<?php
/**
 * Data function get_sales_summary.
 *
 * @package Askshelf
 */

declare( strict_types = 1 );

namespace Askshelf\Tools;

use Askshelf\Data\Analytics;
use Askshelf\Data\Period;
use Askshelf\Settings;

defined( 'ABSPATH' ) || exit;

/**
 * Revenue totals and a series, from Analytics › Revenue.
 */
final class SalesSummary implements Tool {

	/** {@inheritDoc} */
	public function name(): string {
		return 'get_sales_summary';
	}

	/** {@inheritDoc} */
	public function scopes(): array {
		return array( Settings::SCOPE_ORDERS );
	}

	/** {@inheritDoc} */
	public function schema(): array {
		return Schema::object(
			array(
				'start_date' => Schema::date(),
				'end_date'   => Schema::date(),
				'compare'    => Schema::compare(),
			),
			array( 'start_date', 'end_date' )
		);
	}

	/**
	 * Runs the data function.
	 *
	 * @param array<string, mixed> $args Validated arguments.
	 * @return array<string, mixed>
	 */
	public function run( array $args ): array {
		$period  = Schema::period( $args );
		$current = self::fetch( $period, true );
		$result  = array(
			'period'    => $period->to_array(),
			'totals'    => $current['totals'],
			'rows_read' => $current['totals']['orders'],
			'notes'     => array( 'Net sales exclude refunds, coupons, taxes and shipping, as in WooCommerce Analytics.' ),
		);

		$compare = (string) ( $args['compare'] ?? 'none' );
		if ( 'none' !== $compare ) {
			$previous_period      = $period->comparison( $compare );
			$previous             = self::fetch( $previous_period, false );
			$result['comparison'] = array(
				'period' => $previous_period->to_array(),
				'totals' => $previous['totals'],
				'change' => self::change( $current['totals'], $previous['totals'] ),
			);
			$result['rows_read'] += $previous['totals']['orders'];
		}

		$result['chart'] = array(
			'type'   => 'line',
			'title'  => __( 'Net sales', 'askshelf' ),
			'format' => 'money',
			'points' => $current['series'],
		);
		return $result;
	}

	/**
	 * Totals and series for one period.
	 *
	 * @param Period $period      Period.
	 * @param bool   $with_series Also fetch intervals.
	 * @return array{totals: array<string, int|float>, series: list<array{label: string, value: float}>}
	 */
	private static function fetch( Period $period, bool $with_series ): array {
		$response = Analytics::get(
			'/reports/revenue/stats',
			array(
				'after'    => $period->after(),
				'before'   => $period->before(),
				'interval' => $period->chart_interval(),
				'per_page' => 100,
				'order'    => 'asc',
			)
		);
		$data     = is_array( $response['data'] ) ? $response['data'] : array();
		$totals   = is_array( $data['totals'] ?? null ) ? $data['totals'] : array();

		$orders = (int) ( $totals['orders_count'] ?? 0 );
		$net    = Analytics::money( $totals['net_revenue'] ?? 0 );
		$out    = array(
			'net_sales'       => $net,
			'gross_sales'     => Analytics::money( $totals['gross_sales'] ?? 0 ),
			'total_sales'     => Analytics::money( $totals['total_sales'] ?? 0 ),
			'orders'          => $orders,
			'average_order'   => $orders > 0 ? Analytics::money( $net / $orders ) : 0.0,
			'items_sold'      => (int) ( $totals['num_items_sold'] ?? 0 ),
			'refunds'         => Analytics::money( $totals['refunds'] ?? 0 ),
			'coupon_discount' => Analytics::money( $totals['coupons'] ?? 0 ),
			'shipping'        => Analytics::money( $totals['shipping'] ?? 0 ),
			'taxes'           => Analytics::money( $totals['taxes'] ?? 0 ),
		);

		$series = array();
		if ( $with_series && is_array( $data['intervals'] ?? null ) ) {
			foreach ( $data['intervals'] as $interval ) {
				$series[] = array(
					'label' => (string) ( $interval['date_start'] ?? $interval['interval'] ?? '' ),
					'value' => Analytics::money( $interval['subtotals']['net_revenue'] ?? 0 ),
				);
			}
		}
		return array(
			'totals' => $out,
			'series' => $series,
		);
	}

	/**
	 * Percentage changes, or null where the previous value is zero.
	 *
	 * @param array<string, int|float|null> $current  Current totals.
	 * @param array<string, int|float|null> $previous Previous totals.
	 * @return array<string, float|null>
	 */
	public static function change( array $current, array $previous ): array {
		$change = array();
		foreach ( $current as $key => $value ) {
			$before         = (float) ( $previous[ $key ] ?? 0 );
			$change[ $key ] = 0.0 === $before ? null : round( ( (float) $value - $before ) / abs( $before ) * 100, 1 ) + 0.0;
			// + 0.0 turns -0.0 into 0.0.
		}
		return $change;
	}
}