#!/usr/bin/env bash
#
# Package the StoreHealthAnalyzer remote agent into a self-contained ZIP
# for offline / manual transfer to a remote Docker host.
#
# What this script does:
#   1. Reads the version from docker/remote-agent/package.json.
#   2. Builds `sha-remote-agent:<version>` from the local source tree.
#   3. `docker save`s the image, gzip-compressed, into a temp staging dir.
#   4. Copies deploy/docker-compose.yml, deploy/install.sh, deploy/README.md,
#      and .env.example into the staging dir. Rewrites the compose file's
#      __VERSION__ placeholder to match the built image tag.
#   5. Writes VERSION and SHA256SUMS files for identification / integrity.
#   6. Zips the whole staging dir into docker/remote-agent/dist/.
#
# Usage:
#   ./docker/remote-agent/package.sh                            # tag=package.json, platform=linux/amd64
#   ./docker/remote-agent/package.sh --tag 1.0.1                # override tag
#   ./docker/remote-agent/package.sh --platform linux/arm64     # ARM Linux target
#   ./docker/remote-agent/package.sh --platform linux/amd64     # explicit default (Linux RH/Rocky/CentOS/Ubuntu on Intel)
#
# The image is ALWAYS built for the target platform via `docker buildx
# build --platform ...` so the tarball you ship matches the remote host.
# Default is linux/amd64 because that's the overwhelmingly common Linux
# server architecture; override with --platform if your remote host is
# something else (e.g. linux/arm64 for a Raspberry Pi or ARM-based server).
#
# Requires: docker (with buildx), zip, node (for reading package.json),
# sha256sum OR shasum (macOS ships shasum by default).

set -euo pipefail

# --- Locations --------------------------------------------------------------

# Absolute path to this script's directory; then one level up is the repo root.
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
DIST_DIR="$SCRIPT_DIR/dist"
DEPLOY_DIR="$SCRIPT_DIR/deploy"
DOCKERFILE="$SCRIPT_DIR/Dockerfile"

# --- Colors -----------------------------------------------------------------

GRN=$'\033[0;32m'
YLW=$'\033[1;33m'
RED=$'\033[0;31m'
RST=$'\033[0m'

log()  { printf '%s[package]%s %s\n' "$GRN" "$RST" "$*"; }
warn() { printf '%s[package]%s %s\n' "$YLW" "$RST" "$*"; }
die()  { printf '%s[package]%s %s\n' "$RED" "$RST" "$*" >&2; exit 1; }

# --- Argument parsing -------------------------------------------------------

VERSION=""
# Default target platform. Overwhelming majority of Linux server hosts
# (RHEL, Rocky, CentOS, Ubuntu, Debian) run on x86_64. Override with
# --platform for ARM Linux (linux/arm64) or anything else.
PLATFORM="linux/amd64"

while [[ $# -gt 0 ]]; do
  case "$1" in
    --tag)
      shift
      VERSION="${1:-}"
      shift || true
      ;;
    --platform)
      shift
      PLATFORM="${1:-}"
      shift || true
      ;;
    -h|--help)
      grep '^#' "$0" | sed 's/^# \{0,1\}//'
      exit 0
      ;;
    *)
      die "Unknown argument: $1 (try --help)"
      ;;
  esac
done

[[ -n "$PLATFORM" ]] || die "--platform requires a value (e.g. linux/amd64, linux/arm64)"

# --- Preflight --------------------------------------------------------------

command -v docker >/dev/null 2>&1 || die "docker not found on PATH."
command -v zip    >/dev/null 2>&1 || die "zip not found on PATH."
command -v node   >/dev/null 2>&1 || die "node not found on PATH."

