DictionaryCodable.swift

import Foundation

///A type that can be encoded to a string-keyed dictionary.
public protocol DictionaryEncodable: Encodable {}
public protocol DictionaryDecodable: Decodable {}

///A type that can be encoded and decoded to/from a string-keyed dictionary.
public typealias DictionaryCodable = DictionaryEncodable & DictionaryDecodable

extension DictionaryEncodable {
    /**
     Returns a dictionary representation of the object's properties.

     - Parameters:
        - jsonEncoder: The encoder to use to encode the object's properties.

     - Throws: `EncodingError` if the encoding fails.

     - Returns: A dictionary representation of the object's properties.
    */
    public func dictionary(jsonEncoder: JSONEncoder = JSONEncoder()) throws -> [String: Any] {
        let json = try jsonEncoder.encode(self)
        guard let dictionary = try JSONSerialization.jsonObject(with: json, options: .allowFragments) as? [String: Any] else {
            throw EncodingError.invalidValue(self, .init(codingPath: [], debugDescription: "Unable to convert to [String: Any]"))
        }
        return dictionary
    }
}

extension DictionaryDecodable {
    /**
     Attempts to initialize an object from a dictionary of its property values.

     - Parameters:
        - dictionary: The dictionary containing the object's properties.
        - jsonDecoder: The decoder to convert the keys and values to the object.

     - Throws: `DecodingError` if decoding fails.
    */
    public init(dictionary: [String: Any], jsonDecoder: JSONDecoder = JSONDecoder()) throws {
        guard JSONSerialization.isValidJSONObject(dictionary) else {
            throw DecodingError.dataCorrupted(.init(codingPath: [], debugDescription: "Dictionary is not a valid JSON object."))
        }
        let data = try JSONSerialization.data(withJSONObject: dictionary, options: [])
        self = try jsonDecoder.decode(Self.self, from: data)
    }
}