From b12c68ddfb2ab5b209813f72da8916191ed0a62f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bernhard=20Rosenkr=C3=A4nzer?= <bero@federated.computer>
Date: Mon, 16 Dec 2024 20:52:50 +0100
Subject: [PATCH] Add helpers script (currently useful for generating UUIDs for
 the plane database)

---
 lib/helpers.sh | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 lib/helpers.sh

diff --git a/lib/helpers.sh b/lib/helpers.sh
new file mode 100644
index 0000000..7e728f2
--- /dev/null
+++ b/lib/helpers.sh
@@ -0,0 +1,61 @@
+# Helper functions that can be useful for multiple scripts
+
+# random: Create a random string in a specified format
+# Usage: random format
+# Where format is a string to be transformed into a random sequence:
+# 	0 - transformed into a digit (0-9)
+#	x - transformed into a lower case hexadecimal digit (0-9, a-f)
+#	X - transformed into an upper case hexadecimal digit (0-9, A-F)
+#	a - transformed into a lower case letter (a-z)
+#	A - transformed into an upper case letter (A-Z)
+#	l - transformed into a letter (upper or lower case) (a-z, A-Z)
+#	L - transformed into a letter (upper or lower case) or number (a-z, A-Z, 0-9)
+#	\ - skipped; next character is not transformed
+#	anything else - kept as is
+# e.g. to create a plane UUID, use
+# random 
+random() {
+	local TEMPLATE="$1"
+	local RESULT=""
+	local KEEPNEXT=false
+	local ADD
+	for i in $(echo $TEMPLATE |fold -w1); do
+		if $KEEPNEXT; then
+			RESULT="$RESULT$i"
+			KEEPNEXT=false
+			continue
+		fi
+		case "$i" in
+		x)
+			ADD="$(echo $((RANDOM%16))|xargs printf '%x')"
+			;;
+		X)
+			ADD="$(echo $((RANDOM%16))|xargs printf '%X')"
+			;;
+		0)
+			ADD="${RANDOM:0:1}"
+			;;
+		a)
+			ADD="$(head -n1 /dev/urandom |tr -dc a-z |cut -b1)"
+			;;
+		A)
+			ADD="$(head -n1 /dev/urandom |tr -dc A-Z |cut -b1)"
+			;;
+		l)
+			ADD="$(head -n1 /dev/urandom |tr -dc a-zA-Z |cut -b1)"
+			;;
+		L)
+			ADD="$(head -n1 /dev/urandom |tr -dc a-zA-Z0-9 |cut -b1)"
+			;;
+		"\\")
+			KEEPNEXT=true
+			continue
+			;;
+		*)
+			ADD="$i"
+			;;
+		esac
+		RESULT="$RESULT$ADD"
+	done
+	echo -n $RESULT
+}