import Foundation

public struct Logger: Sendable {
    public struct Message: ExpressibleByStringLiteral, Sendable {
        public let description: String
        public init(stringLiteral value: String) { self.description = value }
    }
    public typealias Metadata = [String: String]
    public typealias MetadataProvider = () -> Metadata
    
    public init(label: String) {}
    
    public func trace(_ message: @autoclosure () -> Message) {
        print(message().description)
    }
    public func warning(
        _ message: @autoclosure () -> Message,
        metadata: @autoclosure () -> Metadata? = nil,
        file: String = #fileID,
        function: String = #function,
        line: UInt = #line
    ) {
        print("WARNING: \(message().description)")
    }
    
    private struct SourceLocation: Hashable {
        let file: String
        let line: UInt
    }
    
    public func warnOnce(
        _ message: @autoclosure () -> Message,
        metadata: @autoclosure () -> Metadata? = nil,
        file: String = #fileID,
        function: String = #function,
        line: UInt = #line
    ) {
        warning(message(), metadata: metadata(), file: file, function: function, line: line)
    }
}