package object

import (
	"context"
	"crypto/ecdsa"
	"encoding/hex"
	"errors"
	"fmt"
	"strconv"
	"sync"
	"text/tabwriter"

	internalclient "git.frostfs.info/TrueCloudLab/frostfs-node/cmd/frostfs-cli/internal/client"
	"git.frostfs.info/TrueCloudLab/frostfs-node/cmd/frostfs-cli/internal/commonflags"
	"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/network"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object_manager/placement"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client"
	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
	netmapSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/netmap"
	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
	"github.com/spf13/cobra"
	"golang.org/x/sync/errgroup"
)

const (
	verifyPresenceAllFlag = "verify-presence-all"
)

var errNoAvailableEndpoint = errors.New("failed to create client: no available endpoint")

type objectNodesInfo struct {
	containerID       cid.ID
	objectID          oid.ID
	relatedObjectIDs  []oid.ID
	isLockOrTombstone bool
}

type boolError struct {
	value bool
	err   error
}

var objectNodesCmd = &cobra.Command{
	Use:   "nodes",
	Short: "List of nodes where the object is stored",
	Long: `List of nodes where the object should be stored and where it is actually stored.
	Lock objects must exist on all nodes of the container.
	For complex objects, a node is considered to store an object if the node stores at least one part of the complex object.
	By default, the actual storage of the object is checked only on the nodes that should store the object. To check all nodes, use the flag --verify-presence-all.`,
	Run: objectNodes,
}

func initObjectNodesCmd() {
	commonflags.Init(objectNodesCmd)

	flags := objectNodesCmd.Flags()

	flags.String(commonflags.CIDFlag, "", commonflags.CIDFlagUsage)
	_ = objectGetCmd.MarkFlagRequired(commonflags.CIDFlag)

	flags.String(commonflags.OIDFlag, "", commonflags.OIDFlagUsage)
	_ = objectGetCmd.MarkFlagRequired(commonflags.OIDFlag)

	flags.Bool("verify-presence-all", false, "Verify the actual presence of the object on all netmap nodes")
}

func objectNodes(cmd *cobra.Command, _ []string) {
	var cnrID cid.ID
	var objID oid.ID
	readObjectAddress(cmd, &cnrID, &objID)

	pk := key.GetOrGenerate(cmd)
	cli := internalclient.GetSDKClientByFlag(cmd, pk, commonflags.RPC)

	objectInfo := getObjectInfo(cmd, cnrID, objID, cli, pk)

	placementPolicy, netmap := getPlacementPolicyAndNetmap(cmd, cnrID, cli)

	requiredPlacement := getRequiredPlacement(cmd, objectInfo, placementPolicy, netmap)

	actualPlacement := getActualPlacement(cmd, netmap, requiredPlacement, pk, objectInfo)

	printPlacement(cmd, netmap, requiredPlacement, actualPlacement)
}

func getObjectInfo(cmd *cobra.Command, cnrID cid.ID, objID oid.ID, cli *client.Client, pk *ecdsa.PrivateKey) *objectNodesInfo {
	var addrObj oid.Address
	addrObj.SetContainer(cnrID)
	addrObj.SetObject(objID)

	var prmHead internalclient.HeadObjectPrm
	prmHead.SetClient(cli)
	prmHead.SetAddress(addrObj)
	prmHead.SetRawFlag(true)

	Prepare(cmd, &prmHead)
	readSession(cmd, &prmHead, pk, cnrID, objID)

	res, err := internalclient.HeadObject(cmd.Context(), prmHead)
	if err == nil {
		return &objectNodesInfo{
			containerID:       cnrID,
			objectID:          objID,
			isLockOrTombstone: res.Header().Type() == objectSDK.TypeLock || res.Header().Type() == objectSDK.TypeTombstone,
		}
	}

	var errSplitInfo *objectSDK.SplitInfoError

	if !errors.As(err, &errSplitInfo) {
		commonCmd.ExitOnErr(cmd, "failed to get object info: %w", err)
		return nil
	}

	splitInfo := errSplitInfo.SplitInfo()

	if members, ok := tryGetSplitMembersByLinkingObject(cmd, splitInfo, prmHead, cnrID); ok {
		return &objectNodesInfo{
			containerID:      cnrID,
			objectID:         objID,
			relatedObjectIDs: members,
		}
	}

