package control

import (
	"crypto/ecdsa"
	"fmt"
	"strings"
	"sync/atomic"
	"time"

	"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/rpc/client"
	"git.frostfs.info/TrueCloudLab/frostfs-node/cmd/frostfs-cli/internal/key"
	commonCmd "git.frostfs.info/TrueCloudLab/frostfs-node/cmd/internal/common"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/shard"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/control"
	clientSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client"
	"github.com/spf13/cobra"
)

const (
	awaitFlag      = "await"
	noProgressFlag = "no-progress"
)

var evacuationShardCmd = &cobra.Command{
	Use:   "evacuation",
	Short: "Objects evacuation from shard",
	Long:  "Objects evacuation from shard to other shards",
}

var startEvacuationShardCmd = &cobra.Command{
	Use:   "start",
	Short: "Start evacuate objects from shard",
	Long:  "Start evacuate objects from shard to other shards",
	Run:   startEvacuateShard,
}

var getEvacuationShardStatusCmd = &cobra.Command{
	Use:   "status",
	Short: "Get evacuate objects from shard status",
	Long:  "Get evacuate objects from shard to other shards status",
	Run:   getEvacuateShardStatus,
}

var stopEvacuationShardCmd = &cobra.Command{
	Use:   "stop",
	Short: "Stop running evacuate process",
	Long:  "Stop running evacuate process from shard to other shards",
	Run:   stopEvacuateShardStatus,
}

func startEvacuateShard(cmd *cobra.Command, _ []string) {
	pk := key.Get(cmd)

	ignoreErrors, _ := cmd.Flags().GetBool(ignoreErrorsFlag)

	req := &control.StartShardEvacuationRequest{
		Body: &control.StartShardEvacuationRequest_Body{
			Shard_ID:     getShardIDList(cmd),
			IgnoreErrors: ignoreErrors,
		},
	}

	signRequest(cmd, pk, req)

	cli := getClient(cmd, pk)

	var resp *control.StartShardEvacuationResponse
	var err error
	err = cli.ExecRaw(func(client *client.Client) error {
		resp, err = control.StartShardEvacuation(client, req)
		return err
	})
	commonCmd.ExitOnErr(cmd, "Start evacuate shards failed, rpc error: %w", err)

	verifyResponse(cmd, resp.GetSignature(), resp.GetBody())

	cmd.Println("Shard evacuation has been successfully started.")

	if awaitCompletion, _ := cmd.Flags().GetBool(awaitFlag); awaitCompletion {
		noProgress, _ := cmd.Flags().GetBool(noProgressFlag)
		waitEvacuateCompletion(cmd, pk, cli, !noProgress, true)
	}
}

func getEvacuateShardStatus(cmd *cobra.Command, _ []string) {
	pk := key.Get(cmd)
	req := &control.GetShardEvacuationStatusRequest{
		Body: &control.GetShardEvacuationStatusRequest_Body{},
	}

	signRequest(cmd, pk, req)

	cli := getClient(cmd, pk)

	var resp *control.GetShardEvacuationStatusResponse
	var err error
	err = cli.ExecRaw(func(client *client.Client) error {
		resp, err = control.GetShardEvacuationStatus(client, req)
		return err
	})
	commonCmd.ExitOnErr(cmd, "Get evacuate shards status failed, rpc error: %w", err)

	verifyResponse(cmd, resp.GetSignature(), resp.GetBody())

	printStatus(cmd, resp)
}

func stopEvacuateShardStatus(cmd *cobra.Command, _ []string) {
	pk := key.Get(cmd)
	req := &control.StopShardEvacuationRequest{
		Body: &control.StopShardEvacuationRequest_Body{},
	}

	signRequest(cmd, pk, req)

	cli := getClient(cmd, pk)

	var resp *control.StopShardEvacuationResponse
	var err error
	err = cli.ExecRaw(func(client *client.Client) error {
		resp, err = control.StopShardEvacuation(client, req)
		return err
	})
	commonCmd.ExitOnErr(cmd, "Stop evacuate shards failed, rpc error: %w", err)

