<?php
/**
 * Why chat is, or isn't, on the site.
 *
 * @package StandChat
 */

namespace StandChat;

defined( 'ABSPATH' ) || exit;

/**
 * The one status the Overview and the Dashboard widget show, highest priority
 * first, each with one action. Every reason chat wouldn't show has a name.
 */
final class Status {

	/**
	 * Works out the status.
	 *
	 * @param Connection $connection Connection.
	 * @param Stand      $stand      Stand service.
	 * @return array<string, mixed> state, title, message, action, notes, stale.
	 */
	public static function compute( Connection $connection, Stand $stand ): array {
		$settings = Settings::all();
		$domain   = Environment::home_domain();
		$check    = Installation_Check::last();
		$notes    = array();
		if ( 'consent' === $settings['consent']['mode'] ) {
			$notes[] = __( 'Chat loads after cookie consent', 'stand-chat' );
		}

		if ( $connection->needs_reconnect() ) {
			return self::state(
				'reconnect',
				__( 'Reconnect needed', 'stand-chat' ),
				Api_Client::reconnect_message(),
				self::action( __( 'Reconnect', 'stand-chat' ), 'reconnect' ),
				$notes
			);
		}

		if ( ! $connection->is_connected() ) {
			if ( '' === $settings['site_id'] ) {
				return self::state( 'setup', __( 'Not connected', 'stand-chat' ), '', null, $notes );
			}
			return self::local_status( $settings, $check, $notes );
		}

		$site = $stand->site();
		if ( is_array( $site ) && isset( $site['installed'] ) && ! $site['installed'] ) {
			// Stand marks the Site installed within a minute of the first visit:
			// while waiting, read it again rather than from the cache.
			$site = $stand->site( true );
		}
		if ( is_wp_error( $site ) && 'stand_reconnect_needed' === $site->get_error_code() ) {
			// Stand just rejected the connection.
			return self::state(
				'reconnect',
				__( 'Reconnect needed', 'stand-chat' ),
				Api_Client::reconnect_message(),
				self::action( __( 'Reconnect', 'stand-chat' ), 'reconnect' ),
				$notes
			);
		}
		if ( is_wp_error( $site ) && ! Api_Client::is_temporary( $site ) ) {
			// Stand answered, but not with this Site: it was removed in Stand,
			// or this account can't use it. Chat being live can't be told.
			return self::state(
				'unknown',
				__( 'Stand can\'t show this site', 'stand-chat' ),
				$site->get_error_message(),
				self::action( __( 'Reconnect', 'stand-chat' ), 'reconnect' ),
				$notes
			);
		}
		$stale = is_wp_error( $site );
		// While Stand can't be reached, or fails or is busy for now, the Site as
		// WordPress last saw it, and nothing more is asked of Stand, however that
		// was found out: each try could wait for its timeout.
		$offline = $stale ? $site : null;
		$ask     = static function ( callable $call ) use ( &$offline, &$stale ) {
			if ( null !== $offline ) {
				return $offline;
			}
			$answer = $call();
			if ( is_wp_error( $answer ) && Api_Client::is_temporary( $answer ) ) {
				$offline = $answer;
				$stale   = true;
			}
			return $answer;
		};
		$site    = is_wp_error( $site ) ? (array) ( Connection::stored_metadata()['site'] ?? array() ) : $site;

		if ( ! $settings['chat_enabled'] || ( isset( $site['enabled'] ) && ! $site['enabled'] ) ) {
			$off_in_stand = isset( $site['enabled'] ) && ! $site['enabled'];
			return self::state(
				'off',
				__( 'Stand is off on this site', 'stand-chat' ),
				$off_in_stand
					? __( 'The Site is turned off in Stand, so chat is off on every website that uses this Site ID.', 'stand-chat' )
					: __( 'Your settings are kept. Visitors see no chat until you turn it back on.', 'stand-chat' ),
				State::setup()['live'] || $off_in_stand ? self::action( __( 'Turn on', 'stand-chat' ), $off_in_stand ? 'enable_site' : 'enable_chat' ) : self::action( __( 'Finish setup', 'stand-chat' ), 'setup' ),
				$notes,
				$stale
			);
		}

		$hidden = Environment::hidden_reason();
		if ( '' !== $hidden ) {
			return self::hidden_status( $hidden, $notes, $stale );
		}
		if ( Environment::prints_elsewhere( $settings, Environment::is_production() ) ) {
			return self::state(
				'hidden_environment',
				__( 'Chat doesn\'t show on this address', 'stand-chat' ),
				sprintf(
					/* translators: 1: WordPress address, 2: Stand Site domain */
					__( 'This copy prints the chat script, as set, but it runs on %1$s and Stand only shows chat on %2$s.', 'stand-chat' ),
					Environment::home_domain(),
					Environment::site_domain()
				),
				self::action( __( 'Environment settings', 'stand-chat' ), 'settings_advanced' ),
				$notes,
				$stale
			);
		}

