#!/bin/bash
SCRIPT_NAME="$(basename ${BASH_SOURCE[0]})"
pushd $(dirname ${BASH_SOURCE[0]}) > /dev/null
SCRIPT_DIR=$(pwd)
pushd ../.. > /dev/null
SOURCE_DIR=$(pwd)
popd > /dev/null
pushd ../functions > /dev/null
FN_DIR=$(pwd)
popd > /dev/null
popd > /dev/null

source "${SCRIPT_DIR}/functions.sh"

function usage {
cat <<-EOF
Usage: ${SCRIPT_NAME} [<options ...>] <proto filepath>

Description:
   Generate the Go files from protobuf definitions. In addition to
   running the protoc generator it will also fixup build tags in the
   generated code.

Options:
   --import-replace         Replace imports of google types with those from the gogo/protobuf repo.
   --grpc                   Enable the gRPC plugin
   -h | --help              Print this help text.
EOF
}

function err_usage {
   err "$1"
   err ""
   err "$(usage)"
}

function main {
   local -i grpc=0
   local -i imp_replace=0
   local    proto_path=

   while test $# -gt 0
   do
      case "$1" in
         -h | --help )
            usage
            return 0
            ;;
         --grpc )
            grpc=1
            shift
            ;;
         --import-replace )
            imp_replace=1
            shift
            ;;
         * )
            proto_path="$1"
            shift
            ;;
      esac
   done

   if test -z "${proto_path}"
   then
      err_usage "ERROR: No proto file specified"
      return 1
   fi

   local gogo_proto_path=$(go list -f '{{ .Dir }}' -m github.com/gogo/protobuf)
   local gogo_proto_mod_path=$(sed -e 's,\(.*\)github.com.*,\1,' <<< "${gogo_proto_path}")

   local gogo_proto_imp_replace="Mgoogle/protobuf/timestamp.proto=github.com/gogo/protobuf/types"
   gogo_proto_imp_replace="${gogo_proto_imp_replace},Mgoogle/protobuf/duration.proto=github.com/gogo/protobuf/types"
   gogo_proto_imp_replace="${gogo_proto_imp_replace},Mgoogle/protobuf/empty.proto=github.com/gogo/protobuf/types"
   gogo_proto_imp_replace="${gogo_proto_imp_replace},Mgoogle/protobuf/struct.proto=github.com/gogo/protobuf/types"
   gogo_proto_imp_replace="${gogo_proto_imp_replace},Mgoogle/api/annotations.proto=github.com/gogo/googleapis/google/api"
   gogo_proto_imp_replace="${gogo_proto_imp_replace},Mgoogle/protobuf/field_mask.proto=github.com/gogo/protobuf/types"

   local proto_go_path=${proto_path%%.proto}.pb.go
   local proto_go_bin_path=${proto_path%%.proto}.pb.binary.go
   
   local go_proto_out="paths=source_relative"
   if is_set "${grpc}"
   then
      go_proto_out="${go_proto_out},plugins=grpc"
   fi

   if is_set "${imp_replace}"
   then
      go_proto_out="${go_proto_out},${gogo_proto_imp_replace}"
   fi

   if test -n "${go_proto_out}"
   then
      go_proto_out="${go_proto_out}:"
   fi

   # How we run protoc probably needs some documentation.
   #
   # This is the path to where 
   #  -I="${gogo_proto_path}/protobuf" \
   local -i ret=0
   status_stage "Generating ${proto_path} into ${proto_go_path} and ${proto_go_bin_path}"
   debug_run protoc \
      -I="${gogo_proto_path}/protobuf" \
      -I="${gogo_proto_path}" \
      -I="${gogo_proto_mod_path}" \
      -I="${SOURCE_DIR}" \
      --gofast_out="${go_proto_out}${SOURCE_DIR}" \
      --go-binary_out="${SOURCE_DIR}" \
      "${proto_path}"
   if test $? -ne 0
   then
      err "Failed to generate outputs from ${proto_path}"
      return 1
   fi

   BUILD_TAGS=$(sed -e '/^[[:space:]]*$/,$d' < "${proto_path}" | grep '// +build')
   if test -n "${BUILD_TAGS}"
   then
      echo -e "${BUILD_TAGS}\n" >> "${proto_go_path}.new"
      cat "${proto_go_path}" >> "${proto_go_path}.new"
      mv "${proto_go_path}.new" "${proto_go_path}"
      
      echo -e "${BUILD_TAGS}\n" >> "${proto_go_bin_path}.new"
      cat "${proto_go_bin_path}" >> "${proto_go_bin_path}.new"
      mv "${proto_go_bin_path}.new" "${proto_go_bin_path}"
   fi

   return 0
}

main "$@"
exit $?