//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2015 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
//
//===----------------------------------------------------------------------===//
//
// MessagePack-based serialization and deserialization.
//
//===----------------------------------------------------------------------===//

public struct MsgPackSerializer {
  public static func serialize<
    T : SerializableFixedDictionaryType
  >(var value: T) -> [UInt8] {
    // FIXME(performance): we could serialize directly into a byte stream
    // without creating an intermediate data structure if our MsgPack
    // serializer could accept arrays and dictionaries of unknown length and
    // then back-patch the length into the byte stream when it becomes known.
    var serializerImpl = _MsgPackSerializerImpl()
    value.serializeDeserialize(&serializerImpl)
    return serializerImpl._value!.serialize()
  }
}

internal struct _MsgPackSerializerImpl {
  internal var _value: MsgPackVariant? = nil
}

extension _MsgPackSerializerImpl : ScalarSerializerType {
  internal mutating func add(inout value: Int64) {
    _precondition(_value == nil, "value has been set already")
    _value = .Int64(value)
  }

  internal mutating func add(inout value: UInt64) {
    _precondition(_value == nil, "value has been set already")
    _value = .UInt64(value)
  }

  internal mutating func add(inout value: Float) {
    _precondition(_value == nil, "value has been set already")
    _value = .Float32(value)
  }

  internal mutating func add(inout value: Double) {
    _precondition(_value == nil, "value has been set already")
    _value = .Float64(value)
  }

  internal mutating func add(inout value: Bool) {
    _precondition(_value == nil, "value has been set already")
    _value = .Bool(value)
  }

  internal mutating func add(inout value: String) {
    _precondition(_value == nil, "value has been set already")
    _value = .String(value)
  }
}

% for value_kind in [ 'Scalar', 'Array', 'Dictionary', 'FixedDictionary' ]:
internal func _toMsgPackVariant<
  Value : RangeReplaceableCollectionType
  where
    Value.Generator.Element : Serializable${value_kind}Type
>(inout value: Value) -> MsgPackVariant {
%   if value_kind == 'Scalar':
  if let byteBlob = value as? [UInt8] {
    return .Binary(byteBlob)
  }
%   end
  return .Array(MsgPackVariantArray(map(value) {
    (var element) -> MsgPackVariant in
    var serializerImpl = _MsgPackSerializerImpl()
    element.serializeDeserialize(&serializerImpl)
    return serializerImpl._value!
  }))
}
% end

extension _MsgPackSerializerImpl : ArraySerializerType {
% for value_kind in [ 'Scalar', 'Array', 'Dictionary', 'FixedDictionary' ]:
  internal mutating func add<
    Value : RangeReplaceableCollectionType
    where
      Value.Generator.Element : Serializable${value_kind}Type
  >(inout value: Value) {
    _precondition(_value == nil, "value has been set already")
    _value = _toMsgPackVariant(&value)
  }
% end
}

% for value_kind in [ 'Scalar', 'Array', 'Dictionary', 'FixedDictionary' ]:
internal func _toMsgPackVariant<
  Value : Serializable${value_kind}Type
>(inout value: [String : Value]) -> MsgPackVariant {
  var variantDictionary: [String : MsgPackVariant] = [:]
  for (dictKey, dictValue) in value {
    var mutableValue = dictValue
    var serializerImpl = _MsgPackSerializerImpl()
    mutableValue.serializeDeserialize(&serializerImpl)
    variantDictionary[dictKey] = serializerImpl._value!
  }
  return .Map(MsgPackVariantMap(variantDictionary))
}
% end

extension _MsgPackSerializerImpl : DictionarySerializerType {
% for value_kind in [ 'Scalar', 'Array', 'Dictionary', 'FixedDictionary' ]:
  internal mutating func add<
    Value : Serializable${value_kind}Type
  >(inout value: [String : Value]) {
    _precondition(_value == nil, "value has been set already")
    _value = _toMsgPackVariant(&value)
  }
% end
}

extension _MsgPackSerializerImpl : FixedDictionarySerializerType {
% for value_kind in [ 'Scalar', 'Array', 'Dictionary', 'FixedDictionary' ]:
  internal mutating func addKey<
    Value : Serializable${value_kind}Type
  >(key: String, inout value: Value) {
    var serializerImpl = _MsgPackSerializerImpl()
    value.serializeDeserialize(&serializerImpl)
    _addKeyImpl(key, value: serializerImpl._value!)
  }
% end

  internal mutating func addKey<
    Value : SerializableScalarType
  >(key: String, inout value: [Value]) {
    _addKeyImpl(key, value: _toMsgPackVariant(&value))
  }

  internal mutating func addKey<
    Value : SerializableScalarType
  >(key: String, inout value: [String : Value]) {
    _addKeyImpl(key, value: _toMsgPackVariant(&value))
  }

  internal mutating func _addKeyImpl(key: String, value: MsgPackVariant) {
    if let existingValue = _value {
      switch existingValue {
      case .Map(var map):
        _value = nil
        map._append(key: .String(key), value: value)
        _value = .Map(map)
      default:
        _preconditionFailure("impossible")
      }
    } else {
      _value = .Map(MsgPackVariantMap([key: value]))
    }
  }
}

