import { FC, useEffect, useLayoutEffect, useRef, useState } from 'react';
import { createPortal } from 'react-dom';
import { FaChevronRight } from 'react-icons/fa';
import allIcon from '../../../assets/images/wired/var/var_picker_all.png';
import internalIcon from '../../../assets/images/wired/var/var_picker_internal.png';
import recentIcon from '../../../assets/images/wired/var/var_picker_recent.png';
import searchClearIcon from '../../../assets/images/wired/var/ar_picker_cancel_search.png';
import searchIcon from '../../../assets/images/wired/var/var_picker_search.png';
import smartIcon from '../../../assets/images/wired/var/var_picker_smart.png';
import userMadeIcon from '../../../assets/images/wired/var/var_picker_usermade.png';
import { LocalizeText } from '../../../api';
import { Text } from '../../../common';
import { flattenWiredVariablePickerEntries, IWiredVariablePickerEntry } from './WiredVariablePickerData';

type WiredVariablePickerMode = 'all' | 'recent' | 'usermade' | 'smart' | 'internal' | 'search';

interface WiredVariablePickerProps
{
    emptyText?: string;
    entries: IWiredVariablePickerEntry[];
    placeholder?: string;
    recentScope: string;
    selectedToken: string;
    onSelect: (entry: IWiredVariablePickerEntry) => void;
}

const RECENT_PICKER_LIMIT = 12;
const RECENT_STORAGE_PREFIX = 'nitro.wired.variable-picker.recent';

const PICKER_MODES: Array<{ icon: string; key: WiredVariablePickerMode; }> = [
    { key: 'all', icon: allIcon },
    { key: 'recent', icon: recentIcon },
    { key: 'usermade', icon: userMadeIcon },
    { key: 'smart', icon: smartIcon },
    { key: 'internal', icon: internalIcon },
    { key: 'search', icon: searchIcon }
];

const normalizeSearch = (value: string) => value.trim().toLocaleLowerCase();

const applyQuery = (entries: IWiredVariablePickerEntry[], query: string): IWiredVariablePickerEntry[] =>
{
    if(!query) return entries;

    const nextEntries: IWiredVariablePickerEntry[] = [];

    for(const entry of entries)
    {
        const ownMatch = entry.searchableText.toLocaleLowerCase().includes(query);
        const matchingChildren = entry.children?.length ? applyQuery(entry.children, query) : [];

        if(!ownMatch && !matchingChildren.length) continue;

        nextEntries.push(matchingChildren.length ? { ...entry, children: matchingChildren } : entry);
    }

    return nextEntries;
};

const applyMode = (entries: IWiredVariablePickerEntry[], mode: WiredVariablePickerMode, recentTokens: string[]): IWiredVariablePickerEntry[] =>
{
    const recentSet = new Set(recentTokens);

    const filterEntries = (items: IWiredVariablePickerEntry[]): IWiredVariablePickerEntry[] =>
    {
        const filtered: IWiredVariablePickerEntry[] = [];

        for(const entry of items)
        {
            if(mode === 'smart') continue;

            const nextChildren = entry.children?.length ? filterEntries(entry.children) : [];
            const childVisible = !!nextChildren.length;
            const selfVisible = (() =>
            {
                switch(mode)
                {
                    case 'recent': return recentSet.has(entry.token);
                    case 'usermade': return entry.kind === 'custom';
                    case 'internal': return entry.kind === 'internal';
                    case 'search':
                    case 'all':
                    default:
                        return true;
                }
            })();

            if(!selfVisible && !childVisible) continue;

            filtered.push(childVisible ? { ...entry, children: nextChildren } : entry);
        }

        return filtered;
    };

    if(mode === 'recent')
    {
        const flatEntries = flattenWiredVariablePickerEntries(entries)
            .filter(entry => recentSet.has(entry.token))
            .sort((left, right) => recentTokens.indexOf(left.token) - recentTokens.indexOf(right.token))
            .map(entry => ({ ...entry, label: entry.displayLabel }));

        return flatEntries.filter(entry => !entry.children?.length);
    }

    return filterEntries(entries);
};

export const WiredVariablePicker: FC<WiredVariablePickerProps> = props =>
{
    const { entries = [], selectedToken = '', onSelect, recentScope, placeholder = LocalizeText('wiredfurni.variable_picker.search'), emptyText = 'Nothing to display' } = props;
    const containerRef = useRef<HTMLDivElement>(null);
    const panelRef = useRef<HTMLDivElement>(null);
    const searchInputRef = useRef<HTMLInputElement>(null);
    const submenuRef = useRef<HTMLDivElement>(null);
    const storageKey = `${ RECENT_STORAGE_PREFIX }.${ recentScope }`;
    const [ isOpen, setIsOpen ] = useState(false);
    const [ mode, setMode ] = useState<WiredVariablePickerMode>('all');
    const [ query, setQuery ] = useState('');
    const [ recentTokens, setRecentTokens ] = useState<string[]>([]);
    const [ activeParentToken, setActiveParentToken ] = useState('');
    const [ panelPosition, setPanelPosition ] = useState<{ left: number; top: number; width: number; } | null>(null);
    const [ submenuPosition, setSubmenuPosition ] = useState<{ left: number; top: number; } | null>(null);

