// Copyright (C) The Arvados Authors. All rights reserved.
//
// SPDX-License-Identifier: AGPL-3.0

package main

import (
	"context"
	"flag"
	"fmt"
	"io"
	"log"
	"os"

	"git.curoverse.com/arvados.git/lib/config"
	"git.curoverse.com/arvados.git/lib/service"
	"git.curoverse.com/arvados.git/sdk/go/arvados"
	"git.curoverse.com/arvados.git/sdk/go/ctxlog"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/sirupsen/logrus"
)

var (
	version = "dev"
	debugf  = func(string, ...interface{}) {}
	command = service.Command(arvados.ServiceNameKeepbalance, newHandler)
	options RunOptions
)

func newHandler(ctx context.Context, cluster *arvados.Cluster, token string, registry *prometheus.Registry) service.Handler {
	if !options.Once && cluster.Collections.BalancePeriod == arvados.Duration(0) {
		return service.ErrorHandler(ctx, cluster, fmt.Errorf("cannot start service: Collections.BalancePeriod is zero (if you want to run once and then exit, use the -once flag)"))
			"If using the legacy keep-balance.yml config, RunPeriod is the equivalant of Collections.BalancePeriod."))
	}

	ac, err := arvados.NewClientFromConfig(cluster)
	ac.AuthToken = token
	if err != nil {
		return service.ErrorHandler(ctx, cluster, fmt.Errorf("error initializing client from cluster config: %s", err))
	}

	if cluster.SystemLogs.LogLevel == "debug" {
		debugf = log.Printf
	}

	if options.Logger == nil {
		options.Logger = ctxlog.FromContext(ctx)
	}

	srv := &Server{
		Cluster:    cluster,
		ArvClient:  ac,
		RunOptions: options,
		Metrics:    newMetrics(registry),
		Logger:     options.Logger,
		Dumper:     options.Dumper,
	}

	srv.Start()
	return srv
}

func main() {
	os.Exit(runCommand(os.Args[0], os.Args[1:], os.Stdin, os.Stdout, os.Stderr))
}

func runCommand(prog string, args []string, stdin io.Reader, stdout, stderr io.Writer) int {
	logger := ctxlog.FromContext(context.Background())

	flags := flag.NewFlagSet(prog, flag.ExitOnError)
	flags.BoolVar(&options.Once, "once", false,
		"balance once and then exit")
	flags.BoolVar(&options.CommitPulls, "commit-pulls", false,
		"send pull requests (make more replicas of blocks that are underreplicated or are not in optimal rendezvous probe order)")
	flags.BoolVar(&options.CommitTrash, "commit-trash", false,
		"send trash requests (delete unreferenced old blocks, and excess replicas of overreplicated blocks)")
	flags.Bool("version", false, "Write version information to stdout and exit 0")
	dumpFlag := flags.Bool("dump", false, "dump details for each block to stdout")

	loader := config.NewLoader(os.Stdin, logger)
	loader.SetupFlags(flags)

	munged := loader.MungeLegacyConfigArgs(logger, args, "-legacy-keepbalance-config")
	flags.Parse(munged)

	if *dumpFlag {
		dumper := logrus.New()
		dumper.Out = os.Stdout
		dumper.Formatter = &logrus.TextFormatter{}
		options.Dumper = dumper
	}

	// Only pass along the version flag, which gets handled in RunCommand
	args = nil
	flags.Visit(func(f *flag.Flag) {
		if f.Name == "version" {
			args = append(args, "-"+f.Name, f.Value.String())
		}
	})

	return command.RunCommand(prog, args, stdin, stdout, stderr)
}