using System.ComponentModel.DataAnnotations;

namespace api.Domain;

public sealed class Person
{
    [Key]
    public string Username { get; private set; }

    public string RealName { get; private set; }

    public DateOnly Birthday { get; private set; }

    private Person(string username, string realName, DateOnly birthday)
    {
        Username = username;
        RealName = realName;
        Birthday = birthday;
    }

    public static Person Create(string username, string realName, DateOnly birthday)
    {
        username = NormalizeUsername(username);
        realName = realName.Trim();

        // TODO: Error Handling
        if (username.Length is < 3 or > 32) throw new ArgumentException("Username must be 3-32 chars.");
        if (realName.Length == 0) throw new ArgumentException("Name cannot be empty");
        if (!IsAtLeast16(birthday) || birthday >= DateOnly.FromDateTime(DateTime.Today)) throw new ArgumentException("Person must be at least 16 years old.");

        return new Person(username, realName, birthday);
    }

    public void Update(string realName, DateOnly birthday)
    {
        realName = realName.Trim();

        if (realName.Length == 0) throw new ArgumentException("Name cannot be empty");
        if (!IsAtLeast16(birthday) || birthday >= DateOnly.FromDateTime(DateTime.Today))
            throw new ArgumentException("Person must be at least 16 years old.");

        RealName = realName;
        Birthday = birthday;
    }

    // Konstruktor zum Erzeugen von Nutzerobjekten aus der Datenbank
    internal static Person FromStorage(string username, string realName, DateOnly birthday)
        => new(username, realName, birthday);
    
    public static string NormalizeUsername(string username)
        => username.Trim().ToLowerInvariant();

    public static bool IsAtLeast16(DateOnly birthday)
        => birthday.AddYears(16) <= DateOnly.FromDateTime(DateTime.Today);
}