<?php
/**
 * Curated alternatives for common closed WooCommerce plugins.
 *
 * @package Brachmelder
 */

namespace Brachmelder;

defined( 'ABSPATH' ) || exit;

/**
 * Reads data/alternatives.json. No remote requests.
 */
class Alternatives {

	/**
	 * Path to the JSON file.
	 *
	 * @var string
	 */
	private $file;

	/**
	 * Decoded categories, loaded lazily.
	 *
	 * @var array<string, array<string, mixed>>|null
	 */
	private $categories;

	/**
	 * Constructor.
	 *
	 * @param string $file Path to alternatives.json.
	 */
	public function __construct( string $file ) {
		$this->file = $file;
	}

	/**
	 * Finds alternatives for a plugin.
	 *
	 * Matches the slug against known closed plugins first and falls back to
	 * keywords in the plugin name.
	 *
	 * @param string $slug WordPress.org slug.
	 * @param string $name Plugin name.
	 * @return array<int, array{slug: string, name: string, url: string}>
	 */
	public function find( string $slug, string $name ): array {
		$category = $this->match_category( $slug, $name );
		if ( null === $category ) {
			return array();
		}

		$found = array();
		foreach ( $category['alternatives'] as $alternative ) {
			if ( empty( $alternative['slug'] ) || $alternative['slug'] === $slug ) {
				continue;
			}
			$found[] = array(
				'slug' => (string) $alternative['slug'],
				'name' => (string) ( $alternative['name'] ?? $alternative['slug'] ),
				'url'  => 'https://wordpress.org/plugins/' . rawurlencode( (string) $alternative['slug'] ) . '/',
			);
		}
		return $found;
	}

	/**
	 * Finds the matching category.
	 *
	 * @param string $slug Slug.
	 * @param string $name Plugin name.
	 * @return array<string, mixed>|null
	 */
	private function match_category( string $slug, string $name ): ?array {
		$categories = $this->categories();

		foreach ( $categories as $category ) {
			if ( in_array( $slug, (array) ( $category['closed'] ?? array() ), true ) ) {
				return $category;
			}
		}

		$haystack = self::lower( $name . ' ' . str_replace( '-', ' ', $slug ) );
		foreach ( $categories as $category ) {
			foreach ( (array) ( $category['keywords'] ?? array() ) as $keyword ) {
				if ( preg_match( '/\b' . preg_quote( self::lower( (string) $keyword ), '/' ) . '/u', $haystack ) ) {
					return $category;
				}
			}
		}

		return null;
	}

	/**
	 * UTF-8 safe lower case.
	 *
	 * On PHP < 8, strtolower() depends on the locale and can break multibyte
	 * characters such as "ü", which makes preg_match() with /u fail.
	 *
	 * @param string $text Text.
	 * @return string
	 */
	private static function lower( string $text ): string {
		if ( function_exists( 'mb_strtolower' ) ) {
			return mb_strtolower( $text, 'UTF-8' );
		}
		return strtr( $text, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz' );
	}

	/**
	 * Loads the categories.
	 *
	 * @return array<string, array<string, mixed>>
	 */
	private function categories(): array {
		if ( null === $this->categories ) {
			$this->categories = array();
			if ( is_readable( $this->file ) ) {
				// Local file shipped with the plugin.
				$data = json_decode( (string) file_get_contents( $this->file ), true ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
				if ( isset( $data['categories'] ) && is_array( $data['categories'] ) ) {
					foreach ( $data['categories'] as $key => $category ) {
						if ( is_array( $category ) && ! empty( $category['alternatives'] ) && is_array( $category['alternatives'] ) ) {
							$this->categories[ (string) $key ] = $category;
						}
					}
				}
			}
		}
		return $this->categories;
	}
}