// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.

// Do not use primordials because we do not want to depend on the __bootstrap
// namespace.
//
// deno-lint-ignore-file
(() => {
  const internals = Deno[Deno.internal];
  const core = internals.core;
  const ops = core.ops;

  const {
    setExitHandler,
    Console,
    serializePermissions,
  } = internals;

  const opSanitizerDelayResolveQueue = [];
  let hasSetOpSanitizerDelayMacrotask = false;

  // Even if every resource is closed by the end of a test, there can be a delay
  // until the pending ops have all finished. This function returns a promise
  // that resolves when it's (probably) fine to run the op sanitizer.
  //
  // This is implemented by adding a macrotask callback that runs after the
  // all ready async ops resolve, and the timer macrotask. Using just a macrotask
  // callback without delaying is sufficient, because when the macrotask callback
  // runs after async op dispatch, we know that all async ops that can currently
  // return `Poll::Ready` have done so, and have been dispatched to JS.
  //
  // Worker ops are an exception to this, because there is no way for the user to
  // await shutdown of the worker from the thread calling `worker.terminate()`.
  // Because of this, we give extra leeway for worker ops to complete, by waiting
  // for a whole millisecond if there are pending worker ops.
  function opSanitizerDelay(hasPendingWorkerOps) {
    if (!hasSetOpSanitizerDelayMacrotask) {
      core.setMacrotaskCallback(handleOpSanitizerDelayMacrotask);
      hasSetOpSanitizerDelayMacrotask = true;
    }
    const p = new Promise((resolve) => {
      // Schedule an async op to complete immediately to ensure the macrotask is
      // run. We rely on the fact that enqueueing the resolver callback during the
      // timeout callback will mean that the resolver gets called in the same
      // event loop tick as the timeout callback.
      setTimeout(() => {
        opSanitizerDelayResolveQueue.push(resolve);
      }, hasPendingWorkerOps ? 1 : 0);
    });
    return p;
  }

  function handleOpSanitizerDelayMacrotask() {
    const resolve = opSanitizerDelayResolveQueue.shift();
    if (resolve) {
      resolve();
      return opSanitizerDelayResolveQueue.length === 0;
    }
    return undefined; // we performed no work, so can skip microtasks checkpoint
  }

