#!/usr/bin/env bash
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
DOCKERFILE="${DOCKERFILE:-$REPO_ROOT/docker/validator-runtime.Dockerfile}"
TARGET_ARCH=""
IMAGE_TAG=""
OUT_DIR="${OUT_DIR:-$REPO_ROOT/docker-out}"
ALLOW_DIRTY=0
SAVE_IMAGE=1
LOAD_IMAGE=1
INSTALL_BINFMT=1
BUILDER_IMAGE="${BUILDER_IMAGE:-rust:1-bookworm}"
RUNTIME_IMAGE="${RUNTIME_IMAGE:-debian:bookworm-slim}"

usage() {
  cat <<'USAGE'
Usage:
  scripts/docker/build_image.sh --arch amd64|arm64 [options]

Options:
  --arch <arch>          Target architecture (required)
  --image <tag>          Image tag (default: panda-rpki-validator:<version>-<arch>)
  --out-dir <path>       Image archive/metadata directory (default: docker-out)
  --dockerfile <path>    Dockerfile path
  --builder-image <tag>  Builder base image (pin for a supported release)
  --runtime-image <tag>  Runtime base image (pin for a supported release)
  --allow-dirty          Permit a local build and mark tag/metadata dirty
  --no-binfmt            Do not install binfmt/qemu for a cross-architecture build
  --no-save              Do not write docker save archive
  --no-load              Build without loading the image into the local daemon
  -h, --help             Show this help
USAGE
}

normalize_arch() {
  case "$1" in
    amd64|x86_64) printf '%s\n' amd64 ;;
    arm64|aarch64) printf '%s\n' arm64 ;;
    *) return 1 ;;
  esac
}

safe_name() {
  printf '%s' "$1" | tr '/:' '--'
}

while [[ "$#" -gt 0 ]]; do
  case "$1" in
    --arch)
      TARGET_ARCH="$(normalize_arch "$2")" || { echo "unsupported architecture: $2" >&2; exit 2; }
      shift 2
      ;;
    --image)
      IMAGE_TAG="$2"
      shift 2
      ;;
    --out-dir)
      OUT_DIR="$2"
      shift 2
      ;;
    --dockerfile)
      DOCKERFILE="$2"
      shift 2
      ;;
    --builder-image)
      BUILDER_IMAGE="$2"
      shift 2
      ;;
    --runtime-image)
      RUNTIME_IMAGE="$2"
      shift 2
      ;;
    --allow-dirty)
      ALLOW_DIRTY=1
      shift
      ;;
    --no-binfmt)
      INSTALL_BINFMT=0
      shift
      ;;
    --no-save)
      SAVE_IMAGE=0
      shift
      ;;
    --no-load)
      LOAD_IMAGE=0
      shift
      ;;
    -h|--help)
      usage
      exit 0
      ;;
    *)
      echo "unknown option: $1" >&2
      usage >&2
      exit 2
      ;;
  esac
done

[[ -n "$TARGET_ARCH" ]] || { echo "--arch is required" >&2; usage >&2; exit 2; }
[[ -f "$DOCKERFILE" ]] || { echo "missing Dockerfile: $DOCKERFILE" >&2; exit 2; }
command -v docker >/dev/null 2>&1 || { echo "missing required command: docker" >&2; exit 2; }

if SOURCE_COMMIT_FULL="$(git -C "$REPO_ROOT" rev-parse --verify HEAD 2>/dev/null)"; then
  :
else
  SOURCE_COMMIT_FULL=unknown
fi
if SOURCE_COMMIT_SHORT="$(git -C "$REPO_ROOT" rev-parse --short=8 --verify HEAD 2>/dev/null)"; then
  :
else
  SOURCE_COMMIT_SHORT=unknown
fi
SOURCE_DIRTY=false
if [[ -n "$(git -C "$REPO_ROOT" status --short 2>/dev/null)" || "$SOURCE_COMMIT_FULL" == unknown ]]; then
  SOURCE_DIRTY=true
fi
if [[ "$SOURCE_DIRTY" == true && "$ALLOW_DIRTY" != 1 ]]; then
  echo "refusing dirty tree; pass --allow-dirty for a local development build" >&2
  exit 2
fi

