using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using PowderCoating.Application.Interfaces;
using PowderCoating.Core.Entities;
using PowderCoating.Infrastructure.Data;

namespace PowderCoating.Infrastructure.Services;

/// <summary>
/// Writes one AiUsageLog row per Anthropic API call using a fresh DI scope so the insert
/// is fully isolated from the caller's Unit-of-Work transaction. Registered as Singleton
/// because IServiceScopeFactory is singleton-safe and we want zero allocation overhead on
/// every AI request.
/// </summary>
public class AiUsageLogger : IAiUsageLogger
{
    private readonly IServiceScopeFactory _scopeFactory;
    private readonly ILogger<AiUsageLogger> _logger;

    public AiUsageLogger(IServiceScopeFactory scopeFactory, ILogger<AiUsageLogger> logger)
    {
        _scopeFactory = scopeFactory;
        _logger = logger;
    }

    /// <inheritdoc/>
    public async Task LogAsync(int companyId, string userId, string feature, bool success = true, int inputLength = 0)
    {
        try
        {
            using var scope = _scopeFactory.CreateScope();
            var context = scope.ServiceProvider.GetRequiredService<ApplicationDbContext>();
            context.AiUsageLogs.Add(new AiUsageLog
            {
                CompanyId  = companyId,
                UserId     = userId,
                Feature    = feature,
                Success    = success,
                InputLength = inputLength,
                CalledAt   = DateTime.UtcNow
            });
            await context.SaveChangesAsync();
        }
        catch (Exception ex)
        {
            _logger.LogWarning(ex, "AI usage log write failed for company {CompanyId} feature {Feature} — non-fatal", companyId, feature);
        }
    }
}