From 0d1d3e8398fd0d7844edf1e2ad13d1adc245de17 Mon Sep 17 00:00:00 2001
From: Iain Patterson <me@iain.cx>
Date: Wed, 18 May 2016 16:09:42 +0100
Subject: [PATCH 1/1] Read existing palette colour.

---
 opt/bin/ucolour | 67 ++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 57 insertions(+), 10 deletions(-)

diff --git a/opt/bin/ucolour b/opt/bin/ucolour
index 2b5fc1f..5cfc19f 100755
--- a/opt/bin/ucolour
+++ b/opt/bin/ucolour
@@ -14,8 +14,57 @@
 #          -p   Set palette reference with -P.
 # Notes: Border defaults to background.
 #        The -P and -p flags must be used together.
+#        Colour spec can be a simple number, to copy the
+#        existing palette entry for that index. 
 #
 
+PROG=ucolour
+tmux_prefix=
+[ -n "$TMUX" ] && tmux_prefix="\033Ptmux;\033"
+
+function parse_colour() {
+  local arg=$1; shift
+  local safe=${arg//[1-9]/}
+
+  if [ "$safe" = "0" -o -z "$safe" ]; then
+    # Hack to get existing.
+    local index=$(
+      local index
+      exec < /dev/tty
+      local oldstty=$(stty -g)
+      stty raw -echo min 0
+      echo -en "$tmux_prefix\033]4;$arg;?\007" > /dev/tty
+      local ret=1
+      local tries=0
+      while [ $ret -gt 0 ]; do
+        tries=$((tries+1))
+        IFS='' read -t 0
+        ret=$?
+        if [ $tries -gt 2 ]; then
+          [ $tries -gt 3 ] && break
+          sleep 1
+        fi
+      done
+      IFS='' read -r index
+      stty $oldstty
+      echo "$index"
+    )
+    if [ -n "$index" ]; then
+      index=${index##*;}
+      index=${index%?}
+      echo "$index"
+      echo >&2 "$PROG: Colour $arg is $index."
+      return 0
+    fi
+  else
+    echo "$arg"
+    return 0
+  fi
+
+  echo ""
+  return 1
+}
+
 BG=
 FG=
 bg=
@@ -25,18 +74,17 @@ cu=
 mo=
 pc=
 ps=
-tmux_prefix=
 while getopts ":B:F:P:b:c:d:f:m:p:" opt; do
   case $opt in
-    B) BG=$OPTARG;;
-    F) FG=$OPTARG;;
+    B) BG=$(parse_colour $OPTARG);;
+    F) FG=$(parse_colour $OPTARG);;
     P) pc=$OPTARG;;
-    b) bg=$OPTARG;;
-    c) cu=$OPTARG;;
-    d) bd=$OPTARG;;
-    f) fg=$OPTARG;;
-    m) mo=$OPTARG;;
-    p) ps=$OPTARG;;
+    b) bg=$(parse_colour $OPTARG);;
+    c) cu=$(parse_colour $OPTARG);;
+    d) bd=$(parse_colour $OPTARG);;
+    f) fg=$(parse_colour $OPTARG);;
+    m) mo=$(parse_colour $OPTARG);;
+    p) ps=$(parse_colour $OPTARG);;
   esac
 done
 shift $((OPTIND-1))
@@ -64,7 +112,6 @@ if [ -z "$BG$FG$bd$bg$cu$fg$mo$pc" ]; then
   exit 1
 fi
 
-[ -n "$TMUX" ] && tmux_prefix="\033Ptmux;\033"
 [ -n "$BG" ] && echo -en "$tmux_prefix\033]17;$BG\007"
 [ -n "$FG" ] && echo -en "$tmux_prefix\033]19;$FG\007"
 [ -n "$bg" ] && echo -en "$tmux_prefix\033]11;$bg\007"
-- 
2.7.4