#!/usr/bin/env bash
set -euo pipefail

# ==== Configuración de Kasm =================================================
# Para bumpear: mirá https://kasm.com/downloads y actualizá VERSION + SHA256.
KASM_VERSION="1.17.0"
KASM_HASH="7f020d"
KASM_TARBALL="kasm_release_${KASM_VERSION}.${KASM_HASH}.tar.gz"
KASM_URL="https://kasm-static-content.s3.amazonaws.com/${KASM_TARBALL}"
KASM_SHA256="22a293ea52b2adb7f3f72a2de8e9be799f443b9da040e066df403478da77f62d"

# Versión simple (sin Docker preinstall, sin swap, sin SHA256 check).
KASM_SIMPLE_VERSION="1.18.1"
KASM_SIMPLE_TARBALL="kasm_release_${KASM_SIMPLE_VERSION}.tar.gz"
KASM_SIMPLE_URL="https://kasm-static-content.s3.amazonaws.com/${KASM_SIMPLE_TARBALL}"
# ============================================================================

# ==== Modo simple vs completo ==============================================
echo "¿Ejecutar versión simple? (sólo descarga + install.sh, sin Docker preinstall ni swap)"
echo "  1) Sí — versión simple (Kasm ${KASM_SIMPLE_VERSION})"
echo "  2) No — versión completa (Docker + swap + SHA256, Kasm ${KASM_VERSION})"
read -rp "Opción [1/2]: " modo

if [ "$modo" = "1" ]; then
    cd /tmp
    curl -O "$KASM_SIMPLE_URL"
    tar -xf "$KASM_SIMPLE_TARBALL"
    sudo bash kasm_release/install.sh
    exit 0
fi

if [ "$modo" != "2" ]; then
    echo "Error: opción inválida '$modo'." >&2
    exit 1
fi

# Paquetes base: Docker Engine + Compose V2 (V1 está EOL desde junio 2023).
paquetes_apt=("docker.io" "docker-compose")
paquetes_rhel=("docker" "docker-compose-plugin")
paquetes_arch=("docker" "docker-compose")

paquete_instalado_apt()    { dpkg -s "$1" &>/dev/null; }
paquete_instalado_yum()    { yum list installed "$1" &>/dev/null; }
paquete_instalado_dnf()    { dnf list installed "$1" &>/dev/null; }
paquete_instalado_pacman() { pacman -Qi "$1" &>/dev/null; }

# Detectar el sistema operativo
if [ ! -f /etc/os-release ]; then
    echo "Error: no se puede detectar el OS (/etc/os-release no existe)." >&2
    exit 1
fi
. /etc/os-release
OS="${ID:-unknown}"

install_packages() {
    local pkgs=("$@")
    case "$OS" in
        debian|ubuntu|kali)
            for p in "${pkgs[@]}"; do
                if ! paquete_instalado_apt "$p"; then
                    echo "Instalando $p..."
                    sudo apt-get update -qq
                    sudo apt-get install -y "$p"
                fi
            done
            ;;
        centos|rhel)
            for p in "${pkgs[@]}"; do
                if ! paquete_instalado_yum "$p"; then
                    echo "Instalando $p..."
                    sudo yum install -y "$p"
                fi
            done
            ;;
        fedora)
            for p in "${pkgs[@]}"; do
                if ! paquete_instalado_dnf "$p"; then
                    echo "Instalando $p..."
                    sudo dnf install -y "$p"
                fi
            done
            ;;
        arch)
            for p in "${pkgs[@]}"; do
                if ! paquete_instalado_pacman "$p"; then
                    echo "Instalando $p..."
                    sudo pacman -S --noconfirm "$p"
                fi
            done
            ;;
        *)
            echo "Error: OS '$OS' no soportado." >&2
            exit 1
            ;;
    esac
}

case "$OS" in
    debian|ubuntu|kali) install_packages "${paquetes_apt[@]}" ;;
    centos|rhel|fedora) install_packages "${paquetes_rhel[@]}" ;;
    arch)               install_packages "${paquetes_arch[@]}" ;;
    *)
        echo "Error: OS '$OS' no soportado." >&2
        exit 1
        ;;
esac

# ==== Swap ==================================================================
read -rp "¿Cuántos GB de RAM desea asignar al swap? (4, 6, 8...): " ram_gb

if ! [[ "$ram_gb" =~ ^[0-9]+$ ]] || [ "$ram_gb" -le 0 ]; then
    echo "Error: ingresá un entero positivo." >&2
    exit 1
fi

swap_size_mb=$((ram_gb * 1024))
swap_file="/mnt/${ram_gb}GiB.swap"

if [ -f "$swap_file" ]; then
    echo "El swap '$swap_file' ya existe, lo salteo."
else
    echo "Creando swap de ${ram_gb}GiB en $swap_file..."
    # fallocate es órdenes de magnitud más rápido que dd en ext4/xfs.
    if ! sudo fallocate -l "${swap_size_mb}M" "$swap_file" 2>/dev/null; then
        echo "fallocate no soportado, fallback a dd..."
        sudo dd if=/dev/zero bs=1M count="$swap_size_mb" of="$swap_file" status=progress
    fi
    sudo chmod 600 "$swap_file"
    sudo mkswap "$swap_file"
    sudo swapon "$swap_file"
fi

# Idempotencia: solo agregar a fstab si no está.
if ! grep -qF "$swap_file" /etc/fstab; then
    echo "$swap_file swap swap defaults 0 0" | sudo tee -a /etc/fstab >/dev/null
fi

# ==== Kasm ==================================================================
cd /tmp

if [ ! -f "$KASM_TARBALL" ]; then
    echo "Descargando Kasm ${KASM_VERSION}..."
    curl -fLO "$KASM_URL"
fi

echo "Verificando SHA256..."
echo "${KASM_SHA256}  ${KASM_TARBALL}" | sha256sum -c -

tar -xf "$KASM_TARBALL"
sudo bash kasm_release/install.sh