LOCAL_BRANCH=$1
BUILD_FROM_TAG=$2
REMOTE_BRANCH=$3
CHECKOUT_SUCCESSFUL=0

buildFromTag(){
        local tag=$1
        local localbranch=$1
        local remotebranch=$2
        git fetch --tags
        git show-ref --tags --verify --quiet refs/tags/$tag
        if [ $? -eq 0 ]; then
                echo "Build from tag: Checkout tag ${tag}."
                git checkout $tag
        else
                echo "Build from tag: Checkout local branch ${localbranch} or remote branch ${remotebranch}."
                checkoutLocalOrRemoteBranch $localbranch $remotebranch
        fi
}

checkoutLocalBranch(){
        local localbranch=$1
        local remotebranch=$2

        CHECKOUT_SUCCESSFUL=0
        if [ ! -z "$(git branch | grep $localbranch)" ]; then
                echo "Checkout local branch ${localbranch}."
                git checkout $localbranch
                git pull origin $remotebranch
                CHECKOUT_SUCCESSFUL=1
        else
                echo "Could not checkout local branch ${localbranch}."
        fi
}

checkoutRemoteBranch(){
        local localbranch=$1
        local remotebranch=$2
        local gitremote=`git remote`

        CHECKOUT_SUCCESSFUL=0
        if [ ! -z "$(git branch -r | grep ${gitremote}/$remotebranch)" ]; then
                echo "Checkout remote branch ${gitremote}/${remotebranch}."
                git checkout -b $localbranch ${gitremote}/$remotebranch
                git pull origin $remotebranch
                CHECKOUT_SUCCESSFUL=1
        else
                echo "Could not checkout remote branch ${gitremote}/${remotebranch}."
        fi
}

checkoutLocalOrRemoteBranch(){
        local localbranch=$1
        local remotebranch=$2

        echo "Trying to checkout local branch ${localbranch} or remote branch ${remotebranch}."

        CHECKOUT_SUCCESSFUL=0
        checkoutLocalBranch $localbranch $remotebranch

        if [ $CHECKOUT_SUCCESSFUL -eq 0 ]; then
                checkoutRemoteBranch $localbranch $remotebranch
        fi
}

git rm --cached -r . > /dev/null
git reset --hard > /dev/null

if echo $BUILD_FROM_TAG | grep -q -w "true"; then
        buildFromTag $LOCAL_BRANCH $REMOTE_BRANCH
else
        checkoutLocalOrRemoteBranch $LOCAL_BRANCH $REMOTE_BRANCH
fi