#!/bin/bash

if [[ $# -ne 3 || "$1" == "--help" || "$1" = "-h" ]]; then
    name=$(basename $0)
    cat <<-USAGE
    Usage: $name workbranch base/branch version

    * workbranch will be created locally from base/branch. If it exists,
        it will be reused, so make sure you don't overwrite any work.
    * base/branch may be specified as user:branch to allow easy copying
        from Github PRs.
USAGE
    exit 0
fi

work="$1"
shift

base=$(echo "$1" | sed "s/:/\//")
shift

version=$1
shift

set -e

git fetch upstreams

git checkout -B "${work}" --no-track "${base}"

push=$(git rev-parse --abbrev-ref --symbolic-full-name '@{push}' \
    2>/dev/null) || true
if [[ "${push}" != "" ]]; then
    echo "Warning: ${push} may already exist."
fi

build=$(find -name BuildInfo.cpp)
sed 's/\(^.*versionString =\).*$/\1 "'${version}'"/' ${build} >version.cpp &&
    diff "${build}" version.cpp && exit 1 ||
    mv -vi version.cpp ${build}

git diff

git add ${build}

git commit -S -m "Set version to ${version}"

git log --oneline --first-parent ${base}^..

cat <<PUSH

-------------------------------------------------------------------
This script will not push. Verify everything is correct, then push
to your repo, and create a PR as described in CONTRIBUTING.md.
-------------------------------------------------------------------
PUSH