package frostfs

import (
	"context"
	"fmt"
	"strconv"
	"strings"
	"time"

	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container"
	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
	resolver "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/ns"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/pool"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/user"
	"git.frostfs.info/TrueCloudLab/policy-engine/pkg/chain"
	"git.frostfs.info/TrueCloudLab/policy-engine/schema/native"
	"github.com/nspcc-dev/neo-go/cli/flags"
	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
	"github.com/nspcc-dev/neo-go/pkg/wallet"

	"github.com/rclone/rclone/fs"
)

type endpointInfo struct {
	Address  string
	Priority int
	Weight   float64
}

func publicReadWriteCCPRules() []chain.Rule {
	return []chain.Rule{
		{
			Status: chain.Allow, Actions: chain.Actions{
				Inverted: false,
				Names: []string{
					native.MethodPutObject,
					native.MethodGetObject,
					native.MethodHeadObject,
					native.MethodDeleteObject,
					native.MethodSearchObject,
					native.MethodRangeObject,
					native.MethodHashObject,
					native.MethodPatchObject,
				},
			}, Resources: chain.Resources{
				Inverted: false,
				Names:    []string{native.ResourceFormatRootObjects},
			}, Any: false},
	}
}

func privateCCPRules() []chain.Rule {
	rule := publicReadWriteCCPRules()
	// The same as public-read-write, except that only the owner is allowed to perform the listed actions
	rule[0].Condition = []chain.Condition{
		{
			Op:    chain.CondStringEquals,
			Kind:  chain.KindRequest,
			Key:   native.PropertyKeyActorRole,
			Value: native.PropertyValueContainerRoleOwner,
		},
	}
	return rule
}

func publicReadCCPRules() []chain.Rule {
	rule := privateCCPRules()
	// Add a rule that allows other users to perform reading actions.
	rule = append(rule, chain.Rule{
		Status: chain.Allow, Actions: chain.Actions{
			Inverted: false,
			Names: []string{
				native.MethodGetObject,
				native.MethodHeadObject,
				native.MethodRangeObject,
				native.MethodHashObject,
				native.MethodSearchObject,
			},
		}, Resources: chain.Resources{
			Inverted: false,
			Names:    []string{native.ResourceFormatRootObjects},
		}, Condition: []chain.Condition{
			{
				Op:    chain.CondStringEquals,
				Kind:  chain.KindRequest,
				Key:   native.PropertyKeyActorRole,
				Value: native.PropertyValueContainerRoleOthers,
			},
		}, Any: false})
	return rule
}

func parseContainerCreationPolicyString(policyString string) ([]chain.Rule, error) {
	switch policyString {
	case "private":
		return privateCCPRules(), nil
	case "public-read":
		return publicReadCCPRules(), nil
	case "public-read-write":
		return publicReadWriteCCPRules(), nil
	}
	return nil, fmt.Errorf("invalid container creation policy: %s", policyString)
}

func parseEndpoints(endpointParam string) ([]endpointInfo, error) {
	var err error
	expectedLength := -1 // to make sure all endpoints have the same format

	endpoints := strings.Split(strings.TrimSpace(endpointParam), " ")
	res := make([]endpointInfo, 0, len(endpoints))
	seen := make(map[string]struct{}, len(endpoints))

	for _, endpoint := range endpoints {
		endpointInfoSplit := strings.Split(endpoint, ",")
		address := endpointInfoSplit[0]

		if len(address) == 0 {
			continue
		}
		if _, ok := seen[address]; ok {
			return nil, fmt.Errorf("endpoint '%s' is already defined", address)
		}
		seen[address] = struct{}{}

		epInfo := endpointInfo{
			Address:  address,
			Priority: 1,
			Weight:   1,
		}

		if expectedLength == -1 {
			expectedLength = len(endpointInfoSplit)
		}

		if len(endpointInfoSplit) != expectedLength {
			return nil, fmt.Errorf("all endpoints must have the same format: '%s'", endpointParam)
		}

		switch len(endpointInfoSplit) {
		case 1:
		case 2:
			epInfo.Priority, err = parsePriority(endpointInfoSplit[1])
			if err != nil {
				return nil, fmt.Errorf("invalid endpoint '%s': %w", endpoint, err)
			}
		case 3:
			epInfo.Priority, err = parsePriority(endpointInfoSplit[1])
			if err != nil {
				return nil, fmt.Errorf("invalid endpoint '%s': %w", endpoint, err)
			}

			epInfo.Weight, err = parseWeight(endpointInfoSplit[2])
			if err != nil {
				return nil, fmt.Errorf("invalid endpoint '%s': %w", endpoint, err)
			}
		default:
			return nil, fmt.Errorf("invalid endpoint format '%s'", endpoint)
		}

