[Fleet] Extract hook for agentList table logic (elastic#175528)

Closes elastic#131153
Follow up of elastic#175318

## Summary
Extract the main logic for agentList component in a separate hook.


### Checklist
- [ ] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [ ] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed

---------

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

x-pack/plugins/fleet/public/applications/fleet/sections/agents/agent_list_page/hooks/index.tsx

@@ -11,3 +11,4 @@ export { useLastSeenInactiveAgentsCount } from './use_last_seen_inactive_agents_
 export { useInactiveAgentsCalloutHasBeenDismissed } from './use_inactive_agents_callout_has_been_dismissed';
 export { useAgentSoftLimit } from './use_agent_soft_limit';
 export { useMissingEncryptionKeyCallout } from './use_missing_encryption_key_callout';
+export { useFetchAgentsData } from './use_fetch_agents_data';

x-pack/plugins/fleet/public/applications/fleet/sections/agents/agent_list_page/hooks/use_fetch_agents_data.test.tsx

@@ -0,0 +1,142 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import { renderHook, act } from '@testing-library/react-hooks';
+
+import { useStartServices } from '../../../../hooks';
+
+import { ExperimentalFeaturesService } from '../../../../services';
+
+import { useFetchAgentsData } from './use_fetch_agents_data';
+
+jest.mock('../../../../../../services/experimental_features');
+const mockedExperimentalFeaturesService = jest.mocked(ExperimentalFeaturesService);
+
+jest.mock('../../../../hooks', () => ({
+  ...jest.requireActual('../../../../hooks'),
+  sendGetAgents: jest.fn().mockResolvedValue({
+    data: {
+      total: 5,
+    },
+  }),
+  sendGetAgentStatus: jest.fn().mockResolvedValue({
+    data: {
+      results: {
+        inactive: 2,
+      },
+      totalInactive: 2,
+    },
+  }),
+  sendGetAgentPolicies: jest.fn().mockReturnValue({
+    data: {
+      items: [
+        { id: 'agent-policy-1', name: 'Agent policy 1', namespace: 'default' },
+        {
+          id: 'agent-policy-managed',
+          name: 'Managed Agent policy',
+          namespace: 'default',
+          managed: true,
+        },
+      ],
+    },
+  }),
+  useGetAgentPolicies: jest.fn().mockReturnValue({
+    data: {
+      items: [
+        { id: 'agent-policy-1', name: 'Agent policy 1', namespace: 'default' },
+        {
+          id: 'agent-policy-managed',
+          name: 'Managed Agent policy',
+          namespace: 'default',
+          managed: true,
+        },
+      ],
+    },
+    error: undefined,
+    isLoading: false,
+    resendRequest: jest.fn(),
+  } as any),
+  sendGetAgentTags: jest.fn().mockReturnValue({ data: { items: ['tag1', 'tag2'] } }),
+  useStartServices: jest.fn().mockReturnValue({
+    notifications: {
+      toasts: {
+        addError: jest.fn(),
+      },
+    },
+    cloud: {},
+    data: { dataViews: { getFieldsForWildcard: jest.fn() } },
+  }),
+  usePagination: jest.fn().mockReturnValue({
+    pagination: {
+      currentPage: 1,
+      pageSize: 5,
+    },
+    pageSizeOptions: [5, 20, 50],
+    setPagination: jest.fn(),
+  }),
+  useUrlParams: jest.fn().mockReturnValue({ urlParams: { kuery: '' } }),
+}));
+
+describe('useFetchAgentsData', () => {
+  const startServices = useStartServices();
+  const mockErrorToast = startServices.notifications.toasts.addError as jest.Mock;
+
+  beforeAll(() => {
+    mockedExperimentalFeaturesService.get.mockReturnValue({
+      displayAgentMetrics: true,
+    } as any);
+  });
+
+  beforeEach(() => {
+    mockErrorToast.mockReset();
+    mockErrorToast.mockResolvedValue({});
+  });
+
+  it('should fetch agents and agent policies data', async () => {
+    let result: any | undefined;
+    let waitForNextUpdate: any | undefined;
+    await act(async () => {
+      ({ result, waitForNextUpdate } = renderHook(() => useFetchAgentsData()));
+      await waitForNextUpdate();
+    });
+
+    expect(result?.current.selectedStatus).toEqual(['healthy', 'unhealthy', 'updating', 'offline']);
+    expect(result?.current.agentPolicies).toEqual([
+      {
+        id: 'agent-policy-1',
+        name: 'Agent policy 1',
+        namespace: 'default',
+      },
+      {
+        id: 'agent-policy-managed',
+        managed: true,
+        name: 'Managed Agent policy',
+        namespace: 'default',
+      },
+    ]);
+
+    expect(result?.current.agentPoliciesIndexedById).toEqual({
+      'agent-policy-1': {
+        id: 'agent-policy-1',
+        name: 'Agent policy 1',
+        namespace: 'default',
+      },
+      'agent-policy-managed': {
+        id: 'agent-policy-managed',
+        managed: true,
+        name: 'Managed Agent policy',
+        namespace: 'default',
+      },
+    });
+    expect(result?.current.kuery).toEqual(
+      'status:online or (status:error or status:degraded) or (status:updating or status:unenrolling or status:enrolling) or status:offline'
+    );
+    expect(result?.current.currentRequestRef).toEqual({ current: 1 });
+    expect(result?.current.pagination).toEqual({ currentPage: 1, pageSize: 5 });
+    expect(result?.current.pageSizeOptions).toEqual([5, 20, 50]);
+  });
+});