updated drote

with claud ai's help

dots/bash/.bashrc

@@ -296,10 +296,10 @@ rotl() {
 
 rote() {
     input="${1//./}"
-    rote36 "$input"
+    rote36rotl "$input"
 }
 
-rote36() {
+rote36rotl() {
     if [[ -n $1 ]] ; then
 
         # datestamp as base 36
@@ -312,6 +312,7 @@ rote36() {
         datestamp=${year}${month}${day}_
         datestamp=`echo "${datestamp}" | tr '[A-Z]' '[a-z]'`
 
+        # the last part as: rotate the length (if string is 5 long rotate 5, if length is 6 rotate 6, etc)
         rotl=$(rotl $1 0)
         emailaddress=$datestamp$rotl"@reduxmail.com"
         echo $emailaddress
@@ -319,28 +320,61 @@ rote36() {
     fi
 }
 
+# claud ai
 drote() {
     local email="$1"
-    # Extract base36 date and encoded string
-    local base36date="${email%%_*}"
-    local rest="${email#*_}"
-    rest="${rest%@reduxmail.com}"
 
-    # Decode base36 date
-    local year36="${base36date:0:1}"
-    local month36="${base36date:1:1}"
-    local day36="${base36date:2:1}"
+    # Strip @reduxmail.com
+    local local_part="${email%@reduxmail.com}"
 
-    local year=$(echo "ibase=36; ${year36^^}" | bc)
-    local month=$(echo "ibase=36; ${month36^^}" | bc)
-    local day=$(echo "ibase=36; ${day36^^}" | bc)
+    # Split on _ → datestamp and encoded parts
+    local ds="${local_part%%_*}"
+    local encoded="${local_part#*_}"
 
-    # Decode the rest using rotl with shift 0 (reverse of rotl 0 is itself)
-    # If you have a function to reverse the encoding, use it here.
-    # For now, let's assume rotl 0 is a simple rot13 (as in your example)
-    local decoded=$(echo "$rest" | tr 'a-z' 'n-za-m')
+    # --- Base36 char to decimal ---
+    _b36_to_dec() {
+        local c="${1,,}"  # lowercase
+        if [[ "$c" =~ [0-9] ]]; then
+            echo "$c"
+        else
+            # a=10, b=11, ... z=35
+            # ASCII of a is 97; 97 - 87 = 10 ✓
+            printf "%d" $(( $(printf '%d' "'$c") - 87 ))
+        fi
+    }
 
-    printf "%02d%02d%02d: %s\n" "$year" "$month" "$day" "$decoded"
+    # --- Decode datestamp (3 base36 chars → YYMMDD) ---
+    local yy mm dd yymmdd
+    yy=$(_b36_to_dec "${ds:0:1}")
+    mm=$(_b36_to_dec "${ds:1:1}")
+    dd=$(_b36_to_dec "${ds:2:1}")
+    yymmdd=$(printf "%02d%02d%02d" "$yy" "$mm" "$dd")
+
+    # --- Reverse the rot cipher in pure bash ---
+    local size=${#encoded}
+    if (( size > 25 && size < 51 )); then
+        size=$(( size - 25 ))
+    fi
+    local shift=$(( size % 26 ))
+
+    local decoded="" i c ascii base rotated
+    for (( i = 0; i < ${#encoded}; i++ )); do
+        c="${encoded:$i:1}"
+        ascii=$(printf '%d' "'$c")
+        if (( ascii >= 97 && ascii <= 122 )); then
+            # lowercase: base = 97
+            rotated=$(( (ascii - 97 - shift + 26) % 26 + 97 ))
+            decoded+=$(printf "\\$(printf '%03o' "$rotated")")
+        elif (( ascii >= 65 && ascii <= 90 )); then
+            # uppercase: base = 65
+            rotated=$(( (ascii - 65 - shift + 26) % 26 + 65 ))
+            decoded+=$(printf "\\$(printf '%03o' "$rotated")")
+        else
+            decoded+="$c"
+        fi
+    done
+
+    echo "$yymmdd: $decoded"
 }
 
 # ---