// Copyright 2019 The Prometheus 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.

//go:build !nodiskstats && (openbsd || linux || darwin)
// +build !nodiskstats
// +build openbsd linux darwin

package collector

import (
	"errors"
	"log/slog"

	"github.com/alecthomas/kingpin/v2"
	"github.com/prometheus/client_golang/prometheus"
)

const (
	diskSubsystem = "disk"
)

var (
	diskLabelNames = []string{"device"}

	diskstatsDeviceExcludeSet bool
	diskstatsDeviceExclude    = kingpin.Flag(
		"collector.diskstats.device-exclude",
		"Regexp of diskstats devices to exclude (mutually exclusive to device-include).",
	).Default(diskstatsDefaultIgnoredDevices).PreAction(func(c *kingpin.ParseContext) error {
		diskstatsDeviceExcludeSet = true
		return nil
	}).String()
	oldDiskstatsDeviceExclude = kingpin.Flag(
		"collector.diskstats.ignored-devices",
		"DEPRECATED: Use collector.diskstats.device-exclude",
	).Hidden().String()

	diskstatsDeviceInclude = kingpin.Flag("collector.diskstats.device-include", "Regexp of diskstats devices to include (mutually exclusive to device-exclude).").String()

	readsCompletedDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, diskSubsystem, "reads_completed_total"),
		"The total number of reads completed successfully.",
		diskLabelNames, nil,
	)

	readBytesDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, diskSubsystem, "read_bytes_total"),
		"The total number of bytes read successfully.",
		diskLabelNames, nil,
	)

	writesCompletedDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, diskSubsystem, "writes_completed_total"),
		"The total number of writes completed successfully.",
		diskLabelNames, nil,
	)

	writtenBytesDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, diskSubsystem, "written_bytes_total"),
		"The total number of bytes written successfully.",
		diskLabelNames, nil,
	)

	ioTimeSecondsDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, diskSubsystem, "io_time_seconds_total"),
		"Total seconds spent doing I/Os.",
		diskLabelNames, nil,
	)

	readTimeSecondsDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, diskSubsystem, "read_time_seconds_total"),
		"The total number of seconds spent by all reads.",
		diskLabelNames,
		nil,
	)

	writeTimeSecondsDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, diskSubsystem, "write_time_seconds_total"),
		"This is the total number of seconds spent by all writes.",
		diskLabelNames,
		nil,
	)
)

func newDiskstatsDeviceFilter(logger *slog.Logger) (deviceFilter, error) {
	if *oldDiskstatsDeviceExclude != "" {
		if !diskstatsDeviceExcludeSet {
			logger.Warn("--collector.diskstats.ignored-devices is DEPRECATED and will be removed in 2.0.0, use --collector.diskstats.device-exclude")
			*diskstatsDeviceExclude = *oldDiskstatsDeviceExclude
		} else {
			return deviceFilter{}, errors.New("--collector.diskstats.ignored-devices and --collector.diskstats.device-exclude are mutually exclusive")
		}
	}

	if *diskstatsDeviceExclude != "" && *diskstatsDeviceInclude != "" {
		return deviceFilter{}, errors.New("device-exclude & device-include are mutually exclusive")
	}

	if *diskstatsDeviceExclude != "" {
		logger.Info("Parsed flag --collector.diskstats.device-exclude", "flag", *diskstatsDeviceExclude)
	}

	if *diskstatsDeviceInclude != "" {
		logger.Info("Parsed Flag --collector.diskstats.device-include", "flag", *diskstatsDeviceInclude)
	}

	return newDeviceFilter(*diskstatsDeviceExclude, *diskstatsDeviceInclude), nil
}