/* eslint no-case-declarations: "off" */
import global from 'global';

export default function jarallaxElement( jarallax = global.jarallax ) {
    if ( 'undefined' === typeof jarallax ) {
        return;
    }

    const Jarallax = jarallax.constructor;

    // redefine default methods
    [
        'initImg',
        'canInitParallax',
        'init',
        'destroy',
        'clipContainer',
        'coverImage',
        'isVisible',
        'onScroll',
        'onResize',
    ].forEach( ( key ) => {
        const def = Jarallax.prototype[ key ];
        Jarallax.prototype[ key ] = function( ...args ) {
            const self = this;

            if ( 'initImg' === key && null !== self.$item.getAttribute( 'data-jarallax-element' ) ) {
                self.options.type = 'element';
                self.pureOptions.speed = self.$item.getAttribute( 'data-jarallax-element' ) || self.pureOptions.speed;
            }
            if ( 'element' !== self.options.type ) {
                return def.apply( self, args );
            }

            self.pureOptions.threshold = self.$item.getAttribute( 'data-threshold' ) || '';

            switch ( key ) {
            case 'init':
                const speedArr = self.pureOptions.speed.split( ' ' );
                self.options.speed = self.pureOptions.speed || 0;
                self.options.speedY = speedArr[ 0 ] ? parseFloat( speedArr[ 0 ] ) : 0;
                self.options.speedX = speedArr[ 1 ] ? parseFloat( speedArr[ 1 ] ) : 0;

                const thresholdArr = self.pureOptions.threshold.split( ' ' );
                self.options.thresholdY = thresholdArr[ 0 ] ? parseFloat( thresholdArr[ 0 ] ) : null;
                self.options.thresholdX = thresholdArr[ 1 ] ? parseFloat( thresholdArr[ 1 ] ) : null;

                def.apply( self, args );

                // restore background image if available.
                const originalStylesTag = self.$item.getAttribute( 'data-jarallax-original-styles' );
                if ( originalStylesTag ) {
                    self.$item.setAttribute( 'style', originalStylesTag );
                }

                return true;
            case 'onResize':
                const defTransform = self.css( self.$item, 'transform' );
                self.css( self.$item, { transform: '' } );
                const rect = self.$item.getBoundingClientRect();
                self.itemData = {
                    width: rect.width,
                    height: rect.height,
                    y: rect.top + self.getWindowData().y,
                    x: rect.left,
                };
                self.css( self.$item, { transform: defTransform } );
                break;
            case 'onScroll':
                const wnd = self.getWindowData();
                const centerPercent = ( wnd.y + wnd.height / 2 - self.itemData.y - self.itemData.height / 2 ) / ( wnd.height / 2 );
                const moveY = centerPercent * self.options.speedY;
                const moveX = centerPercent * self.options.speedX;
                let my = moveY;
                let mx = moveX;
                if ( null !== self.options.thresholdY && moveY > self.options.thresholdY ) my = 0;
                if ( null !== self.options.thresholdX && moveX > self.options.thresholdX ) mx = 0;
                self.css( self.$item, { transform: `translate3d(${ mx }px,${ my }px,0)` } );
                break;
            case 'initImg':
            case 'isVisible':
            case 'clipContainer':
            case 'coverImage':
                return true;
            // no default
            }
            return def.apply( self, args );
        };
    } );
}