#!/bin/bash
# Prepare the OpenWrt build dependencies.
#
# Supported distributions:
#   - Debian / Ubuntu / Linux Mint / Raspberry Pi OS   (apt)
#   - Fedora / RHEL / CentOS / Rocky / AlmaLinux       (dnf, yum)
#   - Arch / Manjaro / EndeavourOS                     (pacman)
#   - openSUSE / SLES                                  (zypper)
#   - Alpine                                           (apk)
#
# Package lists follow https://openwrt.org/docs/guide-developer/toolchain/install-buildsystem
# Packages that do not exist on the running release are skipped instead of
# aborting the whole installation.
#
# Usage: ./prepare-openwrt-env.sh [-y] [-n] [--with-go]
#   -y, --yes        do not ask for confirmation
#   -n, --dry-run    only print what would be installed
#       --with-go    also install the Go toolchain
#
# Author: Zhe Yuan

set -euo pipefail
umask 022

ASSUME_YES=false
DRY_RUN=false
WITH_GO=false

while [ $# -gt 0 ]; do
  case "$1" in
    -y|--yes) ASSUME_YES=true ;;
    -n|--dry-run) DRY_RUN=true ;;
    --with-go) WITH_GO=true ;;
    -h|--help)
      sed -n '2,20p' "$0" | sed 's/^# \{0,1\}//'
      exit 0
      ;;
    *)
      echo "[ERROR] Unknown option: $1" >&2
      exit 1
      ;;
  esac
  shift
done

echo "========================================"
echo " OpenWrt Build Environment Preparation"
echo "========================================"

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

# --- Detect distribution ---
DISTRO="unknown"
DISTRO_LIKE=""
VERSION_ID="unknown"
PRETTY_NAME="unknown"

if [ -r /etc/os-release ]; then
  # shellcheck disable=SC1091
  . /etc/os-release
  DISTRO="${ID:-unknown}"
  DISTRO_LIKE="${ID_LIKE:-}"
  VERSION_ID="${VERSION_ID:-unknown}"
  PRETTY_NAME="${PRETTY_NAME:-$DISTRO $VERSION_ID}"
else
  echo "[ERROR] Cannot detect the distribution (no /etc/os-release)." >&2
  exit 1
fi

echo "[INFO] Distribution: $PRETTY_NAME (id=$DISTRO)"

# --- Detect package manager ---
PKG_MGR=""
for candidate in apt-get dnf yum pacman zypper apk; do
  if command -v "$candidate" >/dev/null 2>&1; then
    PKG_MGR="$candidate"
    break
  fi
done

if [ -z "$PKG_MGR" ]; then
  echo "[ERROR] No supported package manager found." >&2
  echo "[ERROR] Supported: apt-get, dnf, yum, pacman, zypper, apk." >&2
  exit 1
fi

echo "[INFO] Package manager: $PKG_MGR"

# --- Privilege escalation ---
SUDO=""
if [ "$(id -u)" -ne 0 ]; then
  if command -v sudo >/dev/null 2>&1; then
    SUDO="sudo"
  else
    echo "[ERROR] Not running as root and 'sudo' is not available." >&2
    exit 1
  fi
fi

is_x86_64() {
  [ "$ARCH" = "x86_64" ] || [ "$ARCH" = "amd64" ]
}

is_arm64() {
  [ "$ARCH" = "aarch64" ] || [ "$ARCH" = "arm64" ]
}

# ---------------------------------------------------------------------------
# Package lists
#
# REQUIRED_PACKAGES  installation fails if one of them cannot be installed
# OPTIONAL_PACKAGES  nice to have; silently skipped when unavailable
# ---------------------------------------------------------------------------
REQUIRED_PACKAGES=""
OPTIONAL_PACKAGES=""
REFRESH_CMD=""
INSTALL_CMD=""

case "$PKG_MGR" in
  apt-get)
    REFRESH_CMD="$SUDO apt-get update"
    INSTALL_CMD="$SUDO apt-get install -y --no-install-recommends"

    REQUIRED_PACKAGES="build-essential clang flex bison g++ gawk gcc gettext git \
      file wget unzip rsync swig time python3 python3-dev python3-setuptools \
      libncurses-dev libssl-dev zlib1g-dev libelf-dev make patch diffutils"

