#!/usr/bin/env node

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

class DapClient {
  constructor() {
    this.child = cp.spawn(
      "cargo",
      ["run", "-q", "-p", "disasmer-dap", "--bin", "disasmer-debug-dap"],
      { cwd: process.cwd() }
    );
    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;
  }

  async failure(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} unexpectedly succeeded`);
    }
    return message;
  }

  waitFor(predicate, timeoutMs = 120000) {
    const existing = this.messages.find(predicate);
    if (existing) return Promise.resolve(existing);

    return new Promise((resolve, reject) => {
      const timer = setTimeout(() => {
        this.child.kill("SIGKILL");
        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() {
    const seq = this.send("disconnect");
    await this.response(seq, "disconnect");
    this.child.stdin.end();
  }
}

function createFailingProject() {
  const root = fs.mkdtempSync(path.join(os.tmpdir(), "disasmer-dap-failing-"));
  fs.mkdirSync(path.join(root, "src"), { recursive: true });
  fs.writeFileSync(
    path.join(root, "Cargo.toml"),
    `[package]
name = "dap-failing-demo"
version = "0.1.0"
edition = "2021"
`
  );
  fs.writeFileSync(
    path.join(root, "src/lib.rs"),
    `#[cfg(test)]
mod tests {
    #[test]
    fn fails_for_restart_smoke() {
        assert_eq!(1, 2);
    }
}
`
  );
  return root;
}

async function launchToBreakpoint({
  runtimeBackend = "simulated",
  breakpointLine,
  project = path.join(process.cwd(), "examples/launch-build-demo")
}) {
  const client = new DapClient();

  const initialize = client.send("initialize", {
    adapterID: "disasmer",
    linesStartAt1: true,
    columnsStartAt1: true
  });
  await client.response(initialize, "initialize");

  const launchArgs = {
    entry: "build",
    project,
    runtimeBackend
  };
  const launch = client.send("launch", launchArgs);
  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: breakpointLine }]
  });
  const breakpointResponse = await client.response(breakpoints, "setBreakpoints");
  assert.strictEqual(breakpointResponse.body.breakpoints[0].verified, true);

  const exceptions = client.send("setExceptionBreakpoints", { filters: [] });
  await client.response(exceptions, "setExceptionBreakpoints");

  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");

  return { client, stopped };
}

(async () => {
  const { client, stopped } = await launchToBreakpoint({
    runtimeBackend: "local-services",
    breakpointLine: 42
  });
  assert.strictEqual(stopped.body.threadId, 2);

  const threadsRequest = client.send("threads");
  const threads = (await client.response(threadsRequest, "threads")).body.threads;
  assert.deepStrictEqual(
    threads.map((thread) => thread.id),
    [1, 2, 3, 4]
  );
  assert(threads.some((thread) => thread.name.includes("compile linux")));
  assert(threads.some((thread) => thread.name.includes("compile windows")));
  assert(threads.some((thread) => thread.name.includes("package artifacts")));

  const stackRequest = client.send("stackTrace", { threadId: 2, startFrame: 0, levels: 1 });
  const stack = (await client.response(stackRequest, "stackTrace")).body.stackFrames;
  assert.strictEqual(stack.length, 1);
  assert.match(stack[0].name, /compile linux::run/);
  assert.strictEqual(stack[0].line, 42);
  assert.strictEqual(stack[0].source.path, "src/build.rs");
  assert.doesNotMatch(stack[0].name, /podman|cmd\.exe|powershell|pid|native child/i);

  const scopesRequest = client.send("scopes", { frameId: stack[0].id });
  const scopes = (await client.response(scopesRequest, "scopes")).body.scopes;
  const argsRef = scopes.find((scope) => scope.name === "Task Args and Handles").variablesReference;
  const runtimeRef = scopes.find((scope) => scope.name === "Disasmer Runtime").variablesReference;
  const outputRef = scopes.find((scope) => scope.name === "Recent Output").variablesReference;