	if members, ok := tryGetSplitMembersBySplitID(cmd, splitInfo, cli, cnrID); ok {
		return &objectNodesInfo{
			containerID:      cnrID,
			objectID:         objID,
			relatedObjectIDs: members,
		}
	}

	members := tryRestoreChainInReverse(cmd, splitInfo, prmHead, cli, cnrID, objID)
	return &objectNodesInfo{
		containerID:      cnrID,
		objectID:         objID,
		relatedObjectIDs: members,
	}
}

func getPlacementPolicyAndNetmap(cmd *cobra.Command, cnrID cid.ID, cli *client.Client) (placementPolicy netmapSDK.PlacementPolicy, netmap *netmapSDK.NetMap) {
	eg, egCtx := errgroup.WithContext(cmd.Context())
	eg.Go(func() (e error) {
		placementPolicy, e = getPlacementPolicy(egCtx, cnrID, cli)
		return
	})
	eg.Go(func() (e error) {
		netmap, e = getNetMap(egCtx, cli)
		return
	})
	commonCmd.ExitOnErr(cmd, "rpc error: %w", eg.Wait())
	return
}

func getPlacementPolicy(ctx context.Context, cnrID cid.ID, cli *client.Client) (netmapSDK.PlacementPolicy, error) {
	prm := internalclient.GetContainerPrm{
		Client: cli,
		ClientParams: client.PrmContainerGet{
			ContainerID: &cnrID,
		},
	}

	res, err := internalclient.GetContainer(ctx, prm)
	if err != nil {
		return netmapSDK.PlacementPolicy{}, err
	}

	return res.Container().PlacementPolicy(), nil
}

func getNetMap(ctx context.Context, cli *client.Client) (*netmapSDK.NetMap, error) {
	var prm internalclient.NetMapSnapshotPrm
	prm.SetClient(cli)

	res, err := internalclient.NetMapSnapshot(ctx, prm)
	if err != nil {
		return nil, err
	}
	nm := res.NetMap()
	return &nm, nil
}

func getRequiredPlacement(cmd *cobra.Command, objInfo *objectNodesInfo, placementPolicy netmapSDK.PlacementPolicy, netmap *netmapSDK.NetMap) map[uint64]netmapSDK.NodeInfo {
	nodes := make(map[uint64]netmapSDK.NodeInfo)
	placementBuilder := placement.NewNetworkMapBuilder(netmap)
	placement, err := placementBuilder.BuildPlacement(objInfo.containerID, &objInfo.objectID, placementPolicy)
	commonCmd.ExitOnErr(cmd, "failed to get required placement: %w", err)
	for repIdx, rep := range placement {
		numOfReplicas := placementPolicy.ReplicaNumberByIndex(repIdx)
		var nodeIdx uint32
		for _, n := range rep {
			if !objInfo.isLockOrTombstone && nodeIdx == numOfReplicas { // lock and tombstone objects should be on all container nodes
				break
			}
			nodes[n.Hash()] = n
			nodeIdx++
		}
	}

	for _, relatedObjID := range objInfo.relatedObjectIDs {
		placement, err = placementBuilder.BuildPlacement(objInfo.containerID, &relatedObjID, placementPolicy)
		commonCmd.ExitOnErr(cmd, "failed to get required placement for related object: %w", err)
		for _, rep := range placement {
			for _, n := range rep {
				nodes[n.Hash()] = n
			}
		}
	}

	return nodes
}

func getActualPlacement(cmd *cobra.Command, netmap *netmapSDK.NetMap, requiredPlacement map[uint64]netmapSDK.NodeInfo,
	pk *ecdsa.PrivateKey, objInfo *objectNodesInfo,
) map[uint64]boolError {
	result := make(map[uint64]boolError)
	resultMtx := &sync.Mutex{}

	var candidates []netmapSDK.NodeInfo
	checkAllNodes, _ := cmd.Flags().GetBool(verifyPresenceAllFlag)
	if checkAllNodes {
		candidates = netmap.Nodes()
	} else {
		for _, n := range requiredPlacement {
			candidates = append(candidates, n)
		}
	}

	eg, egCtx := errgroup.WithContext(cmd.Context())
	for _, cand := range candidates {
		cand := cand

