<?php
/**
 * Human-readable Promo Risk reason copy.
 *
 * @package Kayvandra\MarginBeacon
 */

declare(strict_types=1);

namespace Kayvandra\MarginBeacon\Admin\Orders;

use Kayvandra\MarginBeacon\Domain\Risk\Severity;

/**
 * Builds merchant-facing reason text from snapshot fields.
 */
final class ReasonPresenter {

	/**
	 * Labels for stable reason codes.
	 *
	 * @return array<string,string>
	 */
	public static function code_labels() {
		return array(
			'MB001'                       => __( 'Sold below product cost', 'marginbeacon' ),
			'MB014'                       => __( 'Fully discounted / free-gift line with remaining cost', 'marginbeacon' ),
			'MB_LINE_FULLY_DISCOUNTED'    => __( 'Fully discounted / free-gift line with remaining cost', 'marginbeacon' ),
			'MB013'                       => __( 'Free-shipping coupon — shipping cost out of scope', 'marginbeacon' ),
			'MB015'                       => __( 'Excluded from margin — credit line', 'marginbeacon' ),
			'MB_LINE_CREDIT_EXCLUDED'     => __( 'Excluded from margin — credit line', 'marginbeacon' ),
			'MB_COST_MISSING'             => __( 'Product cost missing', 'marginbeacon' ),
			'MB_COST_INVALID'             => __( 'Product cost invalid', 'marginbeacon' ),
			'MB_COST_PRESENCE_UNRESOLVED' => __( 'Zero cost versus missing cost could not be distinguished', 'marginbeacon' ),
			'MB_COGS_TAX_BASIS_INVALID'   => __( 'COGS tax basis invalid — costs must be tax-exclusive', 'marginbeacon' ),
			'MB_TAX_BASIS_UNRESOLVED'     => __( 'Tax basis could not be resolved for this price', 'marginbeacon' ),
			'MB_SALE_ORIGIN_UNVERIFIED'   => __( 'Sale price origin unverified', 'marginbeacon' ),
			'MB_PRICE_UNRESOLVED'         => __( 'Product price could not be resolved', 'marginbeacon' ),
			'MB_CURRENCY_UNSUPPORTED'     => __( 'Order currency differs from store base currency', 'marginbeacon' ),
			'MB_RENEWAL_UNSUPPORTED'      => __( 'Subscription renewal is not evaluated', 'marginbeacon' ),
			'MB_MONEY_PRECISION_INVALID'  => __( 'Money precision invalid', 'marginbeacon' ),
			'MB_TOTALS_INVALID'           => __( 'Order totals invalid', 'marginbeacon' ),
			'MB_PRICING_UNSUPPORTED'      => __( 'Pricing path unsupported', 'marginbeacon' ),
			'MB_NO_PROMOTION_DETECTED'    => __( 'No promotion detected', 'marginbeacon' ),
			'MB_STATUS_INELIGIBLE'        => __( 'Order status not eligible for evaluation', 'marginbeacon' ),
		);
	}

	/**
	 * Full reason line for order detail panel.
	 *
	 * @param array $row Order risk row.
	 * @return string
	 */
	public static function from_row( array $row ) {
		$code  = ! empty( $row['short_reason_code'] ) ? (string) $row['short_reason_code'] : '';
		$dual  = DualContextPresenter::from_row( $row );
		$loss  = (int) $dual['loss_making_lines'];
		$badge = isset( $row['risk_badge'] ) ? (string) $row['risk_badge'] : '';
		$parts = array();

		// Prefer synthesized below-cost economics when Critical/High with known revenue & COGS.
		$loss_text = self::loss_summary( $row, $loss );
		if ( $loss_text ) {
			$parts[] = $loss_text;
		} elseif ( $code && isset( self::code_labels()[ $code ] ) ) {
			$parts[] = self::code_labels()[ $code ];
		} elseif ( $code ) {
			$parts[] = $code;
		}

		if ( $code && $loss_text && 'MB001' !== $code && 'MB014' !== $code ) {
			array_unshift( $parts, self::code_labels()[ $code ] ?? $code );
		}

		if ( empty( $parts ) && Severity::CRITICAL === $badge ) {
			$parts[] = __( 'Gross product margin below critical threshold', 'marginbeacon' );
		}
		if ( empty( $parts ) && Severity::SAFE === $badge ) {
			$parts[] = __( 'Gross product margin within Safe band', 'marginbeacon' );
		}

		$text = implode( ' · ', array_filter( $parts ) );
		if ( $code && $text && false === strpos( $text, $code ) ) {
			$text .= ' (' . $code . ')';
		} elseif ( $code && ! $text ) {
			$text = $code;
		}

		return $text;
	}

	/**
	 * @param array $row  Risk row.
	 * @param int   $loss Loss-making line count.
	 * @return string
	 */
	private static function loss_summary( array $row, $loss ) {
		if ( null === $row['revenue'] || null === $row['cogs'] || '' === $row['revenue'] || '' === $row['cogs'] ) {
			return '';
		}

		$badge = isset( $row['risk_badge'] ) ? (string) $row['risk_badge'] : '';
		if ( ! in_array( $badge, array( Severity::CRITICAL, Severity::HIGH ), true ) ) {
			return '';
		}

		$rev_str = trim( (string) $row['revenue'] );
		$cog_str = trim( (string) $row['cogs'] );
		$cmp     = function_exists( 'bccomp' )
			? bccomp( $cog_str, $rev_str, 8 )
			: ( preg_match( '/^[1-9]/', ltrim( $cog_str, '0' ) ) && preg_match( '/^[0]/', $rev_str ) ? 1 : 0 );
		if ( $cmp <= 0 ) {
			// Still critical/high on thin margin — not a gross loss headline.
			if ( $loss > 0 ) {
				return sprintf(
					/* translators: %d: count */
					_n( '%d item sold below cost', '%d items sold below cost', $loss, 'marginbeacon' ),
					$loss
				);
			}
			return '';
		}

		// Calculate gap using integer arithmetic (PRD 9.7).
		$gap_scaled = bcsub( $cog_str, $rev_str, 8 );
		$gap_whole  = rtrim( rtrim( $gap_scaled, '0' ), '.' );
		if ( '' === $gap_whole ) {
			$gap_whole = '0';
		}
		if ( function_exists( 'wc_price' ) ) {
			$formatted = wp_strip_all_tags( wc_price( $gap_whole ) );
		} else {
			$parts  = explode( '.', $gap_whole, 2 );
			$digits = ltrim( $parts[0], '-' );
			if ( '' === $digits ) {
				$digits = '0';
			}
			$digits    = str_pad( $digits, 1, '0', STR_PAD_LEFT );
			$formatted = ( '-' === $parts[0][0] ? '-' : '' ) . number_format( (int) $digits, 0, ',', '.' );
		}

		$base = sprintf(
			/* translators: %s: formatted money gap */
			__( 'COGS exceeds revenue by %s', 'marginbeacon' ),
			$formatted
		);

		if ( $loss > 0 ) {
			$base .= '; ' . sprintf(
				/* translators: %d: count */
				_n( '%d item sold below cost', '%d items sold below cost', $loss, 'marginbeacon' ),
				$loss
			);
		}

		return $base;
	}
}