VERSION="$(awk -F'"' '$1 == "version = " { print $2; exit }' "$REPO_ROOT/crates/panda-rpki-validator/Cargo.toml")"
REVISION="$VERSION"
if [[ "$SOURCE_DIRTY" == true ]]; then
  REVISION="${REVISION}-dirty"
fi
if [[ -z "$IMAGE_TAG" ]]; then
  IMAGE_TAG="panda-rpki-validator:${REVISION}-${TARGET_ARCH}"
fi

mkdir -p "$OUT_DIR"
TARGET_PLATFORM="linux/$TARGET_ARCH"
HOST_ARCH=""
case "$(uname -m)" in
  x86_64|amd64) HOST_ARCH=amd64 ;;
  aarch64|arm64) HOST_ARCH=arm64 ;;
  *) echo "unsupported host architecture: $(uname -m)" >&2; exit 2 ;;
esac
if [[ "$HOST_ARCH" != "$TARGET_ARCH" && "$INSTALL_BINFMT" == 1 ]]; then
  echo "installing binfmt/qemu for $TARGET_ARCH"
  docker run --rm --privileged tonistiigi/binfmt --install "$TARGET_ARCH"
fi
METADATA_PATH="$OUT_DIR/$(safe_name "$IMAGE_TAG").build.env"
IMAGE_TAR="$OUT_DIR/$(safe_name "$IMAGE_TAG").tar.gz"

build_args=(
  --platform "$TARGET_PLATFORM"
  --file "$DOCKERFILE"
  --build-arg "BUILDER_IMAGE=$BUILDER_IMAGE"
  --build-arg "RUNTIME_IMAGE=$RUNTIME_IMAGE"
  --build-arg "SOURCE_COMMIT=$SOURCE_COMMIT_FULL"
  --build-arg "SOURCE_DIRTY=$SOURCE_DIRTY"
  --build-arg "BUILD_TIMESTAMP_UTC=$(date -u +%Y-%m-%dT%H:%M:%SZ)"
  --tag "$IMAGE_TAG"
)
if [[ "$LOAD_IMAGE" == 1 ]]; then
  docker buildx build --load "${build_args[@]}" "$REPO_ROOT"
else
  docker buildx build "${build_args[@]}" --output "type=oci,dest=$OUT_DIR/$(safe_name "$IMAGE_TAG").oci.tar" "$REPO_ROOT"
fi

if [[ "$SAVE_IMAGE" == 1 && "$LOAD_IMAGE" == 1 ]]; then
  docker save "$IMAGE_TAG" | gzip -c > "$IMAGE_TAR"
fi

IMAGE_DIGEST=""
IMAGE_ID=""
if [[ "$LOAD_IMAGE" == 1 ]]; then
  IMAGE_DIGEST="$(docker image inspect --format '{{index .RepoDigests 0}}' "$IMAGE_TAG" 2>/dev/null || true)"
  IMAGE_ID="$(docker image inspect --format '{{.Id}}' "$IMAGE_TAG")"
fi
BUILD_TIMESTAMP_UTC="$(date -u +%Y-%m-%dT%H:%M:%SZ)"
{
  printf 'image=%s\n' "$IMAGE_TAG"
  printf 'platform=%s\n' "$TARGET_PLATFORM"
  printf 'arch=%s\n' "$TARGET_ARCH"
  printf 'host_arch=%s\n' "$HOST_ARCH"
  printf 'binfmt_installed=%s\n' "$([[ "$HOST_ARCH" != "$TARGET_ARCH" && "$INSTALL_BINFMT" == 1 ]] && printf true || printf false)"
  printf 'source_commit=%s\n' "$SOURCE_COMMIT_FULL"
  printf 'source_commit_short=%s\n' "$SOURCE_COMMIT_SHORT"
  printf 'source_dirty=%s\n' "$SOURCE_DIRTY"
  printf 'builder_image=%s\n' "$BUILDER_IMAGE"
  printf 'runtime_image=%s\n' "$RUNTIME_IMAGE"
  printf 'image_digest=%s\n' "$IMAGE_DIGEST"
  printf 'image_id=%s\n' "$IMAGE_ID"
  printf 'archive=%s\n' "$IMAGE_TAR"
  printf 'archive_sha256=%s\n' "$(sha256sum "$IMAGE_TAR" 2>/dev/null | awk '{print $1}' || true)"
  printf 'built_at_utc=%s\n' "$BUILD_TIMESTAMP_UTC"
} > "$METADATA_PATH"

echo "built image=$IMAGE_TAG platform=$TARGET_PLATFORM archive=$IMAGE_TAR"