# buildx is required so we can cross-build for a specific target platform
# on any host (e.g. build linux/amd64 from an Apple Silicon Mac).
docker buildx version >/dev/null 2>&1 \
  || die "docker buildx not available. Install Docker Desktop or the buildx plugin."

if [[ -z "$VERSION" ]]; then
  VERSION="$(node -p "require('$SCRIPT_DIR/package.json').version")"
fi
[[ -n "$VERSION" ]] || die "Could not determine version."

log "Packaging sha-remote-agent version: ${VERSION}"
log "Target platform: ${PLATFORM}"

IMAGE_TAG="sha-remote-agent:${VERSION}"
BUNDLE_NAME="sha-remote-agent-${VERSION}"
STAGING_DIR="$(mktemp -d)"
STAGING_ROOT="$STAGING_DIR/$BUNDLE_NAME"
mkdir -p "$STAGING_ROOT"

# Guarantee cleanup even on error.
cleanup() { rm -rf "$STAGING_DIR"; }
trap cleanup EXIT

# Normalize host arch into a linux/* platform string for cross-build detection.
HOST_ARCH_RAW="$(uname -m)"
case "$HOST_ARCH_RAW" in
  x86_64|amd64)  HOST_LINUX_PLATFORM="linux/amd64" ;;
  aarch64|arm64) HOST_LINUX_PLATFORM="linux/arm64" ;;
  armv7l)        HOST_LINUX_PLATFORM="linux/arm/v7" ;;
  *)             HOST_LINUX_PLATFORM="linux/${HOST_ARCH_RAW}" ;;
esac

EXPECTED_ARCH="${PLATFORM##*/}"

# --- 1. Ensure a cross-arch-capable buildx builder --------------------------
# The DEFAULT buildx builder on Docker Desktop uses the "docker" driver, which
# is tied to the daemon's native platform. Passing --platform linux/amd64 on
# an arm64 host with that driver can silently produce an arm64 image (which
# is exactly the "image arch does not match host" failure the install.sh
# sanity check catches on the target machine).
#
# We work around it by creating (once) a dedicated builder with the
# "docker-container" driver, which spins up an isolated BuildKit instance
# capable of cross-arch builds when QEMU/binfmt is available.

BUILDER_NAME="sha-remote-agent-builder"
if ! docker buildx inspect "$BUILDER_NAME" >/dev/null 2>&1; then
  log "Creating dedicated buildx builder '${BUILDER_NAME}' (docker-container driver)..."
  docker buildx create \
    --name "$BUILDER_NAME" \
    --driver docker-container \
    --bootstrap >/dev/null
else
  # Make sure the builder is up (bootstrap is a no-op if it already is).
  docker buildx inspect --bootstrap "$BUILDER_NAME" >/dev/null
fi

# --- 2. Cross-arch binfmt (only when needed) --------------------------------
# Docker Desktop ships QEMU/binfmt handlers by default so this usually no-ops,
# but plain Docker Engine, Colima, or rootless setups often don't. When we're
# cross-building, best-effort install binfmt for the target arch. If it fails
# (e.g. no --privileged, no internet, no image), warn but continue — the
# subsequent build step will fail fast with a clearer error if binfmt truly
# is missing.

if [[ "$PLATFORM" != "$HOST_LINUX_PLATFORM" ]]; then
  log "Cross-arch build (${HOST_LINUX_PLATFORM} -> ${PLATFORM}); ensuring binfmt handlers..."
  if ! docker run --privileged --rm tonistiigi/binfmt --install "$EXPECTED_ARCH" >/dev/null 2>&1; then
    warn "Could not auto-install binfmt for ${EXPECTED_ARCH}. If the build fails, install it manually:"
    warn "  docker run --privileged --rm tonistiigi/binfmt --install all"
  fi
fi

# --- 3. Build directly to a portable tarball --------------------------------
# `--output type=docker,dest=...` writes a `docker load`-compatible tarball
# straight to disk. This intentionally bypasses `--load` (and therefore the
# question of whether the local daemon can even store cross-arch images).

UNZIPPED_TAR="$STAGING_ROOT/${BUNDLE_NAME}.tar"
log "Building ${IMAGE_TAG} for ${PLATFORM} -> $(basename "$UNZIPPED_TAR") (context = ${REPO_ROOT})..."
docker buildx build \
  --builder "$BUILDER_NAME" \
  --platform "$PLATFORM" \
  --output "type=docker,dest=${UNZIPPED_TAR},name=${IMAGE_TAG}" \
  -f "$DOCKERFILE" \
  "$REPO_ROOT"

[[ -s "$UNZIPPED_TAR" ]] || die "buildx produced no output tarball. Aborting."

