// 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.

package service // import "go.opentelemetry.io/collector/service"

import (
	"flag"
	"strings"

	"go.opentelemetry.io/collector/config/configtelemetry"
	"go.opentelemetry.io/collector/service/featuregate"
)

var (
	defaultMetricsAddr   = ":8888"
	defaultMetricsPrefix = "otelcol"
	defaultAddInstanceID = true
	defaultConfig        = ""

	// Command-line flag that control the configuration file.
	configFlag = &defaultConfig
	setFlag    = new(stringArrayValue)
	// Command-line flags that control publication of telemetry data.
	metricsAddrPtr   = &defaultMetricsAddr
	metricsPrefixPtr = &defaultMetricsPrefix
	addInstanceIDPtr = &defaultAddInstanceID
)

type stringArrayValue struct {
	values []string
}

func (s *stringArrayValue) Set(val string) error {
	s.values = append(s.values, val)
	return nil
}

func (s *stringArrayValue) String() string {
	return "[" + strings.Join(s.values, ",") + "]"
}

func flags() *flag.FlagSet {
	flagSet := new(flag.FlagSet)
	configtelemetry.Flags(flagSet)
	featuregate.Flags(flagSet)

	// At least until we can use a generic, i.e.: OpenCensus, metrics exporter
	// we default to Prometheus at port 8888, if not otherwise specified.
	metricsAddrPtr = flagSet.String(
		"metrics-addr",
		defaultMetricsAddr,
		"[address]:port for exposing collector telemetry.")

	metricsPrefixPtr = flagSet.String(
		"metrics-prefix",
		defaultMetricsPrefix,
		"Prefix to the metrics generated by the collector.")

	addInstanceIDPtr = flagSet.Bool(
		"add-instance-id",
		defaultAddInstanceID,
		"Flag to control the addition of 'service.instance.id' to the collector metrics.")

	configFlag = flagSet.String("config", defaultConfig, "Path to the config file")

	flagSet.Var(setFlag, "set",
		"Set arbitrary component config property. The component has to be defined in the config file and the flag"+
			" has a higher precedence. Array config properties are overridden and maps are joined, note that only a single"+
			" (first) array property can be set e.g. -set=processors.attributes.actions.key=some_key. Example --set=processors.batch.timeout=2s")

	return flagSet
}

func getConfigFlag() string {
	return *configFlag
}

func getSetFlag() []string {
	return setFlag.values
}

func getAddInstanceID() bool {
	return *addInstanceIDPtr
}

func getMetricsAddr() string {
	return *metricsAddrPtr
}

func getMetricsPrefix() string {
	return *metricsPrefixPtr
}
