<?php
/**
 * EquaSuite Content Client — the embeddable socle (shared, newest-version-wins).
 *
 * A host plugin (EquaShop, EquaTunnel, EquaSign…) copies the `client/` folder,
 * includes the loader, and mounts EquaMarket content on ITS OWN admin screens:
 *
 *     add_action( 'admin_enqueue_scripts', function ( $hook ) {
 *         if ( 'my-plugin-screen' === $hook ) { EquaSuite_Content_Client::enqueue(); }
 *     } );
 *     // …then, in the screen body:
 *     echo EquaSuite_Content_Client::render_banner( array(
 *         'product_id' => 'equashop', 'slot' => 'pro', 'locale' => get_user_locale(),
 *     ) );
 *
 * The socle talks to the EquaMarket content server over HTTPS only. It owns the
 * cache (WP transients on the host site), the timeouts, the degradation and a
 * same-origin authenticated proxy so the browser never talks cross-origin. It
 * requires NOTHING of EquaMarket on the host site.
 *
 * Host integration points (all filters, sensible defaults):
 *   equasuite_cc_content_base   (string) — server base URL (default production marketing.equadev.fr).
 *   equasuite_cc_optin          (bool, $product_id) — has the host authorised server calls?
 *   equasuite_cc_capability     (string) — capability gating the local /consume proxy.
 *   equasuite_cc_fallback_text  (string, $product_id) — the host's locally-translated
 *                                                (gettext) showcase fallback.
 *
 * Collision-safe: single shared class, all state scoped by product_id, namespaced
 * handles/transients/routes (equasuite_cc*). @see equasuite-content-client.php (loader).
 *
 * @package EquaSuite\ContentClient
 */

defined( 'ABSPATH' ) || exit;

class EquaSuite_Content_Client {

	/** REST namespace of the local (same-origin) proxy on the host site. */
	const REST_NS = 'equasuite-cc/v1';

	/** Cache durations (seconds) — the frozen EquaSuite content-cache policy. */
	const BANNER_CONTENT_TTL   = 28800; // 8h.
	const BANNER_EARLY_REFRESH = 14400; // 4h (TTL/2) — banner refetches from mid-life.
	const BANNER_EMPTY_TTL     = 3600;  // 1h.
	const BANNER_TIMEOUT       = 2.5;   // seconds, off the render path.
	const PAGE_CONTENT_TTL     = 3600;  // 1h.
	const PAGE_EMPTY_TTL       = 3600;  // 1h.
	const PAGE_TIMEOUT         = 10;    // seconds, on the render path (clock-covered).

	/** @var string Absolute dir of the booted copy. */
	private static $dir = '';

	/** @var string Public URL of the booted copy (for assets). */
	private static $url = '';

	/** @var string Booted copy version. */
	private static $version = '0.0.0';

	/** @var bool */
	private static $booted = false;

	/** @var bool Localised config emitted once. */
	private static $localized = false;

	/**
	 * Boots the socle (called once, for the highest-versioned embedded copy).
	 *
	 * @param string $dir     Absolute directory of the winning copy.
	 * @param string $version Its version.
	 * @return void
	 */
	public static function boot( $dir, $version ) {
		if ( self::$booted ) {
			return;
		}
		self::$booted  = true;
		self::$dir     = wp_normalize_path( $dir );
		self::$version = (string) $version;
		self::$url     = self::dir_to_url( self::$dir );
		add_action( 'rest_api_init', array( __CLASS__, 'register_routes' ) );
	}

	/* ====================================================================== */
	/* Host configuration (filterable, self-contained defaults).              */
	/* ====================================================================== */

	/**
	 * Content server base URL (production default; filterable for testing).
	 *
	 * @return string
	 */
	public static function remote_base() {
		return untrailingslashit( (string) apply_filters( 'equasuite_cc_content_base', 'https://marketing.equadev.fr/wp-json/equamarket/v1' ) );
	}

	/**
	 * Has the host authorised contacting the content server for this product?
	 *
	 * @param string $product_id Host product id.
	 * @return bool
	 */
	public static function is_opted_in( $product_id ) {
		return (bool) apply_filters( 'equasuite_cc_optin', false, $product_id );
	}

	/**
	 * Capability gating the local /consume proxy.
	 *
	 * @return string
	 */
	public static function capability() {
		return (string) apply_filters( 'equasuite_cc_capability', 'manage_options' );
	}

	/**
	 * The host's locally-translated dignified showcase fallback text.
	 *
	 * @param string $product_id Host product id.
	 * @return string
	 */
	public static function fallback_text( $product_id ) {
		return (string) apply_filters(
			'equasuite_cc_fallback_text',
			'This EquaSuite presentation is currently unavailable. Please try again later.',
			$product_id
		);
	}

