using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Claims;
using System.Security.Cryptography;
using System.Threading.Tasks;
using SkyArtShop.Models;

namespace SkyArtShop.Services;

public class AuthService
{
	private readonly MongoDBService _mongoService;

	public AuthService(MongoDBService mongoService)
	{
		_mongoService = mongoService;
	}

	public string HashPassword(string password)
	{
		using RandomNumberGenerator randomNumberGenerator = RandomNumberGenerator.Create();
		byte[] array = new byte[16];
		randomNumberGenerator.GetBytes(array);
		using Rfc2898DeriveBytes rfc2898DeriveBytes = new Rfc2898DeriveBytes(password, array, 10000, HashAlgorithmName.SHA256);
		byte[] bytes = rfc2898DeriveBytes.GetBytes(32);
		byte[] array2 = new byte[48];
		Array.Copy(array, 0, array2, 0, 16);
		Array.Copy(bytes, 0, array2, 16, 32);
		return Convert.ToBase64String(array2);
	}

	public bool VerifyPassword(string password, string hashedPassword)
	{
		try
		{
			byte[] array = Convert.FromBase64String(hashedPassword);
			byte[] array2 = new byte[16];
			Array.Copy(array, 0, array2, 0, 16);
			using Rfc2898DeriveBytes rfc2898DeriveBytes = new Rfc2898DeriveBytes(password, array2, 10000, HashAlgorithmName.SHA256);
			byte[] bytes = rfc2898DeriveBytes.GetBytes(32);
			for (int i = 0; i < 32; i++)
			{
				if (array[i + 16] != bytes[i])
				{
					return false;
				}
			}
			return true;
		}
		catch
		{
			return false;
		}
	}

	public async Task<AdminUser?> AuthenticateAsync(string email, string password)
	{
		AdminUser user = (await _mongoService.GetAllAsync<AdminUser>("AdminUsers")).FirstOrDefault((AdminUser u) => u.Email.ToLower() == email.ToLower() && u.IsActive);
		if (user == null || !VerifyPassword(password, user.PasswordHash))
		{
			return null;
		}
		user.LastLogin = DateTime.UtcNow;
		await _mongoService.UpdateAsync("AdminUsers", user.Id, user);
		return user;
	}

	public ClaimsPrincipal CreateClaimsPrincipal(AdminUser user)
	{
		List<Claim> list = new List<Claim>
		{
			new Claim("http://schemas.xmlsoap.org/ws/2005/05/identity/claims/nameidentifier", user.Id),
			new Claim("http://schemas.xmlsoap.org/ws/2005/05/identity/claims/emailaddress", user.Email),
			new Claim("http://schemas.xmlsoap.org/ws/2005/05/identity/claims/name", user.Name),
			new Claim("http://schemas.microsoft.com/ws/2008/06/identity/claims/role", user.Role)
		};
		foreach (string permission in user.Permissions)
		{
			list.Add(new Claim("Permission", permission));
		}
		ClaimsIdentity identity = new ClaimsIdentity(list, "Cookies");
		return new ClaimsPrincipal(identity);
	}

	public async Task<AdminUser?> GetUserByIdAsync(string userId)
	{
		return await _mongoService.GetByIdAsync<AdminUser>("AdminUsers", userId);
	}

	public async Task<AdminUser?> GetUserByEmailAsync(string email)
	{
		return (await _mongoService.GetAllAsync<AdminUser>("AdminUsers")).FirstOrDefault((AdminUser u) => u.Email.ToLower() == email.ToLower());
	}

	public async Task<AdminUser> CreateUserAsync(string email, string password, string name, string role = "Admin")
	{
		AdminUser user = new AdminUser
		{
			Email = email,
			PasswordHash = HashPassword(password),
			Name = name,
			Role = role,
			IsActive = true,
			CreatedAt = DateTime.UtcNow
		};
		await _mongoService.InsertAsync("AdminUsers", user);
		return user;
	}

	public async Task<bool> ChangePasswordAsync(string userId, string oldPassword, string newPassword)
	{
		AdminUser adminUser = await GetUserByIdAsync(userId);
		if (adminUser == null || !VerifyPassword(oldPassword, adminUser.PasswordHash))
		{
			return false;
		}
		adminUser.PasswordHash = HashPassword(newPassword);
		await _mongoService.UpdateAsync("AdminUsers", userId, adminUser);
		return true;
	}

	public async Task<bool> ResetPasswordAsync(string userId, string newPassword)
	{
		AdminUser adminUser = await GetUserByIdAsync(userId);
		if (adminUser == null)
		{
			return false;
		}
		adminUser.PasswordHash = HashPassword(newPassword);
		await _mongoService.UpdateAsync("AdminUsers", userId, adminUser);
		return true;
	}
}