  // An async operation to $0 was started in this test, but never completed. This is often caused by not $1.
  // An async operation to $0 was started in this test, but never completed. Async operations should not complete in a test if they were not started in that test.
  // deno-fmt-ignore
  const OP_DETAILS = {
    "op_blob_read_part": ["read from a Blob or File", "awaiting the result of a Blob or File read"],
    "op_broadcast_recv": ["receive a message from a BroadcastChannel", "closing the BroadcastChannel"],
    "op_broadcast_send": ["send a message to a BroadcastChannel", "closing the BroadcastChannel"],
    "op_chmod_async": ["change the permissions of a file", "awaiting the result of a `Deno.chmod` call"],
    "op_chown_async": ["change the owner of a file", "awaiting the result of a `Deno.chown` call"],
    "op_copy_file_async": ["copy a file", "awaiting the result of a `Deno.copyFile` call"],
    "op_crypto_decrypt": ["decrypt data", "awaiting the result of a `crypto.subtle.decrypt` call"],
    "op_crypto_derive_bits": ["derive bits from a key", "awaiting the result of a `crypto.subtle.deriveBits` call"],
    "op_crypto_encrypt": ["encrypt data", "awaiting the result of a `crypto.subtle.encrypt` call"],
    "op_crypto_generate_key": ["generate a key", "awaiting the result of a `crypto.subtle.generateKey` call"],
    "op_crypto_sign_key": ["sign data", "awaiting the result of a `crypto.subtle.sign` call"],
    "op_crypto_subtle_digest": ["digest data", "awaiting the result of a `crypto.subtle.digest` call"],
    "op_crypto_verify_key": ["verify data", "awaiting the result of a `crypto.subtle.verify` call"],
    "op_net_recv_udp": ["receive a datagram message via UDP", "awaiting the result of `Deno.DatagramConn#receive` call, or not breaking out of a for await loop looping over a `Deno.DatagramConn`"],
    "op_net_recv_unixpacket": ["receive a datagram message via Unixpacket", "awaiting the result of `Deno.DatagramConn#receive` call, or not breaking out of a for await loop looping over a `Deno.DatagramConn`"],
    "op_net_send_udp": ["send a datagram message via UDP", "awaiting the result of `Deno.DatagramConn#send` call"],
    "op_net_send_unixpacket": ["send a datagram message via Unixpacket", "awaiting the result of `Deno.DatagramConn#send` call"],
    "op_dns_resolve": ["resolve a DNS name", "awaiting the result of a `Deno.resolveDns` call"],
    "op_fdatasync_async": ["flush pending data operations for a file to disk", "awaiting the result of a `Deno.fdatasync` call"],
    "op_fetch_send": ["send a HTTP request", "awaiting the result of a `fetch` call"],
    "op_ffi_call_nonblocking": ["do a non blocking ffi call", "awaiting the returned promise"],
    "op_ffi_call_ptr_nonblocking": ["do a non blocking ffi call", "awaiting the returned promise"],
    "op_flock_async": ["lock a file", "awaiting the result of a `Deno.flock` call"],
    "op_fs_events_poll": ["get the next file system event", "breaking out of a for await loop looping over `Deno.FsEvents`"],
    "op_fstat_async": ["get file metadata", "awaiting the result of a `Deno.File#fstat` call"],
    "op_fsync_async": ["flush pending data operations for a file to disk", "awaiting the result of a `Deno.fsync` call"],
    "op_ftruncate_async": ["truncate a file", "awaiting the result of a `Deno.ftruncate` call"],
    "op_funlock_async": ["unlock a file", "awaiting the result of a `Deno.funlock` call"],
    "op_futime_async": ["change file timestamps", "awaiting the result of a `Deno.futime` call"],
    "op_http_accept": ["accept a HTTP request", "closing a `Deno.HttpConn`"],
    "op_http_shutdown": ["shutdown a HTTP connection", "awaiting `Deno.HttpEvent#respondWith`"],
    "op_http_upgrade_websocket": ["upgrade a HTTP connection to a WebSocket", "awaiting `Deno.HttpEvent#respondWith`"],
    "op_http_write_headers": ["write HTTP response headers", "awaiting `Deno.HttpEvent#respondWith`"],
    "op_http_write": ["write HTTP response body", "awaiting `Deno.HttpEvent#respondWith`"],
    "op_link_async": ["create a hard link", "awaiting the result of a `Deno.link` call"],
    "op_make_temp_dir_async": ["create a temporary directory", "awaiting the result of a `Deno.makeTempDir` call"],
    "op_make_temp_file_async": ["create a temporary file", "awaiting the result of a `Deno.makeTempFile` call"],
    "op_message_port_recv_message": ["receive a message from a MessagePort", "awaiting the result of not closing a `MessagePort`"],
    "op_mkdir_async": ["create a directory", "awaiting the result of a `Deno.mkdir` call"],
    "op_net_accept_tcp": ["accept a TCP stream", "closing a `Deno.Listener`"],
    "op_net_accept_unix": ["accept a Unix stream", "closing a `Deno.Listener`"],
    "op_net_connect_tcp": ["connect to a TCP server", "awaiting a `Deno.connect` call"],
    "op_net_connect_unix": ["connect to a Unix server", "awaiting a `Deno.connect` call"],
    "op_open_async": ["open a file", "awaiting the result of a `Deno.open` call"],
    "op_read_dir_async": ["read a directory", "collecting all items in the async iterable returned from a `Deno.readDir` call"],
    "op_read_link_async": ["read a symlink", "awaiting the result of a `Deno.readLink` call"],
    "op_realpath_async": ["resolve a path", "awaiting the result of a `Deno.realpath` call"],
    "op_remove_async": ["remove a file or directory", "awaiting the result of a `Deno.remove` call"],
    "op_rename_async": ["rename a file or directory", "awaiting the result of a `Deno.rename` call"],
    "op_run_status": ["get the status of a subprocess", "awaiting the result of a `Deno.Process#status` call"],
    "op_seek_async": ["seek in a file", "awaiting the result of a `Deno.File#seek` call"],
    "op_signal_poll": ["get the next signal", "un-registering a OS signal handler"],
    "op_sleep": ["sleep for a duration", "cancelling a `setTimeout` or `setInterval` call"],
    "op_stat_async": ["get file metadata", "awaiting the result of a `Deno.stat` call"],
    "op_symlink_async": ["create a symlink", "awaiting the result of a `Deno.symlink` call"],
    "op_net_accept_tls": ["accept a TLS stream", "closing a `Deno.TlsListener`"],
    "op_net_connect_tls": ["connect to a TLS server", "awaiting a `Deno.connectTls` call"],
    "op_tls_handshake": ["perform a TLS handshake", "awaiting a `Deno.TlsConn#handshake` call"],
    "op_tls_start": ["start a TLS connection", "awaiting a `Deno.startTls` call"],
    "op_truncate_async": ["truncate a file", "awaiting the result of a `Deno.truncate` call"],
    "op_utime_async": ["change file timestamps", "awaiting the result of a `Deno.utime` call"],
    "op_host_recv_message": ["receive a message from a web worker", "terminating a `Worker`"],
    "op_host_recv_ctrl": ["receive a message from a web worker", "terminating a `Worker`"],
    "op_ws_close": ["close a WebSocket", "awaiting until the `close` event is emitted on a `WebSocket`, or the `WebSocketStream#closed` promise resolves"],
    "op_ws_create": ["create a WebSocket", "awaiting until the `open` event is emitted on a `WebSocket`, or the result of a `WebSocketStream#connection` promise"],
    "op_ws_next_event": ["receive the next message on a WebSocket", "closing a `WebSocket` or `WebSocketStream`"],
    "op_ws_send_text": ["send a message on a WebSocket", "closing a `WebSocket` or `WebSocketStream`"],
    "op_ws_send_binary": ["send a message on a WebSocket", "closing a `WebSocket` or `WebSocketStream`"],
    "op_ws_send_binary_ab": ["send a message on a WebSocket", "closing a `WebSocket` or `WebSocketStream`"],
    "op_ws_send_ping": ["send a message on a WebSocket", "closing a `WebSocket` or `WebSocketStream`"],
    "op_ws_send_pong": ["send a message on a WebSocket", "closing a `WebSocket` or `WebSocketStream`"],
  };

  let opIdHostRecvMessage = -1;
  let opIdHostRecvCtrl = -1;
  let opNames = null;

  function populateOpNames() {
    opNames = core.ops.op_op_names();
    opIdHostRecvMessage = opNames.indexOf("op_host_recv_message");
    opIdHostRecvCtrl = opNames.indexOf("op_host_recv_ctrl");
  }

  // Wrap test function in additional assertion that makes sure
  // the test case does not leak async "ops" - ie. number of async
  // completed ops after the test is the same as number of dispatched
  // ops. Note that "unref" ops are ignored since in nature that are
  // optional.
  function assertOps(fn) {
    /** @param desc {TestDescription | TestStepDescription} */
    return async function asyncOpSanitizer(desc) {
      if (opNames === null) populateOpNames();
      const res = core.ops.op_test_op_sanitizer_collect(
        desc.id,
        false,
        opIdHostRecvMessage,
        opIdHostRecvCtrl,
      );
      if (res !== 0) {
        await opSanitizerDelay(res === 2);
        core.ops.op_test_op_sanitizer_collect(
          desc.id,
          true,
          opIdHostRecvMessage,
          opIdHostRecvCtrl,
        );
      }
      const preTraces = new Map(core.opCallTraces);
      let postTraces;
      let report = null;

