using System.Text.Json;
using System.Text.Json.Serialization;
using Hutopy.Web.Common.Security;
using Microsoft.AspNetCore.Identity;
using Microsoft.Extensions.Options;

namespace Hutopy.Web.Features.Users.Handlers;

public class FacebookUserInfo
{
    [JsonPropertyName("id")] public required string Id { get; init; }
    [JsonPropertyName("email")] public string? Email { get; init; } // Email might be null if not granted
    [JsonPropertyName("name")] public required string Name { get; init; }
    [JsonPropertyName("picture")] public required FacebookPictureData Picture { get; init; }
}

public class FacebookPictureData
{
    [JsonPropertyName("data")] public required FacebookPicture Picture { get; init; }
}

public class FacebookPicture
{
    [JsonPropertyName("url")] public required string Url { get; init; }
}

[PublicAPI]
public record LoginWithFacebookRequest(
    string Token);

[PublicAPI]
public record LoginWithFacebookResponse(
    string AccessToken,
    string RefreshToken);

[PublicAPI]
public class LoginWithFacebookHandler(
    IHttpClientFactory httpClientFactory,
    IdentityUserManager userManager,
    SignInManager<IdentityUser> signInManager,
    IOptionsSnapshot<JwtOptions> jwtOptions)
    : Endpoint<LoginWithFacebookRequest, LoginWithFacebookResponse>
{
    public override void Configure()
    {
        AllowAnonymous();
        Post("/api/users/login-with-facebook");
        Options(o => o.WithTags("Users"));
    }

    public override async Task HandleAsync(
        LoginWithFacebookRequest request,
        CancellationToken ct)
    {
        // Verify the token with Facebook
        using var httpClient = httpClientFactory.CreateClient();
        using var response = await httpClient.GetAsync(
            $"https://graph.facebook.com/me?access_token={request.Token}&fields=id,name,email,picture.width(200).height(200)",
            ct);
        if (!response.IsSuccessStatusCode)
        {
            await SendStringAsync(
                "The token is not valid",
                400,
                cancellation: ct);
            return;
        }

        // Extract the user info (email, name, profile picture)
        var content = await response.Content.ReadAsStringAsync(ct);
        var userInfo = JsonSerializer.Deserialize<FacebookUserInfo>(content);
        if (userInfo is null || string.IsNullOrEmpty(userInfo.Id))
        {
            await SendStringAsync(
                "Failed to retrieve user information from Facebook",
                400,
                cancellation: ct);
            return;
        }

        // Check if user exists or create a new one
        var user = await userManager.FindByEmailAsync(userInfo.Email!);
        
        if (user is null)
        {
            var generatedPassword = PasswordGenerator.GeneratePassword(10, 12);
            var generatedUser = new IdentityUser
            {
                UserName = userInfo.Email ?? $"fb_{userInfo.Id}",
                Email = userInfo.Email,
                Firstname = userInfo.Name.Split(' ').FirstOrDefault() ?? "",
                Lastname = userInfo.Name.Split(' ').Skip(1).FirstOrDefault() ?? "",
                Alias = userInfo.Name,
                PortraitUrl = userInfo.Picture.Picture.Url,
                FacebookId = userInfo.Id, // Storing Facebook ID
            };
            
            var result = await userManager.CreateAsync(
                generatedUser,
                generatedPassword);
            
            if (!result.Succeeded)
            {
                await SendStringAsync(
                    result.Errors.First().Description,
                    400,
                    cancellation: ct);
                return;
            }

            user = generatedUser;
        }

        await signInManager.SignInAsync(user, isPersistent: false);

        var accessToken = JwtTokenHelper.GenerateJwtToken(
            expiresIn: jwtOptions.Value.Lifetime,
            issuer: jwtOptions.Value.Issuer,
            audience: jwtOptions.Value.Audience,
            key: jwtOptions.Value.Key,
            userId: user.Id.ToString(),
            email: user.Email,
            alias: user.Alias,
            firstname: user.Firstname,
            lastname: user.Lastname,
            portraitUrl: user.PortraitUrl);

        await SendOkAsync(
            new LoginWithFacebookResponse(accessToken, string.Empty),
            cancellation: ct);
    }
}