<?php
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * What the plugin's home shows about WinnyPlus itself: the services and where the brand stands with each, with a few numbers per active one.
 * It is read from the platform, never written in the plugin: a new service, a new number or a new word shows up here without a new plugin version.
 *
 * Connected: the brand's own overview (the installation token). Not connected: the public list of services, so the visitor sees what they get.
 * The answer is kept for a few minutes (a page load never waits on the network twice), and the last good one is kept for when the platform cannot
 * be reached, so the home is never empty.
 */
class WinnyPlus_Connect_Overview {

	const LAST_GOOD = 'winnyplus_connect_overview_last';

	/**
	 * @param bool $force Ask the platform now, whatever is kept.
	 * @return array{data: ?array, error: ?string, stale: bool}
	 */
	public static function get( $force = false ) {
		$connected = WinnyPlus_Connect_Connection::is_connected();
		$lang      = WinnyPlus_Connect_Links::language();
		$key       = 'winnyplus_connect_overview_' . ( $connected ? 'c' : 'p' ) . '_' . $lang;

		if ( ! $force ) {
			$kept = get_transient( $key );
			if ( is_array( $kept ) ) {
				return array( 'data' => $kept, 'error' => null, 'stale' => false );
			}
		}

		$fetched = $connected ? self::fetch_overview( $lang ) : self::fetch_catalog( $lang );
		if ( is_array( $fetched ) ) {
			set_transient( $key, $fetched, $connected ? 5 * MINUTE_IN_SECONDS : HOUR_IN_SECONDS );
			if ( $connected ) {
				update_option( self::LAST_GOOD, array( 'lang' => $lang, 'data' => $fetched ), false );
			}
			return array( 'data' => $fetched, 'error' => null, 'stale' => false );
		}

		// The platform could not be reached: show the last good view (when it is in this language) and say so
		$last = $connected ? get_option( self::LAST_GOOD ) : null;
		if ( is_array( $last ) && ( $last['lang'] ?? '' ) === $lang && is_array( $last['data'] ?? null ) ) {
			return array( 'data' => $last['data'], 'error' => $fetched, 'stale' => true );
		}
		return array( 'data' => null, 'error' => $fetched, 'stale' => false );
	}

	/** Forget what is kept: the next read asks the platform. */
	public static function forget() {
		foreach ( array( 'c', 'p' ) as $kind ) {
			foreach ( array( 'en', 'ar', 'fr' ) as $lang ) {
				delete_transient( 'winnyplus_connect_overview_' . $kind . '_' . $lang );
			}
		}
	}

	/** @return array|string The overview, or the reason it could not be read. */
	private static function fetch_overview( $lang ) {
		$connection = WinnyPlus_Connect_Connection::get();
		$token      = WinnyPlus_Connect_Connection::get_token();
		if ( '' === $token ) {
			return __( 'Invalid connection token.', 'winnyplus' );
		}
		$url = trailingslashit( $connection['site_url'] ) . 'v1/integrations/installations/' . rawurlencode( $connection['installation_id'] ) . '/overview?lang=' . rawurlencode( $lang );
		return self::request( $url, array( 'Authorization' => 'Bearer ' . $token ) );
	}

	/** @return array|string */
	private static function fetch_catalog( $lang ) {
		return self::request( trailingslashit( WinnyPlus_Connect_Links::api() ) . 'v1/integrations/plugin/services?lang=' . rawurlencode( $lang ), array() );
	}

	/** @return array|string */
	private static function request( $url, $headers ) {
		$response = wp_remote_get( $url, array( 'timeout' => 6, 'headers' => $headers + array( 'Accept' => 'application/json' ) ) );
		if ( is_wp_error( $response ) ) {
			return $response->get_error_message();
		}
		$code = wp_remote_retrieve_response_code( $response );
		$body = json_decode( wp_remote_retrieve_body( $response ), true );
		if ( $code < 200 || $code >= 300 || ! is_array( $body ) || ! isset( $body['data']['services'] ) || ! is_array( $body['data']['services'] ) ) {
			return ! empty( $body['error']['message'] ) ? (string) $body['error']['message'] : sprintf( /* translators: %d: HTTP status code */ __( 'WinnyPlus answered with an unexpected response (%d).', 'winnyplus' ), $code );
		}
		return $body['data'];
	}
}