#   -*- mode: makefile; -*-
# Copyright The OpenTelemetry Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# This Makefile.proto has rules to generate *.pb.go files in
# `exporters/otlp/internal/opentelemetry-proto-gen` from the .proto files in
# `exporters/otlp/internal/opentelemetry-proto` using protoc with a go plugin.
#
# The protoc binary and other tools are sourced from a docker image
# `PROTOC_IMAGE`.
#
# Prereqs: The archiving utility `pax` is installed.

PROTOC_IMAGE          := namely/protoc-all:1.29_2
PROTOBUF_VERSION      := v1
OTEL_PROTO_SUBMODULE  := exporters/otlp/internal/opentelemetry-proto
PROTOBUF_GEN_DIR      := exporters/otlp/internal/opentelemetry-proto-gen
PROTOBUF_TEMP_DIR     := gen/pb-go
PROTO_SOURCE_DIR      := gen/proto
SUBMODULE_PROTO_FILES := $(wildcard $(OTEL_PROTO_SUBMODULE)/opentelemetry/proto/*/$(PROTOBUF_VERSION)/*.proto \
                           $(OTEL_PROTO_SUBMODULE)/opentelemetry/proto/collector/*/$(PROTOBUF_VERSION)/*.proto)
SOURCE_PROTO_FILES    := $(subst $(OTEL_PROTO_SUBMODULE),$(PROTO_SOURCE_DIR),$(SUBMODULE_PROTO_FILES))

default: protobuf

.PHONY: protobuf protobuf-source gen-protobuf copy-protobufs
protobuf: protobuf-source gen-protobuf copy-protobufs

protobuf-source: $(SOURCE_PROTO_FILES) | $(PROTO_SOURCE_DIR)/

# Changes go_package in .proto file to point to repo-local location
define exec-replace-pkgname
sed  's,go_package = "github.com/open-telemetry/opentelemetry-proto/gen/go,go_package = "go.opentelemetry.io/otel/exporters/otlp/internal/opentelemetry-proto-gen,' < $(1) > $(2)

endef

# replace opentelemetry-proto package name by go.opentelemetry.io/otel specific version
$(SOURCE_PROTO_FILES): $(PROTO_SOURCE_DIR)/%.proto: $(OTEL_PROTO_SUBMODULE)/%.proto
	@mkdir -p $(@D)
	$(call exec-replace-pkgname,$<,$@)

# Command to run protoc using docker image
define exec-protoc-all
docker run -v `pwd`:/defs $(PROTOC_IMAGE) $(1)

endef

gen-protobuf: $(SOURCE_PROTO_FILES) | $(PROTOBUF_GEN_DIR)/
	$(foreach file,$(subst ${PROTO_SOURCE_DIR}/,,$(SOURCE_PROTO_FILES)),$(call exec-protoc-all, -i $(PROTO_SOURCE_DIR) -f ${file} -l gogo -o ${PROTOBUF_TEMP_DIR}))

# requires `pax` to be installed, as it has consistent options for both BSD (Darwin) and Linux
copy-protobufs: | $(PROTOBUF_GEN_DIR)/
	find ./$(PROTOBUF_TEMP_DIR)/go.opentelemetry.io/otel/$(PROTOBUF_GEN_DIR) -type f -print0 | \
      pax -0 -s ',^./$(PROTOBUF_TEMP_DIR)/go.opentelemetry.io/otel/$(PROTOBUF_GEN_DIR),,' -rw ./$(PROTOBUF_GEN_DIR)

$(PROTO_SOURCE_DIR)/ $(PROTOBUF_GEN_DIR)/:
	mkdir -p $@

.PHONY: clean
clean:
	rm -rf ./gen