    const allEntries = flattenWiredVariablePickerEntries(entries);
    const selectedEntry = allEntries.find(entry => (entry.token === selectedToken)) || null;
    const modeEntries = applyMode(entries, mode, recentTokens);
    const filteredEntries = applyQuery(modeEntries, normalizeSearch(query));
    const activeParent = filteredEntries.find(entry => (entry.token === activeParentToken) && entry.children?.length) || null;
    const portalTarget = (typeof document !== 'undefined') ? (document.getElementById('draggable-windows-container') ?? document.body) : null;

    useEffect(() =>
    {
        try
        {
            const rawValue = window.localStorage.getItem(storageKey);

            if(!rawValue)
            {
                setRecentTokens([]);
                return;
            }

            const parsedValue = JSON.parse(rawValue) as string[];

            setRecentTokens(Array.isArray(parsedValue) ? parsedValue.filter(token => typeof token === 'string') : []);
        }
        catch
        {
            setRecentTokens([]);
        }
    }, [ storageKey ]);

    useEffect(() =>
    {
        if(!isOpen) return;

        const handleClick = (event: MouseEvent) =>
        {
            if(containerRef.current?.contains(event.target as Node)) return;
            if(panelRef.current?.contains(event.target as Node)) return;
            if(submenuRef.current?.contains(event.target as Node)) return;

            setIsOpen(false);
            setActiveParentToken('');
            setPanelPosition(null);
            setSubmenuPosition(null);
        };

        const handleEscape = (event: KeyboardEvent) =>
        {
            if(event.key !== 'Escape') return;

            setIsOpen(false);
            setActiveParentToken('');
            setPanelPosition(null);
            setSubmenuPosition(null);
        };

        document.addEventListener('mousedown', handleClick);
        document.addEventListener('keydown', handleEscape);

        return () =>
        {
            document.removeEventListener('mousedown', handleClick);
            document.removeEventListener('keydown', handleEscape);
        };
    }, [ isOpen ]);

    useLayoutEffect(() =>
    {
        if(!isOpen)
        {
            setPanelPosition(null);
            return;
        }

        const updatePanelPosition = () =>
        {
            const triggerRect = containerRef.current?.getBoundingClientRect();

            if(!triggerRect)
            {
                setPanelPosition(null);
                return;
            }

            const panelWidth = Math.max(202, Math.ceil(triggerRect.width));
            const viewportPadding = 8;
            const left = Math.min(Math.max(viewportPadding, triggerRect.left), Math.max(viewportPadding, window.innerWidth - panelWidth - viewportPadding));

            setPanelPosition({
                left,
                top: triggerRect.bottom + 2,
                width: panelWidth
            });
            setActiveParentToken('');
            setSubmenuPosition(null);
        };

        updatePanelPosition();

        window.addEventListener('resize', updatePanelPosition);
        window.addEventListener('scroll', updatePanelPosition, true);

        return () =>
        {
            window.removeEventListener('resize', updatePanelPosition);
            window.removeEventListener('scroll', updatePanelPosition, true);
        };
    }, [ isOpen ]);

    useEffect(() =>
    {
        if(!isOpen) return;
        if(mode !== 'search') return;

        searchInputRef.current?.focus();
    }, [ isOpen, mode ]);

    useEffect(() =>
    {
        if(!activeParentToken) return;
        if(filteredEntries.some(entry => entry.token === activeParentToken && entry.children?.length)) return;

        setActiveParentToken('');
        setSubmenuPosition(null);
    }, [ activeParentToken, filteredEntries ]);

    const rememberSelection = (token: string) =>
    {
        if(!token) return;

        const nextRecentTokens = [ token, ...recentTokens.filter(currentToken => (currentToken !== token)) ].slice(0, RECENT_PICKER_LIMIT);

        setRecentTokens(nextRecentTokens);

        try
        {
            window.localStorage.setItem(storageKey, JSON.stringify(nextRecentTokens));
        }
        catch
        {
        }
    };

    const handleSelect = (entry: IWiredVariablePickerEntry) =>
    {
        if(!entry.selectable) return;

        rememberSelection(entry.token);
        onSelect(entry);
        setIsOpen(false);
        setActiveParentToken('');
        setSubmenuPosition(null);
    };

    const activateParent = (entry: IWiredVariablePickerEntry, element: HTMLButtonElement) =>
    {
        if(!entry.children?.length)
        {
            setActiveParentToken('');
            setSubmenuPosition(null);
            return;
        }

