package rethinkdb

import (
	"fmt"
	"net/url"
	"sync"

	"github.com/influxdata/telegraf"
	"github.com/influxdata/telegraf/plugins/inputs"

	"gopkg.in/dancannon/gorethink.v1"
)

type RethinkDB struct {
	Servers []string
}

var sampleConfig = `
  ### An array of URI to gather stats about. Specify an ip or hostname
  ### with optional port add password. ie,
  ###   rethinkdb://user:auth_key@10.10.3.30:28105,
  ###   rethinkdb://10.10.3.33:18832,
  ###   10.0.0.1:10000, etc.
  servers = ["127.0.0.1:28015"]
`

func (r *RethinkDB) SampleConfig() string {
	return sampleConfig
}

func (r *RethinkDB) Description() string {
	return "Read metrics from one or many RethinkDB servers"
}

var localhost = &Server{Url: &url.URL{Host: "127.0.0.1:28015"}}

// Reads stats from all configured servers accumulates stats.
// Returns one of the errors encountered while gather stats (if any).
func (r *RethinkDB) Gather(acc telegraf.Accumulator) error {
	if len(r.Servers) == 0 {
		r.gatherServer(localhost, acc)
		return nil
	}

	var wg sync.WaitGroup

	var outerr error

	for _, serv := range r.Servers {
		u, err := url.Parse(serv)
		if err != nil {
			return fmt.Errorf("Unable to parse to address '%s': %s", serv, err)
		} else if u.Scheme == "" {
			// fallback to simple string based address (i.e. "10.0.0.1:10000")
			u.Host = serv
		}
		wg.Add(1)
		go func(serv string) {
			defer wg.Done()
			outerr = r.gatherServer(&Server{Url: u}, acc)
		}(serv)
	}

	wg.Wait()

	return outerr
}

func (r *RethinkDB) gatherServer(server *Server, acc telegraf.Accumulator) error {
	var err error
	connectOpts := gorethink.ConnectOpts{
		Address:       server.Url.Host,
		DiscoverHosts: false,
	}
	if server.Url.User != nil {
		pwd, set := server.Url.User.Password()
		if set && pwd != "" {
			connectOpts.AuthKey = pwd
		}
	}
	server.session, err = gorethink.Connect(connectOpts)
	if err != nil {
		return fmt.Errorf("Unable to connect to RethinkDB, %s\n", err.Error())
	}
	defer server.session.Close()

	return server.gatherData(acc)
}

func init() {
	inputs.Add("rethinkdb", func() telegraf.Input {
		return &RethinkDB{}
	})
}