#!/bin/sh
# Resolve the Wickra C ABI (header + shared library) for the Unix build.
#
# Self-contained by default: download the prebuilt wickra-c-<triple>.tar.gz
# release asset that matches this package's version and stage the shared library
# into src/ so the compiled wickra.so links against it and bundles it (via
# install.libs.R), found post-install through an rpath ($ORIGIN on Linux,
# @loader_path on macOS). Set WICKRA_INCLUDE_DIR + WICKRA_LIB_DIR to build
# against a locally built C ABI instead (dev override; e.g.
# `cargo build -p wickra-c --release`). Download/extract uses base R (always
# present at build time), so there is no curl/wget system dependency.
set -e

inc=""
lib=""

# A freshly-cut GitHub release can briefly return 404 while its assets propagate
# across the CDN, and a transient network blip should not fail the build either.
# Retry base R's download.file with a backoff (~2 min total) instead of giving up
# on the first miss.
wickra_download() {
  _url="$1"
  _dest="$2"
  _attempt=1
  while [ "${_attempt}" -le 6 ]; do
    if "${R_HOME}/bin/Rscript" -e "download.file('${_url}', '${_dest}', mode = 'wb', quiet = TRUE)"; then
      return 0
    fi
    echo "wickra: download attempt ${_attempt}/6 failed (${_url}); the release asset may still be propagating — retrying in 20s..."
    sleep 20
    _attempt=$((_attempt + 1))
  done
  echo "wickra: failed to download ${_url} after 6 attempts"
  return 1
}

# WebAssembly (r-universe / webR): there is no prebuilt wasm C ABI to download,
# but the build image ships cargo (/usr/local/cargo/bin) and emscripten
# (EMSDK on PATH), so build the C ABI staticlib from source for
# wasm32-unknown-emscripten right here. Building it in the same image with the
# same emscripten avoids any ABI/version mismatch a prebuilt lib would risk.
# rayon (threads) is dropped via --no-default-features; the indicators are pure
# computation, so the serial path is functionally identical.
if [ "$(uname -s)" = "Emscripten" ]; then
  version=$(sed -n 's/^Version:[[:space:]]*//p' DESCRIPTION)
  echo "wickra: building C ABI from source for wasm32-unknown-emscripten (v${version})"
  build=$(mktemp -d)
  url="https://github.com/wickra-lib/wickra/archive/refs/tags/v${version}.tar.gz"
  wickra_download "${url}" "${build}/src.tar.gz" || exit 1
  "${R_HOME}/bin/Rscript" -e "untar('${build}/src.tar.gz', exdir = '${build}')"
  root="${build}/wickra-${version}"
  rustup target add wasm32-unknown-emscripten 2>/dev/null || true
  ( cd "${root}" && cargo build -p wickra-c --release \
      --target wasm32-unknown-emscripten --no-default-features ) \
    || { echo "wickra: cargo wasm build failed"; exit 1; }
  cp "${root}/bindings/c/include/wickra.h" src/wickra.h
  cp "${root}/target/wasm32-unknown-emscripten/release/libwickra.a" src/libwickra.a
  rm -rf "${build}"
  # The static archive is linked into the package object; no shared lib to
  # bundle and no rpath needed.
  sed "s|@WICKRA_RPATH@||" src/Makevars.in > src/Makevars
  exit 0
fi

if [ -n "${WICKRA_INCLUDE_DIR}" ] && [ -n "${WICKRA_LIB_DIR}" ]; then
  echo "wickra: using C ABI from WICKRA_INCLUDE_DIR / WICKRA_LIB_DIR (dev override)"
  inc="${WICKRA_INCLUDE_DIR}"
  lib="${WICKRA_LIB_DIR}"
else
  version=$(sed -n 's/^Version:[[:space:]]*//p' DESCRIPTION)
  os=$(uname -s)
  arch=$(uname -m)
  case "${os}" in
    Linux)
      case "${arch}" in
        x86_64) triple="x86_64-unknown-linux-gnu" ;;
        aarch64 | arm64) triple="aarch64-unknown-linux-gnu" ;;
        *) echo "wickra: unsupported Linux arch '${arch}' — set WICKRA_INCLUDE_DIR/WICKRA_LIB_DIR"; exit 1 ;;
      esac
      ;;
    Darwin)
      case "${arch}" in
        x86_64) triple="x86_64-apple-darwin" ;;
        arm64 | aarch64) triple="aarch64-apple-darwin" ;;
        *) echo "wickra: unsupported macOS arch '${arch}' — set WICKRA_INCLUDE_DIR/WICKRA_LIB_DIR"; exit 1 ;;
      esac
      ;;
    *)
      echo "wickra: unsupported OS '${os}' — set WICKRA_INCLUDE_DIR/WICKRA_LIB_DIR"
      exit 1
      ;;
  esac
  url="https://github.com/wickra-lib/wickra/releases/download/v${version}/wickra-c-${triple}.tar.gz"
  echo "wickra: downloading C ABI ${triple} for v${version}"
  wickra_download "${url}" "src/wickra-c.tar.gz" || exit 1
  "${R_HOME}/bin/Rscript" -e "untar('src/wickra-c.tar.gz', exdir = 'src/wickra-c')"
  inc="src/wickra-c/wickra-c-${triple}/include"
  lib="src/wickra-c/wickra-c-${triple}/lib"
fi

# Stage the header and the platform shared library into src/ so the package
# object links with -L. -lwickra and install.libs.R bundles the lib.
cp "${inc}/wickra.h" src/wickra.h
staged=""
for f in libwickra.so libwickra.dylib; do
  if [ -f "${lib}/${f}" ]; then
    cp "${lib}/${f}" "src/${f}"
    staged="${f}"
  fi
done
if [ -z "${staged}" ]; then
  echo "wickra: no libwickra.so/.dylib found under ${lib}"
  exit 1
fi

# rpath so the bundled lib is found next to wickra.so after install.
case "$(uname -s)" in
  Darwin)
    rpath="-Wl,-rpath,@loader_path"
    # Normalise the dylib id to @rpath so @loader_path resolution applies.
    install_name_tool -id "@rpath/${staged}" "src/${staged}" 2>/dev/null || true
    ;;
  *)
    rpath="-Wl,-rpath,'\$\$ORIGIN'"
    ;;
esac

sed "s|@WICKRA_RPATH@|${rpath}|" src/Makevars.in > src/Makevars
echo "wickra: configured (bundled ${staged})"
exit 0
