#!/usr/bin/env bash
download-git-folder() {
    if [[ -z "$1" ]]; then
        echo '$1/path is empty.'
        exit
    fi

    local git_folders=$(ls-git-folder "$1")
    for git_folder in $git_folders; do
        local git_folder_path=$(git config --file .gitmodules --get submodule."$git_folder".path)
        local git_folder_url=$(git config --file .gitmodules --get submodule."$git_folder".url)
        local git_folder_branch=$(git config --file .gitmodules --get submodule."$git_folder".branch)

        # Convert git url to http url.
        git_folder_url="$(echo $git_folder_url | sed 's|git@|https://|g' | sed 's|m:|m/|g' | sed 's|\.git||g')"

        # Get commit ref from .gitmodules
        local commit_ref=$(git config --file .gitmodules --get submodule."$git_folder".commit)
        echo "Download $git_folder_url to $git_folder_path."
        mkdir -p "$git_folder_path"
        curl -L -o "$git_folder_path/archive.tar.gz" \
            "$git_folder_url/archive/$commit_ref.tar.gz"
        echo "Extract and delete $git_folder_path/archive.tar.gz"
        tar -xzf "$git_folder_path/archive.tar.gz" --strip-components=1 -C "$git_folder_path"
        rm "$git_folder_path/archive.tar.gz"
    done
}
dgf() {
    download-git-folder "$@"
}