commit f87acbf98eda27a5f55ffc419f5e093ffc908ccc
Author: Mohammed Sohail <sohailsameja@gmail.com>
Date:   Thu Dec 19 17:23:36 2024 +0300

    feat: add data encode decode fns

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..9770634
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module git.grassecon.net/urdt/ussd-data-connect
+
+go 1.23.3
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..e69de29
diff --git a/pkg/data/decode.go b/pkg/data/decode.go
new file mode 100644
index 0000000..d98bf5b
--- /dev/null
+++ b/pkg/data/decode.go
@@ -0,0 +1,22 @@
+package data
+
+import (
+	"encoding/binary"
+)
+
+const ()
+
+// DecodeKey specifically only decodes user data keys stored as bytes into its respective session ID and data type
+// TODO: Replace return data type with imported data types from the common package once lib-gdbm dependency is removed.
+func DecodeKey(key []byte) (uint16, string) {
+	if key[0] != keyPrefix {
+		return 0, ""
+	}
+
+	return binary.BigEndian.Uint16(key[len(key)-2:]), string(key[1 : len(key)-2])
+}
+
+// DecodeValue returns the utf-8 string representation of the value stored in the storage backend
+func DecodeValue(v []byte) string {
+	return string(v)
+}
diff --git a/pkg/data/decode_test.go b/pkg/data/decode_test.go
new file mode 100644
index 0000000..539c2f4
--- /dev/null
+++ b/pkg/data/decode_test.go
@@ -0,0 +1,43 @@
+package data
+
+import (
+	"encoding/hex"
+	"testing"
+)
+
+func TestDecodeKey(t *testing.T) {
+	type want struct {
+		sessionID string
+		dataType  uint16
+	}
+	type args struct {
+		keyBytesHex string
+	}
+	tests := []struct {
+		name string
+		args args
+		want want
+	}{
+		{
+			"blockchain_address",
+			args{
+				keyBytesHex: "202b3235343731313030303132330001",
+			},
+			want{
+				sessionID: "+254711000123",
+				dataType:  ACCOUNT_BLOCKCHAIN_ADDRESS,
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			keyBytes, err := hex.DecodeString(tt.args.keyBytesHex)
+			if err != nil {
+				t.Fatalf("failed to decode hex string: %v", err)
+			}
+
+			dataType, sessionID := DecodeKey(keyBytes)
+			t.Logf("%s data_type: %d, session_id: %s", tt.name, dataType, sessionID)
+		})
+	}
+}
diff --git a/pkg/data/encode.go b/pkg/data/encode.go
new file mode 100644
index 0000000..046c111
--- /dev/null
+++ b/pkg/data/encode.go
@@ -0,0 +1,23 @@
+package data
+
+import (
+	"encoding/binary"
+)
+
+// EncodeKey returns the byte representation of a urdt/ussd user data key.
+// This key can be used to lookup the value on any storage backend implementation.
+// Warning: This is a shortcut specifically for user data, it is not expected to work for all go-vise keys.
+// TODO: Replace with imported data types from the common package once lib-gdbm dependency is removed.
+func EncodeKey(sessionID string, dataType uint16) []byte {
+	keyBytes := []byte(sessionID)
+	keyBytes = append(keyBytes, uint16ToBytes(dataType)...)
+	keyBytes = append([]uint8{keyPrefix}, keyBytes...)
+
+	return keyBytes
+}
+
+func uint16ToBytes(v uint16) []byte {
+	bytes := make([]byte, 2)
+	binary.BigEndian.PutUint16(bytes, v)
+	return bytes
+}
diff --git a/pkg/data/encode_test.go b/pkg/data/encode_test.go
new file mode 100644
index 0000000..e7248b3
--- /dev/null
+++ b/pkg/data/encode_test.go
@@ -0,0 +1,31 @@
+package data
+
+import (
+	"testing"
+)
+
+// TODO: Import from urdt/ussd
+func TestEncodeKey(t *testing.T) {
+	type args struct {
+		sessionID string
+		dataType  uint16
+	}
+	tests := []struct {
+		name string
+		args args
+	}{
+		{
+			"blockchain_address",
+			args{
+				sessionID: "+254711000123",
+				dataType:  ACCOUNT_BLOCKCHAIN_ADDRESS,
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := EncodeKey(tt.args.sessionID, tt.args.dataType)
+			t.Logf("%s key: %x", tt.name, got)
+		})
+	}
+}
diff --git a/pkg/data/type.go b/pkg/data/type.go
new file mode 100644
index 0000000..49dd78e
--- /dev/null
+++ b/pkg/data/type.go
@@ -0,0 +1,16 @@
+package data
+
+// Subset of urdt/ussd/common specifically for syncing to the central data store i.e Graph.
+// TODO: Replace with imported data types from the common package once lib-gdbm dependency is removed.
+const (
+	keyPrefix = 32
+
+	ACCOUNT_BLOCKCHAIN_ADDRESS = 1
+	ACCOUNT_FIRST_NAME         = 3
+	ACCOUNT_LAST_NAME          = 4
+	ACCOUNT_YOB                = 5
+	ACCOUNT_LOCATION           = 6
+	ACCOUNT_GENDER             = 7
+	ACCOUNT_COMMODITIES        = 8
+	ACCOUNT_ACTIVE_VOUCHER     = 17
+)