# --- 4. Verify the built image actually matches --platform ------------------
# Regression guard: if buildx (or binfmt) silently ignored the requested
# platform, catch it here instead of shipping a broken bundle that only
# fails on the remote host with an "exec format error".

log "Verifying built image architecture..."
docker load -i "$UNZIPPED_TAR" >/dev/null
ACTUAL_ARCH="$(docker image inspect --format '{{.Architecture}}' "$IMAGE_TAG")"
if [[ "$ACTUAL_ARCH" != "$EXPECTED_ARCH" ]]; then
  die "Built image architecture is '${ACTUAL_ARCH}' but '${EXPECTED_ARCH}' was requested.
       This usually means buildx couldn't cross-compile for ${PLATFORM}.
       Try installing binfmt handlers explicitly:
         docker run --privileged --rm tonistiigi/binfmt --install all
       Then re-run:
         $0 --platform ${PLATFORM}"
fi
log "Verified: image architecture is ${ACTUAL_ARCH} (matches requested ${EXPECTED_ARCH})."

# Also tag :latest locally for convenience (only when it matches the host,
# so we don't leave a broken cross-arch :latest sitting in the daemon).
if [[ "$PLATFORM" == "$HOST_LINUX_PLATFORM" ]]; then
  docker tag "$IMAGE_TAG" "sha-remote-agent:latest" 2>/dev/null || true
fi

# --- 5. Compress the tarball ------------------------------------------------

IMAGE_TARBALL="${BUNDLE_NAME}.tar.gz"
log "Compressing image tarball -> ${IMAGE_TARBALL}..."
gzip -c "$UNZIPPED_TAR" > "$STAGING_ROOT/$IMAGE_TARBALL"
rm -f "$UNZIPPED_TAR"

TAR_SIZE_MB="$(du -m "$STAGING_ROOT/$IMAGE_TARBALL" | cut -f1)"
log "Image tarball size: ${TAR_SIZE_MB} MB"

# --- 6. Copy deploy assets --------------------------------------------------

log "Copying deploy assets into bundle..."
cp "$SCRIPT_DIR/.env.example"      "$STAGING_ROOT/.env.example"
cp "$DEPLOY_DIR/install.sh"        "$STAGING_ROOT/install.sh"
cp "$DEPLOY_DIR/README.md"         "$STAGING_ROOT/README.md"

# Template the version into the runtime compose file so it references the
# specific image tag we just built.
sed "s|__VERSION__|${VERSION}|g" \
  "$DEPLOY_DIR/docker-compose.yml" > "$STAGING_ROOT/docker-compose.yml"

chmod +x "$STAGING_ROOT/install.sh"

# --- 7. VERSION + SHA256SUMS -----------------------------------------------

printf '%s\n' "$VERSION" > "$STAGING_ROOT/VERSION"

log "Computing SHA-256 checksum for the image tarball..."
pushd "$STAGING_ROOT" >/dev/null
if command -v sha256sum >/dev/null 2>&1; then
  sha256sum "$IMAGE_TARBALL" > SHA256SUMS
elif command -v shasum >/dev/null 2>&1; then
  # macOS: shasum -a 256 emits the same "<hash>  <filename>" format
  # `sha256sum -c` understands.
  shasum -a 256 "$IMAGE_TARBALL" > SHA256SUMS
else
  warn "No sha256sum/shasum available — skipping checksum file."
fi
popd >/dev/null

# --- 8. Zip -----------------------------------------------------------------

mkdir -p "$DIST_DIR"
ZIP_PATH="$DIST_DIR/${BUNDLE_NAME}.zip"
rm -f "$ZIP_PATH"

log "Creating ZIP: ${ZIP_PATH}"
# Zip from inside the temp dir so the archive contains the top-level folder
# with the bundle name (matching what install.sh expects when unzipped).
(cd "$STAGING_DIR" && zip -qr "$ZIP_PATH" "$BUNDLE_NAME")

ZIP_SIZE_MB="$(du -m "$ZIP_PATH" | cut -f1)"

# --- 9. Done ---------------------------------------------------------------

log ""
log "=========================================================="
log " Bundle ready:"
log "   $ZIP_PATH"
log "   (${ZIP_SIZE_MB} MB, built for ${PLATFORM})"
log "=========================================================="
log ""
log "Transfer to the remote host, then:"
log "  unzip ${BUNDLE_NAME}.zip"
log "  cd ${BUNDLE_NAME}"
log "  ./install.sh"