// Shared by single commands and workflows. No external dependencies.
export function connect(webSocketUrl, { timeoutMs = 30000 } = {}) {
  const socket = new WebSocket(webSocketUrl);
  const pending = new Map();
  let nextRequestId = 0;
  let closed = false;
  let resolveReady;
  let rejectReady;
  const ready = new Promise((resolve, reject) => { resolveReady = resolve; rejectReady = reject; });
  // The connection may fail after readiness or before a caller starts awaiting it.
  void ready.catch(() => {});
  const fail = error => {
    if (closed) return;
    closed = true;
    clearTimeout(timer);
    rejectReady(error);
    for (const request of pending.values()) request.reject(error);
    pending.clear();
    socket.close();
  };
  const timer = setTimeout(() => fail(new Error("CDP deadline exceeded.")), timeoutMs);
  timer.unref();
  socket.onopen = () => resolveReady();
  socket.onerror = () => fail(new Error("CDP connection failed."));
  socket.onclose = () => fail(new Error("CDP connection closed."));
  socket.onmessage = event => {
    let message;
    try { message = JSON.parse(event.data); }
    catch { fail(new Error("Invalid CDP response.")); return; }
    const request = pending.get(message.id);
    if (request === undefined) return;
    pending.delete(message.id);
    if (message.error !== undefined) request.reject(new Error(String(message.error.message ?? "CDP request failed.").slice(0, 500)));
    else request.resolve(message.result);
  };
  return {
    ready,
    send(method, parameters = {}) {
      if (closed) return Promise.reject(new Error("CDP connection closed."));
      return new Promise((resolve, reject) => {
        const requestId = ++nextRequestId;
        pending.set(requestId, { resolve, reject });
        try { socket.send(JSON.stringify({ id: requestId, method, params: parameters })); }
        catch (error) { pending.delete(requestId); reject(error); }
      });
    },
    close() { fail(new Error("CDP connection closed.")); },
  };
}

export async function evaluate(connection, expression) {
  const result = await connection.send("Runtime.evaluate", {
    expression, returnByValue: true, awaitPromise: true, timeout: 5000,
  });
  if (result.exceptionDetails !== undefined) {
    throw new Error(String(result.exceptionDetails.exception?.description ?? result.exceptionDetails.text ?? "Page evaluation failed.").slice(0, 500));
  }
  return result.result?.value;
}

// Shared by single commands and workflows. No external dependencies.
export function connect(webSocketUrl, { timeoutMs = 30000 } = {}) {
  const socket = new WebSocket(webSocketUrl);
  const pending = new Map();
  let nextRequestId = 0;
  let closed = false;
  let resolveReady;
  let rejectReady;
  const ready = new Promise((resolve, reject) => { resolveReady = resolve; rejectReady = reject; });
  // The connection may fail after readiness or before a caller starts awaiting it.
  void ready.catch(() => {});
  const fail = error => {
    if (closed) return;
    closed = true;
    clearTimeout(timer);
    rejectReady(error);
    for (const request of pending.values()) request.reject(error);
    pending.clear();
    socket.close();
  };
  const timer = setTimeout(() => fail(new Error("CDP deadline exceeded.")), timeoutMs);
  timer.unref();
  socket.onopen = () => resolveReady();
  socket.onerror = () => fail(new Error("CDP connection failed."));
  socket.onclose = () => fail(new Error("CDP connection closed."));
  socket.onmessage = event => {
    let message;
    try { message = JSON.parse(event.data); }
    catch { fail(new Error("Invalid CDP response.")); return; }
    const request = pending.get(message.id);
    if (request === undefined) return;
    pending.delete(message.id);
    if (message.error !== undefined) request.reject(new Error(String(message.error.message ?? "CDP request failed.").slice(0, 500)));
    else request.resolve(message.result);
  };
  return {
    ready,
    send(method, parameters = {}) {
      if (closed) return Promise.reject(new Error("CDP connection closed."));
      return new Promise((resolve, reject) => {
        const requestId = ++nextRequestId;
        pending.set(requestId, { resolve, reject });
        try { socket.send(JSON.stringify({ id: requestId, method, params: parameters })); }
        catch (error) { pending.delete(requestId); reject(error); }
      });
    },
    close() { fail(new Error("CDP connection closed.")); },
  };
}

export async function evaluate(connection, expression) {
  const result = await connection.send("Runtime.evaluate", {
    expression, returnByValue: true, awaitPromise: true, timeout: 5000,
  });
  if (result.exceptionDetails !== undefined) {
    throw new Error(String(result.exceptionDetails.exception?.description ?? result.exceptionDetails.text ?? "Page evaluation failed.").slice(0, 500));
  }
  return result.result?.value;
}