Use global porcelain if there is one

porcelain.tmux

@@ -1,8 +1,10 @@
 #!/usr/bin/env bash
 
 CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+PORCELAIN_BIN="$CURRENT_DIR/porcelain"
 
-porcelain_status="#($CURRENT_DIR/porcelain -tmux -path '#{pane_current_path}')"
+global_porcelain=""
+porcelain_status="#($PORCELAIN_BIN -debug -tmux -path '#{pane_current_path}')"
 porcelain_interpolation_string="\#{porcelain}"
 
 do_interpolation() {
@@ -18,17 +20,30 @@ update_tmux_option() {
     tmux set-option -gq "$option" "$new_option_value"
 }
 
+install() {
+    update_tmux_option "status-right"
+    update_tmux_option "status-left"
+}
+
 main() {
-    if ! [[ -f "$CURRENT_DIR/porcelain" ]]
+    global_porcelain="$(command -v porcelain)"
+    if [[ -f "$global_porcelain" ]]
+    then
+        PORCELAIN_BIN=$global_porcelain
+        install
+        exit 0
+    fi
+
+    if ! [[ -f "$PORCELAIN_BIN" ]]
     then
         curl -sL "$(curl -s https://api.github.com/repos/robertgzr/porcelain/releases/latest | grep "browser_download_url" | grep "$(uname | tr '[:upper:]' '[:lower:]')"| cut -d\" -f4)" |\
             tar -C "$CURRENT_DIR" -xzf - porcelain &>/dev/null
     fi
     # try again
-    if [[ -f "$CURRENT_DIR/porcelain" ]]
+    if [[ -f "$PORCELAIN_BIN" ]]
     then
-        update_tmux_option "status-right"
-        update_tmux_option "status-left"
+        install
+        exit 0
     fi
 }
 main