      try {
        const innerResult = await fn(desc);
        if (innerResult) return innerResult;
      } finally {
        let res = core.ops.op_test_op_sanitizer_finish(
          desc.id,
          false,
          opIdHostRecvMessage,
          opIdHostRecvCtrl,
        );
        if (res === 1 || res === 2) {
          await opSanitizerDelay(res === 2);
          res = core.ops.op_test_op_sanitizer_finish(
            desc.id,
            true,
            opIdHostRecvMessage,
            opIdHostRecvCtrl,
          );
        }
        postTraces = new Map(core.opCallTraces);
        if (res === 3) {
          report = core.ops.op_test_op_sanitizer_report(desc.id);
        }
      }

      if (report === null) return null;

      const details = [];
      for (const opReport of report) {
        const opName = opNames[opReport.id];
        const diff = opReport.diff;

        if (diff > 0) {
          const [name, hint] = OP_DETAILS[opName] || [opName, null];
          const count = diff;
          let message = `${count} async operation${
            count === 1 ? "" : "s"
          } to ${name} ${
            count === 1 ? "was" : "were"
          } started in this test, but never completed.`;
          if (hint) {
            message += ` This is often caused by not ${hint}.`;
          }
          const traces = [];
          for (const [id, { opName: traceOpName, stack }] of postTraces) {
            if (traceOpName !== opName) continue;
            if (preTraces.has(id)) continue;
            traces.push(stack);
          }
          if (traces.length === 1) {
            message += " The operation was started here:\n";
            message += traces[0];
          } else if (traces.length > 1) {
            message += " The operations were started here:\n";
            message += traces.join("\n\n");
          }
          details.push(message);
        } else if (diff < 0) {
          const [name, hint] = OP_DETAILS[opName] || [opName, null];
          const count = -diff;
          let message = `${count} async operation${
            count === 1 ? "" : "s"
          } to ${name} ${
            count === 1 ? "was" : "were"
          } started before this test, but ${
            count === 1 ? "was" : "were"
          } completed during the test. Async operations should not complete in a test if they were not started in that test.`;
          if (hint) {
            message += ` This is often caused by not ${hint}.`;
          }
          const traces = [];
          for (const [id, { opName: traceOpName, stack }] of preTraces) {
            if (opName !== traceOpName) continue;
            if (postTraces.has(id)) continue;
            traces.push(stack);
          }
          if (traces.length === 1) {
            message += " The operation was started here:\n";
            message += traces[0];
          } else if (traces.length > 1) {
            message += " The operations were started here:\n";
            message += traces.join("\n\n");
          }
          details.push(message);
        } else {
          throw new Error("unreachable");
        }
      }

      return {
        failed: { leakedOps: [details, core.isOpCallTracingEnabled()] },
      };
    };
  }

  function prettyResourceNames(name) {
    switch (name) {
      case "fsFile":
        return ["A file", "opened", "closed"];
      case "fetchRequest":
        return ["A fetch request", "started", "finished"];
      case "fetchRequestBody":
        return ["A fetch request body", "created", "closed"];
      case "fetchResponse":
        return ["A fetch response body", "created", "consumed"];
      case "httpClient":
        return ["An HTTP client", "created", "closed"];
      case "dynamicLibrary":
        return ["A dynamic library", "loaded", "unloaded"];
      case "httpConn":
        return ["An inbound HTTP connection", "accepted", "closed"];
      case "httpStream":
        return ["An inbound HTTP request", "accepted", "closed"];
      case "tcpStream":
        return ["A TCP connection", "opened/accepted", "closed"];
      case "unixStream":
        return ["A Unix connection", "opened/accepted", "closed"];
      case "tlsStream":
        return ["A TLS connection", "opened/accepted", "closed"];
      case "tlsListener":
        return ["A TLS listener", "opened", "closed"];
      case "unixListener":
        return ["A Unix listener", "opened", "closed"];
      case "unixDatagram":
        return ["A Unix datagram", "opened", "closed"];
      case "tcpListener":
        return ["A TCP listener", "opened", "closed"];
      case "udpSocket":
        return ["A UDP socket", "opened", "closed"];
      case "timer":
        return ["A timer", "started", "fired/cleared"];
      case "textDecoder":
        return ["A text decoder", "created", "finished"];
      case "messagePort":
        return ["A message port", "created", "closed"];
      case "webSocketStream":
        return ["A WebSocket", "opened", "closed"];
      case "fsEvents":
        return ["A file system watcher", "created", "closed"];
      case "childStdin":
        return ["A child process stdin", "opened", "closed"];
      case "childStdout":
        return ["A child process stdout", "opened", "closed"];
      case "childStderr":
        return ["A child process stderr", "opened", "closed"];
      case "child":
        return ["A child process", "started", "closed"];
      case "signal":
        return ["A signal listener", "created", "fired/cleared"];
      case "stdin":
        return ["The stdin pipe", "opened", "closed"];
      case "stdout":
        return ["The stdout pipe", "opened", "closed"];
      case "stderr":
        return ["The stderr pipe", "opened", "closed"];
      case "compression":
        return ["A CompressionStream", "created", "closed"];
      default:
        return [`A "${name}" resource`, "created", "cleaned up"];
    }
  }

