using Fake.Application;
using Fake.DependencyInjection;
using Oms.Domain.MarketingAggregate.Entities;
using Oms.Domain.MarketingAggregate.Enums;
using Oms.Domain.MarketingAggregate.Repositories;

namespace Oms.Application.Shared;

public static class MarketingInviteCodeHelper
{
    private const string Alphabet = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789";

    public static string GenerateCode()
    {
        Span<char> buffer = stackalloc char[8];
        for (var i = 0; i < buffer.Length; i++)
        {
            buffer[i] = Alphabet[Random.Shared.Next(Alphabet.Length)];
        }

        return new string(buffer);
    }
}

public class MarketingReferralCodeProvisioner : IScopedDependency
{
    private readonly ICustomerReferralCodeRepository _referralCodeRepository;

    public MarketingReferralCodeProvisioner(ICustomerReferralCodeRepository referralCodeRepository)
    {
        _referralCodeRepository = referralCodeRepository;
    }

    public async Task<CustomerReferralCode> GetOrCreateAsync(int mainCustomerId, CancellationToken cancellationToken = default)
    {
        var existing = await _referralCodeRepository.GetByCustomerIdAsync(mainCustomerId, cancellationToken);
        if (existing != null)
        {
            return existing;
        }

        for (var i = 0; i < 10; i++)
        {
            var code = MarketingInviteCodeHelper.GenerateCode();
            if (await _referralCodeRepository.ExistsInviteCodeAsync(code, null, cancellationToken))
            {
                continue;
            }

            var entity = new CustomerReferralCode
            {
                CustomerId = mainCustomerId,
                InviteCode = code,
                Status = ReferralCodeStatus.Enabled
            };
            await _referralCodeRepository.InsertAsync(entity, cancellationToken);
            return entity;
        }

        throw new BusinessException("邀请码生成失败");
    }
}