#!/usr/bin/env node

const assert = require("assert");
const cp = require("child_process");
const path = require("path");

const extension = require("../vscode-extension/extension");

class DapClient {
  constructor(spec) {
    this.child = cp.spawn(spec.command, spec.args, {
      cwd: spec.options && spec.options.cwd,
      detached: process.platform !== "win32"
    });
    this.seq = 1;
    this.buffer = Buffer.alloc(0);
    this.messages = [];
    this.waiters = [];
    this.stderr = "";

    this.child.stdout.on("data", (chunk) => {
      this.buffer = Buffer.concat([this.buffer, chunk]);
      this.parse();
    });
    this.child.stderr.on("data", (chunk) => {
      this.stderr += chunk.toString();
    });
    this.child.on("exit", () => this.flushWaiters());
  }

  send(command, args = {}) {
    const seq = this.seq++;
    const message = { seq, type: "request", command, arguments: args };
    const payload = Buffer.from(JSON.stringify(message));
    this.child.stdin.write(`Content-Length: ${payload.length}\r\n\r\n`);
    this.child.stdin.write(payload);
    return seq;
  }

  async response(seq, command) {
    const message = await this.waitFor(
      (item) =>
        item.type === "response" &&
        item.request_seq === seq &&
        item.command === command
    );
    if (!message.success) {
      throw new Error(`DAP ${command} failed: ${message.message || JSON.stringify(message)}`);
    }
    return message;
  }

  terminate() {
    if (this.child.exitCode !== null) return;
    if (process.platform === "win32") {
      this.child.kill("SIGKILL");
      return;
    }
    try {
      process.kill(-this.child.pid, "SIGKILL");
    } catch (_) {
      this.child.kill("SIGKILL");
    }
  }

  waitFor(predicate, timeoutMs = 240000) {
    const existing = this.messages.find(predicate);
    if (existing) return Promise.resolve(existing);

    return new Promise((resolve, reject) => {
      const timer = setTimeout(() => {
        this.terminate();
        reject(new Error(`timed out waiting for DAP message\n${this.stderr}`));
      }, timeoutMs);
      this.waiters.push({ predicate, resolve, timer });
    });
  }

  parse() {
    while (true) {
      const headerEnd = this.buffer.indexOf("\r\n\r\n");
      if (headerEnd < 0) return;
      const header = this.buffer.slice(0, headerEnd).toString();
      const match = header.match(/Content-Length: (\d+)/i);
      if (!match) throw new Error(`bad DAP header: ${header}`);
      const length = Number(match[1]);
      const start = headerEnd + 4;
      const end = start + length;
      if (this.buffer.length < end) return;
      const payload = this.buffer.slice(start, end).toString();
      this.buffer = this.buffer.slice(end);
      this.messages.push(JSON.parse(payload));
      this.flushWaiters();
    }
  }

  flushWaiters() {
    for (const waiter of [...this.waiters]) {
      const message = this.messages.find(waiter.predicate);
      if (!message) continue;
      clearTimeout(waiter.timer);
      this.waiters.splice(this.waiters.indexOf(waiter), 1);
      waiter.resolve(message);
    }
  }

  async close() {
    if (this.child.exitCode !== null) return;
    const seq = this.send("disconnect");
    await this.response(seq, "disconnect");
    this.child.stdin.end();
  }
}

(async () => {
  const repo = path.resolve(__dirname, "..");
  const project = path.join(repo, "examples/launch-build-demo");
  const launchConfig = extension.resolveDisasmerDebugConfiguration(
    { uri: { fsPath: project } },
    {}
  );

  assert.strictEqual(launchConfig.type, "disasmer");
  assert.strictEqual(launchConfig.request, "launch");
  assert.strictEqual(launchConfig.entry, "build");
  assert.strictEqual(launchConfig.project, project);
  assert.strictEqual(launchConfig.runtimeBackend, "local-services");

  const inspection = extension.refreshBundleBeforeLaunch(project, repo);
  assert.match(inspection.metadata.identity, /^sha256:/);

  const client = new DapClient(extension.debugAdapterExecutableSpec(repo));
  try {
    const initialize = client.send("initialize", {
      adapterID: "disasmer",
      linesStartAt1: true,
      columnsStartAt1: true
    });
    await client.response(initialize, "initialize");

    const launch = client.send("launch", launchConfig);
    await client.response(launch, "launch");
    await client.waitFor(
      (message) => message.type === "event" && message.event === "initialized"
    );

    const breakpoints = client.send("setBreakpoints", {
      source: { path: "src/build.rs" },
      breakpoints: [{ line: 42 }]
    });
    const breakpointResponse = await client.response(breakpoints, "setBreakpoints");
    assert.strictEqual(breakpointResponse.body.breakpoints[0].verified, true);

    const configurationDone = client.send("configurationDone");
    await client.response(configurationDone, "configurationDone");
    const stopped = await client.waitFor(
      (message) => message.type === "event" && message.event === "stopped"
    );
    assert.strictEqual(stopped.body.allThreadsStopped, true);
    assert.strictEqual(stopped.body.reason, "breakpoint");

    const threadsRequest = client.send("threads");
    const threads = (await client.response(threadsRequest, "threads")).body.threads;
    const linuxThread = threads.find((thread) => thread.name.includes("compile linux"));
    assert(linuxThread, "F5 launch must expose the Linux task as a virtual thread");

    const stackRequest = client.send("stackTrace", {
      threadId: linuxThread.id,
      startFrame: 0,
      levels: 1
    });
    const stack = (await client.response(stackRequest, "stackTrace")).body.stackFrames;
    assert.strictEqual(stack[0].line, 42);

    const scopesRequest = client.send("scopes", { frameId: stack[0].id });
    const scopes = (await client.response(scopesRequest, "scopes")).body.scopes;
    const runtimeScope = scopes.find((scope) => scope.name === "Disasmer Runtime");
    assert(runtimeScope, "F5 launch must expose Disasmer runtime state");

    const runtimeRequest = client.send("variables", {
      variablesReference: runtimeScope.variablesReference
    });
    const runtime = (await client.response(runtimeRequest, "variables")).body.variables;
    assert(
      runtime.some(
        (variable) => variable.name === "runtime_backend" && variable.value === "LocalServices"
      ),
      "extension-resolved F5 launch must use the real local-services backend"
    );
    assert(
      runtime.some(
        (variable) => variable.name === "coordinator_task_events" && variable.value === 1
      ),
      "F5 launch must cross the coordinator/node boundary and record a task event"
    );
    assert(
      runtime.some(
        (variable) =>
          variable.name === "command_status" &&
          String(variable.value).includes("completed through local services")
      )
    );

    await client.close();
  } catch (error) {
    client.terminate();
    throw error;
  }

  console.log("VS Code F5 smoke passed");
})().catch((error) => {
  console.error(error.stack || error.message);
  process.exit(1);
});