  function resourceCloseHint(name) {
    switch (name) {
      case "fsFile":
        return "Close the file handle by calling `file.close()`.";
      case "fetchRequest":
        return "Await the promise returned from `fetch()` or abort the fetch with an abort signal.";
      case "fetchRequestBody":
        return "Terminate the request body `ReadableStream` by closing or erroring it.";
      case "fetchResponse":
        return "Consume or close the response body `ReadableStream`, e.g `await resp.text()` or `await resp.body.cancel()`.";
      case "httpClient":
        return "Close the HTTP client by calling `httpClient.close()`.";
      case "dynamicLibrary":
        return "Unload the dynamic library by calling `dynamicLibrary.close()`.";
      case "httpConn":
        return "Close the inbound HTTP connection by calling `httpConn.close()`.";
      case "httpStream":
        return "Close the inbound HTTP request by responding with `e.respondWith()` or closing the HTTP connection.";
      case "tcpStream":
        return "Close the TCP connection by calling `tcpConn.close()`.";
      case "unixStream":
        return "Close the Unix socket connection by calling `unixConn.close()`.";
      case "tlsStream":
        return "Close the TLS connection by calling `tlsConn.close()`.";
      case "tlsListener":
        return "Close the TLS listener by calling `tlsListener.close()`.";
      case "unixListener":
        return "Close the Unix socket listener by calling `unixListener.close()`.";
      case "unixDatagram":
        return "Close the Unix datagram socket by calling `unixDatagram.close()`.";
      case "tcpListener":
        return "Close the TCP listener by calling `tcpListener.close()`.";
      case "udpSocket":
        return "Close the UDP socket by calling `udpSocket.close()`.";
      case "timer":
        return "Clear the timer by calling `clearInterval` or `clearTimeout`.";
      case "textDecoder":
        return "Close the text decoder by calling `textDecoder.decode('')` or `await textDecoderStream.readable.cancel()`.";
      case "messagePort":
        return "Close the message port by calling `messagePort.close()`.";
      case "webSocketStream":
        return "Close the WebSocket by calling `webSocket.close()`.";
      case "fsEvents":
        return "Close the file system watcher by calling `watcher.close()`.";
      case "childStdin":
        return "Close the child process stdin by calling `proc.stdin.close()`.";
      case "childStdout":
        return "Close the child process stdout by calling `proc.stdout.close()` or `await child.stdout.cancel()`.";
      case "childStderr":
        return "Close the child process stderr by calling `proc.stderr.close()` or `await child.stderr.cancel()`.";
      case "child":
        return "Close the child process by calling `proc.kill()` or `proc.close()`.";
      case "signal":
        return "Clear the signal listener by calling `Deno.removeSignalListener`.";
      case "stdin":
        return "Close the stdin pipe by calling `Deno.stdin.close()`.";
      case "stdout":
        return "Close the stdout pipe by calling `Deno.stdout.close()`.";
      case "stderr":
        return "Close the stderr pipe by calling `Deno.stderr.close()`.";
      case "compression":
        return "Close the compression stream by calling `await stream.writable.close()`.";
      default:
        return "Close the resource before the end of the test.";
    }
  }

  // Wrap test function in additional assertion that makes sure
  // the test case does not "leak" resources - ie. resource table after
  // the test has exactly the same contents as before the test.
  function assertResources(fn) {
    /** @param desc {TestDescription | TestStepDescription} */
    return async function resourceSanitizer(desc) {
      const pre = core.resources();
      const innerResult = await fn(desc);
      if (innerResult) return innerResult;
      const post = core.resources();

      const allResources = new Set([
        ...Object.keys(pre),
        ...Object.keys(post),
      ]);

      const details = [];
      for (const resource of allResources) {
        const preResource = pre[resource];
        const postResource = post[resource];
        if (preResource === postResource) continue;

        if (preResource === undefined) {
          const [name, action1, action2] = prettyResourceNames(postResource);
          const hint = resourceCloseHint(postResource);
          const detail =
            `${name} (rid ${resource}) was ${action1} during the test, but not ${action2} during the test. ${hint}`;
          details.push(detail);
        } else {
          const [name, action1, action2] = prettyResourceNames(preResource);
          const detail =
            `${name} (rid ${resource}) was ${action1} before the test started, but was ${action2} during the test. Do not close resources in a test that were not created during that test.`;
          details.push(detail);
        }
      }
      if (details.length == 0) {
        return null;
      }
      return { failed: { leakedResources: details } };
    };
  }

  // Wrap test function in additional assertion that makes sure
  // that the test case does not accidentally exit prematurely.
  function assertExit(fn, isTest) {
    return async function exitSanitizer(...params) {
      setExitHandler((exitCode) => {
        throw new Error(
          `${
            isTest ? "Test case" : "Bench"
          } attempted to exit with exit code: ${exitCode}`,
        );
      });

      try {
        const innerResult = await fn(...params);
        if (innerResult) return innerResult;
      } finally {
        setExitHandler(null);
      }
    };
  }

  function wrapOuter(fn, desc) {
    return async function outerWrapped() {
      try {
        if (desc.ignore) {
          return "ignored";
        }
        return await fn(desc) ?? "ok";
      } catch (error) {
        return { failed: { jsError: core.destructureError(error) } };
      } finally {
        const state = testStates.get(desc.id);
        for (const childDesc of state.children) {
          stepReportResult(childDesc, { failed: "incomplete" }, 0);
        }
        state.completed = true;
      }
    };
  }

  function wrapInner(fn) {
    /** @param desc {TestDescription | TestStepDescription} */
    return async function innerWrapped(desc) {
      function getRunningStepDescs() {
        const results = [];
        let childDesc = desc;
        while (childDesc.parent != null) {
          const state = testStates.get(childDesc.parent.id);
          for (const siblingDesc of state.children) {
            if (siblingDesc.id == childDesc.id) {
              continue;
            }
            const siblingState = testStates.get(siblingDesc.id);
            if (!siblingState.completed) {
              results.push(siblingDesc);
            }
          }
          childDesc = childDesc.parent;
        }
        return results;
      }
      const runningStepDescs = getRunningStepDescs();
      const runningStepDescsWithSanitizers = runningStepDescs.filter(
        (d) => usesSanitizer(d),
      );

      if (runningStepDescsWithSanitizers.length > 0) {
        return {
          failed: {
            overlapsWithSanitizers: runningStepDescsWithSanitizers.map(
              getFullName,
            ),
          },
        };
      }

      if (usesSanitizer(desc) && runningStepDescs.length > 0) {
        return {
          failed: {
            hasSanitizersAndOverlaps: runningStepDescs.map(getFullName),
          },
        };
      }
      await fn(testStates.get(desc.id).context);
      let failedSteps = 0;
      for (const childDesc of testStates.get(desc.id).children) {
        const state = testStates.get(childDesc.id);
        if (!state.completed) {
          return { failed: "incompleteSteps" };
        }
        if (state.failed) {
          failedSteps++;
        }
      }
      return failedSteps == 0 ? null : { failed: { failedSteps } };
    };
  }

  function pledgePermissions(permissions) {
    return ops.op_pledge_test_permissions(
      serializePermissions(permissions),
    );
  }

  function restorePermissions(token) {
    ops.op_restore_test_permissions(token);
  }

  function withPermissions(fn, permissions) {
    return async function applyPermissions(...params) {
      const token = pledgePermissions(permissions);

      try {
        return await fn(...params);
      } finally {
        restorePermissions(token);
      }
    };
  }

  const ESCAPE_ASCII_CHARS = [
    ["\b", "\\b"],
    ["\f", "\\f"],
    ["\t", "\\t"],
    ["\n", "\\n"],
    ["\r", "\\r"],
    ["\v", "\\v"],
  ];

