<?php

namespace Yipresser\AdminOptimizer\Support;

// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

use Yipresser\AdminOptimizer\Helpers\Table_Rename_Helper;

/**
 * Persists, deduplicates, and prunes structured logs.
 */
final class AO_Log_Storage {
	private const RATE_LIMIT_ROWS_PER_HOUR = 12;
	private const SCHEMA_VERSION           = '1.1';
	private const SCHEMA_VERSION_OPTION    = 'adminoptim_log_table_schema_version';

	/** @var \wpdb */
	private $wpdb;

	/**
	 * Table variable
	 *
	 * @var string
	 */
	private string $table;

	/**
	 * Constructor.
	 *
	 * @param \wpdb|null $wpdb Optional. The WordPress database object. Defaults to the global $wpdb.
	 */
	public function __construct( $wpdb = null ) {
		$this->wpdb  = $wpdb ?: $GLOBALS['wpdb'];
		$this->table = $this->wpdb->prefix . 'ao_system_logs';
	}

	/**
	 * Creates or updates the table schema. Safe to call for every write.
	 */
	public function ensure_table(): bool {
		if ( get_option( self::SCHEMA_VERSION_OPTION ) === self::SCHEMA_VERSION ) {
			return true;
		}

		if ( ! function_exists( 'dbDelta' ) ) {
			$upgrade = defined( 'ABSPATH' ) ? ABSPATH . 'wp-admin/includes/upgrade.php' : '';
			if ( ! $upgrade || ! is_readable( $upgrade ) ) {
				return false;
			}
			require_once $upgrade;
		}

		Table_Rename_Helper::maybe_rename( $this->wpdb->prefix . 'adminoptim_system_logs', $this->table );

		$charset_collate = $this->wpdb->get_charset_collate();
		$sql             = "CREATE TABLE {$this->table} (
			id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
			created_at DATETIME NOT NULL,
			level VARCHAR(20) NOT NULL,
			channel VARCHAR(100) NOT NULL,
			event VARCHAR(150) NOT NULL,
			message TEXT NOT NULL,
			context LONGTEXT NULL,
			request_id VARCHAR(32) NULL,
			user_id BIGINT UNSIGNED NULL,
			url VARCHAR(500) NULL,
			ao_version VARCHAR(32) NOT NULL,
			fingerprint CHAR(64) NOT NULL,
			occurrence_count BIGINT UNSIGNED NOT NULL DEFAULT 1,
			first_seen_at DATETIME NOT NULL,
			last_seen_at DATETIME NOT NULL,
			PRIMARY KEY  (id),
			KEY level_last_seen (level, last_seen_at),
			KEY channel_last_seen (channel, last_seen_at),
			KEY event_last_seen (event, last_seen_at),
			KEY fingerprint_first_seen (fingerprint, first_seen_at),
			KEY request_id (request_id),
			KEY user_id (user_id),
			KEY last_seen_at (last_seen_at)
		) {$charset_collate};";

		dbDelta( $sql );

		$exists = $this->table_exists();
		if ( $exists ) {
			update_option( self::SCHEMA_VERSION_OPTION, self::SCHEMA_VERSION );
		}
		return $exists;
	}

	/**
	 * Stores or deduplicates a prepared record.
	 *
	 * @param array<string, mixed> $record Prepared record.
	 */
	public function write( array $record ): bool {
		if ( ! $this->ensure_table() ) {
			return false;
		}

		$window = max( 1, (int) apply_filters( 'adminoptim_logger_deduplication_window', 5 * MINUTE_IN_SECONDS ) );
		$now_ts = strtotime( (string) $record['created_at'] );
		$start  = gmdate( 'Y-m-d H:i:s', $now_ts - $window );
		// phpcs:disable WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Table name is an internal fixed identifier ($wpdb->prefix . 'ao_system_logs'), not user input; all values are passed through prepare().
		$row_id = $this->wpdb->get_var(
			$this->wpdb->prepare(
				"SELECT id FROM {$this->table} WHERE fingerprint = %s AND first_seen_at >= %s ORDER BY first_seen_at DESC LIMIT 1",
				$record['fingerprint'],
				$start
			)
		);
		// phpcs:enable WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared

		if ( $row_id ) {
			// phpcs:disable WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Table name is an internal fixed identifier ($wpdb->prefix . 'ao_system_logs'), not user input; all values are passed through prepare().
			$result = $this->wpdb->query(
				$this->wpdb->prepare(
					"UPDATE {$this->table} SET occurrence_count = occurrence_count + 1, last_seen_at = %s WHERE id = %d",
					$record['last_seen_at'],
					$row_id
				)
			);
			// phpcs:enable WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared
			return false !== $result;
		}

		// phpcs:disable WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Table name is an internal fixed identifier ($wpdb->prefix . 'ao_system_logs'), not user input; all values are passed through prepare().
		$recent_rows = (int) $this->wpdb->get_var(
			$this->wpdb->prepare(
				"SELECT COUNT(*) FROM {$this->table} WHERE level = %s AND channel = %s AND event = %s AND created_at >= %s",
				$record['level'],
				$record['channel'],
				$record['event'],
				gmdate( 'Y-m-d H:i:s', $now_ts - HOUR_IN_SECONDS )
			)
		);
		// phpcs:enable WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		if ( $recent_rows >= self::RATE_LIMIT_ROWS_PER_HOUR ) {
			return true;
		}

		return false !== $this->wpdb->insert(
			$this->table,
			$record,
			[ '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%d', '%s', '%s', '%s', '%d', '%s', '%s' ]
		);
	}

	/**
	 * Prunes expired rows and enforces the row cap.
	 */
	public function prune(): int {
		if ( ! $this->table_exists() ) {
			return 0;
		}

		$retention = max( 1, (int) apply_filters( 'adminoptim_logger_retention_days', 30 ) );
		// phpcs:disable WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Table name is an internal fixed identifier ($wpdb->prefix . 'ao_system_logs'), not user input; all values are passed through prepare().
		$deleted = (int) $this->wpdb->query(
			$this->wpdb->prepare(
				"DELETE FROM {$this->table} WHERE last_seen_at < %s",
				gmdate( 'Y-m-d H:i:s', time() - ( $retention * DAY_IN_SECONDS ) )
			)
		);
		// phpcs:enable WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared

		$max_rows = max( 1, (int) apply_filters( 'adminoptim_logger_max_rows', 10000 ) );
		$count    = (int) $this->wpdb->get_var( "SELECT COUNT(*) FROM {$this->table}" ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Table name is an internal fixed identifier ($wpdb->prefix . 'ao_system_logs'), not user input; no user values in this query.
		$excess   = max( 0, $count - $max_rows );
		if ( $excess ) {
			// phpcs:disable WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Table name is an internal fixed identifier ($wpdb->prefix . 'ao_system_logs'), not user input; all values are passed through prepare().
			$deleted += (int) $this->wpdb->query(
				$this->wpdb->prepare(
					"DELETE FROM {$this->table} ORDER BY last_seen_at ASC, id ASC LIMIT %d",
					$excess
				)
			);
			// phpcs:enable WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		}

		if ( $deleted > 0 ) {
			do_action( 'adminoptim_log_pruned', $deleted );
		}
		return $deleted;
	}

	/**
	 * Check table exists function
	 *
	 * @return boolean
	 */
	private function table_exists(): bool {
		$found = $this->wpdb->get_var( $this->wpdb->prepare( 'SHOW TABLES LIKE %s', $this->wpdb->esc_like( $this->table ) ) ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared -- Query is fully prepared; the LIKE value is escaped via esc_like() and passed as a %s placeholder.
		return $this->table === $found;
	}
}