#!/usr/bin/env bash
# Build a portable rcalc AppImage.
#
# The release binary is compiled inside Ubuntu 22.04 (glibc 2.35) so the
# AppImage runs on most modern distros — not only on bleeding-edge hosts.
# AppImage itself does NOT bundle glibc; the Docker base sets the floor.
set -euo pipefail

ROOT="$(cd "$(dirname "$0")/.." && pwd)"
ARCH="$(uname -m)"
OUT_DIR="${ROOT}/dist"
APPDIR="${OUT_DIR}/rcalc.AppDir"
TOOLS_DIR="${ROOT}/.cache/appimage-tools"
VERSION="$(grep -m1 '^version' "${ROOT}/Cargo.toml" | sed 's/.*"\(.*\)".*/\1/')"
IMAGE_NAME="rcalc-${VERSION}-${ARCH}.AppImage"

DOCKER_IMAGE="${DOCKER_IMAGE:-ubuntu:22.04}"
# Set SKIP_DOCKER=1 to package the already-built host binary (same glibc floor as host).
SKIP_DOCKER="${SKIP_DOCKER:-0}"

mkdir -p "${OUT_DIR}" "${TOOLS_DIR}"

need_cmd() {
  command -v "$1" >/dev/null 2>&1 || {
    echo "error: required command not found: $1" >&2
    exit 1
  }
}

download_tool() {
  local url="$1" dest="$2"
  if [[ -x "$dest" ]]; then
    return 0
  fi
  echo "Downloading $(basename "$dest")…"
  curl -fsSL -o "$dest" "$url"
  chmod +x "$dest"
}

build_binary_docker() {
  need_cmd docker
  echo "Building release binary in ${DOCKER_IMAGE} (portable glibc)…"
  mkdir -p "${HOME}/.cargo/registry" "${HOME}/.cargo/git"
  docker run --rm \
    -v "${ROOT}:/src" \
    -v "${HOME}/.cargo/registry:/root/.cargo/registry" \
    -v "${HOME}/.cargo/git:/root/.cargo/git" \
    -w /src \
    "${DOCKER_IMAGE}" \
    bash -lc '
      set -euo pipefail
      export DEBIAN_FRONTEND=noninteractive
      apt-get update -qq
      apt-get install -y -qq curl build-essential pkg-config libfontconfig1-dev ca-certificates
      curl --proto "=https" --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain stable --profile minimal
      # shellcheck disable=SC1091
      source "$HOME/.cargo/env"
      export CARGO_TARGET_DIR=/src/target-appimage
      cargo build --release
      install -D -m755 /src/target-appimage/release/rcalc /src/dist/rcalc
      ldd --version | head -1 > /src/dist/.glibc-build.txt
      # Make artifacts writable by the host user
      chown -R '"$(id -u):$(id -g)"' /src/dist/rcalc /src/dist/.glibc-build.txt /src/target-appimage || true
    '
}

ensure_binary() {
  if [[ "$SKIP_DOCKER" == "1" ]]; then
    if [[ ! -x "${OUT_DIR}/rcalc" ]]; then
      echo "Building on host (SKIP_DOCKER=1)…"
      (cd "${ROOT}" && cargo build --release)
      install -D -m755 "${ROOT}/target/release/rcalc" "${OUT_DIR}/rcalc"
    fi
    ldd --version | head -1 > "${OUT_DIR}/.glibc-build.txt" || true
  else
    build_binary_docker
  fi

  if [[ ! -x "${OUT_DIR}/rcalc" ]]; then
    echo "error: dist/rcalc missing after build" >&2
    exit 1
  fi
}

package_appimage() {
  need_cmd curl

  local linuxdeploy="${TOOLS_DIR}/linuxdeploy-${ARCH}.AppImage"
  download_tool \
    "https://github.com/linuxdeploy/linuxdeploy/releases/download/continuous/linuxdeploy-${ARCH}.AppImage" \
    "${linuxdeploy}"

  rm -rf "${APPDIR}"
  mkdir -p "${APPDIR}/usr/bin" "${APPDIR}/usr/share/icons/hicolor/256x256/apps"

  install -m755 "${OUT_DIR}/rcalc" "${APPDIR}/usr/bin/rcalc"
  install -m644 "${ROOT}/assets/icon-256.png" "${APPDIR}/usr/share/icons/hicolor/256x256/apps/rcalc.png"
  install -m644 "${ROOT}/assets/icon-256.png" "${APPDIR}/rcalc.png"
  install -m644 "${ROOT}/assets/rcalc-appimage.desktop" "${APPDIR}/rcalc.desktop"

  echo "Bundling libraries with linuxdeploy…"
  export APPIMAGE_EXTRACT_AND_RUN=1
  export OUTPUT="${IMAGE_NAME}"
  # Marker: mtime boundary to find the FRESH linuxdeploy output.
  local marker="${OUT_DIR}/.pack-start"
  touch "${marker}"
  (
    cd "${OUT_DIR}"
    "${linuxdeploy}" \
      --appdir "${APPDIR}" \
      --executable "${APPDIR}/usr/bin/rcalc" \
      --desktop-file "${APPDIR}/rcalc.desktop" \
      --icon-file "${APPDIR}/rcalc.png" \
      --output appimage
  )

  # linuxdeploy drops the AppImage next to AppDir (dist/). Only consider files
  # NEWER than the marker: a blind `find | head -1` with several older
  # *.AppImage in dist/ renamed an OLD image OVER the freshly built one
  # (rcalc-0.1.28 got shipped with a 0.1.25 binary from the first build).
  local built
  built="$(find "${OUT_DIR}" -maxdepth 1 -name '*.AppImage' ! -name 'linuxdeploy*' -newer "${marker}" | head -1)"
  rm -f "${marker}"
  if [[ -z "$built" ]]; then
    echo "error: AppImage was not produced (linuxdeploy failed?)" >&2
    exit 1
  fi
  if [[ "$(basename "$built")" != "${IMAGE_NAME}" ]]; then
    mv -f "$built" "${OUT_DIR}/${IMAGE_NAME}"
  fi

  chmod +x "${OUT_DIR}/${IMAGE_NAME}"
}

ensure_binary
package_appimage

echo
echo "OK: ${OUT_DIR}/${IMAGE_NAME}"
if [[ -f "${OUT_DIR}/.glibc-build.txt" ]]; then
  echo "Built against: $(cat "${OUT_DIR}/.glibc-build.txt")"
fi
echo "Run:  ${OUT_DIR}/${IMAGE_NAME}"
echo "Tip:  on the other PC, chmod +x and execute — no install needed."