		eg.Go(func() error {
			cli, err := createClient(egCtx, cmd, cand, pk)
			if err != nil {
				resultMtx.Lock()
				defer resultMtx.Unlock()
				result[cand.Hash()] = boolError{err: err}
				return nil
			}

			eg.Go(func() error {
				var v boolError
				v.value, v.err = isObjectStoredOnNode(egCtx, cmd, objInfo.containerID, objInfo.objectID, cli, pk)
				resultMtx.Lock()
				defer resultMtx.Unlock()
				if prev, exists := result[cand.Hash()]; exists && (prev.err != nil || prev.value) {
					return nil
				}
				result[cand.Hash()] = v
				return nil
			})

			for _, rObjID := range objInfo.relatedObjectIDs {
				rObjID := rObjID
				eg.Go(func() error {
					var v boolError
					v.value, v.err = isObjectStoredOnNode(egCtx, cmd, objInfo.containerID, rObjID, cli, pk)
					resultMtx.Lock()
					defer resultMtx.Unlock()
					if prev, exists := result[cand.Hash()]; exists && (prev.err != nil || prev.value) {
						return nil
					}
					result[cand.Hash()] = v
					return nil
				})
			}
			return nil
		})
	}

	commonCmd.ExitOnErr(cmd, "failed to get actual placement: %w", eg.Wait())
	return result
}

func createClient(ctx context.Context, cmd *cobra.Command, candidate netmapSDK.NodeInfo, pk *ecdsa.PrivateKey) (*client.Client, error) {
	var cli *client.Client
	var addresses []string
	candidate.IterateNetworkEndpoints(func(s string) bool {
		addresses = append(addresses, s)
		return false
	})
	addresses = append(addresses, candidate.ExternalAddresses()...)
	var lastErr error
	for _, address := range addresses {
		var networkAddr network.Address
		lastErr = networkAddr.FromString(address)
		if lastErr != nil {
			continue
		}
		cli, lastErr = internalclient.GetSDKClient(ctx, cmd, pk, networkAddr)
		if lastErr == nil {
			break
		}
	}
	if lastErr != nil {
		return nil, lastErr
	}
	if cli == nil {
		return nil, errNoAvailableEndpoint
	}
	return cli, nil
}

func isObjectStoredOnNode(ctx context.Context, cmd *cobra.Command, cnrID cid.ID, objID oid.ID, cli *client.Client, pk *ecdsa.PrivateKey) (bool, error) {
	var addrObj oid.Address
	addrObj.SetContainer(cnrID)
	addrObj.SetObject(objID)

	var prmHead internalclient.HeadObjectPrm
	prmHead.SetClient(cli)
	prmHead.SetAddress(addrObj)

	Prepare(cmd, &prmHead)
	prmHead.SetTTL(1)
	readSession(cmd, &prmHead, pk, cnrID, objID)

	res, err := internalclient.HeadObject(ctx, prmHead)
	if err == nil && res != nil {
		return true, nil
	}
	var notFound *apistatus.ObjectNotFound
	var removed *apistatus.ObjectAlreadyRemoved
	if errors.As(err, &notFound) || errors.As(err, &removed) {
		return false, nil
	}
	return false, err
}

func printPlacement(cmd *cobra.Command, netmap *netmapSDK.NetMap, requiredPlacement map[uint64]netmapSDK.NodeInfo, actualPlacement map[uint64]boolError) {
	w := tabwriter.NewWriter(cmd.OutOrStdout(), 0, 0, 1, ' ', tabwriter.AlignRight|tabwriter.Debug)
	defer func() {
		commonCmd.ExitOnErr(cmd, "failed to print placement info: %w", w.Flush())
	}()
	fmt.Fprintln(w, "Node ID\tShould contain object\tActually contains object\t")
	for _, n := range netmap.Nodes() {
		nodeID := hex.EncodeToString(n.PublicKey())
		_, required := requiredPlacement[n.Hash()]
		actual, actualExists := actualPlacement[n.Hash()]
		actualStr := ""
		if actualExists {
			if actual.err != nil {
				actualStr = fmt.Sprintf("error: %v", actual.err)
			} else {
				actualStr = strconv.FormatBool(actual.value)
			}
		}
		fmt.Fprintf(w, "%s\t%s\t%s\t\n", nodeID, strconv.FormatBool(required), actualStr)
	}
}