<?php
/**
 * Sequential invoice numbering - format PREFIX-YYYY-XXXX.
 */

defined( 'ABSPATH' ) || exit;

class EightDigits_Factura_Numbering {

	/**
	 * Normalize a series prefix to the supported storage format.
	 */
	public static function normalize_series_prefix( string $prefix ): string {
		return strtoupper( preg_replace( '/[^A-Za-z0-9\-]/', '', trim( $prefix ) ) );
	}

	/**
	 * Resolve the configured invoice series.
	 *
	 * @return array<int,array{prefix:string,name:string,start:int}>
	 */
	public static function get_invoice_series(): array {
		$prefix = self::normalize_series_prefix( (string) get_option( 'eightdigits_factura_invoice_prefix', 'F' ) );

		return array(
			array(
				'prefix' => '' !== $prefix ? $prefix : 'F',
				'name'   => __( 'General', '8digits-factura-for-woocommerce' ),
				'start'  => max( 1, (int) get_option( 'eightdigits_factura_series_start', 1 ) ),
			),
		);
	}

	/**
	 * Resolve a human-readable label for a series prefix.
	 */
	public static function get_series_label( string $prefix ): string {
		$prefix = self::normalize_series_prefix( $prefix );

		if ( '' === $prefix ) {
			return '';
		}

		foreach ( self::get_invoice_series() as $series ) {
			if ( $series['prefix'] === $prefix ) {
				return $series['name'];
			}
		}

		return $prefix;
	}

	/**
	 * Generate and reserve the next invoice number.
	 */
	public static function next( string $type = 'invoice', string $series_prefix = '' ): string {
		global $wpdb;

		$year   = (int) current_time( 'Y' );
		$prefix = self::get_prefix( $series_prefix );

		$wpdb->query( 'START TRANSACTION' ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery

		$option_key = 'eightdigits_factura_invoice_counter';
		$counters   = $wpdb->get_var( // phpcs:ignore WordPress.DB.DirectDatabaseQuery
			$wpdb->prepare(
				"SELECT option_value FROM {$wpdb->options} WHERE option_name = %s FOR UPDATE",
				$option_key
			)
		);

		$counters                     = $counters ? maybe_unserialize( $counters ) : array();
		$counter_key                  = $type . '_' . $year . '_' . $prefix;
		$current                      = isset( $counters[ $counter_key ] ) ? (int) $counters[ $counter_key ] : ( self::get_series_start( $prefix ) - 1 );
		$next_number                  = $current + 1;
		$counters[ $counter_key ]     = $next_number;

		update_option( $option_key, $counters );
		$wpdb->query( 'COMMIT' ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery

		return sprintf( '%s-%04d-%04d', $prefix, $year, $next_number );
	}

	/**
	 * Parse an invoice number back into its components.
	 *
	 * @return array{prefix:string, year:int, sequence:int}|false
	 */
	public static function parse( string $invoice_number ) {
		if ( preg_match( '/^([A-Z0-9\-]+)-(\d{4})-(\d+)$/', $invoice_number, $matches ) ) {
			return array(
				'prefix'   => $matches[1],
				'year'     => (int) $matches[2],
				'sequence' => (int) $matches[3],
			);
		}

		return false;
	}

	/**
	 * Resolve the prefix for an invoice.
	 */
	private static function get_prefix( string $series_prefix = '' ): string {
		$prefix = self::normalize_series_prefix( $series_prefix );
		if ( '' === $prefix ) {
			$series = self::get_invoice_series();
			$prefix = $series[0]['prefix'] ?? 'F';
		}

		return (string) apply_filters( 'eightdigits_factura_invoice_prefix', $prefix );
	}

	/**
	 * Resolve the starting number for the series.
	 */
	private static function get_series_start( string $prefix ): int {
		foreach ( self::get_invoice_series() as $series ) {
			if ( $series['prefix'] === $prefix ) {
				return max( 1, (int) $series['start'] );
			}
		}

		return max( 1, (int) get_option( 'eightdigits_factura_series_start', 1 ) );
	}
}