package distributor

import (
	"flag"
	"os"
	"time"

	"github.com/go-kit/kit/log/level"

	"github.com/cortexproject/cortex/pkg/ring"
	"github.com/cortexproject/cortex/pkg/ring/kv"
	"github.com/cortexproject/cortex/pkg/util"
	"github.com/cortexproject/cortex/pkg/util/flagext"
)

// RingConfig masks the ring lifecycler config which contains
// many options not really required by the distributors ring. This config
// is used to strip down the config to the minimum, and avoid confusion
// to the user.
type RingConfig struct {
	KVStore          kv.Config     `yaml:"kvstore"`
	HeartbeatPeriod  time.Duration `yaml:"heartbeat_period"`
	HeartbeatTimeout time.Duration `yaml:"heartbeat_timeout"`

	// Instance details
	InstanceID             string   `yaml:"instance_id" doc:"hidden"`
	InstanceInterfaceNames []string `yaml:"instance_interface_names"`
	InstancePort           int      `yaml:"instance_port" doc:"hidden"`
	InstanceAddr           string   `yaml:"instance_addr" doc:"hidden"`

	// Injected internally
	ListenPort int `yaml:"-"`
}

// RegisterFlags adds the flags required to config this to the given FlagSet
func (cfg *RingConfig) RegisterFlags(f *flag.FlagSet) {
	hostname, err := os.Hostname()
	if err != nil {
		level.Error(util.Logger).Log("msg", "failed to get hostname", "err", err)
		os.Exit(1)
	}

	// Ring flags
	cfg.KVStore.RegisterFlagsWithPrefix("distributor.ring.", "collectors/", f)
	f.DurationVar(&cfg.HeartbeatPeriod, "distributor.ring.heartbeat-period", 5*time.Second, "Period at which to heartbeat to the ring.")
	f.DurationVar(&cfg.HeartbeatTimeout, "distributor.ring.heartbeat-timeout", time.Minute, "The heartbeat timeout after which distributors are considered unhealthy within the ring.")

	// Instance flags
	cfg.InstanceInterfaceNames = []string{"eth0", "en0"}
	f.Var((*flagext.StringSlice)(&cfg.InstanceInterfaceNames), "distributor.ring.instance-interface-names", "Name of network interface to read address from.")
	f.StringVar(&cfg.InstanceAddr, "distributor.ring.instance-addr", "", "IP address to advertise in the ring.")
	f.IntVar(&cfg.InstancePort, "distributor.ring.instance-port", 0, "Port to advertise in the ring (defaults to server.grpc-listen-port).")
	f.StringVar(&cfg.InstanceID, "distributor.ring.instance-id", hostname, "Instance ID to register in the ring.")
}

// ToLifecyclerConfig returns a LifecyclerConfig based on the distributor
// ring config.
func (cfg *RingConfig) ToLifecyclerConfig() ring.LifecyclerConfig {
	// We have to make sure that the ring.LifecyclerConfig and ring.Config
	// defaults are preserved
	lc := ring.LifecyclerConfig{}
	rc := ring.Config{}

	flagext.DefaultValues(&lc)
	flagext.DefaultValues(&rc)

	// Configure ring
	rc.KVStore = cfg.KVStore
	rc.HeartbeatTimeout = cfg.HeartbeatTimeout
	rc.ReplicationFactor = 1

	// Configure lifecycler
	lc.RingConfig = rc
	lc.ListenPort = cfg.ListenPort
	lc.Addr = cfg.InstanceAddr
	lc.Port = cfg.InstancePort
	lc.ID = cfg.InstanceID
	lc.InfNames = cfg.InstanceInterfaceNames
	lc.UnregisterOnShutdown = true
	lc.HeartbeatPeriod = cfg.HeartbeatPeriod
	lc.ObservePeriod = 0
	lc.NumTokens = 1
	lc.JoinAfter = 0
	lc.MinReadyDuration = 0
	lc.FinalSleep = 0

	return lc
}
