using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Security.Cryptography;
using Domain.Entities.Members.ValueObject;
using Domain.Entities.Wallets;
using NanoidDotNet;

/// <summary>
/// 사용자단 일반 회원 정보
/// </summary>
namespace Domain.Entities.Members;

public class Member
{
    [Key]
    public int ID { get; private set; }

    // 회원 등급 정보
    [ForeignKey(nameof(MemberGradeID))]
    public virtual MemberGrade? MemberGrade { get; private set; }

    // 알림/약관 동의 여부
    public virtual MemberApprove MemberApprove { get; private set; } = null!;

    // 회원 집계 정보
    public virtual MemberStats MemberStats { get; private set; } = null!;

    // 지갑
    public virtual Wallet? Wallet { get; private set; }

    // 채널
    public virtual Channel? Channel { get; private set; }

    public int? MemberGradeID { get; private set; }

    public string SID { get; private set; } = Nanoid.Generate(size: 8); // 무작위 문자열

    public string Email { get; private set; } = default!;

    public string? Name { get; private set; }

    public string? FullName { get; private set; }

    public string? FirstName { get; private set; }

    public string? LastName { get; private set; }

    public string? Password { get; private set; } = string.Empty; // 관리자 수정 시 필요

    public string? PasswordHash { get; private set; }

    public string? Intro { get; private set; }

    public string? Summary { get; private set; }

    public string? Phone { get; private set; }

    public DateOnly? Birthday { get; private set; }

    public Gender? Gender { get; private set; }

    public string? Thumb { get; private set; }

    public string? BannerUrl { get; private set; }

    public string? Icon { get; private set; }

    /// <summary>
    /// PG customerKey (토스페이먼츠 — 예측 가능 값 금지, 회원별 UUID).
    /// 결제 주문 생성 시 없으면 발급·저장한다. 마이그레이션은 후속 처리.
    /// </summary>
    public Guid? PaymentCustomerKey { get; private set; }

    public bool IsEmailVerified { get; private set; } = false;

    public bool IsAuthCertified { get; private set; } = false;

    public bool IsDenied { get; private set; } = false;

    public bool IsAdmin { get; private set; } = false;

    public bool IsWithdraw { get; private set; } = false;

    public bool IsCreator { get; private set; } = false;

    public string? DeviceInfo { get; private set; }

    public string? SignupIP { get; private set; }

    public string? LastLoginIp { get; private set; }

    public string? IpAddress { get; private set; }

    public string? UserAgent { get; private set; }

    public DateTime? LastLoginAt { get; private set; }

    public DateTime? LastEmailChangedAt { get; private set; }

    public DateTime? LastNameChangedAt { get; private set; }

    public DateTime? LastSummaryChangedAt { get; private set; }

    public DateTime? LastIntroChangedAt { get; private set; }

    public DateTime? LastThumbChangedAt { get; private set; }

    public DateTime? EmailVerifiedAt { get; private set; }

    public DateTime? AuthCertifiedAt { get; private set; }

    public DateTime PasswordUpdatedAt { get; private set; }

    public DateTime CreatedAt { get; private set; } = DateTime.UtcNow;

    public DateTime? UpdatedAt { get; private set; }

    public DateTime? DeletedAt { get; private set; }

    public DateTime? DeniedAt { get; private set; }

    private Member() { }

    private Member(string email)
    {
        if (string.IsNullOrWhiteSpace(email))
        {
            throw new ArgumentException("Email is required.", nameof(email));
        }

        if (email.Length > 60)
        {
            throw new ArgumentOutOfRangeException(nameof(email));
        }

        Email = email;
        PasswordUpdatedAt = DateTime.UtcNow;
    }

    public static Member Create(string email)
    {
        return new(email);
    }

    public static Member Create(string email, string password)
    {
        var member = new Member(email);
        member.SetPassword(password);
        return member;
    }

    public void SetPassword(string password)
    {
        PasswordHash = HashPassword(password);
        PasswordUpdatedAt = DateTime.UtcNow;
    }

    public bool VerifyPassword(string password)
    {
        if (string.IsNullOrEmpty(PasswordHash))
        {
            return false;
        }

        return VerifyHashedPassword(PasswordHash, password);
    }

    public void SetEmail(string email)
    {
        Email = email;
        IsEmailVerified = false;
        LastEmailChangedAt = DateTime.UtcNow;
        UpdatedAt = DateTime.UtcNow;
    }

