// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// measured is the Sensor Log Lite measuring daemon. Runs on any device,
// sampling data points and writing them to Syncbase. Sampling configuration
// is read from Syncbase as written by the client.
package main

import (
	"flag"
	"os"

	"v.io/v23"
	"v.io/v23/context"
	"v.io/v23/naming"
	"v.io/x/lib/vlog"
	"v.io/x/ref/lib/signals"
	_ "v.io/x/ref/runtime/factories/generic"
	"v.io/x/sensorlog_lite/internal/config"
	"v.io/x/sensorlog_lite/internal/measure"
	"v.io/x/sensorlog_lite/internal/measure/runloop"
	"v.io/x/sensorlog_lite/internal/sbmodel"
	"v.io/x/sensorlog_lite/internal/sbutil"
	"v.io/x/sensorlog_lite/internal/util"
)

var (
	flagSbService = flag.String("service", config.DefaultSbService, "Location of the Syncbase service to connect to. Can be absolute or relative to the namespace root.")
	flagDevId     = flag.String("devid", "", "DevId to be claimed by this measured. Must be specified.")
	// Flags below are only applied the first time measured is run against a Syncbase service with the same devid.
	flagAdmin     = flag.String("admin", "", "Blessing of admin user allowed to join the syncgroup. Must be specified.")
	flagPublishSb = flag.String("publish-sb", "", "Syncbase service to publish the syncgroup at. Must be absolute. Must be specified. The syncgroup is published as '"+config.SyncgroupName("<publish-sb>", "<devid>")+"'.")
	flagPublishMt = flag.String("publish-mt", "", "Additional mounttable to use for sync rendezvous in addition to namespace roots. Optional.")
)

func main() {
	os.Exit(runMain())
}

func runMain() int {
	ctx, shutdown := v23.Init()
	defer shutdown()

	if *flagDevId == "" {
		vlog.Errorf("-devid must be specified")
		return 1
	}
	if *flagAdmin == "" {
		vlog.Errorf("-admin must be specified")
		return 1
	}
	if !naming.Rooted(*flagPublishSb) {
		vlog.Errorf("-publish-sb must be rooted")
		return 1
	}
	publishMts := v23.GetNamespace(ctx).Roots()
	if *flagPublishMt != "" {
		publishMts = append(publishMts, *flagPublishMt)
	}

	db, err := sbutil.CreateOrOpenDB(ctx, *flagSbService, sbmodel.MeasuredTables)
	if err != nil {
		vlog.Errorf("Failed opening Syncbase db: %v", err)
		return 1
	}
	vlog.VI(0).Infof("measured connected to %s", db.FullName())

	if err := measure.InitSyncgroup(ctx, db, *flagDevId, *flagAdmin, *flagPublishSb, publishMts); err != nil {
		vlog.Errorf("Failed initializing syncgroup: %v", err)
		return 1
	}

	ctx, stop := context.WithCancel(ctx)

	ml := runloop.NewLoop(func(err error) {
		vlog.Errorf("Measure loop failed: %v", err)
		stop()
	})

	writer := func(ctx *context.T, key *sbmodel.KDataPoint, val sbmodel.VDataPoint) error {
		return db.Table(key.Table()).Put(ctx, key.Key(), val)
	}

	waitWatch := util.AsyncRun(func() error {
		return measure.WatchForStreams(ctx, db, *flagDevId, func(key *sbmodel.KStreamDef, val *sbmodel.VStreamDef) error {
			if val.Enabled {
				ml.Register(ctx, key, &val.Sampler, writer)
			} else {
				ml.Unregister(key)
			}
			return nil
		})
	}, func(err error) {
		vlog.Errorf("Watch failed: %v", err)
		stop()
	})

	defer func() {
		_ = waitWatch()
		ml.WaitAll()
	}()

	select {
	case <-signals.ShutdownOnSignals(nil):
		stop()
		vlog.VI(0).Infof("Exiting on signal")
		return 0
	case <-ctx.Done():
		vlog.VI(0).Infof("Exiting on error")
		return 1
	}
}