import React, { useId, useState } from 'react';
import Box from '@mui/material/Box';
import useMediaQuery from '@mui/material/useMediaQuery';
import { useTheme } from '@mui/material/styles';
import Tooltip from '@mui/material/Tooltip';
import InfoOutlinedIcon from '@mui/icons-material/InfoOutlined';
import CheckCircleOutlineIcon from '@mui/icons-material/CheckCircleOutline';
import LocationOnOutlinedIcon from '@mui/icons-material/LocationOnOutlined';
import StarRoundedIcon from '@mui/icons-material/StarRounded';
import VerifiedOutlinedIcon from '@mui/icons-material/VerifiedOutlined';
import ShareOutlinedIcon from '@mui/icons-material/ShareOutlined';
import PrintOutlinedIcon from '@mui/icons-material/PrintOutlined';
import type { SxProps, Theme } from '@mui/material/styles';
import { Typography } from '../../atoms/Typography';
import { Button } from '../../atoms/Button';
import { Badge } from '../../atoms/Badge';
import { Divider } from '../../atoms/Divider';
import { Card } from '../../atoms/Card';
import { WizardLayout } from '../../templates/WizardLayout';
import {
  ComparisonTable,
  type ComparisonPackage,
  type ComparisonCellValue,
} from '../../organisms/ComparisonTable';

// ─── Types ───────────────────────────────────────────────────────────────────

/** Props for the ComparisonPage */
export interface ComparisonPageProps {
  /** User-selected packages to compare (max 3) */
  packages: ComparisonPackage[];
  /** System-recommended package — always shown as an additional column */
  recommendedPackage?: ComparisonPackage;
  /** Called when user clicks CTA on a package */
  onArrange: (packageId: string) => void;
  /** Called when user removes a package from comparison */
  onRemove: (packageId: string) => void;
  /** Called when user clicks Back */
  onBack: () => void;
  /** Called when user clicks Share */
  onShare?: () => void;
  /** Called when user clicks Print */
  onPrint?: () => void;
  /** Navigation bar slot */
  navigation?: React.ReactNode;
  /** MUI sx prop */
  sx?: SxProps<Theme>;
}

// ─── Helpers ────────────────────────────────────────────────────────────────

function formatPrice(amount: number): string {
  return `$${amount.toLocaleString('en-AU', { minimumFractionDigits: amount % 1 !== 0 ? 2 : 0 })}`;
}

function MobileCellValue({ value }: { value: ComparisonCellValue }) {
  switch (value.type) {
    case 'price':
      return (
        <Typography variant="body2" sx={{ fontWeight: 600, textAlign: 'right' }}>
          {formatPrice(value.amount)}
        </Typography>
      );
    case 'allowance':
      return (
        <Typography variant="body2" sx={{ fontWeight: 600, textAlign: 'right' }}>
          {formatPrice(value.amount)}*
        </Typography>
      );
    case 'complimentary':
      return (
        <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.5, justifyContent: 'flex-end' }}>
          <CheckCircleOutlineIcon
            sx={{ fontSize: 16, color: 'var(--fa-color-feedback-success)' }}
            aria-hidden
          />
          <Typography variant="body2" sx={{ color: 'var(--fa-color-feedback-success)' }}>
            Complimentary
          </Typography>
        </Box>
      );
    case 'included':
      return (
        <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.5, justifyContent: 'flex-end' }}>
          <CheckCircleOutlineIcon
            sx={{ fontSize: 16, color: 'var(--fa-color-feedback-success)' }}
            aria-hidden
          />
          <Typography variant="body2" sx={{ color: 'var(--fa-color-feedback-success)' }}>
            Included
          </Typography>
        </Box>
      );
    case 'poa':
      return (
        <Typography
          variant="body2"
          color="text.secondary"
          sx={{ fontStyle: 'italic', textAlign: 'right' }}
        >
          Price On Application
        </Typography>
      );
    case 'unknown':
      return (
        <Badge color="default" variant="soft" size="small">
          Unknown
        </Badge>
      );
    case 'unavailable':
      return (
        <Typography
          variant="body2"
          sx={{ color: 'var(--fa-color-neutral-400)', textAlign: 'right' }}
        >
          —
        </Typography>
      );
  }
}

