frontend/src/components/ExampleDataPanel.jsx

import React, { useState, useEffect } from 'react'
import {
  Text,
  Stack,
  Box,
  UnstyledButton,
  Loader,
  Group,
} from '@mantine/core'
import { IconDatabase, IconFlask } from '@tabler/icons-react'
import { useXRD } from '../context/XRDContext'

const ExampleDataPanel = ({ onSelect }) => {
  const { loadExampleFile } = useXRD()
  const [examples, setExamples] = useState([])
  const [loading, setLoading] = useState(true)
  const [loadingFile, setLoadingFile] = useState(null)

  useEffect(() => {
    const fetchExamples = async () => {
      try {
        const response = await fetch('/api/examples')
        if (response.ok) {
          const data = await response.json()
          setExamples(data)
        }
      } catch (err) {
        console.error('Failed to fetch examples:', err)
      } finally {
        setLoading(false)
      }
    }
    fetchExamples()
  }, [])

  const handleSelect = async (filename) => {
    setLoadingFile(filename)
    const success = await loadExampleFile(filename)
    setLoadingFile(null)
    if (success && onSelect) onSelect()
  }

  if (loading) {
    return (
      <Box p="md" style={{ textAlign: 'center' }}>
        <Loader size="sm" />
      </Box>
    )
  }

  if (examples.length === 0) return null

  return (
    <Box>
      <Group gap="xs" mb="xs">
        <IconDatabase size={16} color="#868e96" />
        <Text size="sm" fw={600} c="dimmed">
          Example Data
        </Text>
      </Group>

      <Stack gap={8}>
        {examples.map((ex) => (
          <UnstyledButton
            key={ex.filename}
            onClick={() => handleSelect(ex.filename)}
            disabled={loadingFile !== null}
            style={{
              padding: '10px 12px',
              borderRadius: '8px',
              border: '1px solid #dee2e6',
              backgroundColor: loadingFile === ex.filename ? '#f1f3f5' : '#fff',
              cursor: loadingFile !== null ? 'wait' : 'pointer',
              transition: 'background-color 150ms ease',
            }}
            onMouseEnter={(e) => {
              if (!loadingFile) e.currentTarget.style.backgroundColor = '#f8f9fa'
            }}
            onMouseLeave={(e) => {
              if (loadingFile !== ex.filename) e.currentTarget.style.backgroundColor = '#fff'
            }}
          >
            <Group justify="space-between" align="center" wrap="nowrap">
              <Group gap={6}>
                <IconFlask size={14} color="#7950f2" />
                <Text size="sm" fw={500} truncate>
                  {ex.material_id || ex.filename}
                </Text>
              </Group>
              {loadingFile === ex.filename && <Loader size={16} />}
            </Group>
          </UnstyledButton>
        ))}
      </Stack>
    </Box>
  )
}

export default ExampleDataPanel