<?php
/**
 * Content summarization experiment implementation.
 *
 * @package WordPress\AI
 */

declare( strict_types=1 );

namespace WordPress\AI\Experiments\Summarization;

use WordPress\AI\Abilities\Summarization\Summarization as Summarization_Ability;
use WordPress\AI\Abstracts\Abstract_Feature;
use WordPress\AI\Asset_Loader;
use WordPress\AI\Experiments\Experiment_Category;

use function WordPress\AI\get_bulk_action_max_items;
use function WordPress\AI\get_min_content_length;
use function WordPress\AI\post_type_supports_bulk_action;

// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Content summarization experiment.
 *
 * @since 0.2.0
 */
class Summarization extends Abstract_Feature {

	/**
	 * One-shot query args the bulk action redirect uses to trigger generation.
	 *
	 * @since 1.3.0
	 *
	 * @var list<string>
	 */
	private const BULK_QUERY_ARGS = array( 'wpai_bulk_summary', 'wpai_post_ids', '_wpai_bulk_nonce' ); // phpcs:ignore SlevomatCodingStandard.Classes.DisallowMultiConstantDefinition -- This is used as an array const.

	/**
	 * Nonce action signing the bulk action redirect.
	 *
	 * @since x.x.x
	 *
	 * @var string
	 */
	private const BULK_NONCE_ACTION = 'wpai_bulk_summary';

	/**
	 * {@inheritDoc}
	 */
	public static function get_id(): string {
		return 'summarization';
	}

	/**
	 * {@inheritDoc}
	 */
	protected function load_metadata(): array {
		return array(
			'label'       => __( 'Content Summarization', 'ai' ),
			'description' => __( 'Summarizes long-form content into digestible overviews. Requires an AI connector that includes support for text generation models.', 'ai' ),
			'category'    => Experiment_Category::EDITOR,
		);
	}

	/**
	 * {@inheritDoc}
	 */
	public function register(): void {
		$this->register_post_meta();
		add_action( 'wp_abilities_api_init', array( $this, 'register_abilities' ) );
		add_action( 'enqueue_block_editor_assets', array( $this, 'enqueue_assets' ), 5 );
		add_action( 'enqueue_block_assets', array( $this, 'enqueue_block_assets' ) );

		add_action( 'load-edit.php', array( $this, 'register_bulk_action_hooks_for_screen' ) );
		add_action( 'admin_enqueue_scripts', array( $this, 'maybe_enqueue_bulk_assets' ) );
		add_filter( 'removable_query_args', array( $this, 'register_removable_query_args' ) );
	}

	/**
	 * Registers the bulk summary trigger params as removable query args.
	 *
	 * The bulk action redirect carries `wpai_bulk_summary` and `wpai_post_ids`
	 * in the URL, and the bulk script runs whenever they are present. Listing
	 * them here lets core clean them out of the address bar on the first paint,
	 * via the canonical URL it prints in `admin_head`, so reloading the results
	 * page does not re-trigger the whole generation. The sort and pagination
	 * links are handled by the request URI scrub in
	 * {@see Summarization::maybe_enqueue_bulk_assets()}.
	 *
	 * @since 1.3.0
	 *
	 * @param list<string> $args Query args removed from admin URLs.
	 * @return list<string> Args including the bulk summary trigger params.
	 */
	public function register_removable_query_args( array $args ): array {
		return array_merge( $args, self::BULK_QUERY_ARGS );
	}

	/**
	 * Registers the bulk action hooks for the current post list table screen.
	 *
	 * Hooked to load-edit.php so it only fires on post list tables. Reads the
	 * requested post type from the query string and restricts bulk summarization
	 * to post types exposed via the REST API.
	 *
	 * @since 1.2.0
	 */
	public function register_bulk_action_hooks_for_screen(): void {
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended
		$post_type = isset( $_GET['post_type'] ) ? sanitize_key( $_GET['post_type'] ) : 'post';

		if ( ! post_type_supports_bulk_action( $post_type, $this->get_id() ) ) {
			return;
		}

		add_filter( "bulk_actions-edit-{$post_type}", array( $this, 'register_bulk_action' ) );
		add_filter( "handle_bulk_actions-edit-{$post_type}", array( $this, 'handle_bulk_action' ), 10, 3 );
	}

	/**
	 * Register any needed post meta.
	 *
	 * @since 0.3.0
	 */
	public function register_post_meta(): void {
		register_meta(
			'post',
			'wpai_generated_summary',
			array(
				'type'         => 'string',
				'single'       => true,
				'show_in_rest' => true,
			)
		);
	}

	/**
	 * Registers any needed abilities.
	 *
	 * @since 0.2.0
	 */
	public function register_abilities(): void {
		wp_register_ability(
			'ai/' . $this->get_id(),
			array(
				'label'         => $this->get_label(),
				'description'   => $this->get_description(),
				'ability_class' => Summarization_Ability::class,
			),
		);
	}

	/**
	 * Enqueues and localizes the block editor script.
	 *
	 * @since 0.3.0
	 */
	public function enqueue_assets(): void {
		$screen = get_current_screen();
		if ( ! $screen || 'post' !== $screen->base ) {
			return;
		}

		Asset_Loader::enqueue_script( 'summarization', 'experiments/summarization', array( 'include_core_abilities' => true ) );

		Asset_Loader::localize_script(
			'summarization',
			'SummarizationData',
			array(
				'enabled'          => $this->is_enabled(),
				'minContentLength' => $this->get_min_content_length(),
			)
		);
	}

