import {
  Alert,
  Box,
  Button,
  Card,
  Chip,
  Stack,
  Table,
  TableCell,
  TableHead,
  TableRow,
  Typography,
} from '@mui/material'
import { useNavigate } from 'react-router'
import { useCompareStore } from '../../stores/compareStore'
import {
  CompareEmptyState,
  CompareColumnHeader,
  AICompareSummary,
  CompareCriteriaCard,
  CompareTableBody,
} from '../../components/compare'
import { AddToPipelineDialog } from '../../components/shortlist'
import {
  LABEL_SX,
  DATA_SX,
} from '../../components/compare/compareUtils'
import { useCompareData } from '../../hooks/useCompareData'

// ── Main component ────────────────────────────────────────────────────────────

export default function Compare() {
  const navigate = useNavigate()
  const { compareItems, removeFromCompare, clearCompare } = useCompareStore()

  const {
    aiSummary,
    aiLoading,
    activeNeed,
    relevantCriteria,
    overallWinnerIdx,
    bestScoreIdx,
    worstConfIdx,
    worstDQIdx,
    missingCriticalCounts,
    maxMissingCritical,
  } = useCompareData(compareItems)

  if (compareItems.length === 0) {
    return (
      <Box>
        <Box sx={{ bgcolor: 'white', borderBottom: '1px solid #e8e7e4', px: 3, py: 2.5 }}>
          <Typography sx={{ fontWeight: 700, fontSize: '1.125rem', lineHeight: 1.3, color: '#0f172a' }}>Vergleich</Typography>
        </Box>
        <CompareEmptyState />
      </Box>
    )
  }

  return (
    <Box>
      <AddToPipelineDialog />

      {/* Page header */}
      <Box sx={{ bgcolor: 'white', borderBottom: '1px solid #e8e7e4', px: 3, py: 2.5, display: 'flex', alignItems: 'center', justifyContent: 'space-between' }}>
        <Box sx={{ display: 'flex', alignItems: 'center', gap: 2 }}>
          <Typography sx={{ fontWeight: 700, fontSize: '1.125rem', lineHeight: 1.3, color: '#0f172a' }}>Vergleich</Typography>
          <Chip label={`${compareItems.length} Ergebnisse`} size="small" />
        </Box>
        <Button variant="outlined" size="small" color="error" onClick={clearCompare}>
          Vergleich leeren
        </Button>
      </Box>

      {/* Mobile notice */}
      <Box sx={{ display: { xs: 'block', md: 'none' }, p: 3 }}>
        <Alert severity="info">
          Die Vergleichsansicht ist für Desktop optimiert. Für beste Erfahrung auf einem grösseren Bildschirm öffnen.
        </Alert>
      </Box>

      {/* Desktop table */}
      <Box sx={{ display: { xs: 'none', md: 'block' }, px: 3, py: 3, pb: 10 }}>

        {/* AI Summary */}
        <AICompareSummary summary={aiSummary} isLoading={aiLoading && compareItems.length >= 2} />

        {/* Criteria Head-to-Head */}
        {activeNeed && relevantCriteria.length > 0 && (
          <CompareCriteriaCard
            compareItems={compareItems}
            relevantCriteria={relevantCriteria}
            overallWinnerIdx={overallWinnerIdx}
            activeNeed={activeNeed}
          />
        )}

        <Card sx={{ overflowX: 'auto' }}>
          <Table sx={{ tableLayout: 'auto' }}>

            {/* Column headers */}
            <TableHead>
              <TableRow sx={{ bgcolor: '#f8fafc' }}>
                <TableCell sx={{ ...LABEL_SX, bgcolor: '#f8fafc', zIndex: 2, fontSize: 11, color: '#64748b', fontWeight: 600 }}>
                  Kriterium
                </TableCell>
                {compareItems.map(item => (
                  <TableCell key={item.matchId} sx={{ ...DATA_SX, bgcolor: '#f8fafc', verticalAlign: 'top' }}>
                    <CompareColumnHeader item={item} onRemove={() => removeFromCompare(item.matchId)} />
                  </TableCell>
                ))}
              </TableRow>
            </TableHead>

            <CompareTableBody
              compareItems={compareItems}
              bestScoreIdx={bestScoreIdx}
              worstConfIdx={worstConfIdx}
              worstDQIdx={worstDQIdx}
              missingCriticalCounts={missingCriticalCounts}
              maxMissingCritical={maxMissingCritical}
            />

          </Table>
        </Card>

        {/* Add more prompt */}
        {compareItems.length < 4 && (
          <Card sx={{ p: 2.5, mt: 2, border: '2px dashed #e2e8f0', boxShadow: 'none' }}>
            <Stack direction="row" sx={{ alignItems: 'center', justifyContent: 'space-between' }}>
              <Box>
                <Typography variant="subtitle2" sx={{ fontWeight: 600 }}>Weiteres Ergebnis hinzufügen</Typography>
                <Typography variant="caption" color="text.secondary">
                  Bis zu {4 - compareItems.length} weitere{4 - compareItems.length === 1 ? 's' : ''} Ergebnis{4 - compareItems.length === 1 ? '' : 'se'} möglich
                </Typography>
              </Box>
              <Button variant="outlined" size="small" onClick={() => navigate('/demand/results')}>
                Zur Suche
              </Button>
            </Stack>
          </Card>
        )}
      </Box>
    </Box>
  )
}