<?php

namespace AdPresso\Admin\Ajax;

use AdPresso\Constants;
use AdPresso\Entities\Ad;
use AdPresso\Entities\Entity;
use AdPresso\Entities\Group;
use AdPresso\Entities\Placement;
use AdPresso\Admin\Screens\SettingsPage;
use AdPresso\Infrastructure\Util;
use WP_Error;
use WP_REST_Request;
use WP_REST_Response;
use WP_REST_Server;

defined( 'ABSPATH' ) || exit;

/**
 * Handles AJAX requests for the global "Command Palette" search.
 * Searches through Ads, Groups, Placements, and Settings without new DB queries.
 */
class GlobalSearchHandler {

	private const MIN_SEARCH_LENGTH = 3;

	/**
	 * Registers the AJAX action hook.
	 */
	public function hooks(): void {
		add_action( 'rest_api_init', [ $this, 'register_routes' ] );
	}

	/**
	 * Register the global search REST route.
	 *
	 * @return void
	 */
	public function register_routes(): void {
		register_rest_route( 'adpresso/v1', '/search', [
			'methods'             => WP_REST_Server::READABLE,
			'callback'            => [ $this, 'handle_search_request' ],
			'permission_callback' => function() {
				return current_user_can( adpresso_get_capability( 'edit_ad' ) );
			},
			'args'                => [
				's' => [
					'required'          => true,
					'type'              => 'string',
					'sanitize_callback' => 'sanitize_text_field',
				],
			],
		] );
	}

	/**
	 * Handles the search request and returns the JSON response.
	 *
	 * @param WP_REST_Request $request The REST request object.
	 *
	 * @return WP_REST_Response|WP_Error
	 */
	public function handle_search_request( WP_REST_Request $request ): WP_Error|WP_REST_Response {
		$search_term = $request->get_param( 's' );

		if ( mb_strlen( $search_term ) < self::MIN_SEARCH_LENGTH ) {
			return rest_ensure_response( [] );
		}

		$results = [];

		$results = array_merge( $results, $this->search_entities( $search_term ) );
		$results = array_merge( $results, $this->search_settings( $search_term ) );

		$unique_results = [];
		$seen_urls      = [];
		foreach ( $results as $result ) {
			if ( isset( $result['url'] ) && ! in_array( $result['url'], $seen_urls, true ) ) {
				$unique_results[] = $result;
				$seen_urls[]      = $result['url'];
			}
		}

		$results = array_slice( $unique_results, 0, 40 );

		return rest_ensure_response( $results );
	}

	/**
	 * Helper function to check if a string contains all words from a search term.
	 *
	 * @param string $haystack    The string to search within.
	 * @param string $search_term The string of keywords to find.
	 *
	 * @return bool True if all keywords are found.
	 */
	private function string_contains_all_keywords( string $haystack, string $search_term ): bool {
		// Split the search term into individual keywords
		$keywords = explode( ' ', $search_term );
		// Remove empty values that can result from multiple spaces
		$keywords = array_filter( $keywords, 'trim' );

		if ( empty( $keywords ) ) {
			return false;
		}

		// Check if all keywords exist in the haystack (case-insensitive)
		foreach ( $keywords as $keyword ) {
			if ( stripos( $haystack, $keyword ) === false ) {
				return false; // If one keyword is not found, it's not a match
			}
		}

		return true; // All keywords were found
	}

	/**
	 * Searches through all loaded Ads, Groups, and Placements.
	 *
	 * @param string $search_term The user's search term.
	 *
	 * @return array A list of formatted result items.
	 */
	private function search_entities( string $search_term ): array {
		$found_items = [];

		$placements = adpresso_get_placement_repository()->get_all();
		$groups     = adpresso_get_group_repository()->get_all();
		$ads        = adpresso_get_ad_repository()->get_all();

		$all_entities = array_merge( $ads, $groups, $placements );

		foreach ( $all_entities as $entity ) {
			/** @var Entity $entity */
			$title   = $entity->get_title();
			$context = '';

			if ( $entity instanceof Ad ) {
				$type_label = __( 'Ad', 'adpresso' );
				$type_slug  = 'ad';
				$list_slug  = 'ads';
				$context    = $entity->get_type_object() ? $entity->get_type_object()->get_title() : $entity->get_type();
			} elseif ( $entity instanceof Group ) {
				$type_label = __( 'Group', 'adpresso' );
				$type_slug  = 'group';
				$list_slug  = 'groups';
			} elseif ( $entity instanceof Placement ) {
				$type_label = __( 'Placement', 'adpresso' );
				$type_slug  = 'placement';
				$list_slug  = 'placements';
				$context    = $entity->get_type_object() ? $entity->get_type_object()->get_title() : $entity->get_type();
			} else {
				continue;
			}

			$url               = Util::get_entity_edit_url( $list_slug, $entity->get_id() );
			$searchable_string = $title . ' ' . $context;

			if ( $this->string_contains_all_keywords( $searchable_string, $search_term ) ) {
				$found_items[] = [
					'title'       => $title,
					'id'          => $entity->get_id(),
					'type'        => $type_label,
					'type_slug'   => $type_slug,
					'list_slug'   => $list_slug,
					'context'     => $context,
					'description' => '',
					'url'         => $url,
				];
			}

			// Search in title and context
			if ( stripos( $title, $search_term ) !== false ) {
				$found_items[] = [
					'title'     => $title,
					'type'      => $type_label,
					'type_slug' => $type_slug,
					'context'   => $context,
					'url'       => $url,
				];
			}
		}

		return $found_items;
	}

	/**
	 * Searches through all registered setting definitions.
	 *
	 * @param string $search_term The user's search term.
	 *
	 * @return array A list of formatted result items.
	 */
	private function search_settings( string $search_term ): array {
		$found_items   = [];
		$settings_page = SettingsPage::get();

		foreach ( $settings_page->get_tabs() as $tab ) {
			$tab_id    = $tab->get_id();
			$tab_title = $tab->get_title();

			foreach ( $tab->get_options() as $option_key => $option_config ) {
				$option_label = $option_config['label'] ?? '';
				$option_desc  = $option_config['description'] ?? '';

				$searchable_string = $option_label . ' ' . $option_desc;

				if ( $this->string_contains_all_keywords( $searchable_string, $search_term ) ) {
					$url = add_query_arg(
						[ 'page' => 'adpresso_settings', 'tab' => $tab_id ],
						admin_url( 'admin.php' )
					);
					// the anchor should point to the field ID, e.g. '#adpresso_ad_label_text'
					$url .= '#' . ( Constants::META_PREFIX ?? 'adpresso_' ) . 'wrapper_' . $option_key;

					$found_items[] = [
						'title'       => $option_label,
						'type'        => __( 'Setting', 'adpresso' ),
						'type_slug'   => 'setting',
						'context'     => $tab_title,
						'description' => $option_desc,
						'url'         => $url,
					];
				}
			}
		}

		return $found_items;
	}
}