import React from 'react';
import Box from '@mui/material/Box';
import Container from '@mui/material/Container';
import ArrowBackIcon from '@mui/icons-material/ArrowBack';
import PhoneIcon from '@mui/icons-material/Phone';
import type { SxProps, Theme } from '@mui/material/styles';
import { Link } from '../../atoms/Link';
import { Typography } from '../../atoms/Typography';

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

/** Layout variant matching the wizard page templates */
export type WizardLayoutVariant =
  | 'centered-form'
  | 'wide-form'
  | 'list-map'
  | 'list-detail'
  | 'grid-sidebar'
  | 'detail-toggles';

/** Props for the WizardLayout template */
export interface WizardLayoutProps {
  /** Which layout variant to render */
  variant: WizardLayoutVariant;
  /** Navigation bar — rendered at the top of the page */
  navigation?: React.ReactNode;
  /** Optional progress stepper — shown below nav on grid-sidebar and detail-toggles variants */
  progressStepper?: React.ReactNode;
  /** Optional running total widget — shown in a bar below nav (grid-sidebar, detail-toggles) */
  runningTotal?: React.ReactNode;
  /** Show a back link above the content area */
  showBackLink?: boolean;
  /** Label for the back link */
  backLabel?: string;
  /** Click handler for the back link */
  onBack?: () => void;
  /** Help bar phone number */
  helpPhone?: string;
  /** Hide the sticky help bar */
  hideHelpBar?: boolean;

  // ─── Slot content ───

  /** Main content — for centered-form this is the form; for split layouts this is the primary (left) panel */
  children: React.ReactNode;
  /** Secondary panel content — right panel for split layouts (map, detail, grid) */
  secondaryPanel?: React.ReactNode;

  /** MUI sx prop for the root container */
  sx?: SxProps<Theme>;
}

// ─── Help bar ────────────────────────────────────────────────────────────────

const HelpBar: React.FC<{ phone: string }> = ({ phone }) => (
  <Box
    component="footer"
    sx={{
      position: 'sticky',
      bottom: 0,
      zIndex: 10,
      bgcolor: 'background.paper',
      borderTop: '1px solid',
      borderColor: 'divider',
      py: 1.5,
      px: { xs: 2, md: 4 },
      textAlign: 'center',
    }}
  >
    <Typography variant="body2" color="text.secondary" component="span">
      <PhoneIcon sx={{ fontSize: 16, verticalAlign: 'text-bottom', mr: 0.5 }} />
      Need help? Call us on{' '}
      <Link href={`tel:${phone.replace(/\s/g, '')}`} sx={{ fontWeight: 600 }}>
        {phone}
      </Link>
    </Typography>
  </Box>
);

// ─── Back link ───────────────────────────────────────────────────────────────

const BackLink: React.FC<{ label: string; onClick?: () => void }> = ({ label, onClick }) => (
  <Link
    component="button"
    onClick={onClick}
    underline="hover"
    sx={{
      display: 'inline-flex',
      alignItems: 'center',
      gap: 0.5,
      color: 'text.secondary',
      fontSize: '0.875rem',
      fontWeight: 500,
      mb: 2,
      '&:hover': { color: 'text.primary' },
    }}
  >
    <ArrowBackIcon sx={{ fontSize: 18 }} />
    {label}
  </Link>
);

// ─── Stepper + total bar ─────────────────────────────────────────────────────

const StepperBar: React.FC<{
  stepper?: React.ReactNode;
  total?: React.ReactNode;
}> = ({ stepper, total }) => {
  if (!stepper && !total) return null;
  return (
    <Box
      sx={{
        borderBottom: '1px solid',
        borderColor: 'divider',
        bgcolor: 'background.paper',
        px: { xs: 2, md: 4 },
        py: 1.5,
        display: 'flex',
        alignItems: 'center',
        gap: 3,
      }}
    >
      <Box sx={{ flex: 1, maxWidth: 700, mx: 'auto' }}>{stepper}</Box>
      {total && <Box sx={{ flexShrink: 0 }}>{total}</Box>}
    </Box>
  );
};

// ─── Layout variants ─────────────────────────────────────────────────────────

/** Centered Form: single column ~600px, heading + fields + CTA */
const CenteredFormLayout: React.FC<{ children: React.ReactNode }> = ({ children }) => (
  <Container
    maxWidth="sm"
    sx={{
      py: { xs: 6, md: 10 },
      px: { xs: 4, md: 3 },
      flex: 1,
    }}
  >
    {children}
  </Container>
);

/** Wide Form: single column maxWidth "lg", for card grids (coffins, etc.) */
const WideFormLayout: React.FC<{ children: React.ReactNode }> = ({ children }) => (
  <Container
    maxWidth="lg"
    sx={{
      py: { xs: 4, md: 6 },
      px: { xs: 2, md: 3 },
      flex: 1,
    }}
  >
    {children}
  </Container>
);

