using Microsoft.AspNetCore.Http;
using System.Globalization;
using System.Security.Claims;

namespace StoreHub.Framework.Security;

/// <summary>
/// 从 <see cref="IHttpContextAccessor"/> 读取当前请求认证票据的默认实现。
/// </summary>
public class CurrentUser : ICurrentUser
{
	private readonly IHttpContextAccessor _httpContextAccessor;

	public CurrentUser(IHttpContextAccessor httpContextAccessor)
	{
		_httpContextAccessor = httpContextAccessor;
	}

	/// <summary>
	/// 当前请求的 <see cref="ClaimsPrincipal"/>
	/// </summary>
	private ClaimsPrincipal? Principal => _httpContextAccessor.HttpContext?.User;

	/// <inheritdoc />
	public bool IsAuthenticated => Principal?.Identity?.IsAuthenticated == true;

	/// <inheritdoc />
	public int? Id
	{
		get
		{
			string? value = GetClaimValue(JwtClaimTypes.UserId);
			return int.TryParse(value, NumberStyles.Integer, CultureInfo.InvariantCulture, out int id) ? id : null;
		}
	}

	/// <inheritdoc />
	public string? UserName => GetClaimValue(JwtClaimTypes.UserName);

	/// <inheritdoc />
	public string? NickName => GetClaimValue(JwtClaimTypes.NickName);

	/// <inheritdoc />
	public IEnumerable<Claim> Claims => Principal?.Claims ?? [];

	/// <inheritdoc />
	public string? GetClaimValue(string claimType)
	{
		if (string.IsNullOrWhiteSpace(claimType))
		{
			return null;
		}

		return Principal?.FindFirst(claimType)?.Value;
	}

	/// <inheritdoc />
	public T? GetClaimValue<T>(string claimType)
	{
		string? value = GetClaimValue(claimType);
		if (value is null)
		{
			return default;
		}

		try
		{
			return (T)Convert.ChangeType(value, typeof(T), CultureInfo.InvariantCulture);
		}
		catch
		{
			return default;
		}
	}
}