package dispatch

import (
	"context"
	"testing"
	"time"

	"example.com/mqtt5-learning/internal/mqtt"
)

func TestPoolReportsFullAndDrainsAcceptedJobs(t *testing.T) {
	pool := New(context.Background(), 1, 1)
	started := make(chan struct{})
	release := make(chan struct{})

	outcome, err := pool.Submit(context.Background(), func(context.Context) error {
		close(started)
		<-release
		return nil
	})
	if err != nil || outcome != Accepted {
		t.Fatalf("first Submit() = (%v, %v), want (Accepted, nil)", outcome, err)
	}
	<-started

	outcome, err = pool.Submit(context.Background(), func(context.Context) error { return nil })
	if err != nil || outcome != Accepted {
		t.Fatalf("second Submit() = (%v, %v), want (Accepted, nil)", outcome, err)
	}
	outcome, err = pool.Submit(context.Background(), func(context.Context) error { return nil })
	if err != nil || outcome != Full {
		t.Fatalf("third Submit() = (%v, %v), want (Full, nil)", outcome, err)
	}

	shutdownCtx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()
	shutdownDone := make(chan error, 1)
	go func() { shutdownDone <- pool.Shutdown(shutdownCtx) }()

	select {
	case err := <-shutdownDone:
		t.Fatalf("Shutdown() returned before accepted work was released: %v", err)
	case <-time.After(10 * time.Millisecond):
	}
	close(release)
	if err := <-shutdownDone; err != nil {
		t.Fatalf("Shutdown() error = %v, want nil", err)
	}

	stats := pool.Stats()
	if stats.Accepted != 2 || stats.Rejected != 1 || stats.Completed != 2 || stats.Failed != 0 {
		t.Fatalf("Stats() = %+v, want accepted=2 rejected=1 completed=2 failed=0", stats)
	}
}

func TestReceiverRoutesResponsesToImportantPool(t *testing.T) {
	telemetry := New(context.Background(), 1, 1)
	important := New(context.Background(), 1, 1)
	receiver := &Receiver{
		Telemetry: telemetry,
		Important: important,
		Process:   func(context.Context, mqtt.Message) error { return nil },
	}

	outcome, err := receiver.Submit(context.Background(), mqtt.Message{
		Topic: "lab/v1/devices/device-001/responses",
	})
	if err != nil || outcome != Accepted {
		t.Fatalf("Submit(response) = (%v, %v), want (Accepted, nil)", outcome, err)
	}

	shutdownCtx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()
	if err := Shutdown(shutdownCtx, telemetry, important); err != nil {
		t.Fatalf("Shutdown() error = %v", err)
	}
	if got := important.Stats().Accepted; got != 1 {
		t.Errorf("important accepted = %d, want 1", got)
	}
	if got := telemetry.Stats().Accepted; got != 0 {
		t.Errorf("telemetry accepted = %d, want 0", got)
	}
}