using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using Microsoft.AspNetCore.Components.Authorization;

namespace TaxBaik.Web.Services;

public class CustomAuthenticationStateProvider : AuthenticationStateProvider
{
    private readonly ILocalStorageService _localStorage;
    private readonly ITokenStore _tokenStore;
    private readonly AuthService _authService;
    private readonly ILogger<CustomAuthenticationStateProvider> _logger;

    public CustomAuthenticationStateProvider(
        ILocalStorageService localStorage,
        ITokenStore tokenStore,
        AuthService authService,
        ILogger<CustomAuthenticationStateProvider> logger)
    {
        _localStorage = localStorage;
        _tokenStore = tokenStore;
        _authService = authService;
        _logger = logger;
    }

    public override async Task<AuthenticationState> GetAuthenticationStateAsync()
    {
        try
        {
            var accessToken = _tokenStore.AccessToken;

            // TokenStore가 비어있으면 localStorage에서 복원 (페이지 리로드 후)
            if (string.IsNullOrEmpty(accessToken))
            {
                accessToken = await _localStorage.GetItemAsStringAsync("accessToken");
                if (!string.IsNullOrEmpty(accessToken))
                {
                    var refreshToken = await _localStorage.GetItemAsStringAsync("refreshToken");
                    var ticksStr = await _localStorage.GetItemAsStringAsync("tokenExpiry");
                    if (long.TryParse(ticksStr, out var ticks))
                    {
                        _tokenStore.AccessToken = accessToken;
                        _tokenStore.RefreshToken = refreshToken;
                        _tokenStore.TokenExpiryTicks = ticks;
                    }
                }
            }

            if (string.IsNullOrEmpty(accessToken))
            {
                return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
            }

            if (_tokenStore.IsAccessTokenExpired())
            {
                _logger.LogWarning("Access token 만료됨");
                await LogoutAsync();
                return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
            }

            var principal = _authService.ValidateToken(accessToken);
            if (principal == null)
            {
                await LogoutAsync();
                return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
            }

            return new AuthenticationState(principal);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "인증 상태 조회 중 오류 발생");
            return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
        }
    }

    public async Task LoginAsync(string accessToken, string refreshToken, int expiresIn)
    {
        var tokenExpiryTicks = DateTime.UtcNow.AddSeconds(expiresIn).Ticks;

        // TokenStore에 저장 (DelegatingHandler에서 사용)
        _tokenStore.AccessToken = accessToken;
        _tokenStore.RefreshToken = refreshToken;
        _tokenStore.TokenExpiryTicks = tokenExpiryTicks;

        // localStorage에도 저장 (페이지 리로드 후 복원)
        await _localStorage.SetItemAsStringAsync("accessToken", accessToken);
        await _localStorage.SetItemAsStringAsync("refreshToken", refreshToken);
        await _localStorage.SetItemAsStringAsync("tokenExpiry", tokenExpiryTicks.ToString());

        NotifyAuthenticationStateChanged(GetAuthenticationStateAsync());
    }

    public async Task LogoutAsync()
    {
        // TokenStore 초기화
        _tokenStore.Clear();

        // localStorage 초기화
        await _localStorage.RemoveItemAsync("accessToken");
        await _localStorage.RemoveItemAsync("refreshToken");
        await _localStorage.RemoveItemAsync("tokenExpiry");

        NotifyAuthenticationStateChanged(GetAuthenticationStateAsync());
    }

    private bool IsTokenExpired(string token)
    {
        try
        {
            var handler = new JwtSecurityTokenHandler();
            var jwtToken = handler.ReadJwtToken(token);
            return jwtToken.ValidTo < DateTime.UtcNow;
        }
        catch
        {
            return true;
        }
    }
}