//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//

// FIXME(ABI)(compiler limitation): This protocol exists to identify
// `AnyHashable` in conditional extensions.  Replace this protocol
// with conditional extensions on `Set` and `Dictionary` "where Key ==
// AnyHashable".
public protocol _AnyHashableProtocol {
  var base: Any { get }
}

extension AnyHashable : _AnyHashableProtocol {}

//===----------------------------------------------------------------------===//
// Convenience APIs for Set<AnyHashable>
//===----------------------------------------------------------------------===//

// FIXME: remove these trampolines when extensions below can be
// properly expressed in the language.
extension Set {
  @inline(__always)
  internal mutating func _concreteElement_insert(
    _ newMember: Element
  ) -> (inserted: Bool, memberAfterInsert: Element) {
    return insert(newMember)
  }

  @inline(__always)
  internal mutating func _concreteElement_update(
    with newMember: Element
  ) -> Element? {
    return update(with: newMember)
  }

  @inline(__always)
  internal mutating func _concreteElement_remove(
    _ member: Element
  ) -> Element? {
    return remove(member)
  }
}

// FIXME(ABI)(compiler limitation): replace with `where Element == AnyHashable`.
extension Set where Element : _AnyHashableProtocol {
  public mutating func insert<ConcreteElement : Hashable>(
    _ newMember: ConcreteElement
  ) -> (inserted: Bool, memberAfterInsert: ConcreteElement) {
    let (inserted, memberAfterInsert) =
      _concreteElement_insert(AnyHashable(newMember) as! Element)
    return (
      inserted: inserted,
      memberAfterInsert: memberAfterInsert.base as! ConcreteElement)
  }

  @discardableResult
  public mutating func update<ConcreteElement : Hashable>(
    with newMember: ConcreteElement
  ) -> ConcreteElement? {
    return _concreteElement_update(with: AnyHashable(newMember) as! Element)
      .map { $0.base as! ConcreteElement }
  }

  @discardableResult
  public mutating func remove<ConcreteElement : Hashable>(
    _ member: ConcreteElement
  ) -> ConcreteElement? {
    return _concreteElement_remove(AnyHashable(member) as! Element)
      .map { $0.base as! ConcreteElement }
  }
}

//===----------------------------------------------------------------------===//
// Convenience APIs for Dictionary<AnyHashable, *>
//===----------------------------------------------------------------------===//

// FIXME: remove these trampolines when extensions below can be
// properly expressed in the language.
extension Dictionary {
  internal subscript(_concreteKey key: Key) -> Value? {
    @inline(__always)
    get {
      return self[key]
    }
    @inline(__always)
    set(newValue) {
      self[key] = newValue
    }
  }

  @inline(__always)
  internal mutating func _concreteKey_updateValue(
    _ value: Value, forKey key: Key
  ) -> Value? {
    return updateValue(value, forKey: key)
  }

  @inline(__always)
  internal mutating func _concreteKey_removeValue(forKey key: Key) -> Value? {
    return removeValue(forKey: key)
  }
}

// FIXME(ABI)(compiler limitation): replace with `where Element == AnyHashable`.
extension Dictionary where Key : _AnyHashableProtocol {
  public subscript(_ key: _Hashable) -> Value? {
    // FIXME(ABI)(compiler limitation): replace this API with a
    // generic subscript.
    get {
      return self[_concreteKey: key._toAnyHashable() as! Key]
    }
    set {
      self[_concreteKey: key._toAnyHashable() as! Key] = newValue
    }
  }

  @discardableResult
  public mutating func updateValue<ConcreteKey : Hashable>(
    _ value: Value, forKey key: ConcreteKey
  ) -> Value? {
    return _concreteKey_updateValue(value, forKey: AnyHashable(key) as! Key)
  }

  @discardableResult
  public mutating func removeValue<ConcreteKey : Hashable>(
    forKey key: ConcreteKey
  ) -> Value? {
    return _concreteKey_removeValue(forKey: AnyHashable(key) as! Key)
  }
}