  const argsRequest = client.send("variables", { variablesReference: argsRef });
  const args = (await client.response(argsRequest, "variables")).body.variables;
  const artifact = args.find((variable) => variable.name === "artifact");
  const sourceSnapshot = args.find((variable) => variable.name === "source_snapshot");
  assert(artifact);
  assert.strictEqual(artifact.value, "/vfs/artifacts/dap-output.txt");
  assert(sourceSnapshot);
  assert.match(sourceSnapshot.value, /^source:\/\/local-checkout\/[a-f0-9]{12}$/);

  const runtimeRequest = client.send("variables", { variablesReference: runtimeRef });
  const runtime = (await client.response(runtimeRequest, "variables")).body.variables;
  const processId = runtime.find((variable) => variable.name === "virtual_process_id");
  assert(processId);
  assert.match(processId.value, /^vp-[a-f0-9]{12}$/);
  assert(runtime.some((variable) => variable.name === "debug_epoch" && variable.value === 1));
  assert(runtime.some((variable) => variable.name === "runtime_backend" && variable.value === "LocalServices"));
  assert(runtime.some((variable) => variable.name === "coordinator_task_events" && variable.value === 1));
  assert(runtime.some((variable) => variable.name === "command_status" && String(variable.value).includes("completed through local services")));

  const outputRequest = client.send("variables", { variablesReference: outputRef });
  const output = (await client.response(outputRequest, "variables")).body.variables;
  assert(output.some((variable) => String(variable.value).includes("all-stop")));
  assert(output.some((variable) => String(variable.value).includes("local node completed task")));
  assert(output.some((variable) => String(variable.value).includes("coordinator recorded 1 task event")));

  const continueRequest = client.send("continue", { threadId: 2 });
  await client.response(continueRequest, "continue");
  await client.waitFor((message) => message.type === "event" && message.event === "continued");

  const pauseRequest = client.send("pause", { threadId: 2 });
  await client.response(pauseRequest, "pause");
  const paused = await client.waitFor(
    (message) => message.type === "event" && message.event === "stopped" && message.body.reason === "pause"
  );
  assert.strictEqual(paused.body.allThreadsStopped, true);

  const restartRequest = client.send("restartFrame", { frameId: stack[0].id });
  await client.response(restartRequest, "restartFrame");
  await client.waitFor(
    (message) =>
      message.type === "event" &&
      message.event === "output" &&
      String(message.body.output).includes("Restarted selected task")
  );

  const incompatibleRestartRequest = client.send("restartFrame", {
    frameId: stack[0].id,
    sourceCompatibility: "incompatible"
  });
  const incompatibleRestart = await client.failure(incompatibleRestartRequest, "restartFrame");
  assert.match(incompatibleRestart.message, /incompatible source edit/i);
  assert.match(incompatibleRestart.message, /whole virtual-process restart/i);

  const continueAfterRestartRequest = client.send("continue", { threadId: 2 });
  await client.response(continueAfterRestartRequest, "continue");
  await client.waitFor((message) => message.type === "event" && message.event === "continued");

  const freezeFailureRequest = client.send("pause", {
    threadId: 2,
    simulateFreezeFailure: true
  });
  const freezeFailure = await client.failure(freezeFailureRequest, "pause");
  assert.match(freezeFailure.message, /all-stop failed/i);
  assert.match(freezeFailure.message, /could not freeze/i);

  await client.close();

  const failingProject = createFailingProject();
  let failedSession;
  try {
    failedSession = await launchToBreakpoint({
      runtimeBackend: "local-services",
      breakpointLine: 42,
      project: failingProject
    });
    assert.strictEqual(failedSession.stopped.body.threadId, 2);

    const failedStackRequest = failedSession.client.send("stackTrace", {
      threadId: 2,
      startFrame: 0,
      levels: 1
    });
    const failedStack = (await failedSession.client.response(failedStackRequest, "stackTrace")).body
      .stackFrames;
    assert.strictEqual(failedStack.length, 1);
    assert.match(failedStack[0].name, /compile linux::run/);

    const failedScopesRequest = failedSession.client.send("scopes", { frameId: failedStack[0].id });
    const failedScopes = (await failedSession.client.response(failedScopesRequest, "scopes")).body
      .scopes;
    const failedRuntimeRef = failedScopes.find((scope) => scope.name === "Disasmer Runtime")
      .variablesReference;
    const failedOutputRef = failedScopes.find((scope) => scope.name === "Recent Output")
      .variablesReference;

