<?php

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

class Argus_Cache_Log {

	const RAW_RETENTION_DAYS = 7;

	public static function log_dir() {
		$uploads = wp_get_upload_dir();
		return trailingslashit( $uploads['basedir'] ) . 'argus-wpd-data/cache-log';
	}

	public static function record( $status, $url, $reason = '', $response_time_ms = null, $rule = '' ) {
		$dir = self::log_dir();
		if ( ! is_dir( $dir ) ) {
			wp_mkdir_p( $dir );

			$htaccess = trailingslashit( $dir ) . '.htaccess';
			if ( ! file_exists( $htaccess ) ) {
				@file_put_contents( $htaccess, "Require all denied\n" ); // phpcs:ignore
			}
		}

		$line = wp_json_encode(
			array(
				't'    => microtime( true ),
				's'    => $status,
				'u'    => mb_substr( (string) $url, 0, 500 ),
				'r'    => mb_substr( (string) $reason, 0, 255 ),
				'ms'   => null === $response_time_ms ? null : (int) $response_time_ms,
				'rule' => $rule,
			)
		);

		$file = trailingslashit( $dir ) . gmdate( 'Y-m-d' ) . '.log';

		@file_put_contents( $file, $line . "\n", FILE_APPEND | LOCK_EX ); // phpcs:ignore
	}

	public static function recent( $limit = 200, $status_filter = null ) {
		$dir = self::log_dir();
		if ( ! is_dir( $dir ) ) {
			return array();
		}

		$files = glob( trailingslashit( $dir ) . '*.log' ) ?: array();
		rsort( $files ); 

		$rows = array();
		foreach ( array_slice( $files, 0, self::RAW_RETENTION_DAYS ) as $file ) {
			$lines = file( $file, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES ) ?: array();
			for ( $i = count( $lines ) - 1; $i >= 0 && count( $rows ) < $limit * 4; $i-- ) {
				$row = json_decode( $lines[ $i ], true );
				if ( ! is_array( $row ) ) {
					continue;
				}
				if ( $status_filter && ( $row['s'] ?? '' ) !== $status_filter ) {
					continue;
				}
				$rows[] = $row;
				if ( count( $rows ) >= $limit ) {
					break 2;
				}
			}
		}

		return $rows;
	}

	public static function paginated( $page = 1, $per_page = 10, $status_filter = null ) {
		$page = max( 1, (int) $page );
		$all  = self::recent( ( $page * $per_page ) + 1, $status_filter );

		$has_next = count( $all ) > ( $page - 1 ) * $per_page + $per_page;
		$rows     = array_slice( $all, ( $page - 1 ) * $per_page, $per_page );

		return array(
			'rows'        => $rows,
			'page'        => $page,
			'total_pages' => $page + ( $has_next ? 1 : 0 ),
		);
	}

	public static function rollup_and_prune() {
		global $wpdb;
		$dir = self::log_dir();
		if ( ! is_dir( $dir ) ) {
			return;
		}

		$table = Argus_DB::table( 'cache_stats_daily' );
		$files = glob( trailingslashit( $dir ) . '*.log' ) ?: array();

		foreach ( $files as $file ) {
			$basename = basename( $file, '.log' );
			if ( ! preg_match( '/^\d{4}-\d{2}-\d{2}$/', $basename ) ) {
				continue;
			}

			$lines = file( $file, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES ) ?: array();
			$by_status = array();
			foreach ( $lines as $line ) {
				$row = json_decode( $line, true );
				if ( ! is_array( $row ) || empty( $row['s'] ) ) {
					continue;
				}
				$status = $row['s'];
				if ( ! isset( $by_status[ $status ] ) ) {
					$by_status[ $status ] = array( 'count' => 0, 'ms' => 0 );
				}
				++$by_status[ $status ]['count'];
				$by_status[ $status ]['ms'] += (int) ( $row['ms'] ?? 0 );
			}

			foreach ( $by_status as $status => $agg ) {
				$wpdb->query(
					$wpdb->prepare(
						"INSERT INTO {$table} (stat_date, status, request_count, total_response_time_ms, total_bytes)
						VALUES (%s, %s, %d, %d, 0)
						ON DUPLICATE KEY UPDATE request_count = VALUES(request_count), total_response_time_ms = VALUES(total_response_time_ms)", // phpcs:ignore
						$basename,
						$status,
						$agg['count'],
						$agg['ms']
					)
				);
			}
		}

		$cutoff = gmdate( 'Y-m-d', strtotime( '-' . self::RAW_RETENTION_DAYS . ' days' ) );
		foreach ( $files as $file ) {
			$basename = basename( $file, '.log' );
			if ( preg_match( '/^\d{4}-\d{2}-\d{2}$/', $basename ) && $basename < $cutoff ) {
				@unlink( $file ); // phpcs:ignore
			}
		}
	}

	public static function summary( $days = 7 ) {
		global $wpdb;
		$table = Argus_DB::table( 'cache_stats_daily' );
		$since = gmdate( 'Y-m-d', strtotime( '-' . (int) $days . ' days' ) );

		$rows = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT status, SUM(request_count) AS cnt, SUM(total_response_time_ms) AS ms
				FROM {$table} WHERE stat_date >= %s GROUP BY status", // phpcs:ignore
				$since
			)
		);

		$out = array();
		foreach ( $rows as $row ) {
			$cnt = (int) $row->cnt;
			$out[ $row->status ] = array(
				'count'  => $cnt,
				'avg_ms' => $cnt > 0 ? (int) round( $row->ms / $cnt ) : null,
			);
		}
		return $out;
	}

	public static function daily_series( $days = 14 ) {
		global $wpdb;
		$table = Argus_DB::table( 'cache_stats_daily' );
		$since = gmdate( 'Y-m-d', strtotime( '-' . (int) $days . ' days' ) );

		$rows = $wpdb->get_results(
			$wpdb->prepare( "SELECT stat_date, status, request_count FROM {$table} WHERE stat_date >= %s", $since ) // phpcs:ignore
		);

		$by_date = array();
		for ( $i = $days - 1; $i >= 0; $i-- ) {
			$d = gmdate( 'Y-m-d', strtotime( "-{$i} days" ) );
			$by_date[ $d ] = array( 'date' => $d, 'hit' => 0, 'miss' => 0, 'bypass' => 0 );
		}
		foreach ( $rows as $row ) {
			if ( ! isset( $by_date[ $row->stat_date ] ) ) {
				continue;
			}
			$key = strtolower( $row->status );
			if ( isset( $by_date[ $row->stat_date ][ $key ] ) ) {
				$by_date[ $row->stat_date ][ $key ] += (int) $row->request_count;
			}
		}

		return array_values( $by_date );
	}
}