public struct MsgPackDeserializer {
  public static func deserialize<
    T : SerializableFixedDictionaryType
  >(bytes: [UInt8]) -> T {
    var value = T(forDeserialization: ())
    var deserializerImpl =
      _MsgPackDeserializerImpl(MsgPackVariant(bytes: bytes)!)
    value.serializeDeserialize(&deserializerImpl)
    return value
  }
}

internal struct _MsgPackDeserializerImpl {
  internal var _value: MsgPackVariant

  internal init(_ value: MsgPackVariant) {
    _value = value
  }
}

extension _MsgPackDeserializerImpl : ScalarSerializerType {
  internal mutating func add(inout value: Int64) {
    switch _value {
    case .Int64(let i):
      value = i
    default:
      _preconditionFailure("bad data")
    }
  }

  internal mutating func add(inout value: UInt64) {
    switch _value {
    case .UInt64(let i):
      value = i
    default:
      _preconditionFailure("bad data")
    }
  }

  internal mutating func add(inout value: Float) {
    switch _value {
    case .Float32(let f):
      value = f
    default:
      _preconditionFailure("bad data")
    }
  }

  internal mutating func add(inout value: Double) {
    switch _value {
    case .Float64(let f):
      value = f
    default:
      _preconditionFailure("bad data")
    }
  }

  internal mutating func add(inout value: Bool) {
    switch _value {
    case .Bool(let b):
      value = b
    default:
      _preconditionFailure("bad data")
    }
  }

  internal mutating func add(inout value: String) {
    switch _value {
    case .String(let s):
      value = s
    default:
      _preconditionFailure("bad data")
    }
  }
}

% for value_kind in [ 'Scalar', 'Array', 'Dictionary', 'FixedDictionary' ]:
internal func _fromMsgPackVariant<
  Value : RangeReplaceableCollectionType
  where
    Value.Generator.Element : Serializable${value_kind}Type
>(msgPackVariant: MsgPackVariant, inout _ value: Value) {
  switch msgPackVariant {
%   if value_kind == 'Scalar':
  case .Binary(let byteBlob):
    value = byteBlob as! Value
%   end
  case .Array(let a):
    var elements: [Value.Generator.Element] = []
    elements.reserveCapacity(a.count())
    for e in a {
      var element = Value.Generator.Element(forDeserialization: ())
      var deserializerImpl = _MsgPackDeserializerImpl(e)
      element.serializeDeserialize(&deserializerImpl)
      elements.append(element)
    }
    value.replaceRange(value.startIndex..<value.endIndex, with: elements)
  default:
    _preconditionFailure("bad data")
  }
}
% end

extension _MsgPackDeserializerImpl : ArraySerializerType {
% for value_kind in [ 'Scalar', 'Array', 'Dictionary', 'FixedDictionary' ]:
  internal mutating func add<
    Value : RangeReplaceableCollectionType
    where
      Value.Generator.Element : Serializable${value_kind}Type
  >(inout value: Value) {
    _fromMsgPackVariant(_value, &value)
  }
% end
}

% for value_kind in [ 'Scalar', 'Array', 'Dictionary', 'FixedDictionary' ]:
internal func _fromMsgPackVariant<
  Value : Serializable${value_kind}Type
>(msgPackVariant: MsgPackVariant, inout _ value: [String : Value]) {
  switch msgPackVariant {
  case .Map(let m):
    value.removeAll()
    for (k, v) in m {
      switch k {
      case .String(let s):
        var element = Value(forDeserialization: ())
        var deserializerImpl = _MsgPackDeserializerImpl(v)
        element.serializeDeserialize(&deserializerImpl)
        value[s] = element
      default:
        _preconditionFailure("bad data")
      }
    }

  default:
    _preconditionFailure("bad data")
  }
}
% end

extension _MsgPackDeserializerImpl : DictionarySerializerType {
% for value_kind in [ 'Scalar', 'Array', 'Dictionary', 'FixedDictionary' ]:
  internal mutating func add<
    Value : Serializable${value_kind}Type
  >(inout value: [String : Value]) {
    _fromMsgPackVariant(_value, &value)
  }
% end
}

extension _MsgPackDeserializerImpl : FixedDictionarySerializerType {
% for value_kind in [ 'Scalar', 'Array', 'Dictionary', 'FixedDictionary' ]:
  internal mutating func addKey<
    Value : Serializable${value_kind}Type>(
  key: String, inout value: Value) {
    var deserializerImpl = _MsgPackDeserializerImpl(_findValueForKey(key))
    value.serializeDeserialize(&deserializerImpl)
  }
% end

  internal mutating func addKey<
    Value : SerializableScalarType
  >(key: String, inout value: [Value]) {
    _fromMsgPackVariant(_findValueForKey(key), &value)
  }

  internal mutating func addKey<
    Value : SerializableScalarType
  >(key: String, inout value: [String : Value]) {
    _fromMsgPackVariant(_findValueForKey(key), &value)
  }

  internal func _findValueForKey(key: String) -> MsgPackVariant {
    switch _value {
    case .Map(let map):
      for (k, v) in map {
        switch k {
        case .String(let s):
          if key == s {
            return v
          }
        default:
          ()
        }
      }
      _preconditionFailure("key not found")
    default:
      _preconditionFailure("bad data")
    }
  }
}