#!/usr/bin/env bash

set -eu

bindir=$( cd "${BASH_SOURCE[0]%/*}" && pwd )

# shellcheck source=_log.sh
. "$bindir"/_log.sh

# TODO this should be set to the canonical public docker registry; we can override this
# docker registry in, for instance, CI.
export DOCKER_REGISTRY=${DOCKER_REGISTRY:-ghcr.io/linkerd}

# When set, causes docker's build output to be emitted to stderr.
export DOCKER_TRACE=${DOCKER_TRACE:-}

# When set, use `docker buildx` and use the github actions cache to store/retrieve images
export DOCKER_BUILDKIT=${DOCKER_BUILDKIT:-}

# buildx cache directory. Needed if DOCKER_BUILDKIT is used
export DOCKER_BUILDKIT_CACHE=${DOCKER_BUILDKIT_CACHE:-}

# When set together with DOCKER_BUILDKIT, it will build the multi-arch images. Currently DOCKER_PUSH is also required
export DOCKER_MULTIARCH=${DOCKER_MULTIARCH:-}

# When set together with DOCKER_MULTIARCH, it will push the multi-arch images to the registry
export DOCKER_PUSH=${DOCKER_PUSH:-}

# Default supported docker image architectures
export SUPPORTED_ARCHS=${SUPPORTED_ARCHS:-linux/amd64,linux/arm64,linux/arm/v7}

docker_repo() {
    repo=$1

    name=$repo
    if [ -n "${DOCKER_REGISTRY:-}" ]; then
        name="$DOCKER_REGISTRY/$name"
    fi

    echo "$name"
}

docker_build() {
    repo=$(docker_repo "$1")
    shift

    tag=$1
    shift

    file=$1
    shift

    output=/dev/null
    if [ -n "$DOCKER_TRACE" ]; then
        output=/dev/stderr
    fi

    rootdir=$( cd "$bindir"/.. && pwd )

    if [ -n "$DOCKER_BUILDKIT" ]; then
      cache_params=""
      if [ -n "$DOCKER_BUILDKIT_CACHE" ]; then
        cache_params="--cache-from type=local,src=${DOCKER_BUILDKIT_CACHE} --cache-to type=local,dest=${DOCKER_BUILDKIT_CACHE},mode=max"
      fi

      output_params="--load"
      if [ -n "$DOCKER_MULTIARCH" ]; then

        # Pushing multi-arch images to gcr.io with the same tag that already exists is not possible
        # The issue is on gcr as pushing the same tag in docker hub works fine
        # Related issues: https://github.com/eclipse/che/issues/16983, https://github.com/open-policy-agent/gatekeeper/issues/665
        if (docker buildx imagetools inspect "$repo:$tag"); then
          echo "Build skipped. Image already exists"
          exit 0
        fi

        output_params="--platform $SUPPORTED_ARCHS"
        if [ -n "$DOCKER_PUSH" ]; then
          output_params+=" --push"
        else
          echo "Error: env DOCKER_PUSH=1 is missing"
          echo "When building the multi-arch images it is required to push the images to the registry"
          echo "See https://github.com/docker/buildx/issues/59 for more details"
          exit 1
        fi
      fi

      log_debug "  :; docker buildx $rootdir $cache_params $output_params -t $repo:$tag -f $file $*"
      # shellcheck disable=SC2086
      docker buildx build "$rootdir" $cache_params \
          $output_params \
          -t "$repo:$tag" \
          -f "$file" \
          "$@" \
          > "$output"
    else
      log_debug "  :; docker build $rootdir -t $repo:$tag -f $file $*"
      docker build "$rootdir" \
          -t "$repo:$tag" \
          -f "$file" \
          "$@" \
          > "$output"
    fi

    echo "$repo:$tag"
}

docker_pull() {
    repo=$(docker_repo "$1")
    tag=$2
    log_debug "  :; docker pull $repo:$tag"
    docker pull "$repo:$tag"
}

docker_push() {
    repo=$(docker_repo "$1")
    tag=$2
    log_debug "  :; docker push $repo:$tag"
    docker push "$repo:$tag"
}

docker_retag() {
    repo=$(docker_repo "$1")
    from=$2
    to=$3
    log_debug "  :; docker tag $repo:$from $repo:$to"
    docker tag "$repo:$from" "$repo:$to"
    echo "$repo:$to"
}