using System.Threading.Channels;
using CareFix.Api.Options;
using Microsoft.Extensions.Options;

namespace CareFix.Api.Ai;

public sealed record AiJob(int TicketId, int? UserId, string Text);

public sealed class AiQueue
{
    private readonly Channel<AiJob> _channel = Channel.CreateUnbounded<AiJob>();
    public ValueTask EnqueueAsync(AiJob job) => _channel.Writer.WriteAsync(job);
    public ChannelReader<AiJob> Reader => _channel.Reader;
}

/// <summary>Runs AI jobs in the background so the console never waits on a long HTTP request.</summary>
public sealed class AiWorker(AiQueue queue, AiOrchestrator orchestrator, IOptions<CareFixOptions> options, ILogger<AiWorker> log) : BackgroundService
{
    protected override Task ExecuteAsync(CancellationToken stoppingToken)
    {
        var workers = Math.Clamp(options.Value.AiWorkers, 1, 16);
        return Task.WhenAll(Enumerable.Range(0, workers).Select(_ => Task.Run(async () =>
        {
            await foreach (var job in queue.Reader.ReadAllAsync(stoppingToken))
            {
                try { await orchestrator.RunAsync(job, stoppingToken); }
                catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested) { return; }
                catch (Exception ex) { log.LogError(ex, "AI job failed for ticket {TicketId}", job.TicketId); }
            }
        }, stoppingToken)));
    }
}