package feed

import (
	"context"
	"errors"
	"io"
	"log/slog"
	"testing"
	"time"

	"tangled.org/core/knotfeed"
)

func TestFeedRefcountsAndReleasesSubscriptions(t *testing.T) {
	entered := make(chan string, 8)
	held := make(chan struct{})
	f := New(slog.New(slog.NewTextHandler(io.Discard, nil)), Hooks{
		LoadCursor: func(ctx context.Context, knot string) (knotfeed.Cursor, error) {
			select {
			case entered <- knot:
			case <-ctx.Done():
				return knotfeed.Cursor{}, ctx.Err()
			}
			select {
			case <-held:
			case <-ctx.Done():
			}
			return knotfeed.Cursor{}, errors.New("no network in tests")
		},
	})
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	const knot = "knot.nel.pet"
	f.Subscribe(ctx, knot)
	f.Subscribe(ctx, knot)
	select {
	case got := <-entered:
		if got != knot {
			t.Fatalf("first session loaded the cursor for %q, want %q", got, knot)
		}
	case <-time.After(2 * time.Second):
		t.Fatal("no session started for a subscribed knot")
	}

	f.Unsubscribe(knot)
	f.Unsubscribe(knot)
	close(held)

	f.Subscribe(ctx, knot)
	select {
	case got := <-entered:
		if got != knot {
			t.Fatalf("second session loaded the cursor for %q, want %q", got, knot)
		}
	case <-time.After(2 * time.Second):
		t.Fatalf("a fresh session didn't start after the knot was released and resubscribed")
	}
}

func TestFeedRejectsUnsubscribableHost(t *testing.T) {
	entered := make(chan string, 1)
	f := New(slog.New(slog.NewTextHandler(io.Discard, nil)), Hooks{
		LoadCursor: func(ctx context.Context, knot string) (knotfeed.Cursor, error) {
			entered <- knot
			return knotfeed.Cursor{}, errors.New("no network in tests")
		},
	})
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	f.Subscribe(ctx, "192.0.2.1")
	f.Unsubscribe("192.0.2.1")
	select {
	case knot := <-entered:
		t.Fatalf("a session started for an unparsable host %q", knot)
	case <-time.After(100 * time.Millisecond):
	}
}