import Foundation


public enum Token : Equatable {
  /// A token representing a piece of text.
  case Text(value:String)

  /// A token representing a variable.
  case Variable(value:String)

  /// A token representing a comment.
  case Comment(value:String)

  /// A token representing a template block.
  case Block(value:String)

  /// Returns the underlying value as an array seperated by spaces
  func components() -> [String] {
    // TODO: Make this smarter and treat quoted strings as a single component
    let characterSet = NSCharacterSet.whitespaceAndNewlineCharacterSet()

    func strip(value: String) -> [String] {
      return value.stringByTrimmingCharactersInSet(characterSet).componentsSeparatedByCharactersInSet(characterSet)
    }

    switch self {
    case .Block(let value):
      return strip(value)
    case .Variable(let value):
      return strip(value)
    case .Text(let value):
      return strip(value)
    case .Comment(let value):
      return strip(value)
    }
  }

  var contents:String {
    switch self {
    case .Block(let value):
      return value
    case .Variable(let value):
      return value
    case .Text(let value):
      return value
    case .Comment(let value):
      return value
    }
  }
}

public func ==(lhs:Token, rhs:Token) -> Bool {
  switch (lhs, rhs) {
  case (.Text(let lhsValue), .Text(let rhsValue)):
    return lhsValue == rhsValue
  case (.Variable(let lhsValue), .Variable(let rhsValue)):
    return lhsValue == rhsValue
  case (.Block(let lhsValue), .Block(let rhsValue)):
    return lhsValue == rhsValue
  case (.Comment(let lhsValue), .Comment(let rhsValue)):
    return lhsValue == rhsValue
  default:
    return false
  }
}