		$plan = $ask( array( $stand, 'plan' ) );
		if ( ! is_wp_error( $plan ) ) {
			$usage = $plan['usage'];
			$quota = $usage['chatQuota'] ?? null;
			if ( null !== $quota && (int) $usage['chatCount'] >= (int) $quota && (int) ( $usage['chatsBalance'] ?? 0 ) <= 0 ) {
				$on_base = 'base' === ( $plan['plan']['planCode'] ?? '' );
				return self::state(
					'quota',
					__( 'New chats are paused', 'stand-chat' ),
					sprintf(
						/* translators: 1: chat quota, 2: reset date */
						__( 'All %1$d of this period\'s chats and any extra chats are used, so visitors can\'t start a new chat until %2$s. Chats already underway continue.', 'stand-chat' ),
						(int) $quota,
						self::date( (string) $usage['periodEnd'] )
					),
					$connection->is_owner() && $on_base ? self::action( __( 'Start 7-day Pro trial', 'stand-chat' ), 'trial' ) : self::action( __( 'See plans', 'stand-chat' ), 'plans' ),
					$notes,
					$stale
				);
			}
		}

		$who     = $ask( array( $stand, 'who_answers' ) );
		$matches = $ask( array( $stand, 'matches' ) );
		if ( ! is_wp_error( $who ) && ! is_wp_error( $matches ) && empty( $matches ) && in_array( $who['mode'], array( 'only_you', 'nobody' ), true ) ) {
			return self::state(
				'nobody',
				__( 'No one is answering yet', 'stand-chat' ),
				__( 'Who answers is set to Only you, and you\'re not Available in the Stand app, so visitors see no chat.', 'stand-chat' ),
				self::action( __( 'Let your AI assistant answer', 'stand-chat' ), 'who_answers' ),
				$notes,
				$stale
			);
		}

		if ( isset( $site['installed'] ) && ! $site['installed'] ) {
			$found = $check && 'found' === ( $check['status'] ?? '' );
			return self::state(
				'waiting',
				__( 'Waiting for installation', 'stand-chat' ),
				$found
					/* translators: %s: address of the page checked */
					? sprintf( __( 'Stand script found on %s. Open your site once; Stand shows it as installed within a minute.', 'stand-chat' ), self::checked_page( $check ) )
					: self::check_message( $check ),
				// A page where chat loads, which may not be the home page.
				self::action( __( 'Open your site', 'stand-chat' ), 'view_site', Installation_Check::page_to_check() ),
				$notes,
				$stale
			);
		}

		$names = ! is_wp_error( $who ) ? array_filter( (array) $who['answering'] ) : array();
		$name  = empty( $names ) ? __( 'Your AI assistant', 'stand-chat' ) : reset( $names );
		$mode  = is_wp_error( $who ) ? '' : $who['mode'];
		if ( is_wp_error( $who ) ) {
			// No mode to describe: nobody is known to answer, nor not to.
			$message = __( 'Stand couldn\'t say who answers new chats just now.', 'stand-chat' );
		} elseif ( in_array( $mode, array( 'only_you', 'nobody' ), true ) ) {
			$message = __( 'New chats come to you while you\'re Available in the Stand app.', 'stand-chat' );
		} elseif ( 'ai_every' === $mode ) {
			/* translators: %s: AI assistant name */
			$message = sprintf( __( '%s answers every new chat.', 'stand-chat' ), $name );
		} else {
			/* translators: %s: AI assistant name */
			$message = sprintf( __( '%s answers whenever you\'re away.', 'stand-chat' ), $name );
		}
		return self::state(
			'live',
			/* translators: %s: domain */
			sprintf( __( 'Chat is live on %s', 'stand-chat' ), $domain ),
			$message,
			self::action( __( 'View your site', 'stand-chat' ), 'view_site', home_url( '/' ) ),
			$notes,
			$stale
		);
	}

	/**
	 * Status with only a pasted Site ID (no connection).
	 *
	 * @param array<string, mixed>      $settings Settings.
	 * @param array<string, mixed>|null $check    Last installation check.
	 * @param string[]                  $notes    Notes.
	 * @return array<string, mixed>
	 */
	private static function local_status( array $settings, ?array $check, array $notes ): array {
		if ( ! $settings['chat_enabled'] ) {
			return self::state(
				'off',
				__( 'Stand is off on this site', 'stand-chat' ),
				__( 'Your settings are kept. Visitors see no chat until you turn it back on.', 'stand-chat' ),
				self::action( __( 'Turn on', 'stand-chat' ), 'enable_chat' ),
				$notes
			);
		}
		$hidden = Environment::hidden_reason();
		if ( '' !== $hidden ) {
			return self::hidden_status( $hidden, $notes, false );
		}
		$found = $check && 'found' === ( $check['status'] ?? '' );
		return self::state(
			$found ? 'printing' : 'waiting',
			$found ? __( 'Stand is on your site', 'stand-chat' ) : __( 'Waiting for installation', 'stand-chat' ),
			$found
				/* translators: %s: address of the page checked */
				? sprintf( __( 'Stand script with this Site ID found on %s. Open your site once, then check Installed on the site card in Stand.', 'stand-chat' ), self::checked_page( $check ) )
				: self::check_message( $check ),
			self::action( __( 'View your site', 'stand-chat' ), 'view_site', Installation_Check::page_to_check() ),
			$notes
		);
	}

