#!/usr/bin/env sh

: ${PREFER_BUILDCTL=}
: ${PREFER_LEGACY=}
: ${TRAVIS_EVENT_TYPE=}
: ${TRAVIS_BRANCH=}

newerEqualThan() { # $1=minimum wanted version $2=actual-version
  [ "$1" = "$(printf "$1\n$2" | sort -V | head -n 1)" ]
}

buildmode="legacy"
if [ "$PREFER_BUILDCTL" = "1" ]; then
  buildmode="buildkit";
else
  serverVersion=$(docker info --format '{{.ServerVersion}}')
  experimental=$(docker info --format '{{.ExperimentalBuild}}')
  if [ "$PREFER_LEGACY" != "1" ] && ( newerEqualThan "18.09" $serverVersion || \
    ( newerEqualThan "18.06" $serverVersion && [ "true" = "$experimental" ] ) || \
    [ "$DOCKER_BUILDKIT" = "1" ]); then
    buildmode="docker-buildkit";
  fi
fi
if [ "$buildmode" = "legacy" ]; then
  echo "\"legacy\" buildmode is no longer supported. Please enable DOCKER_BUILDKIT or install standalone BuildKit." >&2
  exit 1
fi

cacheref=""
currentref=""
if [ "$TRAVIS_EVENT_TYPE" = "pull_request" ]; then
  currentref="git://github.com/moby/buildkit#refs/pull/$TRAVIS_PULL_REQUEST/merge"
  cacheref="cicache.buildk.it/moby/buildkit/pr$TRAVIS_BUILD_ID"
elif [ -n "$TRAVIS_BRANCH" ]; then
  currentref="git://github.com/moby/buildkit#$TRAVIS_BRANCH"
fi


currentcontext="."
currentcontextBuildctl="--local context=. --local dockerfile=."

if [ -n "$currentref" ]; then
  currentcontext="--build-arg BUILDKIT_CONTEXT_KEEP_GIT_DIR=1 $currentref"
  currentcontextBuildctl="--opt context=$currentref --opt build-arg:BUILDKIT_CONTEXT_KEEP_GIT_DIR=1"
fi