import { FontAwesomeIcon } from '@fortawesome/react-fontawesome';
import { IReactionDisposer, action, computed, makeObservable, observable, reaction } from 'mobx';
import { observer } from 'mobx-react';
import * as React from 'react';
import { StopEvent, returnOne, returnZero } from '../../../ClientUtils';
import { Doc, DocListCast, Opt } from '../../../fields/Doc';
import { BoolCast, DocCast, NumCast, ScriptCast, StrCast } from '../../../fields/Types';
import { DocumentType } from '../../documents/DocumentTypes';
import { DragManager } from '../../util/DragManager';
import { ContextMenu } from '../ContextMenu';
import { StyleProp } from '../StyleProp';
import { DocumentView } from '../nodes/DocumentView';
import { FieldViewProps } from '../nodes/FieldView';
import { FormattedTextBox } from '../nodes/formattedText/FormattedTextBox';
import './CollectionCarouselView.scss';
import { CollectionSubView, SubCollectionViewProps } from './CollectionSubView';

enum cardMode {
    PRACTICE = 'practice',
    STAR = 'star',
    QUIZ = 'quiz',
}
enum practiceVal {
    MISSED = 'missed',
    CORRECT = 'correct',
}
@observer
export class CollectionCarouselView extends CollectionSubView() {
    private _dropDisposer?: DragManager.DragDropDisposer;
    get practiceField() { return this.fieldKey + "_practice"; } // prettier-ignore
    get starField()     { return "star"; } // prettier-ignore

    _fadeTimer: NodeJS.Timeout | undefined;
    _resetter: IReactionDisposer | undefined;

    constructor(props: SubCollectionViewProps) {
        super(props);
        makeObservable(this);
    }

    @observable _last_index = this.carouselIndex;
    @observable _last_opacity = 1;

    componentDidMount() {
        this._resetter = reaction(
            // automatically reset practice fields when all cards have been marked as correct
            () => this.carouselItems.length,
            itemsCount => {
                if (this.layoutDoc.filterOp === cardMode.PRACTICE && !itemsCount) {
                    this.layoutDoc.filterOp = undefined; // if all of the cards are correct, show all cards and exit practice mode
                    this.carouselItems.forEach(item => { // reset all the practice values
                        item[this.practiceField] = undefined;
                    });
                }
            } // prettier-ignore
        );
    }
    componentWillUnmount() {
        this._dropDisposer?.();
        this._resetter?.();
    }

    protected createDashEventsTarget = (ele: HTMLDivElement | null) => {
        this._dropDisposer?.();
        if (ele) {
            this._dropDisposer = DragManager.MakeDropTarget(ele, this.onInternalDrop.bind(this), this.layoutDoc);
        }
    };

    @computed get marginX()       { return NumCast(this.layoutDoc.caption_xMargin, 50); } // prettier-ignore
    @computed get carouselIndex() { return NumCast(this.layoutDoc._carousel_index) % this.carouselItems.length; } // prettier-ignore
    @computed get carouselItems() {
        return DocListCast(this.childDocList)
            .filter(doc => doc.type !== DocumentType.LINK)
            .filter(doc => {
                switch (StrCast(this.layoutDoc.filterOp)) {
                    case cardMode.STAR:      return !!doc[this.starField]; // show only cards that are starred
                    case cardMode.PRACTICE:  return doc[this.practiceField] !== practiceVal.CORRECT;// show only cards that aren't marked as correct
                    default:                 return true;
                } // prettier-ignore
            });
    }

    move = action((dir: number) => {
        this._last_index = this.carouselIndex;
        this.layoutDoc._carousel_index = (this.carouselIndex + dir + this.carouselItems.length) % this.carouselItems.length;
    });

    /**
     * Goes to the next Doc in the stack subject to the currently selected filter option.
     */
    advance = (e: React.MouseEvent) => {
        e.stopPropagation();
        this.move(1);
    };

    /**
     * Goes to the previous Doc in the stack subject to the currently selected filter option.
     */
    goback = (e: React.MouseEvent) => {
        e.stopPropagation();
        this.move(-1);
    };

    /*
     * Stars the document when the star button is pressed.
     */
    star = (e: React.MouseEvent) => {
        e.stopPropagation();
        const curDoc = this.carouselItems[this.carouselIndex];
        curDoc && (curDoc[this.starField] = curDoc[this.starField] ? undefined : true);
    };