    const failedRuntimeRequest = failedSession.client.send("variables", {
      variablesReference: failedRuntimeRef
    });
    const failedRuntime = (await failedSession.client.response(failedRuntimeRequest, "variables"))
      .body.variables;
    assert(
      failedRuntime.some(
        (variable) =>
          variable.name === "command_status" &&
          String(variable.value).includes("failed through local services")
      )
    );
    assert(
      failedRuntime.some(
        (variable) => variable.name === "state" && String(variable.value).includes("Failed")
      )
    );

    const failedOutputRequest = failedSession.client.send("variables", {
      variablesReference: failedOutputRef
    });
    const failedOutput = (await failedSession.client.response(failedOutputRequest, "variables")).body
      .variables;
    assert(
      failedOutput.some((variable) => String(variable.value).includes("local node failed task"))
    );

    const failedRestartRequest = failedSession.client.send("restartFrame", {
      frameId: failedStack[0].id,
      sourceEdit: { compatibility: "compatible" }
    });
    await failedSession.client.response(failedRestartRequest, "restartFrame");
    await failedSession.client.waitFor(
      (message) =>
        message.type === "event" &&
        message.event === "output" &&
        String(message.body.output).includes("Restarted failed task")
    );

    const failedRuntimeAfterRestartRequest = failedSession.client.send("variables", {
      variablesReference: failedRuntimeRef
    });
    const failedRuntimeAfterRestart = (
      await failedSession.client.response(failedRuntimeAfterRestartRequest, "variables")
    ).body.variables;
    assert(
      failedRuntimeAfterRestart.some(
        (variable) =>
          variable.name === "command_status" &&
          String(variable.value).includes("failed task restarted")
      )
    );

    const failedOutputAfterRestartRequest = failedSession.client.send("variables", {
      variablesReference: failedOutputRef
    });
    const failedOutputAfterRestart = (
      await failedSession.client.response(failedOutputAfterRestartRequest, "variables")
    ).body.variables;
    assert(
      failedOutputAfterRestart.some((variable) =>
        String(variable.value).includes("task restarted from VFS checkpoint")
      )
    );
  } finally {
    if (failedSession) {
      await failedSession.client.close().catch(() => {});
    }
    fs.rmSync(failingProject, { recursive: true, force: true });
  }

  const mainSession = await launchToBreakpoint({
    runtimeBackend: "local-services",
    breakpointLine: 12
  });
  assert.strictEqual(mainSession.stopped.body.threadId, 1);

  const mainStackRequest = mainSession.client.send("stackTrace", {
    threadId: 1,
    startFrame: 0,
    levels: 1
  });
  const mainStack = (await mainSession.client.response(mainStackRequest, "stackTrace"))
    .body.stackFrames;
  assert.strictEqual(mainStack.length, 1);
  assert.match(mainStack[0].name, /build virtual process::run/);
  assert.strictEqual(mainStack[0].line, 12);
  assert.strictEqual(mainStack[0].source.path, "src/build.rs");

  const mainScopesRequest = mainSession.client.send("scopes", { frameId: mainStack[0].id });
  const mainScopes = (await mainSession.client.response(mainScopesRequest, "scopes")).body.scopes;
  const mainRuntimeRef = mainScopes.find((scope) => scope.name === "Disasmer Runtime")
    .variablesReference;
  const mainRuntimeRequest = mainSession.client.send("variables", {
    variablesReference: mainRuntimeRef
  });
  const mainRuntime = (await mainSession.client.response(mainRuntimeRequest, "variables")).body
    .variables;
  assert(
    mainRuntime.some(
      (variable) => variable.name === "runtime_backend" && variable.value === "LocalServices"
    )
  );
  assert(
    mainRuntime.some(
      (variable) => variable.name === "coordinator_task_events" && variable.value === 1
    )
  );

  await mainSession.client.close();
  console.log("DAP smoke passed");
})().catch((err) => {
  console.error(err.stack || err.message);
  process.exit(1);
});