import Foundation
import RastrilloApple

/// A `NativePathSource` a test drives by hand: `NativeConnectivity(source:)`
/// then sees exactly the path changes the test sends, and none from the
/// machine it runs on.
public final class ScriptedPathSource: NativePathSource, @unchecked Sendable {
  private let lock = NSLock()
  private var update: (@Sendable (NativePath) -> Void)?
  private var initial: NativePath?

  /// `initial` is delivered as soon as a connectivity starts, as NWPathMonitor does.
  public init(_ initial: NativePath.Status? = nil) { self.initial = initial.map { NativePath(status: $0) } }

  public func start(_ update: @escaping @Sendable (NativePath) -> Void) {
    let first: NativePath? = lock.withLock { self.update = update; return initial }
    if let first { update(first) }
  }

  public func cancel() { lock.withLock { update = nil } }

  public func send(_ status: NativePath.Status, isExpensive: Bool = false, isConstrained: Bool = false) {
    let path = NativePath(status: status, isExpensive: isExpensive, isConstrained: isConstrained)
    lock.withLock { update }?(path)
  }
}