    /*
     * Sets a flashcard to either missed or correct depending on if they got the question right in practice mode.
     */
    setPracticeVal = (e: React.MouseEvent, val: string) => {
        e.stopPropagation();
        const curDoc = this.carouselItems[this.carouselIndex];
        curDoc && (curDoc[this.practiceField] = val);
        this.advance(e);
    };

    captionStyleProvider = (doc: Doc | undefined, captionProps: Opt<FieldViewProps>, property: string) => {
        // first look for properties on the document in the carousel, then fallback to properties on the container
        const childValue = doc?.['caption_' + property] ? this._props.styleProvider?.(doc, captionProps, property) : undefined;
        return childValue ?? this._props.styleProvider?.(this.layoutDoc, captionProps, property);
    };
    panelHeight = () => this._props.PanelHeight() - (StrCast(this.layoutDoc._layout_showCaption) ? 50 : 0);
    onContentDoubleClick = () => ScriptCast(this.layoutDoc.onChildDoubleClick);
    onContentClick = () => ScriptCast(this.layoutDoc.onChildClick);
    captionWidth = () => this._props.PanelWidth() - 2 * this.marginX;
    specificMenu = (): void => {
        const cm = ContextMenu.Instance;
        const revealOptions = cm.findByDescription('Filter Flashcards');
        const revealItems = revealOptions?.subitems ?? [];
        revealItems.push({description: 'All',           event: () => {this.layoutDoc.filterOp = undefined;},         icon: 'layer-group',}); // prettier-ignore
        revealItems.push({description: 'Star',          event: () => {this.layoutDoc.filterOp = cardMode.STAR;},     icon: 'star',}); // prettier-ignore
        revealItems.push({description: 'Practice Mode', event: () => {this.layoutDoc.filterOp = cardMode.PRACTICE;}, icon: 'check',}); // prettier-ignore
        revealItems.push({description: 'Quiz Cards',    event: () => {this.layoutDoc.filterOp = cardMode.QUIZ;},     icon: 'pencil',}); // prettier-ignore
        !revealOptions && cm.addItem({ description: 'Filter Flashcards', addDivider: false, noexpand: true, subitems: revealItems, icon: 'layer-group' });
    };

    isChildContentActive = () =>
        this._props.isContentActive?.() === false
            ? false
            : this._props.isDocumentActive?.() && (this._props.childDocumentsActive?.() || BoolCast(this.Document.childDocumentsActive))
              ? true
              : this._props.childDocumentsActive?.() === false || this.Document.childDocumentsActive === false
                ? false
                : undefined;