	/**
	 * "Chat is hidden on this environment".
	 *
	 * @param string   $reason non_production or domain_mismatch.
	 * @param string[] $notes  Notes.
	 * @param bool     $stale  Stand unreachable.
	 * @return array<string, mixed>
	 */
	private static function hidden_status( string $reason, array $notes, bool $stale ): array {
		$site_domain = Environment::site_domain();
		$message     = 'domain_mismatch' === $reason
			? sprintf(
				/* translators: 1: WordPress address, 2: Stand Site domain */
				__( 'This copy runs on %1$s. Stand only shows chat on %2$s.', 'stand-chat' ),
				Environment::home_domain(),
				$site_domain
			)
			: sprintf(
				/* translators: %s: environment type */
				__( 'This WordPress is set up as %s, so chat is hidden here. Production sites show chat.', 'stand-chat' ),
				Environment::type()
			);
		return self::state(
			'hidden_environment',
			__( 'Chat is hidden on this environment', 'stand-chat' ),
			$message,
			'domain_mismatch' === $reason ? self::action( __( 'Review', 'stand-chat' ), 'address' ) : self::action( __( 'Environment settings', 'stand-chat' ), 'settings_advanced' ),
			$notes,
			$stale
		);
	}

	/**
	 * Copy for an installation check result.
	 *
	 * @param array<string, mixed>|null $check Check.
	 */
	public static function check_message( ?array $check ): string {
		$page = self::checked_page( $check );
		switch ( $check['status'] ?? '' ) {
			case 'found':
				/* translators: %s: address of the page checked */
				return sprintf( __( 'Stand script with this Site ID found on %s.', 'stand-chat' ), $page );
			case 'consent_loader':
				return __( 'Chat loads on your pages after cookie consent.', 'stand-chat' );
			case 'missing':
				/* translators: %s: address of the page checked */
				return sprintf( __( 'The Stand script isn\'t on %s. A page cache may still serve an older copy: clear it, then check again. Your theme also needs to call wp_footer().', 'stand-chat' ), $page );
			case 'wrong_site_id':
				/* translators: %s: address of the page checked */
				return sprintf( __( 'The Stand script on %s has another Site ID. Clear your page cache, then check again.', 'stand-chat' ), $page );
			case 'duplicate':
				/* translators: %s: address of the page checked */
				return sprintf( __( 'Another Stand script is on %s, for example in your theme\'s header. Remove it so the chat loads once.', 'stand-chat' ), $page );
			case 'unreachable':
				/* translators: %s: address of the page checked */
				return sprintf( __( 'WordPress couldn\'t load %s to check. Open your site once to finish.', 'stand-chat' ), $page );
			default:
				return __( 'Open your site once to finish.', 'stand-chat' );
		}
	}

	/**
	 * The address of the page an installation check loaded, without the
	 * scheme: the home page, unless Where chat appears leaves it out.
	 *
	 * @param array<string, mixed>|null $check Check.
	 */
	public static function checked_page( ?array $check ): string {
		$url = (string) ( $check['url'] ?? '' );
		return untrailingslashit( (string) preg_replace( '#^https?://#i', '', '' !== $url ? $url : home_url( '/' ) ) );
	}

	/**
	 * Builds a status.
	 *
	 * @param string                     $state   State key.
	 * @param string                     $title   Title.
	 * @param string                     $message Message.
	 * @param array<string, string>|null $action Primary action.
	 * @param string[]                   $notes   Informational lines.
	 * @param bool                       $stale   Stand unreachable; data may be old.
	 * @return array<string, mixed>
	 */
	private static function state( string $state, string $title, string $message, ?array $action, array $notes, bool $stale = false ): array {
		return array(
			'state'   => $state,
			'title'   => $title,
			'message' => $message,
			'action'  => $action,
			'notes'   => $notes,
			'stale'   => $stale,
		);
	}

	/**
	 * An action button.
	 *
	 * @param string $label Label.
	 * @param string $kind  What it does; the admin app maps it to a route or call.
	 * @param string $href  Link, when it's a link.
	 * @return array<string, string>
	 */
	private static function action( string $label, string $kind, string $href = '' ): array {
		return array(
			'label' => $label,
			'kind'  => $kind,
			'href'  => $href,
		);
	}

	/**
	 * A date in the site's format, such as "Mon 20 Oct".
	 *
	 * @param string $iso ISO 8601 date.
	 */
	public static function date( string $iso ): string {
		$time = strtotime( $iso );
		return $time ? wp_date( 'D j M', $time ) : $iso;
	}
}