#!/usr/bin/env bash
#
# This script installs an up-to-date version of CMake.
#
# For MacOS use Homebrew to install the latest version.
#
# For Ubuntu use the official KitWare Apt repository with backports.
# See: https://apt.kitware.com/
#
# For other systems (RHEL 8.x, 9.x, AmazonLinux, SUSE, Fedora, Arch, etc)
# use the official CMake installer script from KitWare.
#
# Note this is similar to how GitHub Actions runners install cmake:
# https://github.com/actions/runner-images/blob/main/images/ubuntu/scripts/build/install-cmake.sh
#
# Upstream:  3.30.4 (2024-09-27)

set -euo pipefail


if [[ "$(uname -s)" == "darwin" ]]; then
  brew --version >/dev/null \
    || echo "Error: Homebrew is required to install cmake on MacOS." && exit 1
  echo "Installing cmake via Homebrew (can't pin to old versions)."
  brew install cmake
  exit 0
elif [ "$(uname -s)" != "Linux" ]; then
  echo "Error: This script is intended for MacOS/Linux systems only."
  exit 1
elif [ -z "${1:-}" ]; then
  echo "Usage: $0 [3.30.4]"
  exit 1
fi
CMAKE_VERSION="${CMAKE_VERSION:-${1:-3.30.4}}"

if [ "$(whoami)" = root ]; then SUDO=; else SUDO="$(command -v sudo || command -v doas || true)"; fi

if cmake --version | grep -q "$CMAKE_VERSION"; then
  echo "CMake $CMAKE_VERSION is already installed."
  exit 0
elif [ -e /usr/local/bin/cmake ]; then
  echo "Warning: existing cmake found at /usr/local/bin/cmake. Skipping installation."
  exit 0
elif [ -e /etc/apt/sources.list.d/kitware.list ]; then
  echo "Warning: existing KitWare repository found. Skipping installation."
  exit 0
elif [ -e /etc/lsb-release ] && grep -qP 'DISTRIB_ID=Ubuntu' /etc/lsb-release; then
  curl -fsSL https://apt.kitware.com/keys/kitware-archive-latest.asc \
    | $SUDO gpg --dearmor - \
    | $SUDO tee /usr/share/keyrings/kitware-archive-keyring.gpg >/dev/null
  echo "deb [signed-by=/usr/share/keyrings/kitware-archive-keyring.gpg] https://apt.kitware.com/ubuntu/ $(lsb_release -cs) main" \
    | $SUDO tee /etc/apt/sources.list.d/kitware.list >/dev/null
  $SUDO apt-get update
  $SUDO apt-get install -y kitware-archive-keyring cmake==$CMAKE_VERSION
else
  arch="$(uname -m)"
  if [ "$arch" != "x86_64" ] && [ "$arch" != "aarch64" ]; then
    echo "Error. Only x86_64 and aarch64 are supported."
    exit 1
  fi
  tempdir=$(mktemp -d)
  pushd "$tempdir"
    CMAKE_REPO="https://github.com/Kitware/CMake"
    CMAKE_INSTALLER="cmake-$CMAKE_VERSION-linux-$arch.sh"
    curl -fsSL --output cmake-$CMAKE_VERSION-SHA-256.txt \
      "$CMAKE_REPO/releases/download/v$CMAKE_VERSION/cmake-$CMAKE_VERSION-SHA-256.txt"
    curl -fsSL --output $CMAKE_INSTALLER \
      "$CMAKE_REPO/releases/download/v$CMAKE_VERSION/cmake-$CMAKE_VERSION-linux-$arch.sh"
    # workaround for old versions of sha256sum not having --ignore-missing
    grep -F "cmake-$CMAKE_VERSION-linux-$arch.sh" "cmake-$CMAKE_VERSION-SHA-256.txt" \
      | sha256sum -c \
      | grep -qP "^${CMAKE_INSTALLER}: OK"
    chmod +x cmake-$CMAKE_VERSION-linux-$arch.sh
    $SUDO ./cmake-$CMAKE_VERSION-linux-$arch.sh --prefix=/usr/local --skip-license
  popd
  rm -rf "$tempdir"
fi