yellow=$(printf "\e[0;33m")
cyan=$(printf "\e[0;36m")
byellow=$(printf "\e[1;33m")
reset=$(printf "\e[0m")

die() {
    >&2 echo "$1"
    exit 1
}

ensure() {
    "$@" || die "command failed: $*"
}

main() {
    # Clone the repository into a temporary directory, but do not check it out.
    # Place the .git directory at ~/.dotfiles.git.
    tmpdir=$(ensure mktemp -d) || die "mktemp failed"
    ensure git clone --no-checkout --separate-git-dir="$HOME/.dotfiles.git" \
        --config status.showUntrackedFiles=no \
        https://github.com/iliana/dotfiles.git "$tmpdir"
    # Clean up the temporary directory.
    ensure rm "$tmpdir/.git"
    ensure rmdir "$tmpdir"
    # Configure git to point to the right place within the rest of this script.
    export GIT_DIR="$HOME/.dotfiles.git"
    export GIT_WORK_TREE="$HOME"
    # Attempt to check out, and prompt the user to try again with `--force` if
    # it fails.
    if ! git checkout; then
        prompt="${yellow}Try again with \"${byellow}git checkout --force${yellow}\" (delete the above files)? ${cyan}[yes/no]${reset} "
        while true; do
            if [ -t 0 ] || [ -t 2 ]; then
                >&2 ensure printf %s "$prompt"
                if [ -t 0 ]; then
                    read -r choice || die "read failed"
                else
                    # stdin is not a TTY but stderr is; probably `curl | sh`.
                    # so read from stderr.
                    <&2 read -r choice || die "read failed"
                fi
            else
                die "command failed: git checkout"
            fi
            prompt="${yellow}Please type '${cyan}yes${yellow}' or '${cyan}no${yellow}':${reset} "
            case "$choice" in
                [yY][eE][sS])
                    ensure git checkout --force
                    break
                    ;;
                [nN][oO])
                    die "Exiting. Remove $GIT_DIR to clean up."
                    ;;
            esac
        done
    fi
    # Initialize and update submodules.
    ensure git submodule update --init
}

main "$@" || exit 1