import assert from "node:assert/strict";
import crypto from "node:crypto";
import fs from "node:fs";
import os from "node:os";
import path from "node:path";
import { pathToFileURL } from "node:url";
import test from "node:test";
import ts from "typescript";

const root = path.resolve(import.meta.dirname, "../../..");
const temporary = fs.mkdtempSync(path.join(os.tmpdir(), "asset-preview-decode-unit-"));
const transpile = (sourceName, outputName, replacements = []) => {
  const sourcePath = path.join(root, "web/protocol", sourceName);
  const result = ts.transpileModule(fs.readFileSync(sourcePath, "utf8"), {
    compilerOptions: { module: ts.ModuleKind.ES2022, target: ts.ScriptTarget.ES2022 },
    fileName: sourcePath,
    reportDiagnostics: true,
  });
  assert.deepEqual(result.diagnostics, []);
  fs.writeFileSync(path.join(temporary, outputName), replacements.reduce((value, [from, to]) => value.replaceAll(from, to), result.outputText));
};
transpile("asset-preview.ts", "asset-preview.mjs");
transpile("asset-preview-decode.ts", "asset-preview-decode.mjs", [['from "./asset-preview"', 'from "./asset-preview.mjs"']]);
const identityProtocol = await import(pathToFileURL(path.join(temporary, "asset-preview.mjs")));
const decode = await import(pathToFileURL(path.join(temporary, "asset-preview-decode.mjs")));
const identity = JSON.parse(fs.readFileSync(path.join(root, "tests/golden/M12-02B/identity.json"), "utf8"));
const content = fs.readFileSync(path.join(root, "tests/golden/M12-02B/preview.png"));
const manifest = JSON.parse(fs.readFileSync(path.join(root, "tests/golden/M12-02C/manifest.json"), "utf8"));
const buffer = (bytes) => bytes.buffer.slice(bytes.byteOffset, bytes.byteOffset + bytes.byteLength);
const sha256 = (bytes) => crypto.createHash("sha256").update(bytes).digest("hex");

async function identityFor(bytes, changes = {}) {
  const base = {
    ...identity,
    content: {
      ...identity.content,
      byteLength: bytes.byteLength,
      sha256: sha256(bytes),
      ...changes,
    },
  };
  delete base.identitySha256;
  return identityProtocol.createAssetPreviewIdentity(base);
}

test("M12-02C plans the checked-in PNG before decode", async () => {
  assert.equal(manifest.task, "M12-02C");
  assert.equal(manifest.enablingTask, true);
  assert.equal(manifest.parityStateChange, false);
  assert.equal(manifest.nextTask, "M12-02D");
  assert.equal(manifest.negativeCaseCount, 8);
  assert.deepEqual(decode.ASSET_PREVIEW_DECODE_BUDGET, manifest.budget);
  for (const artifact of Object.values(manifest.artifacts)) {
    assert.equal(sha256(fs.readFileSync(path.join(root, artifact.path))), artifact.sha256, artifact.path);
  }
  assert.deepEqual(await decode.planAssetPreviewDecode(identity, buffer(content)), {
    schemaVersion: 1,
    identitySha256: identity.identitySha256,
    mimeType: "image/png",
    width: 8,
    height: 8,
    pixelCount: 64,
    encodedByteLength: 513,
    decodedByteLength: 256,
    compressionRatio: 256 / 513,
  });
});

test("M12-02C rejects byte, hash, MIME, dimension, pixel, and compression budgets before decode", async () => {
  const cases = [];
  const changedHash = buffer(content); new Uint8Array(changedHash)[changedHash.byteLength - 1] ^= 1;
  cases.push([identity, changedHash, "ASSET_SOURCE_HASH_MISMATCH"]);
  cases.push([{ ...identity, content: { ...identity.content, byteLength: 512 } }, buffer(content), "ASSET_PREVIEW_IDENTITY_MISMATCH"]);
  cases.push([await identityFor(content, { mimeType: "image/webp" }), buffer(content), "ASSET_MANIFEST_INVALID"]);

  const wrongDimensions = Buffer.from(content);
  wrongDimensions.writeUInt32BE(9, 16);
  cases.push([await identityFor(wrongDimensions), buffer(wrongDimensions), "ASSET_MANIFEST_INVALID"]);

  const hugeDimensions = Buffer.from(content);
  hugeDimensions.writeUInt32BE(4097, 16);
  hugeDimensions.writeUInt32BE(4097, 20);
  cases.push([await identityFor(hugeDimensions, { width: 4097, height: 4097 }), buffer(hugeDimensions), "ASSET_BUDGET_EXCEEDED"]);

  const ratioDimensions = Buffer.from(content);
  ratioDimensions.writeUInt32BE(4096, 16);
  ratioDimensions.writeUInt32BE(4096, 20);
  cases.push([await identityFor(ratioDimensions, { width: 4096, height: 4096 }), buffer(ratioDimensions), "ASSET_BUDGET_EXCEEDED"]);

  const oversized = new Uint8Array(decode.ASSET_PREVIEW_DECODE_BUDGET.maxEncodedBytes + 1);
  cases.push([await identityFor(oversized, { width: 1, height: 1 }), oversized.buffer, "ASSET_BUDGET_EXCEEDED"]);

  const corrupt = Buffer.from(content); corrupt[0] = 0;
  cases.push([await identityFor(corrupt), buffer(corrupt), "ASSET_MANIFEST_INVALID"]);

  for (const [manifest, bytes, code] of cases) {
    await assert.rejects(decode.planAssetPreviewDecode(manifest, bytes), { code });
    assert.equal((await decode.planAssetPreviewDecode(identity, buffer(content))).identitySha256, identity.identitySha256);
  }
});

test.after(() => fs.rmSync(temporary, { recursive: true, force: true }));