, "ascii");
  bytes.writeUInt32LE(124, 4);
  bytes.writeUInt32LE(height, 12);
  bytes.writeUInt32LE(width, 16);
  bytes.writeUInt32LE(mipCount, 28);
  bytes.writeUInt32LE(32, 76);
  bytes.write(fourCC, 84, "ascii");
  for (let index = 128; index < bytes.length; index += 1) bytes[index] = index & 0xff;
  return bytes;
}

test("native water DDS inspection hashes each declared mip and confirms exact consumption", () => {
  const result = inspectNativeWaterDxt1Dds(ddsFixture());
  assert.equal(result.formatFourCC, "DXT1");
  assert.equal(result.width, 8);
  assert.equal(result.height, 8);
  assert.equal(result.mipCount, 3);
  assert.equal(result.exactMipChainConsumption, true);
  assert.deepEqual(result.mips.map(({ width, height, byteLength }) => ({ width, height, byteLength })), [
    { width: 8, height: 8, byteLength: 32 },
    { width: 4, height: 4, byteLength: 8 },
    { width: 2, height: 2, byteLength: 8 },
  ]);
  assert.ok(result.mips.every((mip) => /^[a-f\d]{64}$/.test(mip.sha256)));
});

test("native water DDS inspection rejects truncated, trailing and non-DXT1 data", () => {
  const complete = ddsFixture();
  assert.throws(() => inspectNativeWaterDxt1Dds(complete.subarray(0, complete.length - 1)), /truncated/);
  assert.throws(() => inspectNativeWaterDxt1Dds(ddsFixture({ trailingBytes: 1 })), /trailing bytes/);
  assert.throws(() => inspectNativeWaterDxt1Dds(ddsFixture({ fourCC: "DXT5" })), /Unsupported native water frame format/);
});