#!/usr/bin/env bash
# prereqs.sh — detect distro, install missing prerequisites

# Detect package manager / distro family
detect_distro() {
    if command -v pacman  &>/dev/null; then echo "arch";
    elif command -v apt-get &>/dev/null; then echo "debian";
    elif command -v dnf    &>/dev/null; then echo "rhel";
    elif command -v yum    &>/dev/null; then echo "rhel-yum";
    elif command -v zypper &>/dev/null; then echo "suse";
    else echo "unknown";
    fi
}

install_pkg() {
    local pkg="$1"
    local distro
    distro="$(detect_distro)"

    info "Installing $pkg (distro: $distro)..."
    case "$distro" in
        arch)
            sudo pacman -Sy --noconfirm "$pkg" ;;
        debian)
            sudo apt-get update -qq && sudo apt-get install -y "$pkg" ;;
        rhel)
            sudo dnf install -y "$pkg" ;;
        rhel-yum)
            sudo yum install -y "$pkg" ;;
        suse)
            sudo zypper install -y "$pkg" ;;
        *)
            die "Unsupported distro — please install $pkg manually." ;;
    esac
}

ensure_git() {
    if command -v git &>/dev/null; then
        success "git: $(git --version)"
        return
    fi
    warn "git not found."
    ask_yn _install "Install git now?" "y"
    [[ "$_install" != "y" ]] && die "git is required."
    install_pkg git
    command -v git &>/dev/null || die "git installation failed."
    success "git installed: $(git --version)"
}

ensure_container_runtime() {
    # Already available?
    if command -v podman &>/dev/null; then
        CONTAINER_CMD="podman"
        success "podman: $(podman --version)"
        return
    fi
    if command -v docker &>/dev/null; then
        CONTAINER_CMD="docker"
        success "docker: $(docker --version | head -1)"
        return
    fi

    warn "No container runtime found (podman or docker)."
    echo ""
    echo -e "  ${CYAN}podman${RESET} is preferred (rootless, no daemon)"
    echo -e "  ${CYAN}docker${RESET} is the alternative"
    echo ""
    ask_choice _runtime "Which would you like to install?" \
        "podman (recommended)" \
        "docker"

    case "$_runtime" in
        podman*)
            _install_podman
            CONTAINER_CMD="podman"
            ;;
        docker*)
            _install_docker
            CONTAINER_CMD="docker"
            ;;
    esac

    command -v "$CONTAINER_CMD" &>/dev/null \
        || die "$CONTAINER_CMD installation failed. Please install manually."
    success "$CONTAINER_CMD installed: $($CONTAINER_CMD --version | head -1)"
}

_install_podman() {
    local distro
    distro="$(detect_distro)"
    case "$distro" in
        arch)    install_pkg podman ;;
        debian)  install_pkg podman ;;
        rhel)    install_pkg podman ;;
        rhel-yum) install_pkg podman ;;
        suse)    install_pkg podman ;;
        *)       die "Unsupported distro — install podman manually: https://podman.io/getting-started/installation" ;;
    esac
}

_install_docker() {
    local distro
    distro="$(detect_distro)"
    case "$distro" in
        arch)
            install_pkg docker
            sudo systemctl enable --now docker
            sudo usermod -aG docker "$USER"
            warn "Added $USER to docker group — log out and back in for it to take effect."
            ;;
        debian)
            install_pkg docker.io
            sudo systemctl enable --now docker
            sudo usermod -aG docker "$USER"
            warn "Added $USER to docker group — log out and back in for it to take effect."
            ;;
        rhel)
            install_pkg docker
            sudo systemctl enable --now docker
            sudo usermod -aG docker "$USER"
            warn "Added $USER to docker group — log out and back in for it to take effect."
            ;;
        rhel-yum)
            install_pkg docker
            sudo systemctl enable --now docker
            sudo usermod -aG docker "$USER"
            warn "Added $USER to docker group — log out and back in for it to take effect."
            ;;
        suse)
            install_pkg docker
            sudo systemctl enable --now docker
            sudo usermod -aG docker "$USER"
            warn "Added $USER to docker group — log out and back in for it to take effect."
            ;;
        *)
            die "Unsupported distro — install docker manually: https://docs.docker.com/engine/install/" ;;
    esac
}

check_prerequisites() {
    header "Checking Prerequisites"
    ensure_git
    ensure_container_runtime
}