using System.Text;
using System.Web;
using Hutopy.Infrastructure.Configuration;
using Hutopy.Infrastructure.Emailer.Contracts;
using Hutopy.Modules.Identity.Data;
using Microsoft.Extensions.Options;

namespace Hutopy.Modules.Identity.Handlers;

[PublicAPI]
public record ForgotPasswordRequest(
    string Email);

[PublicAPI]
public class ForgotPasswordHandler(
    UserManager userManager,
    IEmailSender emailSender,
    IOptionsSnapshot<WebsiteOptions> options)
    : Endpoint<ForgotPasswordRequest>
{
    public override void Configure()
    {
        AllowAnonymous();
        Post("/api/users/forgot-password");
        Options(o => o.WithTags("Users"));
    }

    public override async Task HandleAsync(
        ForgotPasswordRequest request,
        CancellationToken ct)
    {
        // Find user by email
        var user = await userManager.FindByEmailAsync(request.Email);
        
        // Always return OK even if user not found to prevent email enumeration
        if (user is null)
        {
            await SendOkAsync(ct);
            return;
        }

        // Generate password reset token
        var token = await userManager.GeneratePasswordResetTokenAsync(user);
        
        // URL encode the token as it may contain characters that are not URL safe
        var encodedToken = HttpUtility.UrlEncode(token);
        
        // Build reset link
        var resetLink = $"{options.Value.FrontendBaseUrl}/reset-password?email={HttpUtility.UrlEncode(request.Email)}&token={encodedToken}";
        
        // TODO: Write a better email template
        var subject = "Reset Your Password";
        var message = new StringBuilder()
            .AppendLine("<h1>Reset Your Password</h1>")
            .AppendLine("<p>Please click the link below to reset your password:</p>")
            .AppendLine($"<p><a href=\"{resetLink}\">Reset Password</a></p>")
            .AppendLine("<p>If you did not request a password reset, please ignore this email.</p>")
            .ToString();
        
        // Send email
        await emailSender.SendEmailAsync(request.Email, subject, message);
        
        await SendOkAsync(ct);
    }
}