  /**
   * @param {string} name
   * @returns {string}
   */
  function escapeName(name) {
    // Check if we need to escape a character
    for (let i = 0; i < name.length; i++) {
      const ch = name.charCodeAt(i);
      if (ch <= 13 && ch >= 8) {
        // Slow path: We do need to escape it
        for (const [escape, replaceWith] of ESCAPE_ASCII_CHARS) {
          name = name.replaceAll(escape, replaceWith);
        }
        return name;
      }
    }

    // We didn't need to escape anything, return original string
    return name;
  }

  /**
   * @typedef {{
   *   id: number,
   *   name: string,
   *   fn: TestFunction
   *   origin: string,
   *   location: TestLocation,
   *   ignore: boolean,
   *   only: boolean.
   *   sanitizeOps: boolean,
   *   sanitizeResources: boolean,
   *   sanitizeExit: boolean,
   *   permissions: PermissionOptions,
   * }} TestDescription
   *
   * @typedef {{
   *   id: number,
   *   name: string,
   *   fn: TestFunction
   *   origin: string,
   *   location: TestLocation,
   *   ignore: boolean,
   *   level: number,
   *   parent: TestDescription | TestStepDescription,
   *   rootId: number,
   *   rootName: String,
   *   sanitizeOps: boolean,
   *   sanitizeResources: boolean,
   *   sanitizeExit: boolean,
   * }} TestStepDescription
   *
   * @typedef {{
   *   context: TestContext,
   *   children: TestStepDescription[],
   *   completed: boolean,
   * }} TestState
   *
   * @typedef {{
   *   context: TestContext,
   *   children: TestStepDescription[],
   *   completed: boolean,
   *   failed: boolean,
   * }} TestStepState
   *
   * @typedef {{
   *   id: number,
   *   name: string,
   *   fn: BenchFunction
   *   origin: string,
   *   ignore: boolean,
   *   only: boolean.
   *   sanitizeExit: boolean,
   *   permissions: PermissionOptions,
   * }} BenchDescription
   */

  /** @type {Map<number, TestState | TestStepState>} */
  const testStates = new Map();
  /** @type {number | null} */
  let currentBenchId = null;
  // These local variables are used to track time measurements at
  // `BenchContext::{start,end}` calls. They are global instead of using a state
  // map to minimise the overhead of assigning them.
  /** @type {number | null} */
  let currentBenchUserExplicitStart = null;
  /** @type {number | null} */
  let currentBenchUserExplicitEnd = null;

  const registerTestIdRetBuf = new Uint32Array(1);
  const registerTestIdRetBufU8 = new Uint8Array(registerTestIdRetBuf.buffer);

  function testInner(
    nameOrFnOrOptions,
    optionsOrFn,
    maybeFn,
    overrides = {},
  ) {
    if (typeof ops.op_register_test != "function") {
      return;
    }

    let testDesc;
    const defaults = {
      ignore: false,
      only: false,
      sanitizeOps: true,
      sanitizeResources: true,
      sanitizeExit: true,
      permissions: null,
    };

    if (typeof nameOrFnOrOptions === "string") {
      if (!nameOrFnOrOptions) {
        throw new TypeError("The test name can't be empty");
      }
      if (typeof optionsOrFn === "function") {
        testDesc = { fn: optionsOrFn, name: nameOrFnOrOptions, ...defaults };
      } else {
        if (!maybeFn || typeof maybeFn !== "function") {
          throw new TypeError("Missing test function");
        }
        if (optionsOrFn.fn != undefined) {
          throw new TypeError(
            "Unexpected 'fn' field in options, test function is already provided as the third argument.",
          );
        }
        if (optionsOrFn.name != undefined) {
          throw new TypeError(
            "Unexpected 'name' field in options, test name is already provided as the first argument.",
          );
        }
        testDesc = {
          ...defaults,
          ...optionsOrFn,
          fn: maybeFn,
          name: nameOrFnOrOptions,
        };
      }
    } else if (typeof nameOrFnOrOptions === "function") {
      if (!nameOrFnOrOptions.name) {
        throw new TypeError("The test function must have a name");
      }
      if (optionsOrFn != undefined) {
        throw new TypeError("Unexpected second argument to Deno.test()");
      }
      if (maybeFn != undefined) {
        throw new TypeError("Unexpected third argument to Deno.test()");
      }
      testDesc = {
        ...defaults,
        fn: nameOrFnOrOptions,
        name: nameOrFnOrOptions.name,
      };
    } else {
      let fn;
      let name;
      if (typeof optionsOrFn === "function") {
        fn = optionsOrFn;
        if (nameOrFnOrOptions.fn != undefined) {
          throw new TypeError(
            "Unexpected 'fn' field in options, test function is already provided as the second argument.",
          );
        }
        name = nameOrFnOrOptions.name ?? fn.name;
      } else {
        if (
          !nameOrFnOrOptions.fn || typeof nameOrFnOrOptions.fn !== "function"
        ) {
          throw new TypeError(
            "Expected 'fn' field in the first argument to be a test function.",
          );
        }
        fn = nameOrFnOrOptions.fn;
        name = nameOrFnOrOptions.name ?? fn.name;
      }
      if (!name) {
        throw new TypeError("The test name can't be empty");
      }
      testDesc = { ...defaults, ...nameOrFnOrOptions, fn, name };
    }

    testDesc = { ...testDesc, ...overrides };

