<?php
/**
 * Stats API Endpoint: Posts
 *
 * @package Parsely
 * @since   3.17.0
 */

declare(strict_types=1);

namespace Parsely\REST_API\Stats;

use Parsely\REST_API\Base_Endpoint;
use Parsely\Services\Content_API\Content_API_Service;
use WP_Error;
use WP_REST_Request;
use WP_REST_Response;
use stdClass;

/**
 * The Stats API Posts endpoint.
 *
 * Provides an endpoint for retrieving posts.
 *
 * @since 3.17.0
 */
class Endpoint_Posts extends Base_Endpoint {
	use Post_Data_Trait;

	public const TOP_POSTS_DEFAULT_LIMIT = 5;
	public const SORT_DEFAULT            = 'views';

	/**
	 * The metrics that can be sorted by.
	 *
	 * @since 3.17.0
	 *
	 * @var array<int, string>
	 * @see https://docs.parse.ly/api-available-metrics/
	 */
	public const SORT_METRICS = array(
		'views',
		'mobile_views',
		'tablet_views',
		'desktop_views',
		'visitors',
		'visitors_new',
		'visitors_returning',
		'engaged_minutes',
		'avg_engaged',
		'avg_engaged_new',
		'avg_engaged_returning',
		'social_interactions',
		'fb_interactions',
		'tw_interactions',
		'pi_interactions',
		'social_referrals',
		'fb_referrals',
		'tw_referrals',
		'pi_referrals',
		'search_refs',
	);

	/**
	 * The Parse.ly Content API service.
	 *
	 * @since 3.17.0
	 *
	 * @var Content_API_Service
	 */
	public $content_api;

	/**
	 * Constructor.
	 *
	 * @since 3.17.0
	 *
	 * @param Stats_Controller $controller The stats controller.
	 */
	public function __construct( Stats_Controller $controller ) {
		parent::__construct( $controller );
		$this->content_api = $this->parsely->get_content_api();
	}

	/**
	 * Returns the endpoint's name.
	 *
	 * @since 3.17.0
	 *
	 * @return string
	 */
	public static function get_endpoint_name(): string {
		return 'posts';
	}

	/**
	 * Registers the routes for the objects of the controller.
	 *
	 * @since 3.17.0
	 */
	public function register_routes(): void {
		/**
		 * GET /posts
		 * Retrieves posts for the given criteria.
		 */
		$this->register_rest_route(
			'/',
			array( 'GET' ),
			array( $this, 'get_posts' ),
			array_merge(
				array(
					'use_wp_permalink' => array(
						'description' => 'Whether to use the WordPress permalink.',
						'type'        => 'boolean',
						'required'    => false,
						'default'     => false,
					),
					'period_start'     => array(
						'description' => 'The start of the period to query.',
						'type'        => 'string',
						'required'    => false,
					),
					'period_end'       => array(
						'description' => 'The end of the period to query.',
						'type'        => 'string',
						'required'    => false,
					),
					'pub_date_start'   => array(
						'description' => 'The start of the publication date range to query.',
						'type'        => 'string',
						'required'    => false,
					),
					'pub_date_end'     => array(
						'description' => 'The end of the publication date range to query.',
						'type'        => 'string',
						'required'    => false,
					),
					'limit'            => array(
						'description' => 'The number of posts to return.',
						'type'        => 'integer',
						'required'    => false,
						'default'     => self::TOP_POSTS_DEFAULT_LIMIT,
					),
					'sort'             => array(
						'description' => 'The sort order of the posts.',
						'type'        => 'string',
						'enum'        => self::SORT_METRICS,
						'default'     => self::SORT_DEFAULT,
						'required'    => false,
					),
					'page'             => array(
						'description' => 'The page to fetch.',
						'type'        => 'integer',
						'required'    => false,
						'default'     => 1,
					),
					'author'           => array(
						'description' => 'The author to filter by.',
						'type'        => 'string',
						'required'    => false,
					),
					'section'          => array(
						'description' => 'The section to filter by.',
						'type'        => 'string',
						'required'    => false,
					),
					'tag'              => array(
						'description'       => 'The tags to filter by (in comma-separated format).',
						'type'              => 'string',
						'required'          => false,
						'validate_callback' => array( $this, 'validate_max_length_is_5' ),
						'sanitize_callback' => array( $this, 'sanitize_string_to_array' ),
					),
					'segment'          => array(
						'description' => 'The segment to filter by.',
						'type'        => 'string',
						'required'    => false,
					),
					'urls'             => array(
						'description'       => 'The URLs to fetch data for.',
						'type'              => 'array',
						'sanitize_callback' => array( $this, 'sanitize_urls' ),
						'validate_callback' => array( $this, 'validate_urls' ),
						'required'          => false,
					),
					// Optional Campaign Parameters.
					'campaign_id'      => array(
						'description' => 'The campaign to filter by.',
						'type'        => 'string',
						'required'    => false,
					),
					'campaign_medium'  => array(
						'description' => 'The medium to filter by.',
						'type'        => 'string',
						'required'    => false,
					),
					'campaign_source'  => array(
						'description' => 'The source to filter by.',
						'type'        => 'string',
						'required'    => false,
					),
					'campaign_content' => array(
						'description' => 'The content to filter by.',
						'type'        => 'string',
						'required'    => false,
					),
					'campaign_term'    => array(
						'description' => 'The term to filter by.',
						'type'        => 'string',
						'required'    => false,
					),
				),
				$this->get_itm_source_param_args()
			)
		);
	}

