package bwtest

import (
	"context"
	"testing"
	"time"
)

func TestUDPPacerUsesDeliveryFeedback(t *testing.T) {
	p := newUDPPacer(0)
	initial := p.rate
	now := p.started.Add(2 * time.Second)
	p.observe(10000, now)
	if p.rate >= initial {
		t.Fatal("automatic rate did not fall after severe loss")
	}
	lower := p.rate
	p.observe(10000+lower/8, now.Add(time.Second))
	if p.rate <= lower {
		t.Fatal("automatic rate did not grow after successful delivery")
	}
	fixed := newUDPPacer(1234567)
	fixed.observe(0, fixed.started.Add(2*time.Second))
	if fixed.rate != 1234567 {
		t.Fatal("receiver feedback changed explicit rate limit")
	}
}
func TestUDPPacerCancellation(t *testing.T) {
	p := newUDPPacer(1)
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Millisecond)
	defer cancel()
	if p.wait(ctx, 1472) {
		t.Fatal("rate limiter ignored cancellation")
	}
}
func TestUDPTrackerStreamsReorderingDuplicates(t *testing.T) {
	var tracker udpTracker
	for _, v := range []struct {
		stream uint8
		seq    uint64
		lost   int64
	}{{0, 1, 0}, {1, 1, 0}, {0, 3, 1}, {1, 2, 1}, {0, 2, 0}, {0, 4, 0}} {
		ok, lost := tracker.accept(v.stream, v.seq)
		if !ok || lost != v.lost {
			t.Fatalf("stream %d seq %d: accepted=%v lost=%d want=%d", v.stream, v.seq, ok, lost, v.lost)
		}
	}
	if ok, lost := tracker.accept(0, 3); ok || lost != 0 {
		t.Fatal("duplicate counted as data or loss")
	}
}
func TestBandwidthUDPDirectionsAndAutomaticPacing(t *testing.T) {
	s := testServer(t)
	for _, direction := range []string{"rx", "both", "tx"} {
		t.Run(direction, func(t *testing.T) {
			c := NewClient()
			t.Cleanup(c.Stop)
			if err := c.Run(context.Background(), SessionRequest{Target: "127.0.0.1", Port: s.config.Port, Protocol: "udp", Direction: direction, Streams: 4, PacketSize: 1472, Duration: 2}); err != nil {
				t.Fatal(err)
			}
			deadline := time.Now().Add(5 * time.Second)
			for c.GetStatus().Running && time.Now().Before(deadline) {
				time.Sleep(10 * time.Millisecond)
			}
			st := c.GetStatus()
			if st.Running || st.Error != "" || st.Summary == nil {
				t.Fatalf("UDP test failed: %+v", st)
			}
			if direction != "rx" && st.Summary.TotalTxBytes < 100000 {
				t.Fatalf("no confirmed TX: %+v", st.Summary)
			}
			if direction != "tx" && st.Summary.TotalRxBytes < 100000 {
				t.Fatalf("no reverse UDP: %+v", st.Summary)
			}
			if st.Summary.AvgLossPct != 0 {
				t.Fatalf("streams or reordered packets falsely counted as loss: %+v", st.Summary)
			}
			if st.Summary.AvgTxMbps > 20 || st.Summary.AvgRxMbps > 20 {
				t.Fatal("automatic UDP started with an unbounded flood")
			}
			if direction == "tx" && st.Summary.TotalRxBytes != 0 {
				t.Fatal("TX delivery reports mislabeled as downloaded data")
			}
		})
	}
}