# adapted from the hack scripts in kubernetes/kubernetes

GIT_COMMIT:=$(shell git rev-parse "HEAD^{commit}" 2>/dev/null)

# the raw git version from `git describe` -- our starting point
GIT_VERSION_RAW:=$(shell git describe --tags --abbrev=14 "$(GIT_COMMIT)^{commit}" 2>/dev/null)

# use the number of dashes in the raw version to figure out what kind of
# version this is, and turn it into a semver-compatible version
DASHES_IN_VERSION:=$(shell echo "$(GIT_VERSION_RAW)" | sed "s/[^-]//g")

# just use the raw version by default
GIT_VERSION:=$(GIT_VERSION_RAW)

ifeq ($(DASHES_IN_VERSION), ---)
# we have a distance to a subversion (v1.1.0-subversion-1-gCommitHash)
GIT_VERSION:=$(shell echo "$(GIT_VERSION_RAW)" | sed "s/-\([0-9]\{1,\}\)-g\([0-9a-f]\{14\}\)$$/.\1\+\2/")
endif
ifeq ($(DASHES_IN_VERSION), --)
# we have distance to base tag (v1.1.0-1-gCommitHash)
GIT_VERSION:=$(shell echo "$(GIT_VERSION_RAW)" | sed "s/-g\([0-9a-f]\{14\}\)$$/+\1/")
endif

# figure out if we have new or changed files
ifeq ($(shell git status --porcelain 2>/dev/null), "")
GIT_TREE_STATE:=clean
else
# append the -dirty manually, since `git describe --dirty` only considers
# changes to existing files
GIT_TREE_STATE:=dirty
GIT_VERSION:=$(GIT_VERSION)-dirty
endif

# construct a "shorter" version without the commit info, etc for use as container image tag, etc
VERSION?=$(shell echo "$(GIT_VERSION)" | grep -E -o '^v[[:digit:]]+\.[[:digit:]]+\.[[:digit:]]+(-(alpha|beta)\.[[:digit:]]+)?')

# construct the build date, taking into account SOURCE_DATE_EPOCH, which is
# used for the purpose of reproducible builds
ifdef SOURCE_DATE_EPOCH
BUILD_DATE:=$(shell date --date=@${SOURCE_DATE_EPOCH} -u +'%Y-%m-%dT%H:%M:%SZ')
else
BUILD_DATE:=$(shell date -u +'%Y-%m-%dT%H:%M:%SZ')
endif

# set the build information version ldflags (but not other ldflags)
VERSION_LDFLAGS:=-X github.com/kubernetes-incubator/metrics-server/pkg/version.gitVersion=$(GIT_VERSION) -X github.com/kubernetes-incubator/metrics-server/pkg/version.gitCommit=$(GIT_COMMIT) -X github.com/kubernetes-incubator/metrics-server/pkg/version.gitTreeState=$(GIT_TREE_STATE) -X github.com/kubernetes-incubator/metrics-server/pkg/version.buildDate=$(BUILD_DATE)

export VERSION
export VERSION_LDFLAGS

# print out a summary of the current version info
version-info:
	@echo "Version: $(GIT_VERSION) ($(VERSION))"
	@echo "    built from $(GIT_COMMIT) ($(GIT_TREE_STATE))"
	@echo "    built on $(BUILD_DATE)"
.PHONY: version-info