    # Extras from the OpenWrt 25.xx / Debian Trixie list. Names come and go
    # between releases, so everything here is filtered before installing.
    OPTIONAL_PACKAGES="bc binutils-gold ccache ecj fastjar help2man libbsd-dev \
      liblzma-dev meson mold mtd-utils ninja-build pbzip2 pigz pkg-config \
      subversion texinfo u-boot-tools xsltproc xxd zstd bzip2 quilt asciidoc \
      device-tree-compiler java-propose-classpath python3-distutils \
      python3-distutils-extra libncurses5-dev"

    if is_x86_64; then
      OPTIONAL_PACKAGES="$OPTIONAL_PACKAGES gcc-multilib g++-multilib glibc-source"
    elif is_arm64; then
      # arm64 has no native multilib; the cross variants are optional and the
      # available set differs a lot between releases (e.g. the s390x variants
      # were dropped in Ubuntu 26.04).
      OPTIONAL_PACKAGES="$OPTIONAL_PACKAGES \
        gcc-multilib-i686-linux-gnu g++-multilib-i686-linux-gnu \
        gcc-multilib-x86-64-linux-gnu g++-multilib-x86-64-linux-gnu \
        gcc-multilib-x86-64-linux-gnux32 g++-multilib-x86-64-linux-gnux32 \
        gcc-multilib-s390x-linux-gnu g++-multilib-s390x-linux-gnu \
        libc6-dev-i386-cross libc6-dev-i386-amd64-cross libc6-dev-i386-x32-cross \
        glibc-source"
    fi

    if [ "$WITH_GO" = true ]; then
      OPTIONAL_PACKAGES="$OPTIONAL_PACKAGES golang golang-go"
    fi
    ;;

  dnf|yum)
    REFRESH_CMD="$SUDO $PKG_MGR makecache"
    INSTALL_CMD="$SUDO $PKG_MGR install -y --setopt=install_weak_deps=False"

    REQUIRED_PACKAGES="gcc gcc-c++ make git-core patch diffutils file wget \
      unzip rsync tar which bzip2 ncurses-devel openssl-devel zlib-devel \
      python3 python3-devel python3-setuptools"

    OPTIONAL_PACKAGES="bash-completion elfutils-libelf-devel zlib-static \
      glibc-static swig quilt ccache perl-base perl-Data-Dumper \
      perl-File-Compare perl-File-Copy perl-FindBin perl-IPC-Cmd perl-JSON-PP \
      perl-lib perl-Thread-Queue perl-Time-Piece libxslt bc texinfo \
      dtc zstd pkgconf-pkg-config"

    if [ "$WITH_GO" = true ]; then
      OPTIONAL_PACKAGES="$OPTIONAL_PACKAGES golang"
    fi
    ;;

  pacman)
    REFRESH_CMD="$SUDO pacman -Sy"
    INSTALL_CMD="$SUDO pacman -S --needed --noconfirm"

    REQUIRED_PACKAGES="base-devel bash bzip2 git libelf libxslt ncurses openssl \
      rsync swig time unzip util-linux wget which zlib python python-setuptools"

    OPTIONAL_PACKAGES="ccache quilt pkgconf diffutils patch tar make gawk \
      subversion asciidoc dtc zstd"

    if [ "$WITH_GO" = true ]; then
      OPTIONAL_PACKAGES="$OPTIONAL_PACKAGES go"
    fi
    ;;

  zypper)
    REFRESH_CMD="$SUDO zypper --non-interactive refresh"
    INSTALL_CMD="$SUDO zypper --non-interactive install --no-recommends"

    REQUIRED_PACKAGES="bash bc binutils bzip2 flex gawk gcc gcc-c++ \
      gettext-tools git-core make ncurses-devel patch rsync unzip util-linux \
      wget zlib-devel libopenssl-devel python3-devel python3-setuptools"

    OPTIONAL_PACKAGES="asciidoc fastjar intltool libxslt-tools mercurial \
      perl-ExtUtils-MakeMaker sdcc quilt ccache libelf-devel swig zstd dtc"

    if [ "$WITH_GO" = true ]; then
      OPTIONAL_PACKAGES="$OPTIONAL_PACKAGES go"
    fi
    ;;

  apk)
    REFRESH_CMD="$SUDO apk update"
    INSTALL_CMD="$SUDO apk add"

    REQUIRED_PACKAGES="argp-standalone bash bc binutils bzip2 coreutils \
      diffutils elfutils-dev findutils flex g++ gawk gcc gettext git grep gzip \
      linux-headers make ncurses-dev openssl-dev patch perl python3-dev rsync \
      tar unzip util-linux wget zlib-dev"

    OPTIONAL_PACKAGES="asciidoc cdrkit intltool libxslt musl-fts-dev \
      musl-libintl musl-obstack-dev swig quilt ccache zstd"

    if [ "$WITH_GO" = true ]; then
      OPTIONAL_PACKAGES="$OPTIONAL_PACKAGES go"
    fi
    ;;
esac

