#!/bin/bash

set -euo pipefail

# Function to detect the operating system
detect_os() {
    if [[ "$OSTYPE" == "darwin"* ]]; then
        echo "macos"
    elif [[ -f /etc/os-release ]]; then
        . /etc/os-release
        echo "$ID"
    else
        echo "unknown"
    fi
}

run_as_root() {
    if (( EUID == 0 )); then
        "$@"
    elif command -v sudo &> /dev/null; then
        sudo "$@"
    else
        echo "Error: sudo is required to install unzip." >&2
        exit 1
    fi
}

install_unzip() {
    command -v unzip &> /dev/null && return

    echo "Installing required dependency: unzip"
    case $(detect_os) in
        ubuntu|debian)
            run_as_root apt-get update
            run_as_root apt-get install -y unzip
            ;;
        fedora)
            run_as_root dnf install -y unzip
            ;;
        centos|rhel)
            if command -v dnf &> /dev/null; then
                run_as_root dnf install -y unzip
            else
                run_as_root yum install -y unzip
            fi
            ;;
        arch|manjaro)
            run_as_root pacman -S --needed --noconfirm unzip
            ;;
        *)
            echo "Error: unzip is required. Install it with your package manager and retry." >&2
            exit 1
            ;;
    esac
}

# Install fnm (Fast Node Manager) if it is not already installed
if command -v fnm &> /dev/null; then
    echo -e "fnm is already installed\n"
    fnm --version
else
    echo -e "Installing fnm (Fast Node Manager)\n"

    os=$(detect_os)

    if [[ "$os" == "macos" ]] && command -v brew &> /dev/null; then
        echo "Installing fnm via Homebrew..."
        brew install fnm
    else
        install_unzip
        install_dir="${XDG_DATA_HOME:-$HOME/.local/share}/fnm"
        installer_args=(--install-dir "$install_dir" --skip-shell)
        [[ "$os" == "macos" ]] && installer_args+=(--force-install)

        echo "Installing fnm via official installer..."
        curl -fsSL https://fnm.vercel.app/install | bash -s -- "${installer_args[@]}"
        export PATH="$install_dir:$PATH"
    fi

    command -v fnm &> /dev/null
    eval "$(fnm env --use-on-cd --shell bash)"
fi

# OPTIONAL: Install the latest LTS version of Node.js
# Uncomment the following lines if you would like to automatically install it
# echo "Installing latest LTS Node.js version..."
# fnm install --lts
# fnm use lts-latest
# fnm default lts-latest

# Always-on fragment: ~/.config/zsh/fnm.zsh (sourced from ~/.zshenv)
curl -fsSL https://git.miomio.moe/mio/easyzsh/raw/branch/master/patch.sh | bash -s -- zsh/fnm
# Drop legacy interactive-only copy if present
rm -f "${XDG_CONFIG_HOME:-$HOME/.config}/zshrc/fnm.zsh"

echo -e "\nfnm installation completed!"
echo -e "To start using fnm, restart your terminal or run: source ~/.zshenv"
echo -e "\nUseful fnm commands:"
echo -e "  fnm install --lts          # Install latest LTS Node.js"
echo -e "  fnm use lts-latest          # Use the latest LTS release"
echo -e "  fnm default lts-latest      # Set the latest LTS as default"
echo -e "  fnm list                    # List installed versions"
echo -e "  fnm list-remote             # List available versions"