import Foundation
import Logging

public enum CodexBarLog {
    public enum Destination: Sendable {
        case stderr
        case oslog(subsystem: String)
    }

    public enum Level: String, Sendable {
        case trace
        case verbose
        case debug
        case info
        case warning
        case error
        case critical

        public var asSwiftLogLevel: Logger.Level {
            switch self {
            case .trace: .trace
            case .verbose: .debug
            case .debug: .debug
            case .info: .info
            case .warning: .warning
            case .error: .error
            case .critical: .critical
            }
        }
    }

    public struct Configuration: Sendable {
        public let destination: Destination
        public let level: Level
        public let json: Bool

        public init(destination: Destination, level: Level, json: Bool) {
            self.destination = destination
            self.level = level
            self.json = json
        }
    }

    private static let lock = NSLock()
    private nonisolated(unsafe) static var isBootstrapped = false

    public static func bootstrapIfNeeded(_ config: Configuration) {
        self.lock.lock()
        defer { lock.unlock() }
        guard !self.isBootstrapped else { return }

        let baseFactory: @Sendable (String) -> any LogHandler = { label in
            switch config.destination {
            case .stderr:
                if config.json { return JSONStderrLogHandler(label: label) }
                return StreamLogHandler.standardError(label: label)
            case let .oslog(subsystem):
                #if canImport(os)
                return OSLogLogHandler(label: label, subsystem: subsystem)
                #else
                if config.json { return JSONStderrLogHandler(label: label) }
                return StreamLogHandler.standardError(label: label)
                #endif
            }
        }

        LoggingSystem.bootstrap { label in
            var handler = baseFactory(label)
            handler.logLevel = config.level.asSwiftLogLevel
            return handler
        }

        self.isBootstrapped = true
    }

    public static func logger(_ category: String) -> CodexBarLogger {
        let logger = Logger(label: "com.steipete.codexbar.\(category)")
        return CodexBarLogger { level, message, metadata in
            let swiftLogLevel = level.asSwiftLogLevel
            let meta = metadata?.reduce(into: Logger.Metadata()) { partial, entry in
                partial[entry.key] = .string(entry.value)
            }
            logger.log(level: swiftLogLevel, "\(message)", metadata: meta)
        }
    }

    public static func parseLevel(_ raw: String?) -> Level? {
        guard let raw, !raw.isEmpty else { return nil }
        return Level(rawValue: raw.trimmingCharacters(in: .whitespacesAndNewlines).lowercased())
    }
}

public struct CodexBarLogger: Sendable {
    private let logFn: @Sendable (CodexBarLog.Level, String, [String: String]?) -> Void

    fileprivate init(_ logFn: @escaping @Sendable (CodexBarLog.Level, String, [String: String]?) -> Void) {
        self.logFn = logFn
    }

    public func trace(_ message: @autoclosure () -> String, metadata: [String: String]? = nil) {
        self.logFn(.trace, message(), metadata)
    }

    public func debug(_ message: @autoclosure () -> String, metadata: [String: String]? = nil) {
        self.logFn(.debug, message(), metadata)
    }

    public func info(_ message: @autoclosure () -> String, metadata: [String: String]? = nil) {
        self.logFn(.info, message(), metadata)
    }

    public func warning(_ message: @autoclosure () -> String, metadata: [String: String]? = nil) {
        self.logFn(.warning, message(), metadata)
    }

    public func error(_ message: @autoclosure () -> String, metadata: [String: String]? = nil) {
        self.logFn(.error, message(), metadata)
    }

    public func critical(_ message: @autoclosure () -> String, metadata: [String: String]? = nil) {
        self.logFn(.critical, message(), metadata)
    }
}