package shell

import (
	"flag"
	"fmt"
	"strings"

	"github.com/dustin/go-humanize"
	"github.com/dustin/go-humanize/english"
	"github.com/seaweedfs/seaweedfs/weed/pb/master_pb"
	"github.com/seaweedfs/seaweedfs/weed/storage/erasure_coding"
	"github.com/seaweedfs/seaweedfs/weed/storage/needle"

	"io"
)

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

type commandClusterStatus struct{}
type ClusterStatusPrinter struct {
	writer   io.Writer
	humanize bool

	locked            bool
	collections       []string
	topology          *master_pb.TopologyInfo
	volumeSizeLimitMb uint64
}

func (c *commandClusterStatus) Name() string {
	return "cluster.status"
}

func (c *commandClusterStatus) Help() string {
	return `outputs a quick overview of the cluster status`
}

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

func (c *commandClusterStatus) Do(args []string, commandEnv *CommandEnv, writer io.Writer) (err error) {
	flags := flag.NewFlagSet(c.Name(), flag.ContinueOnError)
	humanize := flags.Bool("humanize", true, "human-readable output")

	if err = flags.Parse(args); err != nil {
		return err
	}

	collections, err := ListCollectionNames(commandEnv, true, true)
	if err != nil {
		return err
	}
	topology, volumeSizeLimitMb, err := collectTopologyInfo(commandEnv, 0)
	if err != nil {
		return err
	}

	sp := &ClusterStatusPrinter{
		writer:   writer,
		humanize: *humanize,

		locked:            commandEnv.isLocked(),
		collections:       collections,
		topology:          topology,
		volumeSizeLimitMb: volumeSizeLimitMb,
	}
	sp.Print()

	return nil
}

func (sp *ClusterStatusPrinter) uint64(n uint64) string {
	if !sp.humanize {
		return fmt.Sprintf("%d", n)
	}
	return humanize.Comma(int64(n))
}

func (sp *ClusterStatusPrinter) int(n int) string {
	return sp.uint64(uint64(n))
}

func (sp *ClusterStatusPrinter) plural(n int, str string) string {
	if !sp.humanize {
		return fmt.Sprintf("%s(s)", str)
	}
	return english.PluralWord(n, str, "")
}

func (sp *ClusterStatusPrinter) bytes(b uint64) string {
	if !sp.humanize {
		return fmt.Sprintf("%d %s", b, sp.plural(int(b), "byte"))
	}
	return fmt.Sprintf("%s", humanize.Bytes(b))
}

func (sp *ClusterStatusPrinter) uint64Ratio(a, b uint64) string {
	var p float64
	if b != 0 {
		p = float64(a) / float64(b)
	}
	if !sp.humanize {
		return fmt.Sprintf("%.02f", p)
	}
	return fmt.Sprintf("%s", humanize.FtoaWithDigits(p, 2))
}

func (sp *ClusterStatusPrinter) intRatio(a, b int) string {
	return sp.uint64Ratio(uint64(a), uint64(b))
}

func (sp *ClusterStatusPrinter) uint64Pct(a, b uint64) string {
	var p float64
	if b != 0 {
		p = 100 * float64(a) / float64(b)
	}
	if !sp.humanize {
		return fmt.Sprintf("%.02f%%", p)
	}
	return fmt.Sprintf("%s%%", humanize.FtoaWithDigits(p, 2))
}

func (sp *ClusterStatusPrinter) intPct(a, b int) string {
	return sp.uint64Pct(uint64(a), uint64(b))
}

func (sp *ClusterStatusPrinter) write(format string, a ...any) {
	fmt.Fprintf(sp.writer, strings.TrimRight(format, "\r\n "), a...)
	fmt.Fprint(sp.writer, "\n")
}

// TODO: add option to collect detailed file stats
func (sp *ClusterStatusPrinter) Print() {
	sp.write("")
	sp.printClusterInfo()
	sp.printVolumeInfo()
	sp.printStorageInfo()
}

func (sp *ClusterStatusPrinter) printClusterInfo() {
	dcs := len(sp.topology.DataCenterInfos)

	racks := 0
	nodes := 0
	disks := 0
	for _, dci := range sp.topology.DataCenterInfos {
		racks += len(dci.RackInfos)
		for _, ri := range dci.RackInfos {
			for _, dni := range ri.DataNodeInfos {
				nodes++
				disks += len(dni.DiskInfos)
			}
		}
	}

	status := "unlocked"
	if sp.locked {
		status = "LOCKED"
	}

	sp.write("cluster:")
	sp.write("\tid:       %s", sp.topology.Id)
	sp.write("\tstatus:   %s", status)
	sp.write("\tnodes:    %s", sp.int(nodes))
	sp.write("\ttopology: %s %s, %s %s on %s %s",
		sp.int(dcs), sp.plural(dcs, "DC"),
		sp.int(disks), sp.plural(disks, "disk"),
		sp.int(racks), sp.plural(racks, "rack"))
	sp.write("")