// ─── Mobile card view ───────────────────────────────────────────────────────

function MobilePackageCard({
  pkg,
  onArrange,
}: {
  pkg: ComparisonPackage;
  onArrange: (id: string) => void;
}) {
  return (
    <Card
      variant="outlined"
      selected={pkg.isRecommended}
      padding="none"
      sx={{ overflow: 'hidden' }}
    >
      {/* Recommended banner */}
      {pkg.isRecommended && (
        <Box sx={{ bgcolor: 'var(--fa-color-brand-600)', py: 0.75, textAlign: 'center' }}>
          <Typography
            variant="labelSm"
            sx={{
              color: 'var(--fa-color-white)',
              fontWeight: 600,
              letterSpacing: '0.05em',
              textTransform: 'uppercase',
            }}
          >
            Recommended
          </Typography>
        </Box>
      )}

      {/* Provider header */}
      <Box
        sx={{
          bgcolor: pkg.isRecommended
            ? 'var(--fa-color-surface-warm)'
            : 'var(--fa-color-surface-subtle)',
          px: 2.5,
          pt: 2.5,
          pb: 2,
        }}
      >
        {/* Verified badge */}
        {pkg.provider.verified && (
          <Badge
            color="brand"
            variant="soft"
            size="small"
            icon={<VerifiedOutlinedIcon sx={{ fontSize: 14 }} />}
            sx={{ mb: 1 }}
          >
            Verified
          </Badge>
        )}

        {/* Provider name */}
        <Typography variant="label" sx={{ fontWeight: 600, display: 'block', mb: 0.5 }}>
          {pkg.provider.name}
        </Typography>

        {/* Location + Rating */}
        <Box sx={{ display: 'flex', alignItems: 'center', gap: 1, mb: 1.5 }}>
          <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.25 }}>
            <LocationOnOutlinedIcon sx={{ fontSize: 14, color: 'text.secondary' }} aria-hidden />
            <Typography variant="caption" color="text.secondary">
              {pkg.provider.location}
            </Typography>
          </Box>
          {pkg.provider.rating != null && (
            <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.25 }}>
              <StarRoundedIcon
                sx={{ fontSize: 14, color: 'var(--fa-color-brand-500)' }}
                aria-hidden
              />
              <Typography variant="caption" color="text.secondary">
                {pkg.provider.rating}
                {pkg.provider.reviewCount != null && ` (${pkg.provider.reviewCount})`}
              </Typography>
            </Box>
          )}
        </Box>

        <Divider sx={{ mb: 1.5 }} />

        {/* Package name + price */}
        <Typography variant="h5" component="p">
          {pkg.name}
        </Typography>
        <Typography variant="caption" color="text.secondary">
          Total package price
        </Typography>
        <Typography variant="h3" sx={{ color: 'primary.main', fontWeight: 700 }}>
          {formatPrice(pkg.price)}
        </Typography>

        <Button
          variant={pkg.provider.verified ? 'contained' : 'soft'}
          color={pkg.provider.verified ? 'primary' : 'secondary'}
          size="large"
          fullWidth
          onClick={() => onArrange(pkg.id)}
          sx={{ mt: 2 }}
        >
          {pkg.provider.verified ? 'Make Arrangement' : 'Make Enquiry'}
        </Button>
      </Box>

