async function request(path, options = {}) {
  const response = await fetch(path, {
    headers: {
      'Content-Type': 'application/json',
      ...(options.headers || {}),
    },
    ...options,
  });

  if (!response.ok) {
    let message = `API ${response.status}: ${response.statusText}`;
    const contentType = response.headers.get('content-type') || '';

    try {
      if (contentType.includes('application/json')) {
        const payload = await response.json();
        if (payload && typeof payload.error === 'string' && payload.error.trim()) {
          message = payload.error.trim();
        }
      } else {
        const text = await response.text();
        if (text.trim()) {
          message = text.trim();
        }
      }
    } catch {
      // Fall back to the HTTP status message when the error body is unreadable.
    }

    throw new Error(message);
  }

  if (response.status === 204) return null;
  return response.json();
}

export async function loadRuns() {
  return request('/api/runs');
}

export async function createRun(run) {
  return request('/api/runs', {
    method: 'POST',
    body: JSON.stringify(run),
  });
}

export async function updateRun(id, changes) {
  return request(`/api/runs/${encodeURIComponent(id)}`, {
    method: 'PUT',
    body: JSON.stringify(changes),
  });
}

export async function deleteRun(id) {
  return request(`/api/runs/${encodeURIComponent(id)}`, {
    method: 'DELETE',
  });
}