using System.Net.Http.Headers;
using System.Text.Json;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using Microsoft.Identity.Client;
using UniVerse.Application.Interfaces;
using UniVerse.Domain.Exceptions;

namespace UniVerse.Infrastructure.ExternalServices;

public class MicrosoftAuthClient : IMicrosoftAuthClient
{
    private readonly IConfiguration _config;
    private readonly EntraTokenCacheStore _cache;
    private readonly HttpClient _http;
    private readonly ILogger<MicrosoftAuthClient> _logger;

    public MicrosoftAuthClient(IConfiguration config, EntraTokenCacheStore cache, HttpClient http, ILogger<MicrosoftAuthClient> logger)
    {
        _config = config;
        _cache = cache;
        _http = http;
        _logger = logger;
    }

    public async Task<MicrosoftTokenResult> ExchangeAuthorizationCodeAsync(
        string authorizationCode,
        string redirectUri,
        CancellationToken cancellationToken = default)
    {
        var app = CreateClient(redirectUri);
        byte[]? serializedCache = null;
        app.UserTokenCache.SetAfterAccess(args =>
        {
            if (args.HasStateChanged) serializedCache = args.TokenCache.SerializeMsalV3();
        });

        try
        {
            var result = await app.AcquireTokenByAuthorizationCode(["User.Read"], authorizationCode)
                .ExecuteAsync(cancellationToken);

            return new MicrosoftTokenResult(
                result.IdToken,
                serializedCache,
                result.Account.HomeAccountId.Identifier);
        }
        catch (MsalException ex)
        {
            throw new UnauthorizedException($"Ошибка аутентификации Microsoft: {ex.Message}");
        }
    }

    public Task SaveTokenCacheAsync(int userId, MicrosoftTokenResult result, CancellationToken cancellationToken = default)
    {
        if (!_cache.IsConfigured || result.TokenCache is null || string.IsNullOrWhiteSpace(result.AccountId))
            return Task.CompletedTask;
        return _cache.LockedAsync(userId, async () =>
        {
            await _cache.SaveAsync(userId, result.AccountId, result.TokenCache, cancellationToken);
            return true;
        });
    }

    public async Task<MicrosoftPhotoResult?> GetPhotoAsync(int userId, CancellationToken cancellationToken = default)
    {
        if (!_cache.IsConfigured) return null;
        string? accessToken;
        try
        {
            accessToken = await _cache.LockedAsync(userId, async () =>
            {
                var saved = await _cache.ReadAsync(userId, cancellationToken);
                if (saved is null) return null;

                var app = CreateClient();
                byte[]? updatedCache = null;
                app.UserTokenCache.SetBeforeAccess(args => args.TokenCache.DeserializeMsalV3(saved.Cache));
                app.UserTokenCache.SetAfterAccess(args =>
                {
                    if (args.HasStateChanged) updatedCache = args.TokenCache.SerializeMsalV3();
                });
                var account = await app.GetAccountAsync(saved.AccountId);
                if (account is null) return null;

                var result = await app.AcquireTokenSilent(["User.Read"], account)
                    .ExecuteAsync(cancellationToken);
                if (updatedCache is not null)
                    await _cache.SaveAsync(userId, saved.AccountId, updatedCache, cancellationToken);
                return result.AccessToken;
            });
        }
        catch (MsalUiRequiredException)
        {
            _logger.LogInformation("Microsoft requires a new sign-in before the profile photo can be loaded for user {UserId}.", userId);
            return null;
        }
        catch (Exception ex) when (ex is MsalException or IOException or UnauthorizedAccessException or System.Security.Cryptography.CryptographicException or JsonException)
        {
            _logger.LogWarning(ex, "Cannot read Microsoft token cache for user {UserId}.", userId);
            return null;
        }
        if (accessToken is null) return null;

        try
        {
            using var request = new HttpRequestMessage(HttpMethod.Get, "https://graph.microsoft.com/v1.0/me/photo/$value");
            request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
            using var response = await _http.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, cancellationToken);
            if (!response.IsSuccessStatusCode) return null;

            var contentType = response.Content.Headers.ContentType?.MediaType;
            if (contentType is not ("image/jpeg" or "image/png" or "image/gif" or "image/webp"))
                return null;
            await response.Content.LoadIntoBufferAsync(5 * 1024 * 1024, cancellationToken);
            return new MicrosoftPhotoResult(await response.Content.ReadAsByteArrayAsync(cancellationToken), contentType);
        }
        catch (Exception ex) when (ex is HttpRequestException or TaskCanceledException)
        {
            _logger.LogWarning(ex, "Cannot load Microsoft profile photo for user {UserId}.", userId);
            return null;
        }
    }

    public Task RemoveTokenCacheAsync(int userId, CancellationToken cancellationToken = default) =>
        _cache.LockedAsync(userId, async () =>
        {
            await _cache.RemoveAsync(userId);
            return true;
        });

    private IConfidentialClientApplication CreateClient(string? redirectUri = null)
    {
        var tenantId = _config["AzureAd:TenantId"];
        var clientId = _config["AzureAd:ClientId"];
        var clientSecret = _config["AzureAd:ClientSecret"];
        var instance = _config["AzureAd:Instance"] ?? "https://login.microsoftonline.com/";

        if (string.IsNullOrWhiteSpace(tenantId)
            || string.IsNullOrWhiteSpace(clientId)
            || string.IsNullOrWhiteSpace(clientSecret))
            throw new UnauthorizedException("Аутентификация Microsoft не настроена (AzureAd:TenantId/ClientId/ClientSecret).");

        var builder = ConfidentialClientApplicationBuilder.Create(clientId)
            .WithClientSecret(clientSecret)
            .WithAuthority(new Uri($"{instance.TrimEnd('/')}/{tenantId}"));
        if (redirectUri is not null) builder = builder.WithRedirectUri(redirectUri);
        return builder.Build();
    }
}