      {/* Sections — with left accent borders on headings */}
      <Box sx={{ px: 2.5, py: 2.5 }}>
        {pkg.itemizedAvailable === false ? (
          <Box sx={{ textAlign: 'center', py: 3 }}>
            <Typography variant="body2" color="text.secondary" sx={{ fontStyle: 'italic' }}>
              Itemised pricing not available for this provider.
            </Typography>
          </Box>
        ) : (
          pkg.sections.map((section, sIdx) => (
            <Box key={section.heading} sx={{ mb: sIdx < pkg.sections.length - 1 ? 3 : 0 }}>
              {/* Section heading with left accent */}
              <Box
                sx={{
                  borderLeft: '3px solid',
                  borderLeftColor: 'var(--fa-color-brand-500)',
                  pl: 1.5,
                  mb: 1.5,
                  mt: sIdx > 0 ? 1 : 0,
                }}
              >
                <Typography variant="h6" component="h3">
                  {section.heading}
                </Typography>
              </Box>
              <Box sx={{ display: 'flex', flexDirection: 'column', gap: 0 }}>
                {section.items.map((item) => (
                  <Box
                    key={item.name}
                    sx={{
                      display: 'flex',
                      alignItems: 'center',
                      justifyContent: 'space-between',
                      gap: 2,
                      py: 1.5,
                      borderBottom: '1px solid',
                      borderColor: 'divider',
                    }}
                  >
                    <Box sx={{ minWidth: 0, flex: '1 1 50%', maxWidth: '60%' }}>
                      <Typography variant="body2" color="text.secondary" component="span">
                        {item.name}
                      </Typography>
                      {item.info && (
                        <Box component="span" sx={{ whiteSpace: 'nowrap' }}>
                          {'\u00A0'}
                          <Tooltip title={item.info} arrow placement="top">
                            <InfoOutlinedIcon
                              aria-label={`More information about ${item.name}`}
                              sx={{
                                fontSize: 14,
                                color: 'var(--fa-color-neutral-400)',
                                cursor: 'help',
                                verticalAlign: 'middle',
                              }}
                            />
                          </Tooltip>
                        </Box>
                      )}
                    </Box>
                    <MobileCellValue value={item.value} />
                  </Box>
                ))}
              </Box>
            </Box>
          ))
        )}
      </Box>
    </Card>
  );
}

// ─── Component ──────────────────────────────────────────────────────────────

/**
 * Package comparison page for the FA design system.
 *
 * Desktop: Full ComparisonTable with info card, floating verified badges,
 * section tables with left accent borders.
 * Mobile: Tabbed card view with horizontal chip rail.
 *
 * Share + Print utility actions in the page header.
 */
export const ComparisonPage = React.forwardRef<HTMLDivElement, ComparisonPageProps>(
  (
    { packages, recommendedPackage, onArrange, onRemove, onBack, onShare, onPrint, navigation, sx },
    ref,
  ) => {
    const theme = useTheme();
    const isMobile = useMediaQuery(theme.breakpoints.down('md'));
    const tablistId = useId();

    const allPackages = React.useMemo(() => {
      const result = [...packages];
      if (recommendedPackage) {
        result.push({ ...recommendedPackage, isRecommended: true });
      }
      return result;
    }, [packages, recommendedPackage]);

    const [activeTabIdx, setActiveTabIdx] = useState(0);
    const activePackage = allPackages[activeTabIdx] ?? allPackages[0];

    const providerCount = new Set(allPackages.map((p) => p.provider.name)).size;
    const subtitle =
      providerCount > 1
        ? `Comparing ${packages.length} package${packages.length !== 1 ? 's' : ''} from different providers`
        : `Comparing ${packages.length} package${packages.length !== 1 ? 's' : ''}`;

    return (
      <Box ref={ref} sx={sx}>
        <WizardLayout
          variant="wide-form"
          navigation={navigation}
          showBackLink
          backLabel="Back"
          onBack={onBack}
        >
          {/* Page header with Share/Print actions */}
          <Box sx={{ mb: { xs: 3, md: 5 } }}>
            <Box
              sx={{
                display: 'flex',
                alignItems: 'flex-start',
                justifyContent: 'space-between',
                gap: 2,
                flexWrap: 'wrap',
              }}
            >
              <Box>
                <Typography variant="h2" component="h1" sx={{ mb: 1 }}>
                  Compare packages
                </Typography>
                <Typography variant="body1" color="text.secondary" aria-live="polite">
                  {subtitle}
                </Typography>
              </Box>

