package main

import (
	"net"
	"testing"
	"time"

	"dragontcp/internal/cover"
	"dragontcp/internal/wire"
)

func TestAdaptiveSizerRecoversFromMinimum(t *testing.T) {
	opts := chunkClientOptions{
		startSize:      64,
		minSize:        32,
		maxSize:        1024,
		adaptive:       true,
		adaptSuccesses: 2,
	}
	s := newAdaptiveSizer("test", 64, opts)
	_, next := s.Failure(64)
	if next != 32 {
		t.Fatalf("failure should reduce 64 -> 32, got %d", next)
	}
	for i := 0; i < 16; i++ {
		s.Success(32)
	}
	if got := s.Current(); got <= 32 {
		t.Fatalf("adaptive controller remained stuck at minimum: %d", got)
	}
}

func TestReconnectAutoLearnsFromRealReuseFailure(t *testing.T) {
	ln, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	defer ln.Close()
	serverErr := make(chan error, 1)
	go func() {
		first, err := ln.Accept()
		if err != nil {
			serverErr <- err
			return
		}
		if _, err := wire.ReadRequest(first); err != nil {
			serverErr <- err
			return
		}
		if err := wire.WriteResponse(first, wire.StatusOK, nil); err != nil {
			serverErr <- err
			return
		}
		_ = first.Close() // Force the next logical request to reconnect.

		second, err := ln.Accept()
		if err != nil {
			serverErr <- err
			return
		}
		defer second.Close()
		if _, err := wire.ReadRequest(second); err != nil {
			serverErr <- err
			return
		}
		serverErr <- wire.WriteResponse(second, wire.StatusOK, nil)
	}()

	lane := newRequestLane(ln.Addr().String(), 0, 1, time.Second, 0, cover.Profile{})
	defer lane.Close()
	if !lane.autoReconnect || lane.reconnectEvery != 0 {
		t.Fatalf("auto lane started auto=%t reconnectEvery=%d", lane.autoReconnect, lane.reconnectEvery)
	}
	var sid wire.SessionID
	if status, _, err := lane.single(wire.ModeProbe, sid, 1, nil); err != nil || status != wire.StatusOK {
		t.Fatalf("first request status=%d err=%v", status, err)
	}
	if status, _, err := lane.single(wire.ModeProbe, sid, 2, nil); err != nil || status != wire.StatusOK {
		t.Fatalf("retried request status=%d err=%v", status, err)
	}
	if lane.reconnectEvery != 1 || lane.pc != nil {
		t.Fatalf("auto lane did not learn single-request mode: reconnectEvery=%d pc=%v", lane.reconnectEvery, lane.pc)
	}
	if err := <-serverErr; err != nil {
		t.Fatal(err)
	}
}

func TestReconnectZeroMeansPersistent(t *testing.T) {
	lane := newRequestLane("127.0.0.1:1", 0, 0, 0, 0, cover.Profile{})
	if lane.reconnectEvery != 0 {
		t.Fatalf("reconnectEvery=%d, want 0", lane.reconnectEvery)
	}
}

func TestBPAutoStartsPersistent(t *testing.T) {
	lane := newBPLane("127.0.0.1:1", 0, 1, time.Second, cover.Profile{})
	if !lane.autoReconnect || lane.reconnectEvery != 0 {
		t.Fatalf("BP auto lane started auto=%t reconnectEvery=%d", lane.autoReconnect, lane.reconnectEvery)
	}
}