X-Git-Url: https://git.r.bdr.sh/rbdr/mobius/blobdiff_plain/22c599abc18895f73e96095f35b71cf3357d41b4..72f8a1fd5e7fbd5224e3f1393f36cc9b0d58eb78:/hotline/user.go?ds=sidebyside

diff --git a/hotline/user.go b/hotline/user.go
index f80fd72..c4e0790 100644
--- a/hotline/user.go
+++ b/hotline/user.go
@@ -2,24 +2,49 @@ package hotline
 
 import (
 	"encoding/binary"
+	"io"
+	"math/big"
+	"slices"
 )
 
-// User flags are stored as a 2 byte bitmap with the following values:
+// User flags are stored as a 2 byte bitmap and represent various user states
 const (
-	userFlagAway        = 0 // User is away
-	userFlagAdmin       = 1 // User is admin
-	userFlagRefusePM    = 2 // User refuses private messages
-	userFLagRefusePChat = 3 // User refuses private chat
+	UserFlagAway        = 0 // User is away
+	UserFlagAdmin       = 1 // User is admin
+	UserFlagRefusePM    = 2 // User refuses private messages
+	UserFlagRefusePChat = 3 // User refuses private chat
 )
 
+// User options are sent from clients and represent options set in the client's preferences.
+const (
+	UserOptRefusePM     = 0 // User has "Refuse private messages" pref set
+	UserOptRefuseChat   = 1 // User has "Refuse private chat" pref set
+	UserOptAutoResponse = 2 // User has "Automatic response" pref set
+)
+
+type UserFlags [2]byte
+
+func (f *UserFlags) IsSet(i int) bool {
+	flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(f[:])))
+	return flagBitmap.Bit(i) == 1
+}
+
+func (f *UserFlags) Set(i int, newVal uint) {
+	flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(f[:])))
+	flagBitmap.SetBit(flagBitmap, i, newVal)
+	binary.BigEndian.PutUint16(f[:], uint16(flagBitmap.Int64()))
+}
+
 type User struct {
-	ID    []byte // Size 2
+	ID    [2]byte
 	Icon  []byte // Size 2
 	Flags []byte // Size 2
 	Name  string // Variable length user name
+
+	readOffset int // Internal offset to track read progress
 }
 
-func (u User) Payload() []byte {
+func (u *User) Read(p []byte) (int, error) {
 	nameLen := make([]byte, 2)
 	binary.BigEndian.PutUint16(nameLen, uint16(len(u.Name)))
 
@@ -31,39 +56,41 @@ func (u User) Payload() []byte {
 		u.Flags = u.Flags[2:]
 	}
 
-	out := append(u.ID[:2], u.Icon[:2]...)
-	out = append(out, u.Flags[:2]...)
-	out = append(out, nameLen...)
-	out = append(out, u.Name...)
-
-	return out
-}
+	b := slices.Concat(
+		u.ID[:],
+		u.Icon,
+		u.Flags,
+		nameLen,
+		[]byte(u.Name),
+	)
 
-func ReadUser(b []byte) (*User, error) {
-	u := &User{
-		ID:    b[0:2],
-		Icon:  b[2:4],
-		Flags: b[4:6],
-		Name:  string(b[8:]),
+	if u.readOffset >= len(b) {
+		return 0, io.EOF // All bytes have been read
 	}
-	return u, nil
+
+	n := copy(p, b)
+	u.readOffset = n
+
+	return n, nil
 }
 
-// DecodeUserString decodes an obfuscated user string from a client
-// e.g. 98 8a 9a 8c 8b => "guest"
-func DecodeUserString(encodedString []byte) (decodedString string) {
-	for _, char := range encodedString {
-		decodedString += string(rune(255 - uint(char)))
-	}
-	return decodedString
+func (u *User) Write(p []byte) (int, error) {
+	namelen := int(binary.BigEndian.Uint16(p[6:8]))
+	u.ID = [2]byte(p[0:2])
+	u.Icon = p[2:4]
+	u.Flags = p[4:6]
+	u.Name = string(p[8 : 8+namelen])
+
+	return 8 + namelen, nil
 }
 
-// Take a []byte of uncoded ascii as input and encode it
-// TODO: change the method signature to take a string and return []byte
-func NegatedUserString(encodedString []byte) string {
-	var decodedString string
-	for _, char := range encodedString {
-		decodedString += string(255 - uint8(char))[1:]
+// EncodeString takes []byte s containing cleartext and rotates by 255 into obfuscated cleartext.
+// The Hotline protocol uses this format for sending passwords over network.
+// Not secure, but hey, it was the 90s!
+func EncodeString(clearText []byte) []byte {
+	obfuText := make([]byte, len(clearText))
+	for i := 0; i < len(clearText); i++ {
+		obfuText[i] = 255 - clearText[i]
 	}
-	return decodedString
+	return obfuText
 }