import React, { ReactElement, useEffect, useState } from 'react';
import { debounce } from 'debounce';
import styled from 'styled-components/macro';
import tw from 'twin.macro';
import Input from '@/components/elements/Input';
import Label from '@/components/elements/Label';
import InputSpinner from '@/components/elements/InputSpinner';

const Dropdown = styled.div<{ expanded: boolean }>`
    ${tw`absolute mt-1 w-full rounded-md bg-neutral-900 shadow-lg z-10`};
    ${props => !props.expanded && tw`hidden`};
`;

interface SearchableSelectProps<T> {
    id: string;
    name: string;
    nullable: boolean;

    selected: T | null;

    items: T[];
    setItems: (items: T[]) => void;

    onSearch: (query: string) => Promise<void>;
    onSelect: (item: T) => void;

    getSelectedText: (item: T | null) => string;

    children: React.ReactNode;
}

function SearchableSelect<T> ({ id, name, selected, items, setItems, onSearch, onSelect, getSelectedText, children }: SearchableSelectProps<T>) {
    const [ loading, setLoading ] = useState(false);
    const [ expanded, setExpanded ] = useState(false);

    const [ inputText, setInputText ] = useState('');

    const onFocus = () => {
        setInputText('');
        setItems([]);
        setExpanded(true);
    };

    const search = debounce((query: string) => {
        if (!expanded) {
            return;
        }

        if (query === '' || query.length < 2) {
            setItems([]);
            return;
        }

        setLoading(true);
        onSearch(query).then(() => setLoading(false));
    }, 250);

    useEffect(() => {
        setInputText(getSelectedText(selected) || '');
        setExpanded(false);
    }, [ selected ]);

    useEffect(() => {
        const handler = (e: KeyboardEvent) => {
            if (e.key !== 'Escape') {
                return;
            }

            setInputText(getSelectedText(selected) || '');
            setExpanded(false);
        };

        window.addEventListener('keydown', handler);
        return () => {
            window.removeEventListener('keydown', handler);
        };
    }, [ expanded ]);

    const onClick = (item: T) => (e: React.MouseEvent) => {
        e.preventDefault();
        onSelect(item);
    };

    // This shit is really stupid but works, so is it really stupid?
    const c = React.Children.map(children, child => React.cloneElement(child as ReactElement, {
        onClick: onClick.bind(child),
    }));

    return (
        <div>
            <Label htmlFor={id}>{name}</Label>

            <div css={tw`mt-1 relative`}>
                <InputSpinner visible={loading}>
                    <Input type="text" className="ignoreReadOnly" id={id} name={id} value={inputText} readOnly={!expanded} onFocus={onFocus} onChange={e => {
                        setInputText(e.currentTarget.value);
                        search(e.currentTarget.value);
                    }}
                    />
                </InputSpinner>

                <div css={tw`ml-3 absolute inset-y-0 right-0 flex items-center pr-2 pointer-events-none`}>
                    <svg css={tw`h-5 w-5 text-neutral-400`} xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20" fill="currentColor" aria-hidden="true">
                        <path clipRule="evenodd" fillRule="evenodd" d="M10 3a1 1 0 01.707.293l3 3a1 1 0 01-1.414 1.414L10 5.414 7.707 7.707a1 1 0 01-1.414-1.414l3-3A1 1 0 0110 3zm-3.707 9.293a1 1 0 011.414 0L10 14.586l2.293-2.293a1 1 0 011.414 1.414l-3 3a1 1 0 01-1.414 0l-3-3a1 1 0 010-1.414z"/>
                    </svg>
                </div>

                <Dropdown expanded={expanded}>
                    { items.length < 1 ?
                        inputText.length < 2 ?
                            <div css={tw`h-10 flex flex-row items-center px-3`}>
                                <p css={tw`text-sm`}>Please type 2 or more characters.</p>
                            </div>
                            :
                            <div css={tw`h-10 flex flex-row items-center px-3`}>
                                <p css={tw`text-sm`}>No results found.</p>
                            </div>
                        :
                        <ul tabIndex={-1} css={tw`max-h-56 rounded-md py-1 text-base ring-1 ring-black ring-opacity-5 overflow-auto focus:outline-none sm:text-sm`}>
                            {c}
                        </ul>
                    }
                </Dropdown>
            </div>
        </div>
    );
}

interface OptionProps<T> {
    id: string | number;
    item: T;
    active: boolean;

    onClick?: (item: T) => (e: React.MouseEvent) => void;

    children: React.ReactNode;
}

export function Option<T> ({ id, item, active, onClick, children }: OptionProps<T>) {
    if (onClick === undefined) {
        // eslint-disable-next-line @typescript-eslint/no-empty-function
        onClick = () => () => {};
    }

    if (active) {
        return (
            <li id={'select-item-' + id} role="option" css={tw`text-neutral-200 cursor-pointer select-none relative py-2 pl-3 pr-9 hover:bg-neutral-700`} onClick={onClick(item)}>
                <div css={tw`flex items-center`}>
                    <span css={tw`block font-medium truncate`}>
                        {children}
                    </span>
                </div>

                <span css={tw`absolute inset-y-0 right-0 flex items-center pr-4`}>
                    <svg css={tw`h-5 w-5 text-primary-400`} xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20" fill="currentColor" aria-hidden="true">
                        <path clipRule="evenodd" fillRule="evenodd" d="M16.707 5.293a1 1 0 010 1.414l-8 8a1 1 0 01-1.414 0l-4-4a1 1 0 011.414-1.414L8 12.586l7.293-7.293a1 1 0 011.414 0z"/>
                    </svg>
                </span>
            </li>
        );
    }

    return (
        <li id={'select-item-' + id} role="option" css={tw`text-neutral-200 cursor-pointer select-none relative py-2 pl-3 pr-9 hover:bg-neutral-700`} onClick={onClick(item)}>
            <div css={tw`flex items-center`}>
                <span css={tw`block font-normal truncate`}>
                    {children}
                </span>
            </div>
        </li>
    );
}

export default SearchableSelect;