import { execFile } from "node:child_process";
import { mkdtemp, writeFile, rm } from "node:fs/promises";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { promisify } from "node:util";

import { JebAnalysisService } from "../dist/application/jeb/JebAnalysisService.js";
import { createJebAnalysisProvider } from "../dist/composition/jeb.js";

const run = promisify(execFile);

const options = parseArguments(process.argv.slice(2));
if (options.help) {
  process.stdout.write(
    "Usage: npm run verify:jeb [-- --item-address ADDRESS --marker TEXT]\n" +
      "Requires a running JEB client serving MCP at REA_JEB_MCP_URL\n" +
      "(default http://127.0.0.1:8425/mcp) with a project already open.\n" +
      "JEB 5.48 headless instances open their target at start (--infile or\n" +
      "the documented programmatic launcher); open_jeb_project is verified\n" +
      "only when the engine advertises it. Without --item-address, a tiny\n" +
      "Java fixture is compiled and its known method is decompiled.\n",
  );
  process.exit(0);
}

const provider = createJebAnalysisProvider(process.env);
const service = new JebAnalysisService(provider);
const fixtureDirectory = await mkdtemp(join(tmpdir(), "rea-jeb-"));
try {
  const client = await service.execute("inspect_jeb_client", {});
  if (!client.ok) throw new Error(client.error.message);
  const engine = client.value.normalized_result.engine;
  if (engine.version === null)
    throw new Error("The JEB client did not report its version");

  // JEB 5.48 headless clients do not advertise open_project; a project opened
  // at engine start is the supported target-selection route there. Attempt the
  // tool and record the engine's exact refusal when it is unavailable.
  let openRefusal = null;
  const target = await resolveTarget(options, fixtureDirectory);
  const opened = await service.execute("open_jeb_project", {
    path: target.path,
  });
  if (opened.ok) {
    const artifact = opened.value.normalized_result.input_files.find(
      (file) => typeof file === "object" && file !== null,
    );
    if (
      artifact === undefined ||
      !/^[0-9a-f]{64}$/u.test(artifact.contents_sha256_hash)
    )
      throw new Error("The engine did not report an input artifact digest");
  } else {
    openRefusal = opened.error.message;
  }

  const units = await service.execute("list_jeb_units", { count: 100 });
  if (!units.ok) throw new Error(units.error.message);
  if (units.value.normalized_result.units.length === 0)
    throw new Error("The engine reported no project units");

  const decompiled = await service.execute("decompile_jeb_item", {
    item_address: target.itemAddress,
    item_kind: "method",
  });
  if (!decompiled.ok) throw new Error(decompiled.error.message);
  const text = decompiled.value.normalized_result.text;
  if (!text.includes(target.marker))
    throw new Error(
      "Decompiled pseudo-code did not contain the fixture marker",
    );

  const report = {
    ok: true,
    provider: "jeb",
    host_platform: process.platform,
    engine_version: engine.version,
    engine_gui: engine.gui_client,
    endpoint: engine.endpoint,
    open_project_observed: openRefusal === null,
    ...(openRefusal === null ? {} : { open_project_refusal: openRefusal }),
    unit_count: units.value.normalized_result.units.length,
    decompiled_marker_observed: true,
  };
  process.stdout.write(`${JSON.stringify(report)}\n`);
} catch (cause) {
  process.stderr.write(
    `JEB real-provider verification failed: ${cause instanceof Error ? cause.message : String(cause)}\n`,
  );
  process.exitCode = 1;
} finally {
  await provider.close().catch(() => undefined);
  await rm(fixtureDirectory, { recursive: true, force: true }).catch(
    () => undefined,
  );
}

async function resolveTarget(selected, directory) {
  if (selected.itemAddress !== undefined)
    return {
      path: "/engine-side/target",
      itemAddress: selected.itemAddress,
      marker: selected.marker ?? "",
    };
  await writeFile(
    join(directory, "Hello.java"),
    [
      "public class Hello {",
      "  public static String greet(String name) {",
      '    return "Hello, " + name + "!";',
      "  }",
      "}",
      "",
    ].join("\n"),
  );
  try {
    await run("javac", [join(directory, "Hello.java")]);
  } catch {
    throw new Error(
      "javac is required to build the default verification fixture",
    );
  }
  return {
    path: join(directory, "Hello.class"),
    itemAddress: "LHello;->greet(Ljava/lang/String;)Ljava/lang/String;",
    marker: "Hello, ",
  };
}

function parseArguments(args) {
  if (args.length === 1 && args[0] === "--help") return { help: true };
  const values = new Map();
  for (let index = 0; index < args.length; index += 1) {
    const flag = args[index];
    const value = args[index + 1];
    if (
      (flag !== "--item-address" && flag !== "--marker") ||
      value === undefined
    )
      throw new Error(
        "Expected no arguments, or --item-address ADDRESS [--marker TEXT]",
      );
    values.set(flag, value);
    index += 1;
  }
  return {
    help: false,
    ...(values.has("--item-address")
      ? { itemAddress: values.get("--item-address") }
      : {}),
    ...(values.has("--marker") ? { marker: values.get("--marker") } : {}),
  };
}