#!/bin/sh

case "$1" in
  -h|--help)
    echo "usage: git-open BRANCH"
    echo "Creates a new branch named BRANCH by forking master or, if"
    echo "a branch has BRANCH in the name, checks that branch out."
    echo ""
    echo "Given these branches:"
    echo ""
    echo "  sh-$ git branch"
    echo "  * master"
    echo "    performance"
    echo ""
    echo "Creating a new branch"
    echo ""
    echo "  sh-$ git open test"
    echo "  + git checkout -b test"
    echo "  Switched to a new branch \"test\""
    echo ""
    echo "Switching to an existing branch"
    echo ""
    echo "  sh-$ git open perf"
    echo "  + git checkout performance"
    echo "  Switched to branch \"performance\""
    exit 0
    ;;
esac

CURRENT=`git branch | grep -m 1 "\*" | cut -d' ' -f2`
TARGET=`git branch | grep -m 1 "$1" | perl -pe 's/[\s\*]//g'`

if [[ "$CURRENT" == "$TARGET" ]]; then
  echo "Already on branch $TARGET"
  exit
fi

if [[ "$CURRENT" != "master" ]]; then
  echo "+ git checkout master"
  git checkout master
fi

if [[ "$TARGET" == "master" ]]; then
  exit
fi

if [[ -z "$TARGET" ]]; then
  echo "+ git checkout -b $1"
  git checkout -b $1
else
  echo "+ git checkout $TARGET"
  git checkout $TARGET
fi