import { useVirtualizer } from '@tanstack/react-virtual';
import { DetailedHTMLProps, Fragment, HTMLAttributes, ReactElement, Ref, RefObject, useEffect, useRef, useState } from 'react';
import { classNames } from './classNames';
import { NitroLimitedEditionStyledNumberView } from './limited-edition';
import { styleNames } from './styleNames';

type Props<T> = {
    items: T[];
    columnCount: number;
    overscan?: number;
    estimateSize?: number;
    squareItems?: boolean;
    itemMinWidth?: number;
    rowGap?: number;
    itemRender?: (item: T, index?: number) => ReactElement;
}

const GRID_GAP_PX = 4;

const useColumnMeasure = (itemMinWidth: number | null, columnCountProp: number): { parentRef: RefObject<HTMLDivElement | null>; columnCount: number } =>
{
    const parentRef = useRef<HTMLDivElement>(null);
    const [ measuredColumnCount, setMeasuredColumnCount ] = useState<number>(columnCountProp);

    useEffect(() =>
    {
        if(!itemMinWidth || itemMinWidth <= 0) return;

        const element = parentRef.current;
        if(!element) return;

        const recompute = () =>
        {
            const width = element.clientWidth;
            const cols = Math.max(1, Math.floor((width + GRID_GAP_PX) / (itemMinWidth + GRID_GAP_PX)));
            setMeasuredColumnCount(prev => prev === cols ? prev : cols);
        };

        recompute();

        const observer = new ResizeObserver(recompute);
        observer.observe(element);

        return () => observer.disconnect();
    }, [ itemMinWidth ]);

    const columnCount = (itemMinWidth && itemMinWidth > 0) ? measuredColumnCount : columnCountProp;

    return { parentRef, columnCount };
};

const InfiniteGridSquare = <T,>(props: Props<T>) =>
{
    const { items = [], columnCount: columnCountProp = 4, itemMinWidth = null, itemRender = null } = props;
    const { parentRef } = useColumnMeasure(itemMinWidth, columnCountProp);

    const autoFillStyle = (itemMinWidth && itemMinWidth > 0)
        ? { gridTemplateColumns: `repeat(auto-fill, ${ itemMinWidth }px)` }
        : null;
    const fixedColsClass = (itemMinWidth && itemMinWidth > 0) ? '' : `grid-cols-${ columnCountProp }`;

    return (
        <div ref={ parentRef } className="overflow-y-auto size-full">
            <div className={ `grid ${ fixedColsClass } gap-1 w-full` } style={ autoFillStyle ?? undefined }>
                { items.map((item, index) =>
                {
                    if(!item) return <Fragment key={ `${ index }-empty` } />;

                    return <Fragment key={ `${ index }-item` }>{ itemRender(item, index) }</Fragment>;
                }) }
            </div>
        </div>
    );
};

const InfiniteGridVirtualized = <T,>(props: Props<T>) =>
{
    const { items = [], columnCount: columnCountProp = 4, overscan = 5, estimateSize = 45, itemMinWidth = null, rowGap = null, itemRender = null } = props;
    const { parentRef, columnCount } = useColumnMeasure(itemMinWidth, columnCountProp);

    const rowsContainerClassName = (rowGap !== null) ? 'flex flex-col w-full relative' : 'flex flex-col w-full *:pb-1 relative';

    const autoFillStyle = (itemMinWidth && itemMinWidth > 0)
        ? { gridTemplateColumns: `repeat(auto-fill, ${ itemMinWidth }px)` }
        : null;
    const fixedColsClass = (itemMinWidth && itemMinWidth > 0) ? '' : `grid-cols-${ columnCountProp }`;

    const virtualizer = useVirtualizer({
        count: Math.ceil(items.length / columnCount),
        overscan,
        getScrollElement: () => parentRef.current,
        estimateSize: () => estimateSize
    });

    useEffect(() =>
    {
        const element = parentRef.current;

        if(!element || !items) return;

        const checkAndApplyPadding = () =>
        {
            if(!element) return;

            element.style.paddingRight = (element.scrollHeight > element.clientHeight) ? '0.25rem' : '0';
        };

        checkAndApplyPadding();

        window.addEventListener('resize', checkAndApplyPadding);

        return () =>
        {
            window.removeEventListener('resize', checkAndApplyPadding);
        };
    }, [ items, parentRef ]);

    useEffect(() =>
    {
        if(!items || !items.length) return;

        virtualizer.scrollToIndex(0);
    }, [ items, virtualizer ]);

    const virtualItems = virtualizer.getVirtualItems();

