grafana-plugin/enne2corp-fullstacktest-app/src/pages/PageOne.tsx

import React, { useState, useEffect } from 'react';
import { css } from '@emotion/css';
import { GrafanaTheme2 } from '@grafana/data';
import { LinkButton, useStyles2, Input, Button, Alert } from '@grafana/ui';
import { prefixRoute } from '../utils/utils.routing';
import { ROUTES } from '../constants';
import { testIds } from '../components/testIds';
import { PluginPage, getBackendSrv } from '@grafana/runtime';

function PageOne() {
  const s = useStyles2(getStyles);
  const [textValue, setTextValue] = useState('');
  const [savedValue, setSavedValue] = useState('');
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState('');
  const [success, setSuccess] = useState('');

  // Load saved value when component mounts
  useEffect(() => {
    loadSavedValue();
  }, []);

  const loadSavedValue = async () => {
    try {
      const response = await getBackendSrv().get('/api/plugins/enne2corp-fullstacktest-app/resources/get-text');
      setSavedValue(response.message || '');
    } catch (err) {
      console.log('No saved value found or error loading:', err);
      setSavedValue('');
    }
  };

  const handleSaveText = async () => {
    if (!textValue.trim()) {
      setError('Please enter some text');
      return;
    }

    setLoading(true);
    setError('');
    setSuccess('');

    try {
      await getBackendSrv().post('/api/plugins/enne2corp-fullstacktest-app/resources/save-text', {
        message: textValue,
      });
      
      setSuccess('Text saved successfully!');
      setSavedValue(textValue);
      setTextValue('');
      
      // Clear success message after 3 seconds
      setTimeout(() => setSuccess(''), 3000);
    } catch (err) {
      setError('Failed to save text. Please try again.');
      console.error('Error saving text:', err);
    } finally {
      setLoading(false);
    }
  };

  return (
    <PluginPage>
      <div data-testid={testIds.pageOne.container}>
        <h2>Welcome Message App</h2>
        
        {savedValue && (
          <div className={s.welcomeMessage}>
            <h3>Welcome! Your saved message is:</h3>
            <p className={s.savedText}>{savedValue}</p>
          </div>
        )}
        
        {!savedValue && (
          <div className={s.noMessage}>
            <p>No message saved yet. Enter a message below to get started!</p>
          </div>
        )}

        <div className={s.form}>
          <h4>Save a new message:</h4>
          <Input
            placeholder="Enter your message here..."
            value={textValue}
            onChange={(e) => setTextValue(e.currentTarget.value)}
            disabled={loading}
            className={s.input}
          />
          
          <Button
            onClick={handleSaveText}
            disabled={loading || !textValue.trim()}
            className={s.button}
          >
            {loading ? 'Saving...' : 'Save Message'}
          </Button>
        </div>

        {error && (
          <Alert title="Error" severity="error" className={s.alert}>
            {error}
          </Alert>
        )}

        {success && (
          <Alert title="Success" severity="success" className={s.alert}>
            {success}
          </Alert>
        )}

        <div className={s.marginTop}>
          <LinkButton data-testid={testIds.pageOne.navigateToFour} href={prefixRoute(ROUTES.Four)}>
            Full-width page example
          </LinkButton>
        </div>
      </div>
    </PluginPage>
  );
}

export default PageOne;

const getStyles = (theme: GrafanaTheme2) => ({
  marginTop: css`
    margin-top: ${theme.spacing(2)};
  `,
  welcomeMessage: css`
    background: ${theme.colors.background.secondary};
    padding: ${theme.spacing(2)};
    border-radius: ${theme.shape.borderRadius()};
    margin-bottom: ${theme.spacing(2)};
    border-left: 4px solid ${theme.colors.primary.main};
  `,
  savedText: css`
    font-size: ${theme.typography.h4.fontSize};
    font-weight: ${theme.typography.fontWeightMedium};
    color: ${theme.colors.primary.text};
    margin: 0;
  `,
  noMessage: css`
    background: ${theme.colors.warning.transparent};
    padding: ${theme.spacing(2)};
    border-radius: ${theme.shape.borderRadius()};
    margin-bottom: ${theme.spacing(2)};
    border-left: 4px solid ${theme.colors.warning.main};
  `,
  form: css`
    background: ${theme.colors.background.secondary};
    padding: ${theme.spacing(2)};
    border-radius: ${theme.shape.borderRadius()};
    margin-bottom: ${theme.spacing(2)};
  `,
  input: css`
    margin-bottom: ${theme.spacing(2)};
    width: 100%;
    max-width: 400px;
  `,
  button: css`
    margin-top: ${theme.spacing(1)};
  `,
  alert: css`
    margin-top: ${theme.spacing(2)};
    margin-bottom: ${theme.spacing(2)};
  `,
});