              {/* Share + Print */}
              {(onShare || onPrint) && (
                <Box sx={{ display: 'flex', gap: 1, flexShrink: 0 }}>
                  {onShare && (
                    <Button
                      variant="outlined"
                      color="secondary"
                      size="small"
                      startIcon={<ShareOutlinedIcon />}
                      onClick={onShare}
                    >
                      Share
                    </Button>
                  )}
                  {onPrint && (
                    <Button
                      variant="outlined"
                      color="secondary"
                      size="small"
                      startIcon={<PrintOutlinedIcon />}
                      onClick={onPrint}
                    >
                      Print
                    </Button>
                  )}
                </Box>
              )}
            </Box>
          </Box>

          {/* Desktop: ComparisonTable */}
          {!isMobile && (
            <ComparisonTable packages={allPackages} onArrange={onArrange} onRemove={onRemove} />
          )}

          {/* Mobile: Tab rail + card view */}
          {isMobile && allPackages.length > 0 && (
            <>
              {/* Tab rail — mini cards showing provider + package name */}
              <Box
                role="tablist"
                id={tablistId}
                aria-label="Packages to compare"
                sx={{
                  display: 'flex',
                  gap: 1.5,
                  overflowX: 'auto',
                  pb: 1,
                  mb: 2.5,
                  scrollbarWidth: 'none',
                  '&::-webkit-scrollbar': { display: 'none' },
                  WebkitOverflowScrolling: 'touch',
                }}
              >
                {allPackages.map((pkg, idx) => {
                  const isActive = idx === activeTabIdx;
                  return (
                    <Card
                      key={pkg.id}
                      role="tab"
                      aria-selected={isActive}
                      aria-controls={`comparison-tabpanel-${idx}`}
                      id={`comparison-tab-${idx}`}
                      variant="outlined"
                      selected={isActive}
                      padding="none"
                      onClick={() => setActiveTabIdx(idx)}
                      interactive
                      sx={{
                        flexShrink: 0,
                        minWidth: 150,
                        maxWidth: 200,
                        cursor: 'pointer',
                        ...(pkg.isRecommended &&
                          !isActive && {
                            borderColor: 'var(--fa-color-brand-500)',
                          }),
                      }}
                    >
                      <Box sx={{ px: 2, py: 1.5 }}>
                        <Typography
                          variant="labelSm"
                          sx={{
                            fontWeight: 600,
                            display: 'block',
                            overflow: 'hidden',
                            textOverflow: 'ellipsis',
                            whiteSpace: 'nowrap',
                          }}
                        >
                          {pkg.isRecommended ? `★ ${pkg.provider.name}` : pkg.provider.name}
                        </Typography>
                        <Typography
                          variant="caption"
                          color="text.secondary"
                          sx={{
                            display: 'block',
                            overflow: 'hidden',
                            textOverflow: 'ellipsis',
                            whiteSpace: 'nowrap',
                          }}
                        >
                          {pkg.name}
                        </Typography>
                      </Box>
                    </Card>
                  );
                })}
              </Box>

              {activePackage && (
                <Box
                  role="tabpanel"
                  id={`comparison-tabpanel-${activeTabIdx}`}
                  aria-labelledby={`comparison-tab-${activeTabIdx}`}
                >
                  <MobilePackageCard pkg={activePackage} onArrange={onArrange} />
                </Box>
              )}
            </>
          )}
        </WizardLayout>
      </Box>
    );
  },
);

ComparisonPage.displayName = 'ComparisonPage';
export default ComparisonPage;