'use client';

import * as React from 'react';
import useEmblaCarousel, { type UseEmblaCarouselType } from 'embla-carousel-react';
import { ArrowLeft, ArrowRight } from 'lucide-react';

import { cn } from '../../shared/utils';
import { Button } from '../button';

type CarouselApi = UseEmblaCarouselType[1];
type UseCarouselParameters = Parameters<typeof useEmblaCarousel>;
type CarouselOptions = UseCarouselParameters[0];
type CarouselPlugin = UseCarouselParameters[1];

type CarouselProps = {
  opts?: CarouselOptions;
  plugins?: CarouselPlugin;
  orientation?: 'horizontal' | 'vertical';
  setApi?: (api: CarouselApi) => void;
};

type CarouselContextProps = {
  carouselRef: ReturnType<typeof useEmblaCarousel>[0];
  api: ReturnType<typeof useEmblaCarousel>[1];
  scrollPrev: () => void;
  scrollNext: () => void;
  canScrollPrev: boolean;
  canScrollNext: boolean;
} & CarouselProps;

const orientationToEmblaAxis: Record<'horizontal' | 'vertical', 'x' | 'y'> = {
  horizontal: 'x',
  vertical: 'y',
};

const emblaAxisToOrientation: Record<'x' | 'y', 'horizontal' | 'vertical'> = {
  x: 'horizontal',
  y: 'vertical',
};

const carouselContentClasses: Record<'horizontal' | 'vertical', string> = {
  horizontal: '-ml-4',
  vertical: '-mt-4 flex-col',
};

const carouselItemClasses: Record<'horizontal' | 'vertical', string> = {
  horizontal: 'pl-4',
  vertical: 'pt-4',
};

const carouselPreviousPositionClasses: Record<'horizontal' | 'vertical', string> = {
  horizontal: 'top-1/2 -left-12 -translate-y-1/2',
  vertical: '-top-12 left-1/2 -translate-x-1/2 rotate-90',
};

const carouselNextPositionClasses: Record<'horizontal' | 'vertical', string> = {
  horizontal: 'top-1/2 -right-12 -translate-y-1/2',
  vertical: '-bottom-12 left-1/2 -translate-x-1/2 rotate-90',
};

const CarouselContext = React.createContext<CarouselContextProps | null>(null);

function useCarousel() {
  const context = React.useContext(CarouselContext);

  if (!context) {
    throw new Error('useCarousel must be used within a <Carousel />');
  }

  return context;
}

/**
 * Smooth horizontal (or vertical) content slider powered by Embla Carousel.
 *
 * @description
 * Built on embla-carousel. Slide sizing is controlled via Tailwind flex-basis
 * utilities on `<CarouselItem>` (e.g., `basis-1/3` for 3-up layouts).
 *
 * @ai-rules
 * 1. Always include `<CarouselPrevious>` and `<CarouselNext>` for interactive navigation controls.
 * 2. NEVER put infinite data tables inside a Carousel — use `<ScrollArea>` for scrollable lists.
 * 3. Each slide must be wrapped in `<CarouselItem>`.
 */
function Carousel({
  orientation = 'horizontal',
  opts,
  setApi,
  plugins,
  className,
  children,
  ...props
}: React.ComponentProps<'div'> & CarouselProps) {
  const [carouselRef, api] = useEmblaCarousel(
    {
      ...opts,
      axis: orientationToEmblaAxis[orientation],
    },
    plugins
  );
  const [canScrollPrev, setCanScrollPrev] = React.useState(false);
  const [canScrollNext, setCanScrollNext] = React.useState(false);

  const onSelect = React.useCallback((api: CarouselApi) => {
    if (!api) return;
    setCanScrollPrev(api.canScrollPrev());
    setCanScrollNext(api.canScrollNext());
  }, []);

  const scrollPrev = React.useCallback(() => {
    api?.scrollPrev();
  }, [api]);

  const scrollNext = React.useCallback(() => {
    api?.scrollNext();
  }, [api]);

  const handleKeyDown = React.useCallback(
    (event: React.KeyboardEvent<HTMLDivElement>) => {
      if (event.key === 'ArrowLeft') {
        event.preventDefault();
        scrollPrev();
      } else if (event.key === 'ArrowRight') {
        event.preventDefault();
        scrollNext();
      }
    },
    [scrollPrev, scrollNext]
  );

