package shell

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"io"
	"path/filepath"

	"github.com/seaweedfs/seaweedfs/weed/pb"

	"github.com/seaweedfs/seaweedfs/weed/operation"
	"github.com/seaweedfs/seaweedfs/weed/pb/master_pb"
	"github.com/seaweedfs/seaweedfs/weed/pb/volume_server_pb"
	"github.com/seaweedfs/seaweedfs/weed/storage/needle"
	"github.com/seaweedfs/seaweedfs/weed/storage/super_block"
)

func init() {
	Commands = append(Commands, &commandVolumeConfigureReplication{})
}

type commandVolumeConfigureReplication struct {
}

func (c *commandVolumeConfigureReplication) Name() string {
	return "volume.configure.replication"
}

func (c *commandVolumeConfigureReplication) Help() string {
	return `change volume replication value

	This command changes a volume replication value. It should be followed by "volume.fix.replication".

`
}

func (c *commandVolumeConfigureReplication) HasTag(CommandTag) bool {
	return false
}

func (c *commandVolumeConfigureReplication) Do(args []string, commandEnv *CommandEnv, _ io.Writer) (err error) {

	configureReplicationCommand := flag.NewFlagSet(c.Name(), flag.ContinueOnError)
	volumeIdInt := configureReplicationCommand.Int("volumeId", 0, "the volume id")
	replicationString := configureReplicationCommand.String("replication", "", "the intended replication value")
	collectionPattern := configureReplicationCommand.String("collectionPattern", "", "match with wildcard characters '*' and '?'")
	if err = configureReplicationCommand.Parse(args); err != nil {
		return nil
	}

	if err = commandEnv.confirmIsLocked(args); err != nil {
		return
	}

	if *replicationString == "" {
		return fmt.Errorf("empty replication value")
	}

	replicaPlacement, err := super_block.NewReplicaPlacementFromString(*replicationString)
	if err != nil {
		return fmt.Errorf("replication format: %w", err)
	}

	// collect topology information
	topologyInfo, _, err := collectTopologyInfo(commandEnv, 0)
	if err != nil {
		return err
	}

	vid := needle.VolumeId(*volumeIdInt)
	volumeFilter := getVolumeFilter(replicaPlacement, uint32(vid), *collectionPattern)

	// find all data nodes with volumes that needs replication change
	eachDataNode(topologyInfo, func(dc DataCenterId, rack RackId, dn *master_pb.DataNodeInfo) {
		var targetVolumeIds []uint32
		for _, diskInfo := range dn.DiskInfos {
			for _, v := range diskInfo.VolumeInfos {
				if volumeFilter(v) {
					targetVolumeIds = append(targetVolumeIds, v.Id)
				}
			}
		}
		if len(targetVolumeIds) == 0 {
			return
		}
		err = operation.WithVolumeServerClient(false, pb.NewServerAddressFromDataNode(dn), commandEnv.option.GrpcDialOption, func(volumeServerClient volume_server_pb.VolumeServerClient) error {
			for _, targetVolumeId := range targetVolumeIds {
				resp, configureErr := volumeServerClient.VolumeConfigure(context.Background(), &volume_server_pb.VolumeConfigureRequest{
					VolumeId:    targetVolumeId,
					Replication: replicaPlacement.String(),
				})
				if configureErr != nil {
					return configureErr
				}
				if resp.Error != "" {
					return errors.New(resp.Error)
				}
			}
			return nil
		})
		if err != nil {
			return
		}
	})

	return err
}

func getVolumeFilter(replicaPlacement *super_block.ReplicaPlacement, volumeId uint32, collectionPattern string) func(message *master_pb.VolumeInformationMessage) bool {
	replicaPlacementInt32 := uint32(replicaPlacement.Byte())
	if volumeId > 0 {
		return func(v *master_pb.VolumeInformationMessage) bool {
			return v.Id == volumeId && v.ReplicaPlacement != replicaPlacementInt32
		}
	}
	return func(v *master_pb.VolumeInformationMessage) bool {
		var collectionMatched bool
		if collectionPattern == "" {
			// Empty pattern matches all collections
			collectionMatched = true
		} else if collectionPattern == CollectionDefault {
			collectionMatched = v.Collection == ""
		} else {
			m, err := filepath.Match(collectionPattern, v.Collection)
			if err != nil {
				return false
			}
			collectionMatched = m
		}
		return collectionMatched && v.ReplicaPlacement != replicaPlacementInt32
	}
}
