package wol

import (
	"net"
	"syscall"
	"testing"
	"time"
)

func TestParseMAC(t *testing.T) {
	tests := []struct {
		input     string
		wantOK    bool
		wantBytes [6]byte
	}{
		{"AA:BB:CC:DD:EE:FF", true, [6]byte{0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF}},
		{"aa:bb:cc:dd:ee:ff", true, [6]byte{0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF}},
		{"AA-BB-CC-DD-EE-FF", true, [6]byte{0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF}},
		{"11:22:33:44:55:66", true, [6]byte{0x11, 0x22, 0x33, 0x44, 0x55, 0x66}},
		{"not:a:mac:addre", false, [6]byte{}},
		{"GG:HH:II:JJ:KK:LL", false, [6]byte{}},
		{"aa:bb:cc:dd", false, [6]byte{}},
		{"", false, [6]byte{}},
	}

	for _, tt := range tests {
		mac, err := ParseMAC(tt.input)
		if tt.wantOK {
			if err != nil {
				t.Errorf("ParseMAC(%q) unexpected error: %v", tt.input, err)
				continue
			}
			if mac != tt.wantBytes {
				t.Errorf("ParseMAC(%q) = %v, want %v", tt.input, mac, tt.wantBytes)
			}
		} else {
			if err == nil {
				t.Errorf("ParseMAC(%q) expected error, got nil", tt.input)
			}
		}
	}
}

func TestFormatMAC(t *testing.T) {
	mac := [6]byte{0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF}
	got := FormatMAC(mac)
	want := "aa:bb:cc:dd:ee:ff"
	if got != want {
		t.Errorf("FormatMAC() = %q, want %q", got, want)
	}
}

func TestBuildMagicPacket(t *testing.T) {
	mac := [6]byte{0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF}
	packet := BuildMagicPacket(mac)

	if len(packet) != 102 {
		t.Errorf("BuildMagicPacket length = %d, want 102", len(packet))
	}

	for i := 0; i < 6; i++ {
		if packet[i] != 0xFF {
			t.Errorf("packet[%d] = %02x, want FF", i, packet[i])
		}
	}

	for i := 0; i < 16; i++ {
		offset := 6 + i*6
		for j := 0; j < 6; j++ {
			if packet[offset+j] != mac[j] {
				t.Errorf("packet[%d] = %02x, want %02x (rep %d)", offset+j, packet[offset+j], mac[j], i)
			}
		}
	}
}

func TestSendInvalidBroadcast(t *testing.T) {
	mac, _ := ParseMAC("aa:bb:cc:dd:ee:ff")
	err := Send(mac, "not-an-ip")
	if err == nil {
		t.Error("Send with invalid broadcast address expected error, got nil")
	}
}

func TestSendThreePacketsToListener(t *testing.T) {
	mac, _ := ParseMAC("aa:bb:cc:dd:ee:ff")
	ln, err := net.ListenPacket("udp", "127.0.0.1:9")
	if err != nil {
		t.Skipf("skipping test (need port 9, likely requires root): %v", err)
	}
	defer ln.Close()

	err = Send(mac, "127.0.0.1")
	if err != nil {
		t.Errorf("Send to 127.0.0.1: expected nil, got %v", err)
	}
}

func TestSendPacketReceived(t *testing.T) {
	mac, _ := ParseMAC("aa:bb:cc:dd:ee:ff")
	ln, err := net.ListenPacket("udp", "127.0.0.1:0")
	if err != nil {
		t.Skipf("skipping receive test: %v", err)
	}
	defer ln.Close()
	addr := ln.LocalAddr().(*net.UDPAddr)

	deadline := time.Now().Add(5 * time.Second)
	errCh := make(chan error, 1)
	go func() {
		time.Sleep(500 * time.Millisecond)
		conn, err := net.DialUDP("udp4", nil, &net.UDPAddr{IP: net.ParseIP("127.0.0.1"), Port: addr.Port})
		if err != nil {
			errCh <- err
			return
		}
		sc, err := conn.SyscallConn()
		if err != nil {
			conn.Close()
			errCh <- err
			return
		}
		if err := sc.Control(func(fd uintptr) {
			err = syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1)
		}); err != nil {
			conn.Close()
			errCh <- err
			return
		}
		conn.SetWriteDeadline(time.Now().Add(3 * time.Second))
		packet := BuildMagicPacket(mac)
		for i := 0; i < 3; i++ {
			conn.Write(packet)
			time.Sleep(100 * time.Millisecond)
		}
		conn.Close()
		errCh <- nil
	}()

	expected := BuildMagicPacket(mac)
	buf := make([]byte, 102)
	rcvd := 0
	for rcvd < 3 {
		ln.SetReadDeadline(deadline)
		n, _, err := ln.ReadFrom(buf)
		if err != nil {
			if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
				break
			}
			t.Fatalf("unexpected error reading packet %d: %v", rcvd+1, err)
		}
		if n != len(expected) {
			t.Errorf("packet %d: got length %d, want %d", rcvd+1, n, len(expected))
			continue
		}
		if string(buf[:n]) != string(expected[:n]) {
			t.Errorf("packet %d content mismatch", rcvd+1)
		}
		rcvd++
	}
	if rcvd != 3 {
		t.Errorf("expected 3 packets, received %d", rcvd)
	}
	select {
	case sendErr := <-errCh:
		if sendErr != nil {
			t.Logf("sender goroutine error (ignored): %v", sendErr)
		}
	default:
	}
}