<?php
/**
 * Pro module — long-term aggregated bot-visit statistics.
 *
 * @fs_premium_only
 *
 *
 * The ring log (ADG_AIM_OPT_LOG) keeps only the last ~100 visits — history
 * beyond that is lost. This module maintains a compact aggregate that survives
 * log rotation: totals by status, breakdown by bot, by day (for a mini chart)
 * and top pages. Updated from log_visit() — the single point of visit accounting.
 *
 * The store is size-bounded: days are trimmed to the last N, pages to the top-N
 * by visits, so the option does not grow unbounded.
 *
 * @package ADG_AI_Markdown
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class ADG_AIM_Analytics {

	/** How many days to keep in the by_day breakdown. */
	const DAYS_KEEP = 60;

	/** Threshold above which the top pages are shrunk... */
	const PAGES_CAP = 200;

	/** ...down to this number of entries (top by visits). */
	const PAGES_TARGET = 100;

	/** Allowed visit statuses. */
	const STATUSES = array( 'verified', 'unverified', 'suspicious' );

	/**
	 * Default aggregate structure.
	 *
	 * @return array
	 */
	public static function defaults() {
		return array(
			'totals'     => array(
				'verified'   => 0,
				'unverified' => 0,
				'suspicious' => 0,
			),
			'by_bot'     => array(), // label => [verified, unverified, suspicious].
			'by_day'     => array(), // 'Y-m-d' => int (all statuses).
			'by_page'    => array(), // url => int (all statuses).
			'first_seen' => '',
			'last_seen'  => '',
		);
	}

	/**
	 * Get the aggregate (backfilling missing top-level keys).
	 *
	 * @return array
	 */
	public static function get() {
		$stats = get_option( ADG_AIM_OPT_STATS, array() );
		if ( ! is_array( $stats ) ) {
			$stats = array();
		}
		return wp_parse_args( $stats, self::defaults() );
	}

	/**
	 * Record one visit. Called from ADG_AIM_Bot_Detector::log_visit().
	 * Runs independently of the visit log, but controlled by its own setting.
	 *
	 * @param string $bot_label Human-readable bot name.
	 * @param string $status    verified|unverified|suspicious.
	 * @param string $url       Request URL (already sanitized).
	 */
	public static function record( $bot_label, $status, $url ) {
		if ( ! (bool) ADG_AIM_Plugin::get_setting( 'stats_enabled', true ) ) {
			return;
		}

		$status = in_array( $status, self::STATUSES, true ) ? $status : 'unverified';
		$label  = ( '' !== (string) $bot_label ) ? (string) $bot_label : 'unknown';

		$stats = self::get();
		$now   = current_time( 'mysql' );

		// Totals by status.
		$stats['totals'][ $status ] = self::inc( $stats['totals'], $status );

		// By bot (with a status breakdown).
		if ( ! isset( $stats['by_bot'][ $label ] ) || ! is_array( $stats['by_bot'][ $label ] ) ) {
			$stats['by_bot'][ $label ] = array(
				'verified'   => 0,
				'unverified' => 0,
				'suspicious' => 0,
			);
		}
		$stats['by_bot'][ $label ][ $status ] = self::inc( $stats['by_bot'][ $label ], $status );

		// By day (Y-m-d sorts lexicographically = chronologically).
		$day                    = current_time( 'Y-m-d' );
		$stats['by_day'][ $day ] = self::inc( $stats['by_day'], $day );
		$stats['by_day']         = self::trim_days( $stats['by_day'] );

		// Top pages.
		if ( '' !== (string) $url ) {
			$stats['by_page'][ $url ] = self::inc( $stats['by_page'], $url );
			$stats['by_page']         = self::trim_pages( $stats['by_page'] );
		}

		if ( '' === $stats['first_seen'] ) {
			$stats['first_seen'] = $now;
		}
		$stats['last_seen'] = $now;

		update_option( ADG_AIM_OPT_STATS, $stats, false );
	}

	/**
	 * Reset all statistics (button in the admin).
	 */
	public static function reset() {
		delete_option( ADG_AIM_OPT_STATS );
	}

	/**
	 * Total visits across all statuses.
	 *
	 * @param array $stats Aggregate.
	 * @return int
	 */
	public static function total( array $stats ) {
		$t = isset( $stats['totals'] ) && is_array( $stats['totals'] ) ? $stats['totals'] : array();
		return (int) array_sum( array_map( 'intval', $t ) );
	}

	/**
	 * "Last N days" series as an ordered array 'Y-m-d' => count (with zeros).
	 *
	 * @param array $stats Aggregate.
	 * @param int   $days  How many days back to include.
	 * @return array
	 */
	public static function daily_series( array $stats, $days = 14 ) {
		$days   = max( 1, (int) $days );
		$by_day = isset( $stats['by_day'] ) && is_array( $stats['by_day'] ) ? $stats['by_day'] : array();

		// Anchor to the same "today" as record() (current_time('Y-m-d')), and
		// subtract days in a UTC context — so the series does not depend on the server TZ.
		$tz    = new DateTimeZone( 'UTC' );
		$today = DateTimeImmutable::createFromFormat( 'Y-m-d', current_time( 'Y-m-d' ), $tz );
		if ( false === $today ) {
			$today = new DateTimeImmutable( 'now', $tz );
		}

		$series = array();
		for ( $i = $days - 1; $i >= 0; $i-- ) {
			$key            = $today->modify( "-{$i} days" )->format( 'Y-m-d' );
			$series[ $key ] = isset( $by_day[ $key ] ) ? (int) $by_day[ $key ] : 0;
		}
		return $series;
	}

	/**
	 * Top pages by visits.
	 *
	 * @param array $stats Aggregate.
	 * @param int   $n     How many to return.
	 * @return array url => count.
	 */
	public static function top_pages( array $stats, $n = 10 ) {
		$pages = isset( $stats['by_page'] ) && is_array( $stats['by_page'] ) ? $stats['by_page'] : array();
		arsort( $pages );
		return array_slice( $pages, 0, max( 1, (int) $n ), true );
	}

	/* ------------------------------------------------------------------ */

	/**
	 * Increment a counter-array key's value (cast to int).
	 *
	 * @param array      $arr Array.
	 * @param string|int $key Key.
	 * @return int
	 */
	private static function inc( $arr, $key ) {
		return ( isset( $arr[ $key ] ) ? (int) $arr[ $key ] : 0 ) + 1;
	}

	/**
	 * Trim the by-day breakdown to the last DAYS_KEEP.
	 *
	 * @param array $days 'Y-m-d' => int.
	 * @return array
	 */
	private static function trim_days( array $days ) {
		if ( count( $days ) <= self::DAYS_KEEP ) {
			return $days;
		}
		ksort( $days ); // Y-m-d: lexicographically = chronologically.
		return array_slice( $days, - self::DAYS_KEEP, null, true );
	}

	/**
	 * Shrink top pages on overflow (keep the most-visited).
	 *
	 * @param array $pages url => int.
	 * @return array
	 */
	private static function trim_pages( array $pages ) {
		if ( count( $pages ) <= self::PAGES_CAP ) {
			return $pages;
		}
		arsort( $pages );
		return array_slice( $pages, 0, self::PAGES_TARGET, true );
	}
}