  React.useEffect(() => {
    if (!api || !setApi) return;
    setApi(api);
  }, [api, setApi]);

  React.useEffect(() => {
    if (!api) return;
    onSelect(api);
    api.on('reInit', onSelect);
    api.on('select', onSelect);

    return () => {
      api?.off('select', onSelect);
    };
  }, [api, onSelect]);

  return (
    <CarouselContext.Provider
      value={{
        carouselRef,
        api: api,
        opts,
        orientation: orientation || emblaAxisToOrientation[opts?.axis ?? 'x'],
        scrollPrev,
        scrollNext,
        canScrollPrev,
        canScrollNext,
      }}
    >
      <div
        onKeyDownCapture={handleKeyDown}
        className={cn('relative', className)}
        role="region"
        aria-roledescription="carousel"
        data-slot="carousel"
        {...props}
      >
        {children}
      </div>
    </CarouselContext.Provider>
  );
}

function CarouselContent({ className, ...props }: React.ComponentProps<'div'>) {
  const { carouselRef, orientation = 'horizontal' } = useCarousel();

  return (
    <div ref={carouselRef} className="overflow-hidden" data-slot="carousel-content">
      <div
        className={cn('flex', carouselContentClasses[orientation], className)}
        {...props}
      />
    </div>
  );
}

function CarouselItem({ className, ...props }: React.ComponentProps<'div'>) {
  const { orientation = 'horizontal' } = useCarousel();

  return (
    <div
      role="group"
      aria-roledescription="slide"
      data-slot="carousel-item"
      className={cn('min-w-0 shrink-0 grow-0 basis-full', carouselItemClasses[orientation], className)}
      {...props}
    />
  );
}

interface CarouselPreviousProps extends React.ComponentProps<typeof Button> {
  /** Screen-reader label for the previous-slide button. @default "Previous slide" */
  previousLabel?: string;
}

function CarouselPrevious({
  className,
  variant = 'outline',
  size = 'icon',
  previousLabel = 'Previous slide',
  ...props
}: CarouselPreviousProps) {
  const { orientation = 'horizontal', scrollPrev, canScrollPrev } = useCarousel();

  return (
    <Button
      data-slot="carousel-previous"
      variant={variant}
      size={size}
      className={cn(
        'absolute size-8 rounded-full',
        carouselPreviousPositionClasses[orientation],
        className
      )}
      disabled={!canScrollPrev}
      onClick={scrollPrev}
      {...props}
    >
      <ArrowLeft />
      <span className="sr-only">{previousLabel}</span>
    </Button>
  );
}

interface CarouselNextProps extends React.ComponentProps<typeof Button> {
  /** Screen-reader label for the next-slide button. @default "Next slide" */
  nextLabel?: string;
}

function CarouselNext({
  className,
  variant = 'outline',
  size = 'icon',
  nextLabel = 'Next slide',
  ...props
}: CarouselNextProps) {
  const { orientation = 'horizontal', scrollNext, canScrollNext } = useCarousel();

  return (
    <Button
      data-slot="carousel-next"
      variant={variant}
      size={size}
      className={cn(
        'absolute size-8 rounded-full',
        carouselNextPositionClasses[orientation],
        className
      )}
      disabled={!canScrollNext}
      onClick={scrollNext}
      {...props}
    >
      <ArrowRight />
      <span className="sr-only">{nextLabel}</span>
    </Button>
  );
}

export {
  type CarouselApi,
  Carousel,
  CarouselContent,
  CarouselItem,
  CarouselPrevious,
  CarouselNext,
};