/** List + Map: 420px fixed scrollable list (left) / flex map (right) — D-B */
const ListMapLayout: React.FC<{
  children: React.ReactNode;
  secondaryPanel?: React.ReactNode;
  backLink?: React.ReactNode;
}> = ({ children, secondaryPanel, backLink }) => (
  <Box
    sx={{
      display: 'flex',
      flex: 1,
      overflow: 'hidden',
    }}
  >
    {/* Left panel — scrollable list with scrollbar visible on hover */}
    <Box
      sx={{
        width: { xs: '100%', md: 420 },
        flexShrink: 0,
        overflowY: 'auto',
        px: { xs: 2, md: 3 },
        pt: 0,
        pb: 3,
        // Thin scrollbar, hidden until hover
        scrollbarWidth: 'thin',
        scrollbarColor: 'transparent transparent',
        '&:hover': {
          scrollbarColor: 'rgba(0,0,0,0.25) transparent',
        },
        '&::-webkit-scrollbar': { width: 6 },
        '&::-webkit-scrollbar-thumb': {
          background: 'transparent',
          borderRadius: 3,
        },
        '&:hover::-webkit-scrollbar-thumb': {
          background: 'rgba(0,0,0,0.25)',
        },
      }}
    >
      {backLink}
      {children}
    </Box>
    {/* Right panel — map or placeholder, fills available space */}
    <Box
      sx={{
        display: { xs: 'none', md: 'flex' },
        flex: 1,
        minHeight: 0,
      }}
    >
      {secondaryPanel}
    </Box>
  </Box>
);

/** List + Detail: ~40% selection list (left) / ~60% detail panel (right) */
const ListDetailLayout: React.FC<{
  children: React.ReactNode;
  secondaryPanel?: React.ReactNode;
}> = ({ children, secondaryPanel }) => (
  <Container maxWidth="lg" sx={{ flex: 1, py: 3 }}>
    <Box
      sx={{
        display: 'flex',
        gap: { xs: 0, md: 4 },
        flexDirection: { xs: 'column', md: 'row' },
      }}
    >
      <Box sx={{ width: { xs: '100%', md: '40%' } }}>{children}</Box>
      <Box sx={{ width: { xs: '100%', md: '60%' } }}>{secondaryPanel}</Box>
    </Box>
  </Container>
);

/** Grid + Sidebar: ~25% filter sidebar (left) / ~75% card grid (right).
 *  Viewport-locked on desktop — both panels scroll independently.
 *  On mobile, stacks vertically and scrolls as a single page. */
const GridSidebarLayout: React.FC<{
  children: React.ReactNode;
  secondaryPanel?: React.ReactNode;
}> = ({ children, secondaryPanel }) => (
  <Box
    sx={{
      display: 'flex',
      flex: 1,
      overflow: { md: 'hidden' },
      flexDirection: { xs: 'column', md: 'row' },
      maxWidth: 1200,
      mx: 'auto',
      width: '100%',
    }}
  >
    {/* Left sidebar — scrollbar visible on hover */}
    <Box
      component="aside"
      sx={{
        width: { xs: '100%', md: '28%' },
        flexShrink: 0,
        overflowY: 'auto',
        overflowX: 'hidden',
        px: { xs: 2, md: 3 },
        py: 3,
        scrollbarWidth: 'thin',
        scrollbarColor: 'transparent transparent',
        '&:hover': {
          scrollbarColor: 'rgba(0,0,0,0.25) transparent',
        },
        '&::-webkit-scrollbar': { width: 6 },
        '&::-webkit-scrollbar-thumb': {
          background: 'transparent',
          borderRadius: 3,
        },
        '&:hover::-webkit-scrollbar-thumb': {
          background: 'rgba(0,0,0,0.25)',
        },
      }}
    >
      {children}
    </Box>
    {/* Right panel — always scrollable */}
    <Box
      sx={{
        flex: 1,
        overflowY: { md: 'auto' },
        px: { xs: 2, md: 3 },
        py: 3,
        scrollbarWidth: 'thin',
      }}
    >
      {secondaryPanel}
    </Box>
  </Box>
);

