<?php
/**
 * Log querying.
 *
 * @package Rahkar\WP
 */

declare( strict_types = 1 );

namespace Rahkar\WP\Support;

use Rahkar\WP\Database\Schema;

defined( 'ABSPATH' ) || exit;

/**
 * Reads the log table for the admin screen.
 *
 * Every filter maps onto one of the table's two composite indexes —
 * `(channel, created_at)` and `(level, created_at)` — so the common views stay
 * index-only lookups rather than scans. That matters more than it sounds: the
 * log screen is the one place an admin goes when something is already wrong,
 * and a page that times out under load is useless exactly when it is needed.
 */
final class LogRepository {

	/**
	 * Rows shown per page.
	 */
	public const PER_PAGE = 50;

	/**
	 * Channels this plugin writes, with readable names.
	 *
	 * A channel that is not listed still appears in the filter — future modules
	 * should show up without editing this — but a known one gets a proper label
	 * instead of its slug.
	 *
	 * @var array<string, string>
	 */
	private const CHANNEL_LABELS = [
		'notify' => 'ارسال پیامک و ایمیل',
		'otp'    => 'ورود پیامکی',
		'queue'  => 'صف کارها',
		'stock'  => 'موجودی کالا',
		'cart'   => 'سبد رهاشده',
	];

	/**
	 * Fetch a page of log rows.
	 *
	 * @param array{channel?:string, level?:int|null, search?:string, from?:string, to?:string} $filters Active filters.
	 * @param int                                                                               $page    1-based page number.
	 *
	 * @return list<array<string, mixed>>
	 */
	public static function page( array $filters, int $page = 1 ): array {
		global $wpdb;

		$table = Schema::table( 'logs' );

		[ $where, $params ] = self::buildWhere( $filters );

		$offset = max( 0, ( max( 1, $page ) - 1 ) * self::PER_PAGE );

		$params[] = self::PER_PAGE;
		$params[] = $offset;

		// `$where` is assembled in buildWhere() from literal fragments only; every
		// value in it is a placeholder bound through $params.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQLPlaceholders.ReplacementsWrongNumber, PluginCheck.Security.DirectDB.UnescapedDBParameter
		$rows = $wpdb->get_results( $wpdb->prepare( "SELECT * FROM %i {$where} ORDER BY id DESC LIMIT %d OFFSET %d", array_merge( [ $table ], $params ) ), ARRAY_A );

		return is_array( $rows ) ? $rows : [];
	}

	/**
	 * How many rows match the filters.
	 *
	 * @param array{channel?:string, level?:int|null, search?:string, from?:string, to?:string} $filters Active filters.
	 */
	public static function count( array $filters ): int {
		global $wpdb;

		$table = Schema::table( 'logs' );

		[ $where, $params ] = self::buildWhere( $filters );

		// See page() for why `$where` is safe to interpolate.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQLPlaceholders.ReplacementsWrongNumber, PluginCheck.Security.DirectDB.UnescapedDBParameter
		return (int) $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM %i {$where}", array_merge( [ $table ], $params ) ) );
	}

	/**
	 * Total rows in the table, regardless of filters.
	 */
	public static function total(): int {
		global $wpdb;

		$table = Schema::table( 'logs' );

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		return (int) $wpdb->get_var( $wpdb->prepare( 'SELECT COUNT(*) FROM %i', $table ) );
	}

	/**
	 * Approximate disk footprint of the log table, in bytes.
	 *
	 * Read from `information_schema`, which is an estimate rather than exact —
	 * good enough to answer "is this getting out of hand?", which is the only
	 * question being asked, and free compared to counting rows.
	 */
	public static function sizeOnDisk(): int {
		global $wpdb;

		$table = Schema::table( 'logs' );

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		return (int) $wpdb->get_var(
			$wpdb->prepare(
				'SELECT data_length + index_length FROM information_schema.TABLES
				 WHERE table_schema = DATABASE() AND table_name = %s',
				$table
			)
		);
	}

	/**
	 * Channels that actually appear in the table, with labels.
	 *
	 * Discovered rather than hard-coded, so a module added later shows up in the
	 * filter on its own.
	 *
	 * @return array<string, string>
	 */
	public static function channels(): array {
		global $wpdb;

		$table = Schema::table( 'logs' );

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$found = $wpdb->get_col( $wpdb->prepare( 'SELECT DISTINCT channel FROM %i ORDER BY channel', $table ) );

		$channels = [];

		foreach ( (array) $found as $channel ) {
			$channel = (string) $channel;

			if ( '' === $channel ) {
				continue;
			}

			$channels[ $channel ] = self::CHANNEL_LABELS[ $channel ] ?? $channel;
		}

		return $channels;
	}

	/**
	 * Row counts per level, for the summary strip.
	 *
	 * @return array<int, int>
	 */
	public static function countsByLevel(): array {
		global $wpdb;

		$table = Schema::table( 'logs' );

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$rows = $wpdb->get_results( $wpdb->prepare( 'SELECT level, COUNT(*) AS total FROM %i GROUP BY level', $table ), ARRAY_A );

		$counts = [];

		foreach ( (array) $rows as $row ) {
			$counts[ (int) $row['level'] ] = (int) $row['total'];
		}

		return $counts;
	}

	/**
	 * Build the WHERE clause and its bound parameters.
	 *
	 * @param array{channel?:string, level?:int|null, search?:string, from?:string, to?:string} $filters Active filters.
	 *
	 * @return array{0:string, 1:list<mixed>}
	 */
	private static function buildWhere( array $filters ): array {
		$clauses = [];
		$params  = [];

		if ( ! empty( $filters['channel'] ) ) {
			$clauses[] = 'channel = %s';
			$params[]  = (string) $filters['channel'];
		}

		if ( isset( $filters['level'] ) && null !== $filters['level'] && '' !== $filters['level'] ) {
			$clauses[] = 'level <= %d';
			$params[]  = (int) $filters['level'];
		}

		if ( ! empty( $filters['from'] ) ) {
			$clauses[] = 'created_at >= %s';
			$params[]  = (string) $filters['from'] . ' 00:00:00';
		}

		if ( ! empty( $filters['to'] ) ) {
			$clauses[] = 'created_at <= %s';
			$params[]  = (string) $filters['to'] . ' 23:59:59';
		}

		if ( ! empty( $filters['search'] ) ) {
			global $wpdb;

			// Searched against message and context both, because the useful string
			// — an order number, a provider error — is as likely to be in one as
			// the other. Neither column is indexed for this, which is why the
			// search box is not offered as a default view.
			$clauses[] = '(message LIKE %s OR context LIKE %s)';

			$like     = '%' . $wpdb->esc_like( (string) $filters['search'] ) . '%';
			$params[] = $like;
			$params[] = $like;
		}

		return [
			[] === $clauses ? '' : 'WHERE ' . implode( ' AND ', $clauses ),
			$params,
		];
	}
}