    public void SetName(string? name)
    {
        Name = name;
        LastNameChangedAt = DateTime.UtcNow;
        UpdatedAt = DateTime.UtcNow;
    }

    public void SetSummary(string? summary)
    {
        Summary = summary;
        LastSummaryChangedAt = DateTime.UtcNow;
        UpdatedAt = DateTime.UtcNow;
    }

    public void SetIntro(string? intro)
    {
        Intro = intro;
        LastIntroChangedAt = DateTime.UtcNow;
        UpdatedAt = DateTime.UtcNow;
    }

    public void SetThumb(string? thumb)
    {
        Thumb = thumb;
        LastThumbChangedAt = DateTime.UtcNow;
        UpdatedAt = DateTime.UtcNow;
    }

    public void SetBannerUrl(string? bannerUrl)
    {
        BannerUrl = bannerUrl;
        UpdatedAt = DateTime.UtcNow;
    }

    public void SetCreator(bool isCreator)
    {
        IsCreator = isCreator;
        UpdatedAt = DateTime.UtcNow;
    }

    /// <summary>회원 등급 설정 — 보상 엔진 자동 승급(래칫)에서 사용 (d3 M2).</summary>
    public void SetMemberGrade(int memberGradeID)
    {
        MemberGradeID = memberGradeID;
        UpdatedAt = DateTime.UtcNow;
    }

    /// <summary>PG customerKey 확보 — 없으면 이 시점에 UUID 발급 (호출측이 SaveChanges 로 영속화)</summary>
    public Guid EnsurePaymentCustomerKey()
    {
        if (PaymentCustomerKey is null)
        {
            PaymentCustomerKey = Guid.NewGuid();
            UpdatedAt = DateTime.UtcNow;
        }

        return PaymentCustomerKey.Value;
    }

    public void MarkEmailVerified()
    {
        IsEmailVerified = true;
        EmailVerifiedAt = DateTime.UtcNow;
        UpdatedAt = DateTime.UtcNow;
    }

    public void Withdraw()
    {
        IsWithdraw = true;
        DeletedAt = DateTime.UtcNow;
        UpdatedAt = DateTime.UtcNow;
    }

    public void RecordLogin(string? ipAddress, string? userAgent = null)
    {
        // DB 컬럼 길이 방어 — Cloudflare 더블 경유 등으로 비정상 길이 값이 와도 throw 대신 truncate.
        // (IpAddress/LastLoginIp nvarchar(45), UserAgent nvarchar(255))
        if (ipAddress is not null && ipAddress.Length > 45)
        {
            ipAddress = ipAddress[..45];
        }

        if (userAgent is not null && userAgent.Length > 255)
        {
            userAgent = userAgent[..255];
        }

        LastLoginAt = DateTime.UtcNow;
        LastLoginIp = ipAddress;

        if (!string.IsNullOrWhiteSpace(ipAddress))
        {
            IpAddress = ipAddress;
        }

        if (!string.IsNullOrWhiteSpace(userAgent))
        {
            UserAgent = userAgent;
        }

        UpdatedAt = DateTime.UtcNow;
    }

    // PBKDF2 (RFC 2898) - 순수 C# 비밀번호 해싱
    // public: Admin 회원 생성/수정의 bulk ExecuteUpdate 에서 평문 대신 해시를 저장하기 위해 노출
    public static string HashPassword(string password)
    {
        var salt = RandomNumberGenerator.GetBytes(16);
        var hash = Rfc2898DeriveBytes.Pbkdf2(
            password,
            salt,
            iterations: 100_000,
            HashAlgorithmName.SHA256,
            outputLength: 32
        );

        // salt + hash → Base64
        var combined = new byte[salt.Length + hash.Length];
        Buffer.BlockCopy(salt, 0, combined, 0, salt.Length);
        Buffer.BlockCopy(hash, 0, combined, salt.Length, hash.Length);

        return Convert.ToBase64String(combined);
    }

    // 비밀번호 검증
    private static bool VerifyHashedPassword(string hashedPassword, string password)
    {
        var combined = Convert.FromBase64String(hashedPassword);

        if (combined.Length != 48) // 16(salt) + 32(hash)
        {
            return false;
        }

        var salt = combined[..16];
        var storedHash = combined[16..];

        var hash = Rfc2898DeriveBytes.Pbkdf2(
            password,
            salt,
            iterations: 100_000,
            HashAlgorithmName.SHA256,
            outputLength: 32
        );

        return CryptographicOperations.FixedTimeEquals(storedHash, hash);
    }
}