package outcome

import (
	"context"
	"errors"
	"testing"

	domain "proxy-pool/internal/domain/outcome"
)

type metricsRecorder struct {
	events  []domain.Event
	dropped int
}

func (recorder *metricsRecorder) Observe(event domain.Event) {
	recorder.events = append(recorder.events, event)
}

func (recorder *metricsRecorder) ObserveDropped() {
	recorder.dropped++
}

func TestQueueBatchesWithoutBlockingAndCountsOverflow(t *testing.T) {
	queue, err := NewQueue(QueueOptions{Capacity: 2, MaxBatch: 2})
	if err != nil {
		t.Fatalf("NewQueue() = %v", err)
	}
	queue.Record(domain.Event{ProxyID: "proxy-a"})
	queue.Record(domain.Event{ProxyID: "proxy-b"})
	queue.Record(domain.Event{ProxyID: "proxy-c"})
	if queue.Dropped() != 1 {
		t.Fatalf("Dropped() = %d, want 1", queue.Dropped())
	}
	batch, err := queue.Next(context.Background())
	if err != nil || len(batch) != 2 || batch[0].ProxyID != "proxy-a" || batch[1].ProxyID != "proxy-b" {
		t.Fatalf("Next() = %+v, %v", batch, err)
	}
	if batch, ok := queue.TryNext(); ok || batch != nil {
		t.Fatalf("TryNext() = %+v, %t; want nil, false", batch, ok)
	}
}

func TestQueueHonorsCanceledContext(t *testing.T) {
	queue, err := NewQueue(QueueOptions{Capacity: 1, MaxBatch: 1})
	if err != nil {
		t.Fatalf("NewQueue() = %v", err)
	}
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	if _, err := queue.Next(ctx); !errors.Is(err, context.Canceled) {
		t.Fatalf("Next(canceled) = %v, want context canceled", err)
	}
}

func TestQueueReportsAttemptedOutcomesAndOverflow(t *testing.T) {
	metrics := &metricsRecorder{}
	queue, err := NewQueue(QueueOptions{Capacity: 1, MaxBatch: 1, Metrics: metrics})
	if err != nil {
		t.Fatalf("NewQueue() = %v", err)
	}
	first := domain.Event{ProxyID: "proxy-a", Stage: domain.StageDial, Success: true}
	second := domain.Event{ProxyID: "proxy-b", Stage: domain.StageTunnel, Success: false}
	queue.Record(first)
	queue.Record(second)

	if len(metrics.events) != 2 || metrics.events[0] != first || metrics.events[1] != second {
		t.Fatalf("observed events = %+v, want both attempts", metrics.events)
	}
	if metrics.dropped != 1 {
		t.Fatalf("observed dropped = %d, want 1", metrics.dropped)
	}
}