#!/usr/bin/env bash
# This script returns the current BuildKit ref being used in moby.

: "${BUILDKIT_REPO=moby/buildkit}"
: "${BUILDKIT_REF=}"

if [ -n "$BUILDKIT_REF" ]; then
	echo "$BUILDKIT_REF"
	exit 0
fi

# prepare go mod
./hack/go-mod-prepare.sh

# get buildkit version from vendor.mod
BUILDKIT_REF=$(GO111MODULE=on go list -mod=mod -modfile=vendor.mod -u -m -f '{{.Version}}' "github.com/${BUILDKIT_REPO}")
if [[ "${BUILDKIT_REF}" == *-*-* ]]; then
	# if pseudo-version, figure out just the uncommon sha (https://github.com/golang/go/issues/34745)
	BUILDKIT_REF=$(echo "${BUILDKIT_REF}" | awk -F"-" '{print $NF}' | awk 'BEGIN{FIELDWIDTHS="7"} {print $1}')
	# use github api to return full sha to be able to use it as ref
	BUILDKIT_REF=$(curl -s "https://api.github.com/repos/${BUILDKIT_REPO}/commits/${BUILDKIT_REF}" | jq -r .sha)
fi

echo "$BUILDKIT_REF"