#!/bin/bash

set -o errexit

VERSION="$1"
LINUX_SRC="${2:-linux}"

if [ -z "$VERSION" ]; then
    echo "usage: $0 VERSION"
    exit 1
fi

function check_version_and_checkout {
    local REF="$1"
    if git -C "$LINUX_SRC" show-ref "$REF" > /dev/null; then
        git -C "$LINUX_SRC" checkout $REF
        return 0
    else
        return 1
    fi
}

check_version_and_checkout "$VERSION" && exit 0
check_version_and_checkout "v$VERSION" && exit 0
check_version_and_checkout "linux-$VERSION" && exit 0

echo "No tag or branch corresponding to version $VERSION found"
exit 1