	/**
	 * Sanitizes a string to an array, splitting it by commas.
	 *
	 * @since 3.17.0
	 *
	 * @param string|array<string> $str The string to sanitize.
	 * @return array<string> The sanitized array.
	 */
	public function sanitize_string_to_array( $str ): array {
		if ( is_array( $str ) ) {
			return $str;
		}

		return explode( ',', $str );
	}

	/**
	 * Sanitizes all the items of an array as URLs.
	 *
	 * @since 3.18.0
	 *
	 * @param array<string> $urls The array to sanitize.
	 * @return array<string> The sanitized array.
	 */
	public function sanitize_urls( array $urls ): array {
		return array_map( 'sanitize_url', $urls );
	}

	/**
	 * Validates if the provided array is a list of URLs.
	 *
	 * @since 3.19.0
	 *
	 * @param array<string> $urls The array to validate.
	 * @return true|WP_Error
	 */
	public function validate_urls( array $urls ) {
		foreach ( $urls as $url ) {
			if ( false === filter_var( $url, FILTER_VALIDATE_URL ) ) {
				return new WP_Error( 'invalid_param', __( 'The parameter must be a list of URLs.', 'wp-parsely' ) );
			}
		}

		return true;
	}

	/**
	 * Validates that the parameter has at most 5 items.
	 *
	 * @since 3.17.0
	 *
	 * @param string|array<string> $string_or_array The string or array to validate.
	 * @return true|WP_Error
	 */
	public function validate_max_length_is_5( $string_or_array ) {
		if ( is_string( $string_or_array ) ) {
			$string_or_array = $this->sanitize_string_to_array( $string_or_array );
		}

		if ( count( $string_or_array ) > 5 ) {
			return new WP_Error( 'invalid_param', __( 'The parameter must have at most 5 items.', 'wp-parsely' ) );
		}

		return true;
	}

	/**
	 * API Endpoint: GET /stats/posts
	 *
	 * Retrieves the posts with the given query parameters.
	 *
	 * @since 3.17.0
	 *
	 * @param WP_REST_Request $request The request.
	 * @return array<string, stdClass>|WP_Error|WP_REST_Response
	 */
	public function get_posts( WP_REST_Request $request ) {
		$params = $request->get_params();

		// Setup the itm_source if it is provided.
		$this->set_itm_source_from_request( $request );

		// Determine if we should use the campaign parameters.
		$use_campaign_params = false;
		if ( isset( $params['campaign_id'] ) ||
			isset( $params['campaign_medium'] ) ||
			isset( $params['campaign_source'] ) ||
			isset( $params['campaign_content'] ) ||
			isset( $params['campaign_term'] ) ) {
			$use_campaign_params = true;
		}

		// If we are using the WordPress permalink, generate a canonical URL for each URL.
		if ( isset( $params['use_wp_permalink'] ) && $params['use_wp_permalink'] && isset( $params['urls'] ) && is_array( $params['urls'] ) ) {
			$new_urls = array();

			foreach ( $params['urls'] as $url ) {
				// Generate a canonical URL for the WordPress permalink.
				$new_urls[] = \Parsely\Parsely::get_canonical_url( $url );

				// Also append the WordPress permalink to the new URLs as a fallback.
				$new_urls[] = $url;
			}

			$params['urls'] = $new_urls;
		}

		// Build the request params.
		$request_params = array(
			'period_start'   => $params['period_start'] ?? null,
			'period_end'     => $params['period_end'] ?? null,
			'pub_date_start' => $params['pub_date_start'] ?? null,
			'pub_date_end'   => $params['pub_date_end'] ?? null,
			'limit'          => $params['limit'] ?? self::TOP_POSTS_DEFAULT_LIMIT,
			'sort'           => $params['sort'] ?? self::SORT_DEFAULT,
			'page'           => $params['page'] ?? 1,
			'author'         => $params['author'] ?? null,
			'section'        => $params['section'] ?? null,
			'tag'            => $params['tag'] ?? null,
			'segment'        => $params['segment'] ?? null,
			'itm_source'     => $params['itm_source'] ?? null,
			'urls'           => $params['urls'] ?? null,
		);

