#!/bin/bash

checkout-git-folder() {
    if [[ -z "$1" ]]; then
        echo '$1/branch is empty.'
        exit
    fi
    if [[ -z "$2" ]]; then
        echo '$2/path is empty.'
        exit
    fi

    local git_branch="$1"
    local git_folders=$(ls-git-folder "$2")
    for git_folder in $git_folders; do

        git_folder="${git_folder#./}"

        local shallow=$(git config --file .gitmodules --get submodule."$git_folder".shallow)
        local commit_ref=$(grep "$git_folder" ".gitmodules.csv" | cut -d',' -f2)

        if [[ "$shallow" = "true" ]]; then
            echo "Checkout git folder $git_folder (shallow) to $commit_ref"
            git -C "$git_folder" stash
            git -C "$git_folder" fetch origin "$git_branch:$git_branch"
            git -C "$git_folder" checkout "$commit_ref"
        else
            echo "Checkout git folder $git_folder to $commit_ref"
            git -C "$git_folder" stash
            git -C "$git_folder" checkout "$commit_ref"
        fi
    done
}