    return (
        <div
            ref={ parentRef }
            className="overflow-y-auto size-full">
            <div
                className={ rowsContainerClassName }
                style={ {
                    height: virtualizer.getTotalSize()
                } }>
                { virtualItems.map(virtualRow => (
                    <div
                        key={ virtualRow.key + 'a' }
                        ref={ virtualizer.measureElement }
                        className={ `grid ${ fixedColsClass } gap-1 absolute top-0 left-0 last:pb-0 w-full` }
                        data-index={ virtualRow.index }
                        style={ {
                            ...(rowGap === null && { height: virtualRow.size }),
                            ...(autoFillStyle ?? {}),
                            ...(rowGap !== null && { paddingBottom: `${ rowGap }px` }),
                            transform: `translateY(${ virtualRow.start }px)`
                        } }>
                        { Array.from(Array(columnCount)).map((e, i) =>
                        {
                            const index = (i + (virtualRow.index * columnCount));
                            const item = items[index];

                            if(!item) return <Fragment
                                key={ virtualRow.index + i + 'b' } />;

                            return (
                                <Fragment key={ i }>
                                    { itemRender(item, index) }
                                </Fragment>
                            );
                        }) }
                    </div>
                )) }
            </div>
        </div>
    );
};

const InfiniteGridRoot = <T,>(props: Props<T>) =>
{
    return props.squareItems
        ? <InfiniteGridSquare<T> { ...props } />
        : <InfiniteGridVirtualized<T> { ...props } />;
};

type InfiniteGridItemProps = {
    itemImage?: string;
    itemColor?: string;
    itemActive?: boolean;
    itemCount?: number;
    itemCountMinimum?: number;
    itemUniqueSoldout?: boolean;
    itemUniqueNumber?: number;
    itemUnseen?: boolean;
    itemHighlight?: boolean;
    disabled?: boolean;
    ref?: Ref<HTMLDivElement>;
} & DetailedHTMLProps<HTMLAttributes<HTMLDivElement>, HTMLDivElement>;

const InfiniteGridItem = ({ ref, itemImage = undefined, itemColor = undefined, itemActive = false, itemCount = 1, itemCountMinimum = 1, itemUniqueSoldout = false, itemUniqueNumber = -2, itemUnseen = false, itemHighlight = false, disabled = false, className = null, style = {}, children = null, ...rest }: InfiniteGridItemProps) =>
{
    const [ backgroundImageUrl, setBackgroundImageUrl ] = useState<string>(null);
    const disposed = useRef<boolean>(false);

    useEffect(() =>
    {
        if(!itemImage || !itemImage.length)
        {
            setBackgroundImageUrl(null);

            return;
        }

        const image = new Image();

        image.onload = () =>
        {
            if(disposed.current) return;

            setBackgroundImageUrl(image.src);
        };

        image.src = itemImage;
    }, [ itemImage ]);

    useEffect(() =>
    {
        disposed.current = false;

        return () =>
        {
            disposed.current = true;
        };
    }, []);

    return (
        <div
            ref={ ref }
            className={ classNames(
                'flex flex-col items-center justify-center cursor-pointer overflow-hidden relative bg-center bg-no-repeat w-full rounded-md border-2',
                (itemImage && (!backgroundImageUrl || !backgroundImageUrl.length)) && 'nitro-icon icon-loading',
                itemActive
                    ? (itemColor ? 'border-card-grid-item-active' : 'border-card-grid-item-active bg-card-grid-item-active')
                    : (itemColor ? 'border-card-grid-item-border' : 'border-card-grid-item-border bg-card-grid-item'),
                (itemUniqueSoldout || (itemUniqueNumber > 0)) && 'unique-item',
                itemUniqueSoldout && 'sold-out',
                itemUnseen && ' animate-pulse-glow-gold border-yellow-400/60',
                className
            ) }
            style={ styleNames(
                backgroundImageUrl && backgroundImageUrl.length && !(itemUniqueSoldout || (itemUniqueNumber > 0)) && {
                    backgroundImage: `url(${ backgroundImageUrl })`
                },
                itemColor && {
                    backgroundColor: itemColor
                },
                style
            ) }
            { ...rest }>
            { (itemCount > itemCountMinimum) &&
                <div className="absolute align-middle rounded bg-red-700 bg-opacity-80 text-white border-black border top-[2px] right-[2px] text-[9.5px] p-[2px] z-1 leading-[8px]">{ itemCount }</div> }
            { (itemUniqueNumber > 0) &&
                <>
                    <div
                        className="size-full unique-bg-override"
                        style={ {
                            backgroundImage: `url(${ backgroundImageUrl })`
                        } } />
                    <div className="absolute bottom-0 unique-item-counter">
                        <NitroLimitedEditionStyledNumberView value={ itemUniqueNumber } />
                    </div>
                </> }
            { children }
        </div>
    );
};

export const InfiniteGrid = Object.assign(InfiniteGridRoot, {
    Item: InfiniteGridItem
});