        const rowRect = element.getBoundingClientRect();
        const panelRect = panelRef.current?.getBoundingClientRect();
        const submenuWidth = 140;
        const submenuHeight = Math.min((entry.children.length * 20) + 22, 168);
        const viewportWidth = window.innerWidth;
        const viewportHeight = window.innerHeight;
        const leftAnchor = panelRect ? panelRect.right : rowRect.right;
        const rightSpace = viewportWidth - leftAnchor;
        const canOpenRight = (rightSpace >= (submenuWidth + 8));
        const left = canOpenRight
            ? (leftAnchor + 6)
            : Math.max(8, (panelRect ? panelRect.left : rowRect.left) - submenuWidth - 6);
        const top = Math.min(Math.max(8, rowRect.top), Math.max(8, viewportHeight - submenuHeight - 8));

        setSubmenuPosition({
            left,
            top
        });
        setActiveParentToken(entry.token);
    };

    const renderEntry = (entry: IWiredVariablePickerEntry) =>
    {
        const hasChildren = !!entry.children?.length;

        return (
            <button
                key={ entry.id }
                type="button"
                className={ `nitro-wired__variable-picker-row ${ entry.selectable ? '' : 'is-disabled' } ${ selectedToken === entry.token ? 'is-selected' : '' }` }
                onMouseEnter={ event => activateParent(entry, event.currentTarget) }
                onClick={ event =>
                {
                    if(hasChildren)
                    {
                        activateParent(entry, event.currentTarget);
                        return;
                    }

                    if(entry.selectable) handleSelect(entry);
                } }>
                <span className="nitro-wired__variable-picker-row-label">{ entry.label }</span>
                { hasChildren && <FaChevronRight className="nitro-wired__variable-picker-row-arrow" /> }
            </button>
        );
    };

    const renderPanel = () =>
    {
        if(!panelPosition) return null;

        return (
            <div
                ref={ panelRef }
                className="nitro-wired__variable-picker-panel is-portal"
                style={ { left: panelPosition.left, top: panelPosition.top, width: panelPosition.width } }>
                <div className="nitro-wired__variable-picker-toolbar">
                    { PICKER_MODES.map(button => (
                        <button
                            key={ button.key }
                            type="button"
                            className={ `nitro-wired__variable-picker-mode ${ mode === button.key ? 'is-active' : '' }` }
                            onClick={ () =>
                            {
                                setMode(button.key);
                                if(button.key === 'search') setTimeout(() => searchInputRef.current?.focus(), 0);
                            } }>
                            <img src={ button.icon } alt={ button.key } />
                        </button>
                    )) }
                </div>

                <div className="nitro-wired__variable-picker-search">
                    <img className="nitro-wired__variable-picker-search-icon" src={ searchIcon } alt="search" />
                    <input
                        ref={ searchInputRef }
                        className="nitro-wired__variable-picker-search-input"
                        placeholder={ placeholder }
                        type="text"
                        value={ query }
                        onChange={ event => setQuery(event.target.value) } />
                    { !!query.length &&
                        <button type="button" className="nitro-wired__variable-picker-clear" onClick={ () => setQuery('') }>
                            <img src={ searchClearIcon } alt="clear" />
                        </button> }
                </div>

                <div className="nitro-wired__variable-picker-list">
                    { filteredEntries.length
                        ? filteredEntries.map(renderEntry)
                        : <Text small className="nitro-wired__variable-picker-empty">{ emptyText }</Text> }
                </div>
            </div>
        );
    };

    return (
        <div className="nitro-wired__variable-picker" ref={ containerRef }>
            <button type="button" className="form-select form-select-sm nitro-wired__variable-picker-trigger" onClick={ () => setIsOpen(value => !value) }>
                <span className={ selectedEntry ? '' : 'nitro-wired__variable-picker-placeholder' }>{ selectedEntry?.displayLabel || placeholder }</span>
            </button>

            { isOpen && panelPosition && portalTarget && createPortal(
                <div className="nitro-wired nitro-wired__variable-picker-portal">
                    { renderPanel() }

                    { activeParent?.children?.length && submenuPosition &&
                        <div
                            ref={ submenuRef }
                            className="nitro-wired__variable-picker-submenu"
                            style={ { left: submenuPosition.left, top: submenuPosition.top } }>
                            { activeParent.children.map(child => (
                                <button
                                    key={ child.id }
                                    type="button"
                                    className={ `nitro-wired__variable-picker-row nitro-wired__variable-picker-subrow ${ child.selectable ? '' : 'is-disabled' } ${ selectedToken === child.token ? 'is-selected' : '' }` }
                                    onClick={ () => handleSelect(child) }>
                                    <span className="nitro-wired__variable-picker-row-label">{ child.label }</span>
                                </button>
                            )) }
                        </div> }
                </div>,
                portalTarget
            ) }
        </div>
    );
};