<?php
/**
 * The ambient record of whether protection is actually working.
 *
 * @package AIBlackout
 */

namespace AIBlackout\Audit;

use AIBlackout\Crawlers\Policy;
use AIBlackout\Crawlers\Registry;
use AIBlackout\Declarations\History;
use AIBlackout\Declarations\Tdmrep;

defined( 'ABSPATH' ) || exit;

/**
 * Answers the two questions a site owner three months in cannot otherwise
 * answer without going and looking.
 *
 * @since 2.0.0
 */
class ProtectionRecord {

	/**
	 * Option holding the daily verified-state history.
	 *
	 * @var string
	 */
	const STATE_OPTION = 'aiblackout_state_history';

	/**
	 * Most daily entries retained.
	 *
	 * @var int
	 */
	const MAX_STATE_ENTRIES = 90;

	/**
	 * Option holding the lifetime blocked-request total.
	 *
	 * @var string
	 */
	const TOTAL_OPTION = 'aiblackout_crawler_block_total';

	/**
	 * Truth Audit.
	 *
	 * @var Auditor
	 */
	private $auditor;

	/**
	 * Declaration history.
	 *
	 * @var History
	 */
	private $history;

	/**
	 * Crawler registry.
	 *
	 * @var Registry
	 */
	private $registry;

	/**
	 * Policy resolver.
	 *
	 * @var Policy
	 */
	private $policy;

	/**
	 * Constructor.
	 *
	 * @param Auditor  $auditor  Truth Audit.
	 * @param History  $history  Declaration history.
	 * @param Registry $registry Crawler registry.
	 * @param Policy   $policy   Policy resolver.
	 */
	public function __construct( Auditor $auditor, History $history, Registry $registry, Policy $policy ) {
		$this->auditor  = $auditor;
		$this->history  = $history;
		$this->registry = $registry;
		$this->policy   = $policy;
	}

	/**
	 * Registers hooks.
	 *
	 * @return void
	 */
	public function register(): void {
		add_action( 'aiblackout_prune_logs', array( $this, 'record_daily_check' ) );
		add_action( 'aiblackout_crawler_blocked', array( $this, 'record_blocked_request' ) );
	}

	/**
	 * Re-runs the non-loopback checks and records today's state.
	 *
	 * @return void
	 */
	public function record_daily_check(): void {
		$report = $this->auditor->report( false );
		$status = isset( $report['summary']['status'] ) ? (string) $report['summary']['status'] : Result::UNKNOWN;

		$now   = current_time( 'mysql' );
		$today = substr( $now, 0, 10 );

		$history = $this->get_state_history();
		$last    = count( $history ) - 1;

		// One entry per day; a second run the same day replaces it.
		if ( $last >= 0 && isset( $history[ $last ]['date'] ) && $today === $history[ $last ]['date'] ) {
			$history[ $last ]['status'] = $status;
		} else {
			$history[] = array(
				'date'   => $today,
				'status' => $status,
			);
		}

		if ( count( $history ) > self::MAX_STATE_ENTRIES ) {
			$history = array_slice( $history, -1 * self::MAX_STATE_ENTRIES );
		}

		update_option( self::STATE_OPTION, $history, false );
	}

	/**
	 * Records one request the PHP gate refused.
	 *
	 * @param string $token The crawler token that matched. Unused.
	 * @return void
	 */
	public function record_blocked_request( string $token ): void {
		unset( $token );

		$data          = $this->get_total_data();
		$data['total'] = $data['total'] + 1;

		if ( 0 === $data['since'] ) {
			$data['since'] = time();
		}

		update_option( self::TOTAL_OPTION, $data, false );
	}

	/**
	 * Returns the current consecutive-days-protected streak.
	 *
	 * @return int Days, counting back from the most recent entry.
	 */
	public function get_streak(): int {
		$history = $this->get_state_history();
		$streak  = 0;

		for ( $i = count( $history ) - 1; $i >= 0; $i-- ) {
			if ( ! isset( $history[ $i ]['status'] ) || Result::PROTECTED_STATE !== $history[ $i ]['status'] ) {
				break;
			}

			++$streak;
		}

		return $streak;
	}

	/**
	 * Returns the current protection status, computed fresh.
	 *
	 * @return string One of the Result::* status constants.
	 */
	public function get_live_status(): string {
		$report = $this->auditor->report( false );

		return isset( $report['summary']['status'] ) ? (string) $report['summary']['status'] : Result::UNKNOWN;
	}

	/**
	 * Returns the lifetime total of requests the PHP gate has refused.
	 *
	 * @return int Total requests.
	 */
	public function get_lifetime_total(): int {
		return $this->get_total_data()['total'];
	}

	/**
	 * Returns when the lifetime total started counting.
	 *
	 * @return int|null Unix timestamp, or null before the first blocked request.
	 */
	public function get_blocking_since(): ?int {
		$since = $this->get_total_data()['since'];

		return $since > 0 ? $since : null;
	}

	/**
	 * Returns when the reservation of rights first went live.
	 *
	 * @return int|null Unix timestamp, or null when never published.
	 */
	public function get_protecting_since(): ?int {
		return $this->history->first_published( Tdmrep::TYPE );
	}

	/**
	 * Returns the labels of AI companies currently blocked or signal-only.
	 *
	 * @return string[] Company labels.
	 */
	public function get_blocked_companies(): array {
		$blocked   = $this->policy->agents_with( array( Policy::BLOCK, Policy::SIGNAL_ONLY ) );
		$group_ids = array();

		foreach ( $blocked as $agent ) {
			if ( ! empty( $agent['group'] ) ) {
				$group_ids[ $agent['group'] ] = true;
			}
		}

		$companies = array();

		foreach ( $this->registry->get_groups() as $group ) {
			if ( isset( $group_ids[ $group['id'] ] ) ) {
				$companies[] = $group['label'];
			}
		}

		return $companies;
	}

	/**
	 * Returns the total number of known AI companies.
	 *
	 * @return int Company count.
	 */
	public function get_total_company_count(): int {
		return count( $this->registry->get_groups() );
	}

	/**
	 * Returns the daily state history, oldest first.
	 *
	 * @return array List of entries.
	 */
	private function get_state_history(): array {
		$stored = get_option( self::STATE_OPTION, array() );

		return is_array( $stored ) ? array_values( $stored ) : array();
	}

	/**
	 * Returns the lifetime total data, normalized.
	 *
	 * @return array Array with 'total' and 'since'.
	 */
	private function get_total_data(): array {
		$stored = get_option( self::TOTAL_OPTION, array() );
		$stored = is_array( $stored ) ? $stored : array();

		return array(
			'total' => isset( $stored['total'] ) ? (int) $stored['total'] : 0,
			'since' => isset( $stored['since'] ) ? (int) $stored['since'] : 0,
		);
	}
}