	verifyResponse(cmd, resp.GetSignature(), resp.GetBody())

	waitEvacuateCompletion(cmd, pk, cli, false, false)

	cmd.Println("Evacuation stopped.")
}

func waitEvacuateCompletion(cmd *cobra.Command, pk *ecdsa.PrivateKey, cli *clientSDK.Client, printProgress, printCompleted bool) {
	const statusPollingInterval = 1 * time.Second
	const reportIntervalSeconds = 5
	var resp *control.GetShardEvacuationStatusResponse
	reportResponse := new(atomic.Pointer[control.GetShardEvacuationStatusResponse])
	pollingCompleted := make(chan struct{})
	progressReportCompleted := make(chan struct{})

	go func() {
		defer close(progressReportCompleted)
		if !printProgress {
			return
		}
		cmd.Printf("Progress will be reported every %d seconds.\n", reportIntervalSeconds)
		for {
			select {
			case <-pollingCompleted:
				return
			case <-time.After(reportIntervalSeconds * time.Second):
				r := reportResponse.Load()
				if r == nil || r.GetBody().GetStatus() == control.GetShardEvacuationStatusResponse_Body_COMPLETED {
					continue
				}
				printStatus(cmd, r)
			}
		}
	}()

	for {
		req := &control.GetShardEvacuationStatusRequest{
			Body: &control.GetShardEvacuationStatusRequest_Body{},
		}
		signRequest(cmd, pk, req)

		var err error
		err = cli.ExecRaw(func(client *client.Client) error {
			resp, err = control.GetShardEvacuationStatus(client, req)
			return err
		})

		reportResponse.Store(resp)

		if err != nil {
			commonCmd.ExitOnErr(cmd, "Failed to get evacuate status, rpc error: %w", err)
			return
		}
		if resp.GetBody().GetStatus() != control.GetShardEvacuationStatusResponse_Body_RUNNING {
			break
		}

		time.Sleep(statusPollingInterval)
	}
	close(pollingCompleted)
	<-progressReportCompleted
	if printCompleted {
		printCompletedStatusMessage(cmd, resp)
	}
}

func printCompletedStatusMessage(cmd *cobra.Command, resp *control.GetShardEvacuationStatusResponse) {
	cmd.Println("Shard evacuation has been completed.")
	sb := &strings.Builder{}
	appendShardIDs(sb, resp)
	appendCounts(sb, resp)
	appendError(sb, resp)
	appendStartedAt(sb, resp)
	appendDuration(sb, resp)
	cmd.Println(sb.String())
}

func printStatus(cmd *cobra.Command, resp *control.GetShardEvacuationStatusResponse) {
	if resp.GetBody().GetStatus() == control.GetShardEvacuationStatusResponse_Body_EVACUATE_SHARD_STATUS_UNDEFINED {
		cmd.Println("There is no running or completed evacuation.")
		return
	}
	sb := &strings.Builder{}
	appendShardIDs(sb, resp)
	appendStatus(sb, resp)
	appendCounts(sb, resp)
	appendError(sb, resp)
	appendStartedAt(sb, resp)
	appendDuration(sb, resp)
	appendEstimation(sb, resp)
	cmd.Println(sb.String())
}

func appendEstimation(sb *strings.Builder, resp *control.GetShardEvacuationStatusResponse) {
	if resp.GetBody().GetStatus() != control.GetShardEvacuationStatusResponse_Body_RUNNING ||
		resp.GetBody().GetDuration() == nil ||
		resp.GetBody().GetTotal() == 0 ||
		resp.GetBody().GetEvacuated()+resp.GetBody().GetFailed()+resp.Body.GetSkipped() == 0 {
		return
	}

	durationSeconds := float64(resp.GetBody().GetDuration().GetSeconds())
	evacuated := float64(resp.GetBody().GetEvacuated() + resp.GetBody().GetFailed() + resp.GetBody().GetSkipped())
	avgObjEvacuationTimeSeconds := durationSeconds / evacuated
	objectsLeft := float64(resp.GetBody().GetTotal()) - evacuated
	leftSeconds := avgObjEvacuationTimeSeconds * objectsLeft
	leftMinutes := int(leftSeconds / 60)

