package protocol

import (
	"bytes"
	"testing"

	"spark-server/internal/pkg/errs"
)

func TestPeekBodyLengthAndPrefix(t *testing.T) {
	raw, err := Encode(Frame{Version: CurrentVersion, Command: CmdHeartbeat, Body: []byte("abc")})
	if err != nil {
		t.Fatal(err)
	}
	n, err := PeekBodyLength(raw[:HeaderSize])
	if err != nil || n != 3 {
		t.Fatalf("peek body %d %v", n, err)
	}
	if !LooksLikeFrame(raw) {
		t.Fatal("looks like frame")
	}
	if !MaybeFramePrefix(raw[:1]) {
		t.Fatal("single magic byte is a frame prefix")
	}
	if MaybeFramePrefix([]byte("P")) {
		t.Fatal("P is not a frame prefix")
	}
}

func TestCompressRoundTrip(t *testing.T) {
	body := bytes.Repeat([]byte("spark-im-compress"), 40)
	out, flags, err := PrepareBody(body, 32)
	if err != nil {
		t.Fatal(err)
	}
	if flags&FlagCompress == 0 {
		t.Fatal("expected compress flag")
	}
	got, err := DecodeBody(out, flags, 65536)
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(got, body) {
		t.Fatal("decompress mismatch")
	}
}

func TestParsePrefixV1AndV2(t *testing.T) {
	line := []byte("PROXY TCP4 203.0.113.10 192.0.2.1 443 9000\r\n")
	h, n, err := ParsePrefix(append(append([]byte{}, line...), 'S', 'P'))
	if err != nil {
		t.Fatal(err)
	}
	if h.SrcIP.String() != "203.0.113.10" || h.SrcPort != 443 || n != len(line) {
		t.Fatalf("v1 %+v n=%d want %d", h, n, len(line))
	}
	if _, _, err := ParsePrefix([]byte("P")); !NeedMore(err) {
		t.Fatalf("partial v1: %v", err)
	}
	v2 := buildProxyV2(t)
	h2, n2, err := ParsePrefix(v2)
	if err != nil {
		t.Fatal(err)
	}
	if h2.SrcIP.String() != "203.0.113.10" || h2.SrcPort != 443 || n2 != len(v2) {
		t.Fatalf("v2 %+v n=%d", h2, n2)
	}
	if _, _, err := ParsePrefix([]byte("GET /")); err != errs.ErrProxyHeader {
		t.Fatalf("garbage: %v", err)
	}
}

func buildProxyV2(t *testing.T) []byte {
	t.Helper()
	buf := make([]byte, 16+12)
	copy(buf, proxyV2Sig)
	buf[12] = 0x21
	buf[13] = 0x11
	buf[14] = 0
	buf[15] = 12
	copy(buf[16:20], []byte{203, 0, 113, 10})
	copy(buf[20:24], []byte{192, 0, 2, 1})
	buf[24] = 1
	buf[25] = 187 // 443
	buf[26] = 0x23
	buf[27] = 0x28 // 9000
	return buf
}