<?php
/**
 * REST routes used by the block editor (live preview + category and channel
 * lists) and by the frontend live-filter script (assets/frontend.js).
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class DynamiRSS_Rest_Controller {

	const API_NAMESPACE = 'dynamirss/v1';

	private static ?DynamiRSS_Rest_Controller $instance = null;

	public static function instance(): DynamiRSS_Rest_Controller {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	private function __construct() {
		add_action( 'rest_api_init', array( $this, 'register_routes' ) );
	}

	public function register_routes(): void {
		register_rest_route(
			self::API_NAMESPACE,
			'/articles',
			array(
				'methods'             => 'GET',
				'callback'            => array( $this, 'get_articles' ),
				'permission_callback' => '__return_true',
				'args'                => array(
					'search'         => array( 'type' => 'string', 'default' => '' ),
					// category, source, exclude_source and exclude_query take either
					// one value or a list (key[]=a&key[]=b), so they're left untyped
					// here and normalized by the API client instead.
					'category'       => array( 'default' => '' ),
					'source'         => array( 'default' => '' ),
					'exclude_source' => array( 'default' => '' ),
					'exclude_query'  => array( 'default' => '' ),
					'language'       => array( 'type' => 'string', 'default' => '' ),
					'date_preset'    => array( 'type' => 'string', 'default' => '' ),
					'date'           => array( 'type' => 'string', 'default' => '' ),
					'date_from'      => array( 'type' => 'string', 'default' => '' ),
					'date_to'        => array( 'type' => 'string', 'default' => '' ),
					'query_mode'     => array( 'type' => 'string', 'default' => '' ),
					'search_in'      => array( 'type' => 'string', 'default' => '' ),
					'has_image'      => array( 'type' => 'boolean', 'default' => false ),
					'sort'           => array( 'type' => 'string', 'default' => '' ),
					'limit'          => array( 'type' => 'integer', 'default' => 12 ),
					'offset'         => array( 'type' => 'integer', 'default' => 0 ),
					'fetch_extras'   => array( 'type' => 'boolean', 'default' => true ),
					'template'       => array( 'type' => 'string', 'default' => '' ),
				),
			)
		);

		// Editor-only: the list comes from an endpoint that needs the site's API key.
		register_rest_route(
			self::API_NAMESPACE,
			'/channels',
			array(
				'methods'             => 'GET',
				'callback'            => array( $this, 'get_channels' ),
				'permission_callback' => static fn() => current_user_can( 'edit_posts' ),
			)
		);

		register_rest_route(
			self::API_NAMESPACE,
			'/categories',
			array(
				'methods'             => 'GET',
				'callback'            => array( $this, 'get_categories' ),
				'permission_callback' => '__return_true',
			)
		);
	}

	public function get_categories(): WP_REST_Response {
		return rest_ensure_response( DynamiRSS_Settings::get_categories() );
	}

	public function get_channels(): WP_REST_Response {
		return rest_ensure_response( DynamiRSS_Settings::get_channels() );
	}

	public function get_articles( WP_REST_Request $request ) {
		$search   = (string) $request->get_param( 'search' );
		$terms    = array_values( array_filter( array_map( 'trim', explode( ',', $search ) ) ) );
		$category = DynamiRSS_Api_Client::to_list( $request->get_param( 'category' ) );
		$limit    = max( 1, min( 200, (int) $request->get_param( 'limit' ) ) );
		$offset   = max( 0, (int) $request->get_param( 'offset' ) );
		$fetch_extras = (bool) $request->get_param( 'fetch_extras' );

		// Excluded words may arrive comma-separated in one string, same as "search".
		$exclude_query = $request->get_param( 'exclude_query' );
		if ( is_string( $exclude_query ) ) {
			$exclude_query = explode( ',', $exclude_query );
		}

		$filters = DynamiRSS_Api_Client::normalize_filters(
			array(
				'language'       => $request->get_param( 'language' ),
				'source'         => $request->get_param( 'source' ),
				'exclude_source' => $request->get_param( 'exclude_source' ),
				'date_preset'    => $request->get_param( 'date_preset' ),
				'date'           => $request->get_param( 'date' ),
				'date_from'      => $request->get_param( 'date_from' ),
				'date_to'        => $request->get_param( 'date_to' ),
				'query_mode'     => $request->get_param( 'query_mode' ),
				'search_in'      => $request->get_param( 'search_in' ),
				'exclude_query'  => $exclude_query,
				'has_image'      => $request->get_param( 'has_image' ),
				'sort'           => $request->get_param( 'sort' ),
			)
		);

		$result = DynamiRSS_Api_Client::instance()->scan( $terms, $category, $limit, $offset, $fetch_extras, $filters );

		if ( $result['error'] ) {
			return new WP_Error( 'dynamirss_scan_failed', $result['error'], array( 'status' => 502 ) );
		}

		// The API does the source filtering now (it used to be done here, on
		// one already-fetched page), so every article returned is a match.
		$articles = $result['articles'];

		// Only meaningful for a request that isn't narrowed to specific sources;
		// the frontend ignores it otherwise so the dropdown never shrinks down
		// to one option once a visitor has already picked a source.
		$available_sources = array_values( array_unique( array_filter( array_map(
			static fn( $a ) => (string) ( $a['source'] ?? '' ),
			$articles
		) ) ) );
		sort( $available_sources );

		$template_hash   = sanitize_key( (string) $request->get_param( 'template' ) );
		$template_blocks = $template_hash ? DynamiRSS_Blocks::get_cached_template( $template_hash ) : DynamiRSS_Blocks::default_template_blocks();

		return rest_ensure_response(
			array(
				'articles'          => $articles,
				'has_more'          => $result['has_more'],
				// Older cached results have no page_size; their page length is the same thing.
				'next_offset'       => $offset + ( $result['page_size'] ?? count( $articles ) ),
				'available_sources' => $available_sources,
				'html'              => DynamiRSS_Blocks::render_articles( $articles, $template_blocks ),
			)
		);
	}
}