	sb.WriteString(fmt.Sprintf(" Estimated time left: %d minutes.", leftMinutes))
}

func appendDuration(sb *strings.Builder, resp *control.GetShardEvacuationStatusResponse) {
	if resp.GetBody().GetDuration() != nil {
		duration := time.Second * time.Duration(resp.GetBody().GetDuration().GetSeconds())
		hour := int(duration.Seconds() / 3600)
		minute := int(duration.Seconds()/60) % 60
		second := int(duration.Seconds()) % 60
		sb.WriteString(fmt.Sprintf(" Duration: %02d:%02d:%02d.", hour, minute, second))
	}
}

func appendStartedAt(sb *strings.Builder, resp *control.GetShardEvacuationStatusResponse) {
	if resp.GetBody().GetStartedAt() != nil {
		startedAt := time.Unix(resp.GetBody().GetStartedAt().GetValue(), 0).UTC()
		sb.WriteString(fmt.Sprintf(" Started at: %s UTC.", startedAt.Format(time.RFC3339)))
	}
}

func appendError(sb *strings.Builder, resp *control.GetShardEvacuationStatusResponse) {
	if len(resp.Body.GetErrorMessage()) > 0 {
		sb.WriteString(fmt.Sprintf(" Error: %s.", resp.Body.GetErrorMessage()))
	}
}

func appendStatus(sb *strings.Builder, resp *control.GetShardEvacuationStatusResponse) {
	var status string
	switch resp.GetBody().GetStatus() {
	case control.GetShardEvacuationStatusResponse_Body_COMPLETED:
		status = "completed"
	case control.GetShardEvacuationStatusResponse_Body_RUNNING:
		status = "running"
	default:
		status = "undefined"
	}
	sb.WriteString(fmt.Sprintf(" Status: %s.", status))
}

func appendShardIDs(sb *strings.Builder, resp *control.GetShardEvacuationStatusResponse) {
	sb.WriteString("Shard IDs: ")
	for idx, shardID := range resp.GetBody().GetShard_ID() {
		shardIDStr := shard.NewIDFromBytes(shardID).String()
		if idx > 0 {
			sb.WriteString(", ")
		}
		sb.WriteString(shardIDStr)
		if idx == len(resp.GetBody().GetShard_ID())-1 {
			sb.WriteString(".")
		}
	}
}

func appendCounts(sb *strings.Builder, resp *control.GetShardEvacuationStatusResponse) {
	sb.WriteString(fmt.Sprintf(" Evacuated %d objects out of %d, failed to evacuate: %d, skipped: %d.",
		resp.GetBody().GetEvacuated(),
		resp.GetBody().GetTotal(),
		resp.GetBody().GetFailed(),
		resp.GetBody().GetSkipped()))
}

func initControlEvacuationShardCmd() {
	evacuationShardCmd.AddCommand(startEvacuationShardCmd)
	evacuationShardCmd.AddCommand(getEvacuationShardStatusCmd)
	evacuationShardCmd.AddCommand(stopEvacuationShardCmd)

	initControlStartEvacuationShardCmd()
	initControlFlags(getEvacuationShardStatusCmd)
	initControlFlags(stopEvacuationShardCmd)
}

func initControlStartEvacuationShardCmd() {
	initControlFlags(startEvacuationShardCmd)

	flags := startEvacuationShardCmd.Flags()
	flags.StringSlice(shardIDFlag, nil, "List of shard IDs in base58 encoding")
	flags.Bool(shardAllFlag, false, "Process all shards")
	flags.Bool(ignoreErrorsFlag, true, "Skip invalid/unreadable objects")
	flags.Bool(awaitFlag, false, "Block execution until evacuation is completed")
	flags.Bool(noProgressFlag, false, fmt.Sprintf("Print progress if %s provided", awaitFlag))

	startEvacuationShardCmd.MarkFlagsMutuallyExclusive(shardIDFlag, shardAllFlag)
}