package e2e

import (
	"fmt"
	"net"
	"testing"
	"time"

	"github.com/iceBear67/redapricot/client"
)

// expectClosedSoon fails unless conn is closed (or reset) within d. A player
// that entered pending stays open until pendingTimeoutMs, so a fast EOF is
// how we tell the limiter dropped the socket before match-side bookkeeping.
func expectClosedSoon(t *testing.T, conn net.Conn, d time.Duration) {
	t.Helper()
	_ = conn.SetReadDeadline(time.Now().Add(d))
	n, err := conn.Read(make([]byte, 16))
	if err == nil {
		t.Fatalf("expected the hub to close the player, read %d bytes", n)
	}
}

// TestPlayerBurstDropsExtraHandshakes: more arrivals than playerBurst from the
// same IP are closed after the handshake and never become pending.
func TestPlayerBurstDropsExtraHandshakes(t *testing.T) {
	const psk = "e2e-rate-burst"
	port := freePort(t)
	hubAddr := fmt.Sprintf("127.0.0.1:%d", port)
	startHubCfg(t, port, psk, map[string]any{
		"playerRatePerSec": 1,
		"playerBurst":      2,
		"maxPlayersPerIp":  64,
	})
	dest := newMockDest(t, modeEcho)
	startClient(t, hubAddr, psk, 8, []client.Mapping{
		{Pattern: "mc.local", Destination: dest.addr},
	})

	kept := make([]net.Conn, 0, 2)
	defer func() {
		for _, c := range kept {
			_ = c.Close()
		}
	}()
	for i := 0; i < 2; i++ {
		pc := dialPlayer(t, hubAddr, "mc.local")
		playerEcho(t, pc, []byte(fmt.Sprintf("ok-%d", i)))
		kept = append(kept, pc)
	}

	// Tokens spent, first two still held: extras must die well inside pendingTimeout.
	for i := 0; i < 2; i++ {
		extra := dialPlayer(t, hubAddr, "mc.local")
		expectClosedSoon(t, extra, 1500*time.Millisecond)
		_ = extra.Close()
	}

	// The admitted players are unaffected.
	playerEcho(t, kept[0], []byte("still-here"))
}

// TestMaxPlayersPerIpCapsConcurrentSockets: a second player from the same IP
// is refused while the first is still open, and admitted again after it closes.
func TestMaxPlayersPerIpCapsConcurrentSockets(t *testing.T) {
	const psk = "e2e-rate-conc"
	port := freePort(t)
	hubAddr := fmt.Sprintf("127.0.0.1:%d", port)
	startHubCfg(t, port, psk, map[string]any{
		"playerRatePerSec": 0,
		"playerBurst":      16,
		"maxPlayersPerIp":  1,
	})
	dest := newMockDest(t, modeEcho)
	startClient(t, hubAddr, psk, 4, []client.Mapping{
		{Pattern: "mc.local", Destination: dest.addr},
	})

	first := dialPlayer(t, hubAddr, "mc.local")
	defer first.Close()
	playerEcho(t, first, []byte("first"))

	second := dialPlayer(t, hubAddr, "mc.local")
	expectClosedSoon(t, second, 1500*time.Millisecond)
	_ = second.Close()

	playerEcho(t, first, []byte("still-first"))
	_ = first.Close()
	// The closeHandler runs on the hub event loop; give it a beat to release.
	time.Sleep(200 * time.Millisecond)

	third := dialPlayer(t, hubAddr, "mc.local")
	defer third.Close()
	playerEcho(t, third, []byte("after-release"))
}

// TestUnmatchedHostConsumesRateBudget: a hostname scan is not a free flood.
// Two unmatched handshakes spend the burst, so a later matching player is
// also dropped.
func TestUnmatchedHostConsumesRateBudget(t *testing.T) {
	const psk = "e2e-rate-scan"
	port := freePort(t)
	hubAddr := fmt.Sprintf("127.0.0.1:%d", port)
	startHubCfg(t, port, psk, map[string]any{
		"playerRatePerSec": 1,
		"playerBurst":      2,
		"maxPlayersPerIp":  64,
	})
	dest := newMockDest(t, modeEcho)
	startClient(t, hubAddr, psk, 4, []client.Mapping{
		{Pattern: "mc.local", Destination: dest.addr},
	})

	for i := 0; i < 2; i++ {
		miss := dialPlayer(t, hubAddr, "no.such.host")
		expectClosedSoon(t, miss, 1500*time.Millisecond)
		_ = miss.Close()
	}

	matched := dialPlayer(t, hubAddr, "mc.local")
	expectClosedSoon(t, matched, 1500*time.Millisecond)
	_ = matched.Close()
}

// TestIntent17IgnoresPlayerLimiter: the control session and worker conns are
// Intent 17, so a limiter tight enough to refuse a second player must not
// prevent the client from connecting or taking over the first player.
func TestIntent17IgnoresPlayerLimiter(t *testing.T) {
	const psk = "e2e-rate-intent17"
	port := freePort(t)
	hubAddr := fmt.Sprintf("127.0.0.1:%d", port)
	startHubCfg(t, port, psk, map[string]any{
		"playerRatePerSec": 1,
		"playerBurst":      1,
		"maxPlayersPerIp":  1,
	})
	dest := newMockDest(t, modeEcho)
	startClient(t, hubAddr, psk, 4, []client.Mapping{
		{Pattern: "mc.local", Destination: dest.addr},
	})

	pc := dialPlayer(t, hubAddr, "mc.local")
	defer pc.Close()
	playerEcho(t, pc, []byte("intent17-ok"))
}

// TestPlayerLimiterOffSwitch: both knobs at 0 restore phase-1 behaviour —
// many players from 127.0.0.1 all get through.
func TestPlayerLimiterOffSwitch(t *testing.T) {
	const psk = "e2e-rate-off"
	const n = 6
	port := freePort(t)
	hubAddr := fmt.Sprintf("127.0.0.1:%d", port)
	startHubCfg(t, port, psk, map[string]any{
		"playerRatePerSec": 0,
		"maxPlayersPerIp":  0,
	})
	dest := newMockDest(t, modeEcho)
	startClient(t, hubAddr, psk, n, []client.Mapping{
		{Pattern: "mc.local", Destination: dest.addr},
	})

	conns := make([]net.Conn, 0, n)
	defer func() {
		for _, c := range conns {
			_ = c.Close()
		}
	}()
	for i := 0; i < n; i++ {
		pc := dialPlayer(t, hubAddr, "mc.local")
		playerEcho(t, pc, []byte(fmt.Sprintf("off-%d", i)))
		conns = append(conns, pc)
	}
}