/** Detail + Toggles: scrollable left (image/desc) / sticky right (info/CTA) */
const DetailTogglesLayout: React.FC<{
  children: React.ReactNode;
  secondaryPanel?: React.ReactNode;
  backLink?: React.ReactNode;
}> = ({ children, secondaryPanel, backLink }) => (
  <Box
    sx={{
      display: 'flex',
      flex: 1,
      overflow: 'hidden',
      maxWidth: 1200,
      mx: 'auto',
      width: '100%',
    }}
  >
    {/* Left panel — scrollable content */}
    <Box
      sx={{
        width: { xs: '100%', md: '58%' },
        flexShrink: 0,
        overflowY: 'auto',
        px: { xs: 2, md: 5 },
        pt: 0,
        pb: 3,
        scrollbarWidth: 'thin',
        scrollbarColor: 'transparent transparent',
        '&:hover': {
          scrollbarColor: 'rgba(0,0,0,0.25) transparent',
        },
        '&::-webkit-scrollbar': { width: 6 },
        '&::-webkit-scrollbar-thumb': {
          background: 'transparent',
          borderRadius: 3,
        },
        '&:hover::-webkit-scrollbar-thumb': {
          background: 'rgba(0,0,0,0.25)',
        },
      }}
    >
      {backLink && <Box sx={{ pt: 1.5 }}>{backLink}</Box>}
      {children}
    </Box>
    {/* Right panel — sticky info */}
    <Box
      sx={{
        display: { xs: 'none', md: 'block' },
        width: { md: '42%' },
        overflowY: 'auto',
        px: 5,
        py: 3,
        borderLeft: '1px solid',
        borderColor: 'divider',
        scrollbarWidth: 'thin',
        scrollbarColor: 'transparent transparent',
        '&:hover': {
          scrollbarColor: 'rgba(0,0,0,0.25) transparent',
        },
        '&::-webkit-scrollbar': { width: 6 },
        '&::-webkit-scrollbar-thumb': {
          background: 'transparent',
          borderRadius: 3,
        },
        '&:hover::-webkit-scrollbar-thumb': {
          background: 'rgba(0,0,0,0.25)',
        },
      }}
    >
      {secondaryPanel}
    </Box>
  </Box>
);

// ─── Variant map ─────────────────────────────────────────────────────────────

const LAYOUT_MAP: Record<
  WizardLayoutVariant,
  React.FC<{
    children: React.ReactNode;
    secondaryPanel?: React.ReactNode;
    backLink?: React.ReactNode;
  }>
> = {
  'centered-form': CenteredFormLayout,
  'wide-form': WideFormLayout,
  'list-map': ListMapLayout,
  'list-detail': ListDetailLayout,
  'grid-sidebar': GridSidebarLayout,
  'detail-toggles': DetailTogglesLayout,
};

/* Stepper bar renders on any variant when progressStepper or runningTotal is provided */

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

/**
 * Page-level layout template for the FA arrangement wizard.
 *
 * Provides 5 layout variants matching the wizard page templates:
 * - **centered-form**: Single centered column for form steps (intro, auth, date/time, etc.)
 * - **list-map**: Split view with scrollable card list and map panel (providers)
 * - **list-detail**: Master-detail split for selection + detail (packages, preview)
 * - **grid-sidebar**: Filter sidebar + card grid (coffins)
 * - **detail-toggles**: Hero image + info column (venue, coffin details)
 *
 * All variants share: navigation slot, optional back link, sticky help bar,
 * and optional progress stepper + running total bar (shown when props provided).
 */
export const WizardLayout = React.forwardRef<HTMLDivElement, WizardLayoutProps>(
  (
    {
      variant,
      navigation,
      progressStepper,
      runningTotal,
      showBackLink = false,
      backLabel = 'Back',
      onBack,
      helpPhone = '1800 987 888',
      hideHelpBar = false,
      children,
      secondaryPanel,
      sx,
    },
    ref,
  ) => {
    const LayoutComponent = LAYOUT_MAP[variant];

    return (
      <Box
        ref={ref}
        sx={[
          {
            display: 'flex',
            flexDirection: 'column',
            minHeight: '100vh',
            bgcolor: 'background.default',
            // list-map + detail-toggles: lock to viewport so panels scroll independently
            ...((variant === 'list-map' || variant === 'detail-toggles') && {
              height: '100vh',
              overflow: 'hidden',
            }),
            ...(variant === 'grid-sidebar' && {
              height: { xs: 'auto', md: '100vh' },
              overflow: { xs: 'visible', md: 'hidden' },
            }),
          },
          ...(Array.isArray(sx) ? sx : [sx]),
        ]}
      >
        {/* Navigation */}
        {navigation}

        {/* Stepper + running total bar (grid-sidebar, detail-toggles only) */}
        <StepperBar stepper={progressStepper} total={runningTotal} />

        {/* Back link — inside left panel for list-map/detail-toggles, above content for others */}
        {showBackLink && variant !== 'list-map' && variant !== 'detail-toggles' && (
          <Container
            maxWidth={variant === 'centered-form' ? 'sm' : 'lg'}
            sx={{ pt: 2, px: { xs: 4, md: 3 } }}
          >
            <BackLink label={backLabel} onClick={onBack} />
          </Container>
        )}

        {/* Main content area */}
        <Box
          component="main"
          sx={{ display: 'flex', flexDirection: 'column', flex: 1, minHeight: 0 }}
        >
          <LayoutComponent
            secondaryPanel={secondaryPanel}
            backLink={
              showBackLink && (variant === 'list-map' || variant === 'detail-toggles') ? (
                <Box sx={{ pt: 1.5 }}>
                  <BackLink label={backLabel} onClick={onBack} />
                </Box>
              ) : undefined
            }
          >
            {children}
          </LayoutComponent>
        </Box>

        {/* Sticky help bar */}
        {!hideHelpBar && <HelpBar phone={helpPhone} />}
      </Box>
    );
  },
);

WizardLayout.displayName = 'WizardLayout';
export default WizardLayout;