    renderDoc = (doc: Doc, showCaptions: boolean, overlayFunc?: (r: DocumentView | null) => void) => {
        return (
            <DocumentView
                {...this._props}
                ref={overlayFunc}
                Document={doc}
                NativeWidth={returnZero}
                NativeHeight={returnZero}
                fitWidth={undefined}
                containerViewPath={this.childContainerViewPath}
                setContentViewBox={undefined}
                onDoubleClickScript={this.onContentDoubleClick}
                onClickScript={this.onContentClick}
                isDocumentActive={this._props.childDocumentsActive?.() ? this._props.isDocumentActive : this._props.isContentActive}
                isContentActive={this.isChildContentActive}
                hideCaptions={showCaptions}
                renderDepth={this._props.renderDepth + 1}
                LayoutTemplate={this._props.childLayoutTemplate}
                LayoutTemplateString={this._props.childLayoutString}
                TemplateDataDocument={DocCast(Doc.Layout(doc).resolvedDataDoc)}
                PanelHeight={this.panelHeight}
            />
        );
    };
    /**
     * Display an overlay of the previous card that crossfades to the next card
     */
    @computed get overlay() {
        const fadeTime = 500;
        const lastDoc = this.carouselItems?.[this._last_index];
        return !lastDoc || this.carouselIndex === this._last_index ? null : (
            <div className="collectionCarouselView-image" style={{ opacity: this._last_opacity, position: 'absolute', top: 0, left: 0, transition: `opacity ${fadeTime}ms` }}>
                {this.renderDoc(
                    lastDoc,
                    false, // hide captions if the carousel is configured to show the captions
                    action((r: DocumentView | null) => {
                        if (r) {
                            this._fadeTimer && clearTimeout(this._fadeTimer);
                            this._last_opacity = 0;
                            this._fadeTimer = setTimeout(
                                action(() => {
                                    this._last_index = -1;
                                    this._last_opacity = 1;
                                }),
                                fadeTime
                            );
                        }
                    })
                )}
            </div>
        );
    }
    @computed get content() {
        const index = this.carouselIndex;
        const curDoc = this.carouselItems?.[index];
        const captionProps = { ...this._props, NativeScaling: returnOne, PanelWidth: this.captionWidth, fieldKey: 'caption', setHeight: undefined, setContentView: undefined };
        const carouselShowsCaptions = StrCast(this.layoutDoc._layout_showCaption);
        return !curDoc ? null : (
            <>
                <div className="collectionCarouselView-image" key="image">
                    {this.renderDoc(curDoc, !!carouselShowsCaptions)}
                    {this.overlay}
                </div>
                {!carouselShowsCaptions ? null : (
                    <div
                        className="collectionCarouselView-caption"
                        key="caption"
                        onWheel={StopEvent}
                        style={{
                            borderRadius: this._props.styleProvider?.(this.layoutDoc, captionProps, StyleProp.BorderRounding) as string,
                            marginRight: this.marginX,
                            marginLeft: this.marginX,
                            width: `calc(100% - ${this.marginX * 2}px)`,
                        }}>
                        <FormattedTextBox key={index} xPadding={10} yPadding={10} {...captionProps} fieldKey={carouselShowsCaptions} styleProvider={this.captionStyleProvider} Document={curDoc} TemplateDataDocument={undefined} />
                    </div>
                )}
            </>
        );
    }
    @computed get buttons() {
        if (!this.carouselItems?.[this.carouselIndex]) return null;
        return (
            <>
                <div key="back" className="carouselView-back" onClick={this.goback}>
                    <FontAwesomeIcon icon="chevron-left" size="2x" />
                </div>
                <div key="fwd" className="carouselView-fwd" onClick={this.advance}>
                    <FontAwesomeIcon icon="chevron-right" size="2x" />
                </div>
                <div key="star" className="carouselView-star" onClick={this.star}>
                    <FontAwesomeIcon icon="star" color={this.carouselItems?.[this.carouselIndex][this.starField] ? 'yellow' : 'gray'} size="1x" />
                </div>
                <div key="remove" className="carouselView-remove" onClick={e => this.setPracticeVal(e, practiceVal.MISSED)} style={{ visibility: this.layoutDoc.filterOp === cardMode.PRACTICE ? 'visible' : 'hidden' }}>
                    <FontAwesomeIcon icon="xmark" color="red" size="1x" />
                </div>
                <div key="check" className="carouselView-check" onClick={e => this.setPracticeVal(e, practiceVal.CORRECT)} style={{ visibility: this.layoutDoc.filterOp === cardMode.PRACTICE ? 'visible' : 'hidden' }}>
                    <FontAwesomeIcon icon="check" color="green" size="1x" />
                </div>
            </>
        );
    }

    /**
     * Prompts user to add more flashcaards if  they are in practice mode but there are no flashcards
     */
    renderAddFlashcards = () => <p
            className="collectionCarouselView-addFlashcards"
            style={{display: !this.carouselItems?.[this.carouselIndex] && this.layoutDoc.filterOp === cardMode.PRACTICE ? 'flex' : 'none'}}>
            Add flashcards!
        </p> // prettier-ignore

    /**
     *  Displays message that a flashcard was recently missed if it had previously been marked as wrong.
     *  */
    renderRecentlyMissed = () => <p
            className="collectionCarouselView-recentlyMissed"
            style={{display: this.carouselItems?.[this.carouselIndex]?.[this.practiceField] === practiceVal.MISSED ? 'block' : 'none'}}>
            Recently missed!
        </p> // prettier-ignore

    render() {
        return (
            <div
                className="collectionCarouselView-outer"
                ref={this.createDashEventsTarget}
                onContextMenu={this.specificMenu}
                style={{
                    background: this._props.styleProvider?.(this.layoutDoc, this._props, StyleProp.BackgroundColor) as string,
                    color: this._props.styleProvider?.(this.layoutDoc, this._props, StyleProp.Color) as string,
                }}>
                {this.content}
                {this.renderAddFlashcards()}
                {this.renderRecentlyMissed()}
                {this.Document._chromeHidden ? null : this.buttons}
            </div>
        );
    }
}
