1 files changed, 69 insertions, 0 deletions
diff --git a/user.go b/user.go
new file mode 100644
index 0000000..f80fd72
--- /dev/null
+++ b/user.go
@@ -0,0 +1,69 @@
+package hotline
+
+import (
+	"encoding/binary"
+)
+
+// User flags are stored as a 2 byte bitmap with the following values:
+const (
+	userFlagAway        = 0 // User is away
+	userFlagAdmin       = 1 // User is admin
+	userFlagRefusePM    = 2 // User refuses private messages
+	userFLagRefusePChat = 3 // User refuses private chat
+)
+
+type User struct {
+	ID    []byte // Size 2
+	Icon  []byte // Size 2
+	Flags []byte // Size 2
+	Name  string // Variable length user name
+}
+
+func (u User) Payload() []byte {
+	nameLen := make([]byte, 2)
+	binary.BigEndian.PutUint16(nameLen, uint16(len(u.Name)))
+
+	if len(u.Icon) == 4 {
+		u.Icon = u.Icon[2:]
+	}
+
+	if len(u.Flags) == 4 {
+		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
+}
+
+func ReadUser(b []byte) (*User, error) {
+	u := &User{
+		ID:    b[0:2],
+		Icon:  b[2:4],
+		Flags: b[4:6],
+		Name:  string(b[8:]),
+	}
+	return u, 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
+}
+
+// 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:]
+	}
+	return decodedString
+}