import MetaCodable

/// An `HelperCoder` that helps decoding/encoding

/// using existing property wrappers.

///

/// This type can be used to reuse existing property

/// wrappers with custom decoding/encoding with

/// `MetaCodable` generated implementations.

public struct PropertyWrapperCoder<Wrapper: PropertyWrappable>: HelperCoder {

/// Creates a new instance of `HelperCoder` that decodes/encodes

/// using existing property wrappers.

///

/// The property wrapper type `Wrapper` is used for decoding/encoding.

public init() {}

/// Decodes using `Wrapper` type from the given `decoder`.

///

/// - Parameter decoder: The decoder to read data from.

/// - Returns: The wrapped value decoded.

/// - Throws: If the property wrapper throws error.

@inlinable

public func decode(from decoder: Decoder) throws -> Wrapper.Wrapped {

return try Wrapper(from: decoder).wrappedValue

}

/// Encodes given value using `Wrapper` type to the provided `encoder`.

///

/// - Parameters:

/// - value: The wrapped value to encode.

/// - encoder: The encoder to write data to.

///

/// - Throws: If the property wrapper throws error.

@inlinable

public func encode(_ value: Wrapper.Wrapped, to encoder: Encoder) throws {

try Wrapper(wrappedValue: value).encode(to: encoder)

}

}

/// A type representing a [property wrapper].

///

/// A property wrapper adds a layer of separation

/// between code that manages how a property is stored

/// and the code that defines a property.

///

/// [property wrapper]: https://docs.swift.org/swift-book/documentation/the-swift-programming-language/properties/#Property-Wrappers

public protocol PropertyWrappable: Codable {

/// The type of the value wrapped.

associatedtype Wrapped

/// The value wrapped.

var wrappedValue: Wrapped { get }

/// Creates new instance wrapping provided value.

///

/// - Parameters:

/// - wrappedValue: The value to be wrapped.

init(wrappedValue: Wrapped)

}