	/* ====================================================================== */
	/* Assets — enqueue triggerable by the host on ITS hooks.                 */
	/* ====================================================================== */

	/**
	 * Registers + enqueues the socle CSS/JS and localises the shared config.
	 * Idempotent; call from the host's own admin_enqueue_scripts for its screen.
	 *
	 * @return void
	 */
	public static function enqueue() {
		if ( ! self::$booted ) {
			return;
		}
		wp_enqueue_style( 'equasuite-cc-client', self::$url . '/assets/equasuite-content-client.css', array(), self::$version );
		wp_enqueue_script( 'equasuite-cc-client', self::$url . '/assets/equasuite-content-client.js', array(), self::$version, true );
		if ( ! self::$localized ) {
			self::$localized = true;
			wp_localize_script(
				'equasuite-cc-client',
				'EQUASUITE_CC',
				array(
					'rest'  => esc_url_raw( rest_url( self::REST_NS . '/consume' ) ),
					'nonce' => wp_create_nonce( 'wp_rest' ),
					// Client abort budget = server remote-fetch timeout + headroom for
					// the local proxy round-trip, so a cold-cache fetch that succeeds
					// server-side is not aborted before its response reaches the browser.
					'bannerMs' => (int) round( self::BANNER_TIMEOUT * 1000 ) + 2000,
					'pageMs'   => (int) ( self::PAGE_TIMEOUT * 1000 ) + 3000,
				)
			);
		}
	}

	/* ====================================================================== */
	/* Public mount API.                                                      */
	/* ====================================================================== */

	/**
	 * Banner container with an inline first paint from cache (no network). The
	 * host echoes the returned string at its chosen insertion point.
	 *
	 * @param array $args product_id (required), slot (required), locale (optional).
	 * @return string
	 */
	public static function render_banner( array $args ) {
		self::enqueue(); // defensive; best practice is to enqueue on the host hook.
		$product = self::norm_product( isset( $args['product_id'] ) ? $args['product_id'] : '' );
		$slot    = sanitize_key( isset( $args['slot'] ) ? $args['slot'] : '' );
		$locale  = self::norm_locale( isset( $args['locale'] ) ? $args['locale'] : get_user_locale() );
		$optin   = self::is_opted_in( $product );

		// Only paint cached server content while opted in — if the host revoked the
		// opt-in, the banner shows nothing (consistent with the showcase, which
		// shows its local fallback). No stale server content survives an opt-out.
		$seed   = $optin ? self::servable_from_cache( 'banner', $product, $slot, $locale ) : array( 'status' => 'empty' );
		$inline = ( 'content' === $seed['status'] )
			? '<div class="equasuite-cc-banner__inner">' . wp_kses_post( $seed['html'] ) . '</div>'
			: '';

		return sprintf(
			'<div class="equasuite-cc-banner%s" data-equasuite-cc-kind="banner" data-equasuite-cc-product="%s" data-equasuite-cc-slot="%s" data-equasuite-cc-locale="%s" data-equasuite-cc-optin="%s">%s</div>',
			'' === $inline ? '' : ' is-shown',
			esc_attr( $product ),
			esc_attr( $slot ),
			esc_attr( $locale ),
			$optin ? '1' : '0',
			$inline
		);
	}

	/**
	 * Showcase container. JS fetches on the render path (clock) then shows content
	 * or the host's dignified fallback. `<noscript>` carries the fallback too.
	 *
	 * @param array $args product_id (required), slot (required), locale (optional).
	 * @return string
	 */
	public static function render_showcase( array $args ) {
		self::enqueue();
		$product  = self::norm_product( isset( $args['product_id'] ) ? $args['product_id'] : '' );
		$slot     = sanitize_key( isset( $args['slot'] ) ? $args['slot'] : '' );
		$locale   = self::norm_locale( isset( $args['locale'] ) ? $args['locale'] : get_user_locale() );
		$optin    = self::is_opted_in( $product );
		$fallback = self::fallback_text( $product );

		return sprintf(
			'<div class="equasuite-cc-showcase is-loading" data-equasuite-cc-kind="showcase" data-equasuite-cc-product="%s" data-equasuite-cc-slot="%s" data-equasuite-cc-locale="%s" data-equasuite-cc-optin="%s" data-equasuite-cc-fallback="%s">'
			. '<div class="equasuite-cc-showcase__clock" aria-hidden="true"></div>'
			. '<div class="equasuite-cc-showcase__body"></div>'
			. '<noscript><p class="equasuite-cc-showcase__fallback">%s</p></noscript>'
			. '</div>',
			esc_attr( $product ),
			esc_attr( $slot ),
			esc_attr( $locale ),
			$optin ? '1' : '0',
			esc_attr( $fallback ),
			esc_html( $fallback )
		);
	}

