#!/bin/bash
#
# Update a subtree.
#

# Parameters
BASENAME="`basename $0`"
REMOTE="$1"
FOLDER="$2"

# Syntax
if [ -z "$2" ]; then
  echo "usage: $BASENAME <gitremote> <folder>"
  exit 1
fi

# Check remote
if ! git remote | grep -qe "^$REMOTE"; then
  echo "fatal: no such remote $REMOTE"
  exit
fi

# Fetch the remote
git fetch $REMOTE master

# Process
if [ ! -d "$FOLDER" ]; then
  # Add a subtree
  git subtree add --prefix $FOLDER $REMOTE master --squash
else
  # Update a subtree
  git subtree pull --prefix $FOLDER $REMOTE master --squash
fi