package shell

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"io"

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

	"github.com/seaweedfs/seaweedfs/weed/storage/needle"
)

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

type commandVolumeMark struct {
}

func (c *commandVolumeMark) Name() string {
	return "volume.mark"
}

func (c *commandVolumeMark) Help() string {
	return `Mark volume writable or readonly from one volume server, or all volume replicas in one collection

	volume.mark -node <volume server host:port> -volumeId <volume id> -writable, -readonly or -readonlyCanDelete
	volume.mark -collection <collection> -writable, -readonly or -readonlyCanDelete

	Use -collection ` + CollectionDefault + ` to target volumes that belong to no named collection.

	-readonlyCanDelete rejects new writes but keeps accepting deletes, so a
	volume holding expiring data drains over time until it can be vacuumed
	away or merged into other volumes with fs.mergeVolumes.
`
}

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

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

	volMarkCommand := flag.NewFlagSet(c.Name(), flag.ContinueOnError)
	volumeIdInt := volMarkCommand.Int("volumeId", 0, "the volume id")
	nodeStr := volMarkCommand.String("node", "", "the volume server <host>:<port>")
	collection := volMarkCommand.String("collection", "", "the collection name")
	writable := volMarkCommand.Bool("writable", false, "volume mark writable")
	readonly := volMarkCommand.Bool("readonly", false, "volume mark readonly")
	readonlyCanDelete := volMarkCommand.Bool("readonlyCanDelete", false, "volume mark readonly but still accepting deletes")
	if err = volMarkCommand.Parse(args); err != nil {
		return nil
	}
	collectionSet, nodeSet, volumeIdSet := false, false, false
	volMarkCommand.Visit(func(f *flag.Flag) {
		switch f.Name {
		case "collection":
			collectionSet = true
		case "node":
			nodeSet = true
		case "volumeId":
			volumeIdSet = true
		}
	})
	modeCount := 0
	for _, set := range []bool{*writable, *readonly, *readonlyCanDelete} {
		if set {
			modeCount++
		}
	}
	if modeCount != 1 {
		return fmt.Errorf("use exactly one of -writable, -readonly or -readonlyCanDelete")
	}
	markWritable := *writable

	if collectionSet {
		if *collection == "" {
			return fmt.Errorf("collection is required")
		}
		if nodeSet || volumeIdSet {
			return fmt.Errorf("cannot use -collection with -node or -volumeId")
		}
	} else if !nodeSet || !volumeIdSet || *nodeStr == "" || *volumeIdInt == 0 {
		return fmt.Errorf("use -node and -volumeId, or -collection")
	}

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

	if collectionSet {
		topologyInfo, _, err := collectTopologyInfo(commandEnv, 0)
		if err != nil {
			return err
		}
		targets, err := collectVolumeMarkTargetsByCollection(topologyInfo, *collection)
		if err != nil {
			return err
		}
		state := "readonly"
		if markWritable {
			state = "writable"
		} else if *readonlyCanDelete {
			state = "readonly (can delete)"
		}
		var failures []error
		for _, target := range targets {
			if err := markVolumeState(context.Background(), commandEnv.option.GrpcDialOption, target.volumeId, target.sourceVolumeServer, markWritable, *readonlyCanDelete, true); err != nil {
				failures = append(failures, fmt.Errorf("mark volume %d on %s: %w", target.volumeId, target.sourceVolumeServer, err))
				fmt.Fprintf(writer, "volume %d on %s: %v\n", target.volumeId, target.sourceVolumeServer, err)
				continue
			}
			fmt.Fprintf(writer, "volume %d on %s marked %s\n", target.volumeId, target.sourceVolumeServer, state)
		}
		if len(failures) > 0 {
			return fmt.Errorf("marked %d of %d volumes %s, %d failed: %w", len(targets)-len(failures), len(targets), state, len(failures), errors.Join(failures...))
		}
		return nil
	}

	sourceVolumeServer := pb.ServerAddress(*nodeStr)

	volumeId := needle.VolumeId(*volumeIdInt)

	return markVolumeState(context.Background(), commandEnv.option.GrpcDialOption, volumeId, sourceVolumeServer, markWritable, *readonlyCanDelete, true)
}

type volumeMarkTarget struct {
	volumeId           needle.VolumeId
	sourceVolumeServer pb.ServerAddress
}

func collectVolumeMarkTargetsByCollection(topoInfo *master_pb.TopologyInfo, collection string) ([]volumeMarkTarget, error) {
	if collection == "" {
		return nil, fmt.Errorf("collection is required")
	}

	// _default targets volumes that belong to no named collection.
	matchCollection := collection
	if matchCollection == CollectionDefault {
		matchCollection = ""
	}

	var targets []volumeMarkTarget
	eachDataNode(topoInfo, func(dc DataCenterId, rack RackId, dn *master_pb.DataNodeInfo) {
		if dn == nil {
			return
		}
		sourceVolumeServer := pb.NewServerAddressFromDataNode(dn)
		for _, diskInfo := range dn.GetDiskInfos() {
			for _, v := range diskInfo.GetVolumeInfos() {
				if v.GetCollection() == matchCollection {
					targets = append(targets, volumeMarkTarget{
						volumeId:           needle.VolumeId(v.GetId()),
						sourceVolumeServer: sourceVolumeServer,
					})
				}
			}
		}
	})
	if len(targets) == 0 {
		return nil, fmt.Errorf("collection %s has no volumes", collection)
	}
	return targets, nil
}