	/* ====================================================================== */
	/* Local same-origin proxy (REST) + remote fetch + cache.                 */
	/* ====================================================================== */

	/**
	 * Registers the authenticated same-origin proxy route on the host site.
	 *
	 * @return void
	 */
	public static function register_routes() {
		register_rest_route(
			self::REST_NS,
			'/consume',
			array(
				'methods'             => 'GET',
				'callback'            => array( __CLASS__, 'rest_consume' ),
				'permission_callback' => array( __CLASS__, 'rest_permission' ),
				'args'                => array(
					'product_id' => array( 'sanitize_callback' => 'sanitize_text_field' ),
					'kind'       => array( 'sanitize_callback' => 'sanitize_key' ),
					'slot'       => array( 'sanitize_callback' => 'sanitize_text_field' ),
					'locale'     => array( 'sanitize_callback' => 'sanitize_text_field' ),
				),
			)
		);
	}

	/**
	 * Proxy permission — filterable capability.
	 *
	 * @return bool
	 */
	public static function rest_permission() {
		return current_user_can( self::capability() );
	}

	/**
	 * Proxy callback: applies opt-in + cache policy and returns the servable
	 * envelope. Never contacts the server before the host opt-in is granted.
	 *
	 * @param WP_REST_Request $req Request.
	 * @return WP_REST_Response
	 */
	public static function rest_consume( $req ) {
		$kind    = sanitize_key( (string) $req->get_param( 'kind' ) );
		$product = self::norm_product( (string) $req->get_param( 'product_id' ) );
		if ( 'banner' !== $kind && 'showcase' !== $kind ) {
			return new WP_REST_Response( array( 'status' => 'empty' ), 200 );
		}
		if ( ! self::is_opted_in( $product ) ) {
			return new WP_REST_Response( array( 'status' => 'empty', 'blocked' => 'optin' ), 200 );
		}
		$env = self::consume(
			$kind,
			$product,
			sanitize_key( (string) $req->get_param( 'slot' ) ),
			self::norm_locale( (string) $req->get_param( 'locale' ) )
		);
		return new WP_REST_Response( $env, 200 );
	}

	/**
	 * Cache-policy consumer: returns the servable envelope, refreshing from the
	 * server per the policy. Expired content is never served; a network failure
	 * never rewrites the cache.
	 *
	 * @param string $kind    banner|showcase.
	 * @param string $product Product id.
	 * @param string $slot    Slot.
	 * @param string $locale  Locale.
	 * @return array {status, html?, refreshed}.
	 */
	public static function consume( $kind, $product, $slot, $locale ) {
		$key    = self::cache_key( $kind, $product, $slot, $locale );
		$entry  = get_transient( $key );
		$entry  = is_array( $entry ) ? $entry : null;
		$now    = time();
		$banner = ( 'banner' === $kind );
		$c_ttl  = $banner ? self::BANNER_CONTENT_TTL : self::PAGE_CONTENT_TTL;
		$e_ttl  = $banner ? self::BANNER_EMPTY_TTL : self::PAGE_EMPTY_TTL;
		$early  = $banner ? self::BANNER_EARLY_REFRESH : 0;

		$need_fetch = true;
		if ( $entry ) {
			$age = $now - (int) $entry['stored_at'];
			if ( 'content' === $entry['status'] ) {
				$need_fetch = $banner ? ( $age >= $early ) : ( $age >= $c_ttl );
			} elseif ( 'empty' === $entry['status'] ) {
				$need_fetch = ( $age >= $e_ttl );
			}
		}

		if ( $need_fetch ) {
			$fresh = self::fetch_remote( $kind, $product, $slot, $locale );
			if ( null !== $fresh ) {
				$entry = array(
					'status'    => $fresh['status'],
					'html'      => isset( $fresh['html'] ) ? $fresh['html'] : '',
					'stored_at' => $now,
				);
				set_transient( $key, $entry, ( 'content' === $fresh['status'] ) ? $c_ttl : $e_ttl );
			}
			// Failure → keep the existing cache untouched (retry next cycle).
		}

		if ( is_array( $entry ) && 'content' === $entry['status'] ) {
			$age = $now - (int) $entry['stored_at'];
			if ( $age < $c_ttl && '' !== trim( (string) $entry['html'] ) ) {
				return array(
					'status'    => 'content',
					'html'      => $entry['html'],
					'refreshed' => $need_fetch,
				);
			}
		}
		return array( 'status' => 'empty', 'refreshed' => $need_fetch );
	}

