import type {EmblaCarouselSvelteType} from 'embla-carousel-svelte';
import type emblaCarouselSvelte from 'embla-carousel-svelte';
import {getContext, hasContext, setContext} from 'svelte';
import type {WithElementRef} from 'bits-ui';
import type {HTMLAttributes} from 'svelte/elements';

export type CarouselAPI =
    NonNullable<NonNullable<EmblaCarouselSvelteType['$$_attributes']>['on:emblaInit']> extends (
            evt: CustomEvent<infer CarouselAPI>
        ) => void
        ? CarouselAPI
        : never;

type EmblaCarouselConfig = NonNullable<Parameters<typeof emblaCarouselSvelte>[1]>;

export type CarouselOptions = EmblaCarouselConfig['options'];
export type CarouselPlugins = EmblaCarouselConfig['plugins'];

////

export type CarouselProps = {
    opts?: CarouselOptions;
    plugins?: CarouselPlugins;
    setApi?: (api: CarouselAPI | undefined) => void;
    orientation?: 'horizontal' | 'vertical';
} & WithElementRef<HTMLAttributes<HTMLDivElement>>;

const EMBLA_CAROUSEL_CONTEXT = Symbol('EMBLA_CAROUSEL_CONTEXT');

export type EmblaContext = {
    api: CarouselAPI | undefined;
    orientation: 'horizontal' | 'vertical';
    scrollNext: () => void;
    scrollPrev: () => void;
    canScrollNext: boolean;
    canScrollPrev: boolean;
    handleKeyDown: (e: KeyboardEvent) => void;
    options: CarouselOptions;
    plugins: CarouselPlugins;
    onInit: (e: CustomEvent<CarouselAPI>) => void;
    scrollTo: (index: number, jump?: boolean) => void;
    scrollSnaps: number[];
    selectedIndex: number;
};

export function setEmblaContext(config: EmblaContext): EmblaContext {
    setContext(EMBLA_CAROUSEL_CONTEXT, config);
    return config;
}

export function getEmblaContext(name = 'This component') {
    if (!hasContext(EMBLA_CAROUSEL_CONTEXT)) {
        throw new Error(`${name} must be used within a <Carousel.Root> component`);
    }
    return getContext<ReturnType<typeof setEmblaContext>>(EMBLA_CAROUSEL_CONTEXT);
}