	/**
	 * Gets the minimum content length required to enable summarization.
	 *
	 * @since 1.2.0
	 *
	 * @return int The minimum number of characters required.
	 */
	protected function get_min_content_length(): int {
		/**
		 * Filters the minimum content length required to enable summarization.
		 *
		 * @since 1.0.0
		 * @deprecated 1.1.0 Use {@see 'wpai_min_content_length'} instead.
		 *
		 * @param int $min_content_length The minimum number of characters required. Default 250.
		 */
		return (int) apply_filters_deprecated(
			'wpai_summarization_min_content_length',
			array( get_min_content_length( 'summarization', 250 ) ),
			'1.1.0',
			'wpai_min_content_length'
		);
	}

	/**
	 * Adds the "Generate Summary" option to the posts list bulk actions menu.
	 *
	 * @since 1.2.0
	 *
	 * @param array<string, string> $actions The existing bulk actions.
	 * @return array<string, string> The modified bulk actions.
	 */
	public function register_bulk_action( array $actions ): array {
		if ( ! $this->is_enabled() ) {
			return $actions;
		}

		$actions['wpai_generate_summary'] = __( 'Generate Summary', 'ai' );

		return $actions;
	}

	/**
	 * Handles the "Generate Summary" bulk action by redirecting with selected post IDs.
	 *
	 * The actual generation is performed client-side after the redirect so that slow
	 * AI API calls do not risk hitting PHP's execution time limit.
	 *
	 * @since 1.2.0
	 *
	 * @param string    $redirect_url The current redirect URL.
	 * @param string    $doaction     The bulk action being performed.
	 * @param list<int> $post_ids     The list of post IDs to process.
	 * @return string The redirect URL, possibly with bulk summary query args appended.
	 */
	public function handle_bulk_action( string $redirect_url, string $doaction, array $post_ids ): string {
		if ( 'wpai_generate_summary' !== $doaction || ! current_user_can( 'edit_posts' ) ) {
			return $redirect_url;
		}

		// Only keep posts the current user is allowed to edit.
		$editable_ids = array_values(
			array_filter(
				$post_ids,
				static function ( $id ) {
					return current_user_can( 'edit_post', (int) $id );
				}
			)
		);

		if ( empty( $editable_ids ) ) {
			return $redirect_url;
		}

		return add_query_arg(
			array(
				'wpai_bulk_summary' => 1,
				'wpai_post_ids'     => implode( ',', array_map( 'absint', $editable_ids ) ),
				'_wpai_bulk_nonce'  => wp_create_nonce( self::BULK_NONCE_ACTION ),
			),
			$redirect_url
		);
	}

	/**
	 * Enqueues the bulk summarization script when a bulk action redirect is detected.
	 *
	 * @since 1.2.0
	 *
	 * @param string $hook_suffix Current admin page hook suffix.
	 */
	public function maybe_enqueue_bulk_assets( string $hook_suffix ): void {
		if ( 'edit.php' !== $hook_suffix || ! isset( $_GET['wpai_bulk_summary'] ) || ! current_user_can( 'edit_posts' ) ) {
			return;
		}

		$nonce = isset( $_GET['_wpai_bulk_nonce'] ) ? sanitize_text_field( wp_unslash( $_GET['_wpai_bulk_nonce'] ) ) : '';

		if ( ! wp_verify_nonce( $nonce, self::BULK_NONCE_ACTION ) ) {
			return;
		}

		$raw_ids = isset( $_GET['wpai_post_ids'] ) ? sanitize_text_field( wp_unslash( $_GET['wpai_post_ids'] ) ) : '';
		$ids     = array_values( array_unique( array_filter( array_map( 'absint', explode( ',', $raw_ids ) ) ) ) );

		if ( empty( $ids ) ) {
			return;
		}

		// One billed model call per post, so bound the batch.
		$max_items       = get_bulk_action_max_items( $this->get_id() );
		$truncated_count = max( 0, count( $ids ) - $max_items );
		$ids             = array_slice( $ids, 0, $max_items );

		/*
		 * The trigger params have been read; scrub them from the request URI so
		 * the sort header links the list table builds from it do not carry them.
		 * Sorting links only strip `paged`, not removable query args, so this
		 * mirrors what core does for its own one-shot params in wp-admin/edit.php.
		 * The script receives the post IDs through wp_localize_script() below and
		 * does not need them to stay in the URL. The value is only rewritten, not
		 * output, so no sanitization applies.
		 */
		if ( isset( $_SERVER['REQUEST_URI'] ) ) {
			$_SERVER['REQUEST_URI'] = remove_query_arg( self::BULK_QUERY_ARGS, (string) $_SERVER['REQUEST_URI'] ); // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized
		}

		// Resolve the REST base once all posts in a list table share the same post type.
		$post_type = isset( $_GET['post_type'] ) ? sanitize_key( $_GET['post_type'] ) : 'post';

		// Mirror the post type restriction the bulk action itself is registered under.
		if ( ! post_type_supports_bulk_action( $post_type, $this->get_id() ) ) {
			return;
		}

		$post_type_obj = get_post_type_object( $post_type );
		$rest_base     = $post_type_obj && $post_type_obj->rest_base ? (string) $post_type_obj->rest_base : 'posts';

		Asset_Loader::enqueue_script( 'summarization_bulk', 'experiments/summarization-bulk', array( 'include_core_abilities' => true ) );
		Asset_Loader::localize_script(
			'summarization_bulk',
			'SummarizationBulkData',
			array(
				'postIds'          => $ids,
				'restBase'         => $rest_base,
				'minContentLength' => $this->get_min_content_length(),
				'truncatedCount'   => $truncated_count,
			)
		);
	}

	/**
	 * Enqueues the block stylesheet for the editor iframe and the front end.
	 *
	 * @since 0.9.0
	 */
	public function enqueue_block_assets(): void {
		Asset_Loader::enqueue_style( 'summarization', 'experiments/summarization' );
	}
}