#!/bin/bash
# Automatically prepare OpenWRT build dependencies for Debian/Ubuntu
# Supports both x86_64 and arm64
# Detects Ubuntu 22.04, 24.04, 26.04, Debian 12/13 and newer
# Author: Zhe Yuan

set -e
umask 022

echo "========================================"
echo " OpenWRT Build Environment Preparation"
echo "========================================"

# --- Detect architecture ---
ARCH=$(uname -m)
echo "[INFO] Detected architecture: $ARCH"

# --- Detect OS version ---
if [ -f /etc/os-release ]; then
  . /etc/os-release
  DISTRO="$ID"
  VERSION_ID="${VERSION_ID:-unknown}"
else
  echo "[ERROR] Cannot detect system version (no /etc/os-release)"
  exit 1
fi

echo "[INFO] Detected distribution: $DISTRO $VERSION_ID"

# --- Version helpers ---
version_ge() {
  local current="${1:-unknown}"
  local minimum="$2"

  if [[ "$current" == "unknown" ]]; then
    return 1
  fi

  if command -v dpkg >/dev/null 2>&1; then
    dpkg --compare-versions "$current" ge "$minimum"
  else
    [[ "$(printf '%s\n%s\n' "$minimum" "$current" | sort -V | head -n1)" == "$minimum" ]]
  fi
}

IS_UBUNTU_24_OR_NEWER=false
IS_UBUNTU_26_OR_NEWER=false
IS_DEBIAN_13_OR_NEWER=false

if [[ "$DISTRO" == "ubuntu" ]] && version_ge "$VERSION_ID" "24.04"; then
  IS_UBUNTU_24_OR_NEWER=true
fi

if [[ "$DISTRO" == "ubuntu" ]] && version_ge "$VERSION_ID" "26.04"; then
  IS_UBUNTU_26_OR_NEWER=true
fi

if [[ "$DISTRO" == "debian" ]] && version_ge "$VERSION_ID" "13"; then
  IS_DEBIAN_13_OR_NEWER=true
fi

# --- Base packages (common to all) ---
COMMON_PACKAGES="build-essential clang flex bison g++ gawk \
gettext git libssl-dev rsync swig unzip zlib1g-dev file wget bzip2"

# --- Determine specific package set ---
if [[ "$ARCH" == "x86_64" || "$ARCH" == "amd64" ]]; then
  echo "[INFO] Preparing environment for x86_64."

  if [[ "$IS_UBUNTU_26_OR_NEWER" == "true" ]]; then
    echo "[INFO] Detected Ubuntu 26.04+ (no python3-distutils; OpenWrt docs use libncurses-dev)."
    EXTRA_PACKAGES="gcc-multilib g++-multilib glibc-source libncurses-dev python3-setuptools"
  elif [[ "$IS_UBUNTU_24_OR_NEWER" == "true" ]]; then
    echo "[INFO] Detected Ubuntu 24.04+ (Python 3.12+, no python3-distutils)."
    EXTRA_PACKAGES="gcc-multilib g++-multilib libncurses5-dev python3-setuptools"
  elif [[ "$IS_DEBIAN_13_OR_NEWER" == "true" ]]; then
    echo "[INFO] Detected Debian 13+ (no python3-distutils)."
    EXTRA_PACKAGES="gcc-multilib g++-multilib libncurses-dev python3-setuptools"
  else
    echo "[INFO] Detected older Ubuntu/Debian (with python3-distutils)."
    EXTRA_PACKAGES="gcc-multilib g++-multilib libncurses-dev python3-distutils python3-setuptools"
  fi

  INSTALL_PACKAGES="$COMMON_PACKAGES $EXTRA_PACKAGES"

elif [[ "$ARCH" == "aarch64" || "$ARCH" == "arm64" ]]; then
  echo "[INFO] Preparing environment for ARM64."

  # Note: arm64 has no native multilib; install cross multilib packages
  MULTILIB_PACKAGES="
    gcc-multilib-i686-linux-gnu gcc-multilib-s390x-linux-gnu \
    gcc-multilib-x86-64-linux-gnu gcc-multilib-x86-64-linux-gnux32 \
    g++-multilib-i686-linux-gnu g++-multilib-s390x-linux-gnu \
    g++-multilib-x86-64-linux-gnu g++-multilib-x86-64-linux-gnux32 \
    libc6-dev-i386-amd64-cross libc6-dev-i386-cross libc6-dev-i386-x32-cross"

  if [[ "$IS_UBUNTU_26_OR_NEWER" == "true" ]]; then
    EXTRA_PACKAGES="glibc-source libncurses-dev python3-setuptools"
  elif [[ "$IS_UBUNTU_24_OR_NEWER" == "true" ]]; then
    EXTRA_PACKAGES="libncurses5-dev python3-setuptools"
  elif [[ "$IS_DEBIAN_13_OR_NEWER" == "true" ]]; then
    EXTRA_PACKAGES="libncurses-dev python3-setuptools"
  else
    EXTRA_PACKAGES="libncurses-dev python3-distutils python3-setuptools"
  fi

  INSTALL_PACKAGES="$COMMON_PACKAGES $EXTRA_PACKAGES $MULTILIB_PACKAGES golang"

else
  echo "[WARN] Unknown architecture: $ARCH"
  echo "[WARN] Attempting to use x86_64 package list."
  if [[ "$IS_UBUNTU_26_OR_NEWER" == "true" ]]; then
    INSTALL_PACKAGES="$COMMON_PACKAGES gcc-multilib g++-multilib glibc-source libncurses-dev python3-setuptools"
  else
    INSTALL_PACKAGES="$COMMON_PACKAGES gcc-multilib g++-multilib libncurses-dev python3-setuptools"
  fi
fi

# --- Display package list ---
echo
echo "========================================"
echo "📦 Packages to install:"
echo "$INSTALL_PACKAGES"
echo "========================================"
echo

echo "[INFO] Updating APT repositories..."
sudo apt update -y

echo "[INFO] Installing packages..."
sudo apt install -y $INSTALL_PACKAGES

# --- Post installation notice ---
echo
echo "========================================"
echo "✅ OpenWRT build environment setup complete!"
echo "========================================"
echo

if [[ "$ARCH" == "x86_64" || "$ARCH" == "amd64" ]]; then
  echo "👉 [NOTE] Go language is optional on x86_64."
  echo "   If you plan to compile packages requiring Go (e.g. firewall4, netifd), install it manually:"
  echo "     sudo apt install golang -y"
else
  echo "👉 [INFO] Go language installed for ARM64 cross compilation."
fi

echo
echo "⚙️  After running 'make menuconfig', set Go toolchain path if required:"
echo "   Example: /usr/lib/go-1.18"
echo
echo "👉 Next step:"
echo "   ./prepare-openwrt.sh   # to clone and set up OpenWRT source"
echo