package runner

import (
	"context"
	"fmt"
	"log/slog"
	"queryorchestration/internal/serviceconfig/queue"
)

type Server struct {
	cleanup func() error
	cfg     ListenerConfig
}

func (c *Server) Listen(ctx context.Context) {
	slog.Info("Listening to queue")
	defer func() {
		if err := c.cleanup(); err != nil {
			fmt.Printf("Error during cleanup: %v", err)
		}
	}()

	// TODO need to slow down the polling so we are not spinning the cpu or burning up API calls.
	for {
		select {
		case <-ctx.Done():
			return
		default:
			err := c.pollMessage(ctx)
			if err != nil {
				slog.Error(err.Error())
			}
		}
	}

}

// Alternative without go func if no pool is needed.
// Just for comment for the next function which needs to be made safe.
//func (c *Server) pollMessage(ctx context.Context) error {
//	cfg := &queue.Config{
//		URL:    c.queueURL,
//		Client: c.client,
//	}
//	result, err := queue.Receive(ctx, cfg, []string{"type"})
//	if err != nil {
//		return fmt.Errorf("message fetch fail: %v", err)
//	}
//
//	for _, message := range result.Messages {
//		if err := c.controller.Process(ctx, &message); err != nil {
//			return fmt.Errorf("message process fail: %v", err)
//		}
//
//		if err := queue.Delete(ctx, cfg, &message); err != nil {
//			return fmt.Errorf("message delete fail: %v", err)
//		}
//	}
//
//	return nil
//}

func (c *Server) pollMessage(ctx context.Context) error {
	result, err := c.cfg.ReceiveFromQueue(ctx, &queue.ReceiveParams{
		QueueURL: c.cfg.GetQueueURL(),
	})
	if err != nil {
		return fmt.Errorf("message fetch fail: %v", err)
	}

	for _, message := range result.Messages {
		// TODO Need to remove this go func() !!
		// Must not have uncontrolled go routine creation.  See commented example above if
		// simple case.
		// if process takes too long to complete then we need to use a thread pool.
		go func() {
			err := c.cfg.GetController().Process(ctx, &message)
			if err != nil {
				slog.Error("message process fail", "err", err)
			}

			err = c.cfg.DeleteFromQueue(ctx, &queue.DeleteParams{
				QueueURL:      c.cfg.GetQueueURL(),
				ReceiptHandle: message.ReceiptHandle,
			})
			if err != nil {
				slog.Error("message delete fail", "err", err)
			}
		}()
	}

	return nil
}