    // Delete this prop in case the user passed it. It's used to detect steps.
    delete testDesc.parent;

    testDesc.location = core.currentUserCallSite();
    testDesc.fn = wrapTest(testDesc);
    testDesc.name = escapeName(testDesc.name);

    const origin = ops.op_register_test(
      testDesc.fn,
      testDesc.name,
      testDesc.ignore,
      testDesc.only,
      testDesc.location.fileName,
      testDesc.location.lineNumber,
      testDesc.location.columnNumber,
      registerTestIdRetBufU8,
    );
    testDesc.id = registerTestIdRetBuf[0];
    testDesc.origin = origin;
    testStates.set(testDesc.id, {
      context: createTestContext(testDesc),
      children: [],
      completed: false,
    });
  }

  // Main test function provided by Deno.
  function test(
    nameOrFnOrOptions,
    optionsOrFn,
    maybeFn,
  ) {
    return testInner(nameOrFnOrOptions, optionsOrFn, maybeFn);
  }

  test.ignore = function (nameOrFnOrOptions, optionsOrFn, maybeFn) {
    return testInner(nameOrFnOrOptions, optionsOrFn, maybeFn, { ignore: true });
  };

  test.only = function (
    nameOrFnOrOptions,
    optionsOrFn,
    maybeFn,
  ) {
    return testInner(nameOrFnOrOptions, optionsOrFn, maybeFn, { only: true });
  };

  let registeredWarmupBench = false;

  // Main bench function provided by Deno.
  function bench(
    nameOrFnOrOptions,
    optionsOrFn,
    maybeFn,
  ) {
    if (typeof ops.op_register_bench != "function") {
      return;
    }

    if (!registeredWarmupBench) {
      registeredWarmupBench = true;
      const warmupBenchDesc = {
        name: "<warmup>",
        fn: function warmup() {},
        async: false,
        ignore: false,
        baseline: false,
        only: false,
        sanitizeExit: true,
        permissions: null,
        warmup: true,
      };
      warmupBenchDesc.fn = wrapBenchmark(warmupBenchDesc);
      const { id, origin } = ops.op_register_bench(warmupBenchDesc);
      warmupBenchDesc.id = id;
      warmupBenchDesc.origin = origin;
    }

    let benchDesc;
    const defaults = {
      ignore: false,
      baseline: false,
      only: false,
      sanitizeExit: true,
      permissions: null,
    };

    if (typeof nameOrFnOrOptions === "string") {
      if (!nameOrFnOrOptions) {
        throw new TypeError("The bench name can't be empty");
      }
      if (typeof optionsOrFn === "function") {
        benchDesc = { fn: optionsOrFn, name: nameOrFnOrOptions, ...defaults };
      } else {
        if (!maybeFn || typeof maybeFn !== "function") {
          throw new TypeError("Missing bench function");
        }
        if (optionsOrFn.fn != undefined) {
          throw new TypeError(
            "Unexpected 'fn' field in options, bench function is already provided as the third argument.",
          );
        }
        if (optionsOrFn.name != undefined) {
          throw new TypeError(
            "Unexpected 'name' field in options, bench name is already provided as the first argument.",
          );
        }
        benchDesc = {
          ...defaults,
          ...optionsOrFn,
          fn: maybeFn,
          name: nameOrFnOrOptions,
        };
      }
    } else if (typeof nameOrFnOrOptions === "function") {
      if (!nameOrFnOrOptions.name) {
        throw new TypeError("The bench function must have a name");
      }
      if (optionsOrFn != undefined) {
        throw new TypeError("Unexpected second argument to Deno.bench()");
      }
      if (maybeFn != undefined) {
        throw new TypeError("Unexpected third argument to Deno.bench()");
      }
      benchDesc = {
        ...defaults,
        fn: nameOrFnOrOptions,
        name: nameOrFnOrOptions.name,
      };
    } else {
      let fn;
      let name;
      if (typeof optionsOrFn === "function") {
        fn = optionsOrFn;
        if (nameOrFnOrOptions.fn != undefined) {
          throw new TypeError(
            "Unexpected 'fn' field in options, bench function is already provided as the second argument.",
          );
        }
        name = nameOrFnOrOptions.name ?? fn.name;
      } else {
        if (
          !nameOrFnOrOptions.fn || typeof nameOrFnOrOptions.fn !== "function"
        ) {
          throw new TypeError(
            "Expected 'fn' field in the first argument to be a bench function.",
          );
        }
        fn = nameOrFnOrOptions.fn;
        name = nameOrFnOrOptions.name ?? fn.name;
      }
      if (!name) {
        throw new TypeError("The bench name can't be empty");
      }
      benchDesc = { ...defaults, ...nameOrFnOrOptions, fn, name };
    }

    const AsyncFunction = (async () => {}).constructor;
    benchDesc.async = AsyncFunction === benchDesc.fn.constructor;
    benchDesc.fn = wrapBenchmark(benchDesc);
    benchDesc.warmup = false;
    benchDesc.name = escapeName(benchDesc.name);

    const { id, origin } = ops.op_register_bench(benchDesc);
    benchDesc.id = id;
    benchDesc.origin = origin;
  }

  function compareMeasurements(a, b) {
    if (a > b) return 1;
    if (a < b) return -1;

    return 0;
  }

  function benchStats(
    n,
    highPrecision,
    usedExplicitTimers,
    avg,
    min,
    max,
    all,
  ) {
    return {
      n,
      min,
      max,
      p75: all[Math.ceil(n * (75 / 100)) - 1],
      p99: all[Math.ceil(n * (99 / 100)) - 1],
      p995: all[Math.ceil(n * (99.5 / 100)) - 1],
      p999: all[Math.ceil(n * (99.9 / 100)) - 1],
      avg: !highPrecision ? (avg / n) : Math.ceil(avg / n),
      highPrecision,
      usedExplicitTimers,
    };
  }

  async function benchMeasure(timeBudget, fn, async, context) {
    let n = 0;
    let avg = 0;
    let wavg = 0;
    let usedExplicitTimers = false;
    const all = [];
    let min = Infinity;
    let max = -Infinity;
    const lowPrecisionThresholdInNs = 1e4;