	/**
	 * Network-free read of fresh cached content for the banner's inline paint.
	 *
	 * @param string $kind    Kind.
	 * @param string $product Product id.
	 * @param string $slot    Slot.
	 * @param string $locale  Locale.
	 * @return array {status, html?}.
	 */
	public static function servable_from_cache( $kind, $product, $slot, $locale ) {
		$entry = get_transient( self::cache_key( $kind, $product, $slot, $locale ) );
		if ( ! is_array( $entry ) || empty( $entry['status'] ) ) {
			return array( 'status' => 'empty' );
		}
		$age = time() - (int) $entry['stored_at'];
		$ttl = ( 'banner' === $kind ) ? self::BANNER_CONTENT_TTL : self::PAGE_CONTENT_TTL;
		if ( 'content' === $entry['status'] && $age < $ttl && '' !== trim( (string) $entry['html'] ) ) {
			return array( 'status' => 'content', 'html' => $entry['html'] );
		}
		return array( 'status' => 'empty' );
	}

	/**
	 * One HTTPS GET to the content server. Returns {status, html?} or null on any
	 * failure. Received HTML is re-sanitised (wp_kses_post) as defence-in-depth.
	 *
	 * @param string $kind    Kind.
	 * @param string $product Product id.
	 * @param string $slot    Slot.
	 * @param string $locale  Locale.
	 * @return array|null
	 */
	private static function fetch_remote( $kind, $product, $slot, $locale ) {
		$endpoint = self::remote_base() . '/' . ( 'banner' === $kind ? 'banner' : 'showcase' );
		$url      = add_query_arg(
			array(
				'product_id' => rawurlencode( $product ),
				'locale'     => rawurlencode( $locale ),
				'slot'       => rawurlencode( $slot ),
			),
			$endpoint
		);
		$timeout = ( 'banner' === $kind ) ? self::BANNER_TIMEOUT : self::PAGE_TIMEOUT;
		$resp    = wp_remote_get(
			$url,
			array(
				'timeout'   => $timeout,
				'headers'   => array( 'Accept' => 'application/json' ),
				'sslverify' => true,
			)
		);
		if ( is_wp_error( $resp ) || 200 !== (int) wp_remote_retrieve_response_code( $resp ) ) {
			return null;
		}
		$data = json_decode( (string) wp_remote_retrieve_body( $resp ), true );
		if ( ! is_array( $data ) || empty( $data['status'] ) ) {
			return null;
		}
		if ( 'content' === $data['status'] && ! empty( $data['html'] ) ) {
			// The server sanitises at storage; we re-sanitise on the host as
			// defence-in-depth. Displayed as-is, never executed.
			return array( 'status' => 'content', 'html' => wp_kses_post( (string) $data['html'] ) );
		}
		return array( 'status' => 'empty' );
	}

	/* ====================================================================== */
	/* Helpers.                                                               */
	/* ====================================================================== */

	/**
	 * Transient key — namespaced + scoped by product_id so no host's cache ever
	 * leaks into another's.
	 *
	 * @param string $kind    Kind.
	 * @param string $product Product id.
	 * @param string $slot    Slot.
	 * @param string $locale  Locale.
	 * @return string
	 */
	private static function cache_key( $kind, $product, $slot, $locale ) {
		return 'equasuite_cc_' . md5( $product . '|' . $kind . '|' . $slot . '|' . $locale );
	}

	/**
	 * Normalises a product id (slug-like, <= 64).
	 *
	 * @param string $product Raw.
	 * @return string
	 */
	private static function norm_product( $product ) {
		return substr( sanitize_key( (string) $product ), 0, 64 );
	}

	/**
	 * Light client-side locale normalisation; the server does the real fallback.
	 *
	 * @param string $locale Raw.
	 * @return string
	 */
	private static function norm_locale( $locale ) {
		$locale = strtolower( preg_replace( '/[^A-Za-z0-9_-]/', '', (string) $locale ) );
		return '' !== $locale ? substr( $locale, 0, 12 ) : 'en';
	}

	/**
	 * Maps an absolute dir under wp-content to a public URL (plugins, mu-plugins,
	 * themes — wherever the host embedded the socle).
	 *
	 * @param string $dir Absolute dir.
	 * @return string
	 */
	private static function dir_to_url( $dir ) {
		$dir     = wp_normalize_path( $dir );
		$content = wp_normalize_path( WP_CONTENT_DIR );
		if ( 0 === strpos( $dir, $content ) ) {
			return untrailingslashit( content_url( substr( $dir, strlen( $content ) ) ) );
		}
		return untrailingslashit( plugins_url( '', $dir . '/x' ) );
	}
}