		res = append(res, epInfo)
	}

	return res, nil
}

func parsePriority(priorityStr string) (int, error) {
	priority, err := strconv.Atoi(priorityStr)
	if err != nil {
		return 0, fmt.Errorf("invalid priority '%s': %w", priorityStr, err)
	}
	if priority <= 0 {
		return 0, fmt.Errorf("priority must be positive '%s'", priorityStr)
	}

	return priority, nil
}

func parseWeight(weightStr string) (float64, error) {
	weight, err := strconv.ParseFloat(weightStr, 64)
	if err != nil {
		return 0, fmt.Errorf("invalid weight '%s': %w", weightStr, err)
	}
	if weight <= 0 {
		return 0, fmt.Errorf("weight must be positive '%s'", weightStr)
	}

	return weight, nil
}

func createPool(ctx context.Context, key *keys.PrivateKey, cfg *Options) (*pool.Pool, error) {
	var prm pool.InitParameters
	prm.SetKey(&key.PrivateKey)
	prm.SetNodeDialTimeout(time.Duration(cfg.FrostfsConnectionTimeout))
	prm.SetHealthcheckTimeout(time.Duration(cfg.FrostfsRequestTimeout))
	prm.SetClientRebalanceInterval(time.Duration(cfg.FrostfsRebalanceInterval))
	prm.SetSessionExpirationDuration(cfg.FrostfsSessionExpiration)

	nodes, err := getNodePoolParams(cfg.FrostfsEndpoint)
	if err != nil {
		return nil, err
	}
	for _, node := range nodes {
		prm.AddNode(node)
	}

	p, err := pool.NewPool(prm)
	if err != nil {
		return nil, fmt.Errorf("create pool: %w", err)
	}

	if err = p.Dial(ctx); err != nil {
		return nil, fmt.Errorf("dial pool: %w", err)
	}

	return p, nil
}

func getNodePoolParams(endpointParam string) ([]pool.NodeParam, error) {
	endpointInfos, err := parseEndpoints(endpointParam)
	if err != nil {
		return nil, fmt.Errorf("parse endpoints params: %w", err)
	}

	res := make([]pool.NodeParam, len(endpointInfos))
	for i, info := range endpointInfos {
		res[i] = pool.NewNodeParam(info.Priority, info.Address, info.Weight)
	}

	return res, nil
}

func createNNSResolver(cfg *Options) (*resolver.NNS, error) {
	if cfg.RPCEndpoint == "" {
		return nil, nil
	}

	var nns resolver.NNS
	if err := nns.Dial(cfg.RPCEndpoint); err != nil {
		return nil, fmt.Errorf("dial NNS resolver: %w", err)
	}

	return &nns, nil
}

func getAccount(cfg *Options) (*wallet.Account, error) {
	w, err := wallet.NewWalletFromFile(cfg.Wallet)
	if err != nil {
		return nil, err
	}

	addr := w.GetChangeAddress()
	if cfg.Address != "" {
		addr, err = flags.ParseAddress(cfg.Address)
		if err != nil {
			return nil, fmt.Errorf("invalid address")
		}
	}
	acc := w.GetAccount(addr)
	err = acc.Decrypt(cfg.Password, w.Scrypt)
	if err != nil {
		return nil, err
	}

	return acc, nil
}

func newAddress(cnrID cid.ID, objID oid.ID) oid.Address {
	var addr oid.Address
	addr.SetContainer(cnrID)
	addr.SetObject(objID)
	return addr
}

func formObject(own *user.ID, cnrID cid.ID, name string, header map[string]string) *object.Object {
	attributes := make([]object.Attribute, 0, 1+len(header))
	filename := object.NewAttribute()
	filename.SetKey(object.AttributeFileName)
	filename.SetValue(name)

	attributes = append(attributes, *filename)

	for key, val := range header {
		attr := object.NewAttribute()
		attr.SetKey(key)
		attr.SetValue(val)
		attributes = append(attributes, *attr)
	}

	obj := object.New()
	obj.SetOwnerID(*own)
	obj.SetContainerID(cnrID)
	obj.SetAttributes(attributes...)

	return obj
}

func newDir(cnrID cid.ID, cnr container.Container, defaultZone string) *fs.Dir {
	remote := cnrID.EncodeToString()
	timestamp := container.CreatedAt(cnr)

	if domain := container.ReadDomain(cnr); domain.Name() != "" {
		if defaultZone != domain.Zone() {
			remote = domain.Zone() + "." + domain.Name()
		} else {
			remote = domain.Name()
		}
	}

	dir := fs.NewDir(remote, timestamp)
	dir.SetID(cnrID.String())

	return dir
}

func getZoneAndContainerNames(containerStr, defaultZone string) (cnrZone string, cnrName string) {
	defer func() {
		if len(cnrZone) == 0 {
			cnrZone = "container"
		}
	}()
	if idx := strings.Index(containerStr, "."); idx >= 0 {
		return containerStr[:idx], containerStr[idx+1:]
	}
	return defaultZone, containerStr
}