using System.Xml.Serialization; // XmlSerializer
using Packt.Shared; // Person 
using FastJson = System.Text.Json.JsonSerializer;

using static System.Environment;
using static System.IO.Path;

// create an object graph
List<Person> people = new()
{
  new(30000M)
  {
    FirstName = "Alice",
    LastName = "Smith",
    DateOfBirth = new(year: 1974, month: 3, day: 14)
  },
  new(40000M)
  {
    FirstName = "Bob",
    LastName = "Jones",
    DateOfBirth = new(year: 1969, month: 11, day: 23)
  },
  new(20000M)
  {
    FirstName = "Charlie",
    LastName = "Cox",
    DateOfBirth = new(year: 1984, month: 5, day: 4),
    Children = new()
    {
      new(0M)
      {
        FirstName = "Sally",
        LastName = "Cox",
        DateOfBirth = new(year: 2012, month: 7, day: 12)
      }
    }
  }
};

// create object that will format a List of Persons as XML
XmlSerializer xs = new(type: people.GetType());

// create a file to write to
string path = Combine(CurrentDirectory, "people.xml");

using (FileStream stream = File.Create(path))
{
  // serialize the object graph to the stream
  xs.Serialize(stream, people);
}

WriteLine("Written {0:N0} bytes of XML to {1}",
  arg0: new FileInfo(path).Length,
  arg1: path);
WriteLine();

// Display the serialized object graph
WriteLine(File.ReadAllText(path));

WriteLine();
WriteLine("* Deserializing XML files");

using (FileStream xmlLoad = File.Open(path, FileMode.Open))
{
  // deserialize and cast the object graph into a List of Person
  List<Person>? loadedPeople =
    xs.Deserialize(xmlLoad) as List<Person>;

  if (loadedPeople is not null)
  {
    foreach (Person p in loadedPeople)
    {
      WriteLine("{0} has {1} children.",
        p.LastName, p.Children?.Count ?? 0);
    }
  }
}

// create a file to write to
string jsonPath = Combine(CurrentDirectory, "people.json");

using (StreamWriter jsonStream = File.CreateText(jsonPath))
{
  // create an object that will format as JSON
  Newtonsoft.Json.JsonSerializer jss = new();

  // serialize the object graph into a string
  jss.Serialize(jsonStream, people);
}

WriteLine();
WriteLine("Written {0:N0} bytes of JSON to: {1}",
  arg0: new FileInfo(jsonPath).Length,
  arg1: jsonPath);

// display the serialized object graph
WriteLine(File.ReadAllText(jsonPath));

WriteLine();
WriteLine("* Deserializing JSON files");

using (FileStream jsonLoad = File.Open(jsonPath, FileMode.Open))
{
  // deserialize object graph into a List of Person
  List<Person>? loadedPeople =
    await FastJson.DeserializeAsync(utf8Json: jsonLoad,
      returnType: typeof(List<Person>)) as List<Person>;

  if (loadedPeople is not null)
  {
    foreach (Person p in loadedPeople)
    {
      WriteLine("{0} has {1} children.",
        p.LastName, p.Children?.Count ?? 0);
    }
  }
}