sys

#!/usr/bin/env bash

username="${USER:-murtaza}"

function update() {
    nix flake update
}

function switch_nixos() {
    sudo nixos-rebuild switch --flake .# "$@"
}

function switch_home_manager() {
    nix run .#homeConfigurations.$username.activationPackage
}

function install_scripts() {
    local target="$HOME/.local"
    mkdir -p "$target"
    ln -sft "$target" "$PWD/static/scripts"
}

function install_neovim() {
    local target="$HOME/.config"
    mkdir -p "$target"
    ln -sft "$target" "$PWD/static/nvim"
}

function install_emacs() {
    local target="$HOME/.config/emacs"
    mkdir -p "$target"
    ln -sft "$target" "$PWD/static/emacs/init.el"
    ln -sft "$target" "$PWD/static/emacs/early-init.el"
}

######## bash completion context ########

root=(update switch install)
switch=(nixos home-manager)
install=(scripts neovim emacs)

comp() {
    local arg="$1"
    shift

    for c in "$@"; do
        [[ "${c:0:${#arg}}" == "${arg,,}" ]] && echo "$c"
    done
}

if [[ -n "$COMP_LINE" ]]; then
    if [[ "$1" == "$3" ]]; then
        comp "$2" "${root[@]}"
        exit 0
    fi

    if [[ "$3" == "switch" ]]; then
        comp "$2" "${switch[@]}"
    elif [[ "$3" == "install" ]]; then
        comp "$2" "${install[@]}"
    fi

    exit 0
fi

numargs="${#@}"

if [[ "$numargs" -lt 1 ]]; then
    echo "very few arguments"
    exit 1
fi

cmd="$1"; shift
arg="$1"; shift

case "$cmd" in
    "update")
        update
        ;;
    "switch")
        case "$arg" in
            "") switch_nixos "$@" ;;
            nixos) switch_nixos "$@" ;;
            home-manager) switch_home_manager ;;
            *) echo "invalid command: $arg" ;;
        esac
        ;;
    "install")
        case "$arg" in
            scripts) install_scripts ;;
            neovim) install_neovim ;;
            emacs) install_emacs ;;
            *) echo "invalid command: $arg" ;;
        esac
        ;;
    *) echo "invalid command: $cmd" ;;
esac