using System.Net.Http.Json;
using System.Text.Json;
using eprintServer.Models;
using eprintServer.Entities;
using eprintServer.Enums;




namespace eprintServer.Services;

public class GoogleOAuthService : BaseOAuthService
{
    private readonly OAuthSettingsService _settingsService;
    private readonly IHttpClientFactory _httpClientFactory;

    public GoogleOAuthService(OAuthSettingsService settingsService, UserService userService, TokenService tokenService, IHttpClientFactory httpClientFactory) 
        : base(userService, tokenService)
    {
        _settingsService = settingsService;
        _httpClientFactory = httpClientFactory;
    }

    public async Task<(User? user, string? token, string? error)> HandleLoginCallbackAsync(string code)
    {
        var settings = await _settingsService.GetOrCreateSettingsAsync();
        var client = _httpClientFactory.CreateClient();

        // 1. Exchange Code for Access Token
        var tokenResponse = await client.PostAsync("https://oauth2.googleapis.com/token", new FormUrlEncodedContent(new Dictionary<string, string>
        {
            ["code"] = code,
            ["client_id"] = settings.GoogleClientId!,
            ["client_secret"] = settings.GoogleClientSecret!,
            ["redirect_uri"] = "https://server.etbaaonline.com/api/v1/oauth/google/callback", // Must match your front-end config
            ["grant_type"] = "authorization_code"
        }));

        if (!tokenResponse.IsSuccessStatusCode) return (null, null, "Google code exchange failed.");

        var tokenData = await tokenResponse.Content.ReadFromJsonAsync<JsonElement>();
        var accessToken = tokenData.GetProperty("access_token").GetString();

        // 2. Get User Info
        client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", accessToken);
        var userResponse = await client.GetAsync("https://www.googleapis.com/oauth2/v2/userinfo");
        var googleUser = await userResponse.Content.ReadFromJsonAsync<JsonElement>();

        var externalUser = new ExternalUserData
        {
            Email = googleUser.GetProperty("email").GetString()!,
            Name = googleUser.GetProperty("name").GetString()!,
            ProviderUserId = googleUser.GetProperty("id").GetString()
        };

        return await SignInUserAsync(externalUser, Provider.GOOGLE);
    }
}