		/**
		 * The raw analytics data, received by the API.
		 *
		 * @var array<array<string, mixed>>|WP_Error $analytics_request
		 */
		$analytics_request = $this->content_api->get_posts( $request_params );

		if ( is_wp_error( $analytics_request ) ) {
			return $analytics_request;
		}

		// If we are using campaign parameters, fetch the additional campaign data.
		if ( $use_campaign_params ) {
			$analytics_request = $this->fetch_campaign_data( $analytics_request, $params, $request_params );

			if ( is_wp_error( $analytics_request ) ) {
				return $analytics_request;
			}
		}

		// Process the data.
		$posts = array();

		/**
		 * The analytics data object.
		 *
		 * @var array<string,array<mixed>> $analytics_request
		 */
		foreach ( $analytics_request as $item ) {
			$posts[] = $this->extract_post_data( $item );
		}

		$response_data = array(
			'params' => $params,
			'data'   => $posts,
		);

		return new WP_REST_Response( $response_data, 200 );
	}

	/**
	 * Fetches the campaign data for the posts.
	 *
	 * @since 3.19.0
	 *
	 * @param array<int<0, max>, array<string, mixed>> $posts The posts.
	 * @param array<string, mixed>                     $params The parameters.
	 * @param array<string, mixed>                     $request_params The request parameters.
	 * @return array<int<0, max>, array<string, mixed>>|WP_Error The posts with the campaign parameters added.
	 */
	public function fetch_campaign_data( array $posts, array $params, array $request_params = array() ) {
		$campaign_params = array();

		// Build the campaign params for the request.
		if ( isset( $params['campaign_id'] ) ) {
			$campaign_params['campaign_id'] = $params['campaign_id'];
		}
		if ( isset( $params['campaign_medium'] ) ) {
			$campaign_params['campaign_medium'] = $params['campaign_medium'];
		}
		if ( isset( $params['campaign_source'] ) ) {
			$campaign_params['campaign_source'] = $params['campaign_source'];
		}
		if ( isset( $params['campaign_content'] ) ) {
			$campaign_params['campaign_content'] = $params['campaign_content'];
		}
		if ( isset( $params['campaign_term'] ) ) {
			$campaign_params['campaign_term'] = $params['campaign_term'];
		}

		// Merge the campaign params with the request params.
		/** @var array<string, array<string, mixed>> $request_params_with_campaign */
		$request_params_with_campaign = array_merge( $campaign_params, $request_params );

		$post_urls = array();
		foreach ( $posts as $post ) {
			if ( ! is_string( $post['link'] ) ) {
				continue;
			}

			/**
			 * Post URL without ITM parameters.
			 *
			 * @var string $post_url
			 */
			$post_url    = \Parsely\Parsely::get_url_with_itm_source( $post['link'], null );
			$post_urls[] = $post_url;
		}

		// Fill the URLs with the campaign params.
		/** @var array<string, array<string, mixed>> $request_params_with_campaign */
		$request_params_with_campaign['urls'] = $post_urls;

		/**
		 * The raw analytics data, received by the API.
		 *
		 * @var array<array<string, mixed>>|WP_Error $campaign_request
		 */
		$campaign_request = $this->content_api->get_posts( $request_params_with_campaign );

		if ( is_wp_error( $campaign_request ) ) {
			/** @var WP_Error $campaign_request */
			return $campaign_request;
		}

		$posts_with_campaign_data = array();
		foreach ( $posts as $post ) {
			// Find the post by URL in the campaign request.
			$campaign_post = array_filter(
				$campaign_request,
				function ( array $item ) use ( $post ) {
					return $item['link'] === $post['link'];
				}
			);

			if ( array() === $campaign_post ) {
				// If there are no campaign metrics available, skip this one.
				$posts_with_campaign_data[] = $post;
				continue;
			}

			/** @var array<string, array<string, mixed>> $campaign_post */
			$campaign_post = $campaign_post[0];

			$post['campaign_metrics'] = array(
				'views'              => $campaign_post['metrics']['views'],
				'visitors'           => $campaign_post['metrics']['visitors'],
				'recirculation_rate' => $campaign_post['metrics']['recirculation_rate'],
				'avg_engaged'        => $campaign_post['metrics']['avg_engaged'],
			);

			$posts_with_campaign_data[] = $post;
		}

		return $posts_with_campaign_data;
	}
}