package main

import (
	"context"
	"flag"
	"fmt"

	"github.com/chrislusf/seaweedfs/weed/operation"
	"github.com/chrislusf/seaweedfs/weed/pb/volume_server_pb"
	"github.com/chrislusf/seaweedfs/weed/security"
	weed_server "github.com/chrislusf/seaweedfs/weed/server"
	"github.com/chrislusf/seaweedfs/weed/storage"
	"github.com/spf13/viper"
	"golang.org/x/tools/godoc/util"
	"google.golang.org/grpc"

	"io"
	"log"
)

var (
	master         = flag.String("master", "localhost:9333", "master server host and port")
	volumeId       = flag.Int("volumeId", -1, "a volume id")
	timeoutSeconds = flag.Int("timeoutSeconds", 0, "disconnect if no activity after these seconds")
	showTextFile   = flag.Bool("showTextFile", false, "display textual file content")
)

func main() {
	flag.Parse()

	weed_server.LoadConfiguration("security", false)
	grpcDialOption := security.LoadClientTLS(viper.Sub("grpc"), "client")

	vid := storage.VolumeId(*volumeId)

	err := TailVolume(*master, grpcDialOption, vid, func(n *storage.Needle) (err error) {
		if n.Size == 0 {
			println("-", n.String())
			return nil
		} else {
			println("+", n.String())
		}

		if *showTextFile {

			data := n.Data
			if n.IsGzipped() {
				if data, err = operation.UnGzipData(data); err != nil {
					return err
				}
			}
			if util.IsText(data) {
				println(string(data))
			}

			println("-", n.String(), "compressed", n.IsGzipped(), "original size", len(data))
		}
		return nil
	})

	if err != nil {
		log.Printf("Error VolumeTail volume %d: %v", vid, err)
	}

}

func TailVolume(master string, grpcDialOption grpc.DialOption, vid storage.VolumeId, fn func(n *storage.Needle) error) error {
	// find volume location, replication, ttl info
	lookup, err := operation.Lookup(master, vid.String())
	if err != nil {
		return fmt.Errorf("Error looking up volume %d: %v", vid, err)
	}
	if len(lookup.Locations) == 0 {
		return fmt.Errorf("unable to locate volume %d", vid)
	}

	volumeServer := lookup.Locations[0].Url

	return operation.WithVolumeServerClient(volumeServer, grpcDialOption, func(client volume_server_pb.VolumeServerClient) error {

		stream, err := client.VolumeTail(context.Background(), &volume_server_pb.VolumeTailRequest{
			VolumeId:        uint32(vid),
			SinceNs:         0,
			DrainingSeconds: uint32(*timeoutSeconds),
		})
		if err != nil {
			return err
		}

		for {
			resp, recvErr := stream.Recv()
			if recvErr != nil {
				if recvErr == io.EOF {
					break
				} else {
					return recvErr
				}
			}

			needleHeader := resp.NeedleHeader
			needleBody := resp.NeedleBody

			if len(needleHeader) == 0 {
				continue
			}

			for !resp.IsLastChunk {
				resp, recvErr = stream.Recv()
				if recvErr != nil {
					if recvErr == io.EOF {
						break
					} else {
						return recvErr
					}
				}
				needleBody = append(needleBody, resp.NeedleBody...)
			}

			n := new(storage.Needle)
			n.ParseNeedleHeader(needleHeader)
			n.ReadNeedleBodyBytes(needleBody, storage.CurrentVersion)

			err = fn(n)

			if err != nil {
				return err
			}

		}
		return nil
	})
}