}

func (sp *ClusterStatusPrinter) printVolumeInfo() {
	collections := len(sp.collections)
	var maxVolumes uint64
	volumeIds := map[needle.VolumeId]bool{}
	ecVolumeIds := map[needle.VolumeId]bool{}

	var replicas, roReplicas, rwReplicas, ecShards int

	for _, dci := range sp.topology.DataCenterInfos {
		for _, ri := range dci.RackInfos {
			for _, dni := range ri.DataNodeInfos {
				for _, di := range dni.DiskInfos {
					maxVolumes += uint64(di.MaxVolumeCount)
					for _, vi := range di.VolumeInfos {
						vid := needle.VolumeId(vi.Id)
						volumeIds[vid] = true
						replicas++
						if vi.ReadOnly {
							roReplicas++
						} else {
							rwReplicas++
						}
					}
					for _, eci := range di.EcShardInfos {
						vid := needle.VolumeId(eci.Id)
						ecVolumeIds[vid] = true
						ecShards += erasure_coding.ShardBits(eci.EcIndexBits).ShardIdCount()
					}
				}
			}
		}
	}

	volumes := len(volumeIds)
	ecVolumes := len(ecVolumeIds)
	totalVolumes := volumes + ecVolumes

	sp.write("volumes:")
	sp.write("\ttotal:    %s %s, %s %s",
		sp.int(totalVolumes), sp.plural(totalVolumes, "volume"),
		sp.int(collections), sp.plural(collections, "collection"))
	sp.write("\tmax size: %s", sp.bytes(sp.volumeSizeLimitMb*1024*1024))
	sp.write("\tregular:  %s/%s %s on %s %s, %s writable (%s), %s read-only (%s)",
		sp.int(volumes), sp.uint64(maxVolumes), sp.plural(volumes, "volume"),
		sp.int(replicas), sp.plural(replicas, "replica"),
		sp.int(rwReplicas), sp.intPct(rwReplicas, replicas),
		sp.int(roReplicas), sp.intPct(roReplicas, replicas))
	sp.write("\tEC:       %s EC %s on %s %s (%s shards/volume)",
		sp.int(ecVolumes), sp.plural(ecVolumes, "volume"),
		sp.int(ecShards), sp.plural(ecShards, "shard"),
		sp.intRatio(ecShards, ecVolumes))
	sp.write("")

}

func (sp *ClusterStatusPrinter) printStorageInfo() {
	perVolumeSize := map[needle.VolumeId]uint64{}
	perEcVolumeSize := map[needle.VolumeId]uint64{}
	var rawVolumeSize, rawEcVolumeSize uint64

	for _, dci := range sp.topology.DataCenterInfos {
		for _, ri := range dci.RackInfos {
			for _, dni := range ri.DataNodeInfos {
				for _, di := range dni.DiskInfos {
					for _, vi := range di.VolumeInfos {
						vid := needle.VolumeId(vi.Id)
						perVolumeSize[vid] = vi.Size
						rawVolumeSize += vi.Size
					}
					for _, eci := range di.EcShardInfos {
						vid := needle.VolumeId(eci.Id)
						var size uint64
						for _, ss := range eci.ShardSizes {
							size += uint64(ss)
						}
						perEcVolumeSize[vid] += size
						rawEcVolumeSize += size
					}

				}
			}
		}
	}
	// normalize EC logical volume sizes given shard settings
	for vid := range perEcVolumeSize {
		perEcVolumeSize[vid] = perEcVolumeSize[vid] * erasure_coding.DataShardsCount / erasure_coding.TotalShardsCount
	}

	var volumeSize, ecVolumeSize uint64
	for _, s := range perVolumeSize {
		volumeSize += s
	}
	for _, s := range perEcVolumeSize {
		ecVolumeSize += s
	}
	totalSize := volumeSize + ecVolumeSize

	sp.write("storage:")
	sp.write("\ttotal:           %s", sp.bytes(totalSize))
	sp.write("\tregular volumes: %s", sp.bytes(volumeSize))
	sp.write("\tEC volumes:      %s", sp.bytes(ecVolumeSize))
	sp.write("\traw:             %s on volume replicas, %s on EC shards", sp.bytes(rawVolumeSize), sp.bytes(rawEcVolumeSize))
	sp.write("")
}