#! /usr/bin/env bash
#
# Recursively check outs the most recent version of all submodules on a given
# branch, and commits the updates to the parents.

branch=$1

if [ "$branch" == "" ]; then
    echo "usage: $(basename $0) <branch>"
    exit 1
fi

paths_to_push=()

function update_module {
    local cwd=$1
    local i
    local modules=""

    cd $cwd

    # These submodules should be ignored by the loop below.
    local ignored_modules=(
        "3rdparty"
        "IXWebSocket"
        "c-ares"
        "caf"
        "cppzmq"
        "expected-lite"
        "filesystem"
        "highwayhash"
        "libkqueue"
        "libunistd"
        "out_ptr"
        "prometheus-cpp"
        "rapidjson"
        "vcpkg")

    # Note we don't use --recursive here, as we want to do a depth-first
    # search so that we update children first.
    for i in $(git submodule foreach -q 'echo $path' | grep -vE $(
        IFS="|"
        echo "${ignored_modules[*]}"
    )); do
        # See if repository has a branch of the given name. Otherwise leave it alone.
        (cd $i && git show-ref --verify --quiet refs/heads/$branch) || continue

        modules="$modules $i"

        echo "--- Checking out $branch of $(basename $i)"
        cd $i
        git fetch -q || exit 1
        git checkout -q $branch || exit 1
        git merge origin/master || exit 1

        update_module $cwd/$i

        cd $cwd
    done

    if [ "$modules" != "" ]; then
        if [ -n "$(git status --untracked-files=no --porcelain)" ]; then
            echo "+++ Committing updates to $(basename $cwd)"
            git commit -m 'Updating submodule(s) [nomail]' --only $modules
            paths_to_push+=($cwd)
        fi
    fi

}

update_module $(pwd)

echo
echo "Added ${#paths_to_push[@]} commits. Run the following commands to push them:"
for path in "${paths_to_push[@]}"; do
    echo "(cd ${path} && git push)"
done