    // warmup step
    let c = 0;
    let iterations = 20;
    let budget = 10 * 1e6;

    if (!async) {
      while (budget > 0 || iterations-- > 0) {
        const t1 = benchNow();
        fn(context);
        const t2 = benchNow();
        const totalTime = t2 - t1;
        if (currentBenchUserExplicitStart !== null) {
          currentBenchUserExplicitStart = null;
          usedExplicitTimers = true;
        }
        if (currentBenchUserExplicitEnd !== null) {
          currentBenchUserExplicitEnd = null;
          usedExplicitTimers = true;
        }

        c++;
        wavg += totalTime;
        budget -= totalTime;
      }
    } else {
      while (budget > 0 || iterations-- > 0) {
        const t1 = benchNow();
        await fn(context);
        const t2 = benchNow();
        const totalTime = t2 - t1;
        if (currentBenchUserExplicitStart !== null) {
          currentBenchUserExplicitStart = null;
          usedExplicitTimers = true;
        }
        if (currentBenchUserExplicitEnd !== null) {
          currentBenchUserExplicitEnd = null;
          usedExplicitTimers = true;
        }

        c++;
        wavg += totalTime;
        budget -= totalTime;
      }
    }

    wavg /= c;

    // measure step
    if (wavg > lowPrecisionThresholdInNs) {
      let iterations = 10;
      let budget = timeBudget * 1e6;

      if (!async) {
        while (budget > 0 || iterations-- > 0) {
          const t1 = benchNow();
          fn(context);
          const t2 = benchNow();
          const totalTime = t2 - t1;
          let measuredTime = totalTime;
          if (currentBenchUserExplicitStart !== null) {
            measuredTime -= currentBenchUserExplicitStart - t1;
            currentBenchUserExplicitStart = null;
          }
          if (currentBenchUserExplicitEnd !== null) {
            measuredTime -= t2 - currentBenchUserExplicitEnd;
            currentBenchUserExplicitEnd = null;
          }

          n++;
          avg += measuredTime;
          budget -= totalTime;
          all.push(measuredTime);
          if (measuredTime < min) min = measuredTime;
          if (measuredTime > max) max = measuredTime;
        }
      } else {
        while (budget > 0 || iterations-- > 0) {
          const t1 = benchNow();
          await fn(context);
          const t2 = benchNow();
          const totalTime = t2 - t1;
          let measuredTime = totalTime;
          if (currentBenchUserExplicitStart !== null) {
            measuredTime -= currentBenchUserExplicitStart - t1;
            currentBenchUserExplicitStart = null;
          }
          if (currentBenchUserExplicitEnd !== null) {
            measuredTime -= t2 - currentBenchUserExplicitEnd;
            currentBenchUserExplicitEnd = null;
          }

          n++;
          avg += measuredTime;
          budget -= totalTime;
          all.push(measuredTime);
          if (measuredTime < min) min = measuredTime;
          if (measuredTime > max) max = measuredTime;
        }
      }
    } else {
      context.start = function start() {};
      context.end = function end() {};
      let iterations = 10;
      let budget = timeBudget * 1e6;

      if (!async) {
        while (budget > 0 || iterations-- > 0) {
          const t1 = benchNow();
          for (let c = 0; c < lowPrecisionThresholdInNs; c++) {
            fn(context);
          }
          const iterationTime = (benchNow() - t1) / lowPrecisionThresholdInNs;

          n++;
          avg += iterationTime;
          all.push(iterationTime);
          if (iterationTime < min) min = iterationTime;
          if (iterationTime > max) max = iterationTime;
          budget -= iterationTime * lowPrecisionThresholdInNs;
        }
      } else {
        while (budget > 0 || iterations-- > 0) {
          const t1 = benchNow();
          for (let c = 0; c < lowPrecisionThresholdInNs; c++) {
            await fn(context);
            currentBenchUserExplicitStart = null;
            currentBenchUserExplicitEnd = null;
          }
          const iterationTime = (benchNow() - t1) / lowPrecisionThresholdInNs;

          n++;
          avg += iterationTime;
          all.push(iterationTime);
          if (iterationTime < min) min = iterationTime;
          if (iterationTime > max) max = iterationTime;
          budget -= iterationTime * lowPrecisionThresholdInNs;
        }
      }
    }

    all.sort(compareMeasurements);
    return benchStats(
      n,
      wavg > lowPrecisionThresholdInNs,
      usedExplicitTimers,
      avg,
      min,
      max,
      all,
    );
  }

  /** @param desc {BenchDescription} */
  function createBenchContext(desc) {
    return {
      [Symbol.toStringTag]: "BenchContext",
      name: desc.name,
      origin: desc.origin,
      start() {
        if (currentBenchId !== desc.id) {
          throw new TypeError(
            "The benchmark which this context belongs to is not being executed.",
          );
        }
        if (currentBenchUserExplicitStart != null) {
          throw new TypeError(
            "BenchContext::start() has already been invoked.",
          );
        }
        currentBenchUserExplicitStart = benchNow();
      },
      end() {
        const end = benchNow();
        if (currentBenchId !== desc.id) {
          throw new TypeError(
            "The benchmark which this context belongs to is not being executed.",
          );
        }
        if (currentBenchUserExplicitEnd != null) {
          throw new TypeError("BenchContext::end() has already been invoked.");
        }
        currentBenchUserExplicitEnd = end;
      },
    };
  }

