/**
 * Gets an array of funnel segment colors
 *
 * @param num_segments - the number of segments to generate colors for
 *
 * @return an array of colors
 */
/* global zbs_root */
function jpcrm_get_segment_colors( num_segments ) {
	const COLORS = [
		zbs_root.jp_green[ '20' ],
		zbs_root.jp_green[ '30' ],
		zbs_root.jp_green[ '40' ],
		zbs_root.jp_green[ '50' ],
		zbs_root.jp_green[ '60' ],
		zbs_root.jp_green[ '70' ],
		zbs_root.jp_green[ '80' ],
		zbs_root.jp_green[ '90' ],
		zbs_root.jp_green[ '100' ],
		'#000000', // add black for good measure
	];

	if ( num_segments === COLORS.length ) {
		// use full set of colors
		return COLORS;
	} else if ( num_segments < COLORS.length ) {
		// use a middle subset of colors
		const midpoint = Math.floor( COLORS.length / 2 );
		const start_index = Math.floor( midpoint - num_segments / 2 );
		return COLORS.slice( start_index, start_index + num_segments );
	}

	// use full set of colors, repeated and variably reversed
	let lotsa_colors = COLORS.slice();
	while ( num_segments > lotsa_colors.length ) {
		lotsa_colors = lotsa_colors.concat( COLORS.reverse().slice( 1 ) );
	}
	return lotsa_colors.slice( 0, num_segments );
}

/**
 * Draws a simple funnel
 *
 * Inspired in part by https://codepen.io/tylerlwsmith/pen/RwNZKgp
 *
 * @param funnel_data    - array of funnel data (count, backfill_count, contact_status, and link)
 * @param funnel_element - HTML element to turn into a funnel
 */

function jpcrm_build_funnel( funnel_data, funnel_element ) {
	// something's wrong, so stop
	if ( ! funnel_element || ! funnel_data ) {
		return;
	}

	// show legend if desired
	const SHOW_FUNNEL_LEGEND = false;

	// number of funnel sections
	const NUM_FUNNEL_SECTIONS = funnel_data.length;

	// height of each section
	const SECTION_HEIGHT = 50;

	// colors to use
	const SEGMENT_COLORS = jpcrm_get_segment_colors( NUM_FUNNEL_SECTIONS );

	let funnel_html = `<div class="jpcrm_funnel" style="height: ${
		SECTION_HEIGHT * NUM_FUNNEL_SECTIONS
	}px">`;
	let legend_html = '';

	if ( SHOW_FUNNEL_LEGEND ) {
		legend_html = '<div class="jpcrm_funnel_legend">';
	}
	for ( let i = 0; i < NUM_FUNNEL_SECTIONS; i++ ) {
		const section_color = SEGMENT_COLORS[ i ];
		funnel_html += `<a
			${ funnel_data[ i ].link ? 'href=' + funnel_data[ i ].link : '' }
			class="funnel_section"
			data-hover="${ funnel_data[ i ].contact_status + ': \u00a0' }"
			alt="${ funnel_data[ i ].contact_status }: ${ funnel_data[ i ].backfill_count }"
			style="background-color: ${ section_color };"
			>${ funnel_data[ i ].backfill_count }</a>`;

		if ( SHOW_FUNNEL_LEGEND ) {
			legend_html += `<div class="legend-color" style="background-color: ${ section_color }"></div><div class="legend-label">${ funnel_data[ i ].contact_status }</div>`;
		}
	}
	funnel_html += '</div>';

	if ( SHOW_FUNNEL_LEGEND ) {
		legend_html += '</div>';
	}

	if ( SHOW_FUNNEL_LEGEND ) {
		funnel_html += '<br>' + legend_html;
	}
	funnel_element.innerHTML = funnel_html + '<br>';
}

if ( typeof module !== 'undefined' ) {
	module.exports = { jpcrm_build_funnel };
}
