import Foundation
import OSLog

/// Shared logger for Bugger. View output in Xcode console or Console.app
/// (filter by subsystem: com.xorbitlab.bugger).
enum BuggerLog {
    private static let logger = Logger(subsystem: "com.xorbitlab.bugger", category: "general")
    private static let queue = DispatchQueue(label: "com.xorbitlab.bugger.log")
    private static let logURL: URL = {
        FileManager.default.homeDirectoryForCurrentUser
            .appendingPathComponent("Library/Logs/Bugger.log")
    }()

    static func info(_ message: String) {
        logger.info("\(message, privacy: .public)")
        write("INFO", message)
    }

    static func error(_ message: String) {
        logger.error("\(message, privacy: .public)")
        write("ERROR", message)
    }

    static func debug(_ message: String) {
        logger.debug("\(message, privacy: .public)")
        write("DEBUG", message)
    }

    /// Unified logging for this ad-hoc app has been empty, so keep a file too.
    private static func write(_ level: String, _ message: String) {
        queue.async {
            let stamp = ISO8601DateFormatter().string(from: Date())
            let line = "\(stamp) \(level) \(message)\n"
            guard let data = line.data(using: .utf8) else { return }
            if FileManager.default.fileExists(atPath: logURL.path),
               let handle = try? FileHandle(forWritingTo: logURL) {
                defer { try? handle.close() }
                _ = try? handle.seekToEnd()
                try? handle.write(contentsOf: data)
            } else {
                try? data.write(to: logURL)
            }
        }
    }
}