  /** Wrap a user benchmark function in one which returns a structured result. */
  function wrapBenchmark(desc) {
    const fn = desc.fn;
    return async function outerWrapped() {
      let token = null;
      const originalConsole = globalThis.console;
      currentBenchId = desc.id;

      try {
        globalThis.console = new Console((s) => {
          ops.op_dispatch_bench_event({ output: s });
        });

        if (desc.permissions) {
          token = pledgePermissions(desc.permissions);
        }

        if (desc.sanitizeExit) {
          setExitHandler((exitCode) => {
            throw new Error(
              `Bench attempted to exit with exit code: ${exitCode}`,
            );
          });
        }

        const benchTimeInMs = 500;
        const context = createBenchContext(desc);
        const stats = await benchMeasure(
          benchTimeInMs,
          fn,
          desc.async,
          context,
        );

        return { ok: stats };
      } catch (error) {
        return { failed: core.destructureError(error) };
      } finally {
        globalThis.console = originalConsole;
        currentBenchId = null;
        currentBenchUserExplicitStart = null;
        currentBenchUserExplicitEnd = null;
        if (bench.sanitizeExit) setExitHandler(null);
        if (token !== null) restorePermissions(token);
      }
    };
  }

  function benchNow() {
    return ops.op_bench_now();
  }

  function getFullName(desc) {
    if ("parent" in desc) {
      return `${getFullName(desc.parent)} ... ${desc.name}`;
    }
    return desc.name;
  }

  function usesSanitizer(desc) {
    return desc.sanitizeResources || desc.sanitizeOps || desc.sanitizeExit;
  }

  function stepReportResult(desc, result, elapsed) {
    const state = testStates.get(desc.id);
    for (const childDesc of state.children) {
      stepReportResult(childDesc, { failed: "incomplete" }, 0);
    }
    if (result === "ok") {
      ops.op_test_event_step_result_ok(desc.id, elapsed);
    } else if (result === "ignored") {
      ops.op_test_event_step_result_ignored(desc.id, elapsed);
    } else {
      ops.op_test_event_step_result_failed(desc.id, result.failed, elapsed);
    }
  }

  /** @param desc {TestDescription | TestStepDescription} */
  function createTestContext(desc) {
    let parent;
    let level;
    let rootId;
    let rootName;
    if ("parent" in desc) {
      parent = testStates.get(desc.parent.id).context;
      level = desc.level;
      rootId = desc.rootId;
      rootName = desc.rootName;
    } else {
      parent = undefined;
      level = 0;
      rootId = desc.id;
      rootName = desc.name;
    }
    return {
      [Symbol.toStringTag]: "TestContext",
      /**
       * The current test name.
       */
      name: desc.name,
      /**
       * Parent test context.
       */
      parent,
      /**
       * File Uri of the test code.
       */
      origin: desc.origin,
      /**
       * @param nameOrFnOrOptions {string | TestStepDefinition | ((t: TestContext) => void | Promise<void>)}
       * @param maybeFn {((t: TestContext) => void | Promise<void>) | undefined}
       */
      async step(nameOrFnOrOptions, maybeFn) {
        if (testStates.get(desc.id).completed) {
          throw new Error(
            "Cannot run test step after parent scope has finished execution. " +
              "Ensure any `.step(...)` calls are executed before their parent scope completes execution.",
          );
        }

        let stepDesc;
        if (typeof nameOrFnOrOptions === "string") {
          if (
            !Object.prototype.isPrototypeOf.call(Function.prototype, maybeFn)
          ) {
            throw new TypeError("Expected function for second argument.");
          }
          stepDesc = {
            name: nameOrFnOrOptions,
            fn: maybeFn,
          };
        } else if (typeof nameOrFnOrOptions === "function") {
          if (!nameOrFnOrOptions.name) {
            throw new TypeError("The step function must have a name.");
          }
          if (maybeFn != undefined) {
            throw new TypeError(
              "Unexpected second argument to TestContext.step()",
            );
          }
          stepDesc = {
            name: nameOrFnOrOptions.name,
            fn: nameOrFnOrOptions,
          };
        } else if (typeof nameOrFnOrOptions === "object") {
          stepDesc = nameOrFnOrOptions;
        } else {
          throw new TypeError(
            "Expected a test definition or name and function.",
          );
        }
        stepDesc.ignore ??= false;
        stepDesc.sanitizeOps ??= desc.sanitizeOps;
        stepDesc.sanitizeResources ??= desc.sanitizeResources;
        stepDesc.sanitizeExit ??= desc.sanitizeExit;
        stepDesc.location = core.currentUserCallSite();
        stepDesc.level = level + 1;
        stepDesc.parent = desc;
        stepDesc.rootId = rootId;
        stepDesc.name = escapeName(stepDesc.name);
        stepDesc.rootName = escapeName(rootName);
        stepDesc.fn = wrapTest(stepDesc);
        const id = ops.op_register_test_step(
          stepDesc.name,
          stepDesc.location.fileName,
          stepDesc.location.lineNumber,
          stepDesc.location.columnNumber,
          stepDesc.level,
          stepDesc.parent.id,
          stepDesc.rootId,
          stepDesc.rootName,
        );
        stepDesc.id = id;
        stepDesc.origin = desc.origin;
        const state = {
          context: createTestContext(stepDesc),
          children: [],
          failed: false,
          completed: false,
        };
        testStates.set(stepDesc.id, state);
        testStates.get(stepDesc.parent.id).children.push(
          stepDesc,
        );

        ops.op_test_event_step_wait(stepDesc.id);
        const earlier = Date.now();
        const result = await stepDesc.fn(stepDesc);
        const elapsed = Date.now() - earlier;
        state.failed = !!result.failed;
        stepReportResult(stepDesc, result, elapsed);
        return result == "ok";
      },
    };
  }

  /**
   * Wrap a user test function in one which returns a structured result.
   * @template T {Function}
   * @param testFn {T}
   * @param desc {TestDescription | TestStepDescription}
   * @returns {T}
   */
  function wrapTest(desc) {
    let testFn = wrapInner(desc.fn);
    if (desc.sanitizeOps) {
      testFn = assertOps(testFn);
    }
    if (desc.sanitizeResources) {
      testFn = assertResources(testFn);
    }
    if (desc.sanitizeExit) {
      testFn = assertExit(testFn, true);
    }
    if (!("parent" in desc) && desc.permissions) {
      testFn = withPermissions(testFn, desc.permissions);
    }
    return wrapOuter(testFn, desc);
  }

  globalThis.Deno.bench = bench;
  globalThis.Deno.test = test;
})();