# ---------------------------------------------------------------------------
# Availability filtering
# ---------------------------------------------------------------------------
pkg_available() {
  local pkg="$1"

  case "$PKG_MGR" in
    apt-get)
      # apt-cache policy prints no "Candidate:" line for purely virtual names
      # and "(none)" when no installable version exists in the repositories.
      local policy=""
      policy="$(apt-cache policy "$pkg" 2>/dev/null || true)"
      case "$policy" in
        *"Candidate: (none)"*) return 1 ;;
        *"Candidate:"*) return 0 ;;
        *) return 1 ;;
      esac
      ;;
    dnf)     dnf -q info "$pkg" >/dev/null 2>&1 ;;
    yum)     yum -q info "$pkg" >/dev/null 2>&1 ;;
    pacman)  pacman -Si "$pkg" >/dev/null 2>&1 || pacman -Sg "$pkg" >/dev/null 2>&1 ;;
    zypper)  zypper --non-interactive --quiet search --match-exact "$pkg" >/dev/null 2>&1 ;;
    apk)     [ -n "$(apk search -x "$pkg" 2>/dev/null)" ] ;;
    *)       return 0 ;;
  esac
}

filter_available() {
  local pkg
  local kept=""
  local dropped=""

  for pkg in $1; do
    if pkg_available "$pkg"; then
      kept="$kept $pkg"
    else
      dropped="$dropped $pkg"
    fi
  done

  FILTER_KEPT="${kept# }"
  FILTER_DROPPED="${dropped# }"
}

echo
echo "[INFO] Refreshing package metadata..."
if [ "$DRY_RUN" = true ]; then
  echo "[DRY-RUN] $REFRESH_CMD"
else
  $REFRESH_CMD
fi

echo "[INFO] Checking package availability for this release..."

filter_available "$REQUIRED_PACKAGES"
REQUIRED_AVAILABLE="$FILTER_KEPT"
REQUIRED_MISSING="$FILTER_DROPPED"

filter_available "$OPTIONAL_PACKAGES"
OPTIONAL_AVAILABLE="$FILTER_KEPT"
OPTIONAL_MISSING="$FILTER_DROPPED"

INSTALL_PACKAGES="$REQUIRED_AVAILABLE $OPTIONAL_AVAILABLE"
INSTALL_PACKAGES="$(echo "$INSTALL_PACKAGES" | tr -s '[:space:]' ' ' | sed 's/^ //;s/ $//')"

if [ -z "$INSTALL_PACKAGES" ]; then
  echo "[ERROR] No installable package found. Are the repositories configured?" >&2
  exit 1
fi

echo
echo "========================================"
echo "📦 Packages to install:"
echo "$INSTALL_PACKAGES" | tr ' ' '\n' | sed 's/^/   /'
echo "========================================"

if [ -n "$REQUIRED_MISSING" ]; then
  echo
  echo "[WARN] Required packages not offered by this release (build may fail):"
  echo "   $REQUIRED_MISSING"
fi

if [ -n "$OPTIONAL_MISSING" ]; then
  echo
  echo "[INFO] Optional packages unavailable here, skipped:"
  echo "   $OPTIONAL_MISSING"
fi

if [ "$DRY_RUN" = true ]; then
  echo
  echo "[DRY-RUN] $INSTALL_CMD $INSTALL_PACKAGES"
  exit 0
fi

if [ "$ASSUME_YES" != true ]; then
  echo
  read -r -p "Proceed with installation? [Y/n]: " reply
  case "$reply" in
    [nN]|[nN][oO]) echo "[INFO] Aborted by user."; exit 0 ;;
  esac
fi

echo
echo "[INFO] Installing packages..."

FAILED_PACKAGES=""
if ! $INSTALL_CMD $INSTALL_PACKAGES; then
  echo
  echo "[WARN] Bulk installation failed. Retrying package by package..."
  for pkg in $INSTALL_PACKAGES; do
    if ! $INSTALL_CMD "$pkg" >/dev/null 2>&1; then
      FAILED_PACKAGES="$FAILED_PACKAGES $pkg"
      echo "   [FAIL] $pkg"
    fi
  done
  FAILED_PACKAGES="${FAILED_PACKAGES# }"
fi

echo
echo "========================================"
if [ -n "$FAILED_PACKAGES" ]; then
  echo "⚠️  Setup finished with errors."
  echo "   Failed packages: $FAILED_PACKAGES"
else
  echo "✅ OpenWrt build environment setup complete!"
fi
echo "========================================"
echo

if [ "$WITH_GO" != true ]; then
  echo "👉 [NOTE] The Go toolchain is only needed for Go based packages"
  echo "   (e.g. xray-core, v2ray). Install it with:"
  echo "     ./prepare-openwrt-env.sh --with-go"
  echo
fi

if is_arm64; then
  echo "👉 [NOTE] arm64 has no native multilib. The cross-multilib packages are"
  echo "   optional and only needed for x86 targets; missing ones were skipped."
  echo
fi

echo "👉 Next step:"
echo "   ./prepare-openwrt.sh   # clone and set up the OpenWrt source"
echo