import Foundation

public enum WatchExclusiveResource: String, Codable, Sendable {
  case heartRateMeasurement
  case hapticRegulation
}

public enum WatchResourceError: LocalizedError, Equatable {
  case busy(WatchExclusiveResource)
  case releaseMismatch

  public var errorDescription: String? {
    switch self {
    case let .busy(resource): "Une activité \(resource.rawValue) est déjà en cours."
    case .releaseMismatch: "La ressource libérée ne correspond pas à l’activité en cours."
    }
  }
}

public actor WatchResourceArbiter {
  public static let shared = WatchResourceArbiter()

  public private(set) var current: WatchExclusiveResource?

  public init() {}

  public func acquire(_ resource: WatchExclusiveResource) throws {
    if let current { throw WatchResourceError.busy(current) }
    current = resource
  }

  public func release(_ resource: WatchExclusiveResource) throws {
    guard current == resource else { throw WatchResourceError.releaseMismatch }
    current = nil
  }

  public func forceRelease() {
    current = nil
  }
}