package logic

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"net"
	"sort"
	"sync"
	"time"

	validator "github.com/go-playground/validator/v10"
	"github.com/google/uuid"
	"github.com/gravitl/netmaker/database"
	"github.com/gravitl/netmaker/logger"
	"github.com/gravitl/netmaker/logic/acls"
	"github.com/gravitl/netmaker/logic/acls/nodeacls"
	"github.com/gravitl/netmaker/models"
	"github.com/gravitl/netmaker/servercfg"
	"github.com/gravitl/netmaker/validation"
	"golang.org/x/exp/slog"
)

var (
	nodeCacheMutex = &sync.RWMutex{}
	nodesCacheMap  = make(map[string]models.Node)
)

func getNodeFromCache(nodeID string) (node models.Node, ok bool) {
	nodeCacheMutex.RLock()
	node, ok = nodesCacheMap[nodeID]
	nodeCacheMutex.RUnlock()
	return
}
func getNodesFromCache() (nodes []models.Node) {
	nodeCacheMutex.RLock()
	for _, node := range nodesCacheMap {
		nodes = append(nodes, node)
	}
	nodeCacheMutex.RUnlock()
	return
}

func deleteNodeFromCache(nodeID string) {
	nodeCacheMutex.Lock()
	delete(nodesCacheMap, nodeID)
	nodeCacheMutex.Unlock()
}

func storeNodeInCache(node models.Node) {
	nodeCacheMutex.Lock()
	nodesCacheMap[node.ID.String()] = node
	nodeCacheMutex.Unlock()
}

func loadNodesIntoCache(nMap map[string]models.Node) {
	nodeCacheMutex.Lock()
	nodesCacheMap = nMap
	nodeCacheMutex.Unlock()
}
func ClearNodeCache() {
	nodeCacheMutex.Lock()
	nodesCacheMap = make(map[string]models.Node)
	nodeCacheMutex.Unlock()
}

const (
	// RELAY_NODE_ERR - error to return if relay node is unfound
	RELAY_NODE_ERR = "could not find relay for node"
	// NodePurgeTime time to wait for node to response to a NODE_DELETE actions
	NodePurgeTime = time.Second * 10
	// NodePurgeCheckTime is how often to check nodes for Pending Delete
	NodePurgeCheckTime = time.Second * 30
)

// GetNetworkNodes - gets the nodes of a network
func GetNetworkNodes(network string) ([]models.Node, error) {
	allnodes, err := GetAllNodes()
	if err != nil {
		return []models.Node{}, err
	}

	return GetNetworkNodesMemory(allnodes, network), nil
}

// GetHostNodes - fetches all nodes part of the host
func GetHostNodes(host *models.Host) []models.Node {
	nodes := []models.Node{}
	for _, nodeID := range host.Nodes {
		node, err := GetNodeByID(nodeID)
		if err == nil {
			nodes = append(nodes, node)
		}
	}
	return nodes
}

// GetNetworkNodesMemory - gets all nodes belonging to a network from list in memory
func GetNetworkNodesMemory(allNodes []models.Node, network string) []models.Node {
	var nodes = []models.Node{}
	for i := range allNodes {
		node := allNodes[i]
		if node.Network == network {
			nodes = append(nodes, node)
		}
	}
	return nodes
}

// UpdateNodeCheckin - updates the checkin time of a node
func UpdateNodeCheckin(node *models.Node) error {
	node.SetLastCheckIn()
	data, err := json.Marshal(node)
	if err != nil {
		return err
	}
	err = database.Insert(node.ID.String(), string(data), database.NODES_TABLE_NAME)
	if err != nil {
		return err
	}
	if servercfg.CacheEnabled() {
		storeNodeInCache(*node)
	}
	return nil
}

// UpsertNode - updates node in the DB
func UpsertNode(newNode *models.Node) error {
	newNode.SetLastModified()
	data, err := json.Marshal(newNode)
	if err != nil {
		return err
	}
	err = database.Insert(newNode.ID.String(), string(data), database.NODES_TABLE_NAME)
	if err != nil {
		return err
	}
	if servercfg.CacheEnabled() {
		storeNodeInCache(*newNode)
	}
	return nil
}

// UpdateNode - takes a node and updates another node with it's values
func UpdateNode(currentNode *models.Node, newNode *models.Node) error {
	if newNode.Address.IP.String() != currentNode.Address.IP.String() {
		if network, err := GetParentNetwork(newNode.Network); err == nil {
			if !IsAddressInCIDR(newNode.Address.IP, network.AddressRange) {
				return fmt.Errorf("invalid address provided; out of network range for node %s", newNode.ID)
			}
		}
	}
	nodeACLDelta := currentNode.DefaultACL != newNode.DefaultACL
	newNode.Fill(currentNode, servercfg.IsPro)

	// check for un-settable server values
	if err := ValidateNode(newNode, true); err != nil {
		return err
	}

	if newNode.ID == currentNode.ID {
		if nodeACLDelta {
			if err := UpdateProNodeACLs(newNode); err != nil {
				logger.Log(1, "failed to apply node level ACLs during creation of node", newNode.ID.String(), "-", err.Error())
				return err
			}
		}

		newNode.SetLastModified()
		if data, err := json.Marshal(newNode); err != nil {
			return err
		} else {
			err = database.Insert(newNode.ID.String(), string(data), database.NODES_TABLE_NAME)
			if err != nil {
				return err
			}
			if servercfg.CacheEnabled() {
				storeNodeInCache(*newNode)
			}
			return nil
		}
	}

	return fmt.Errorf("failed to update node " + currentNode.ID.String() + ", cannot change ID.")
}

// DeleteNode - marks node for deletion (and adds to zombie list) if called by UI or deletes node if called by node
func DeleteNode(node *models.Node, purge bool) error {
	alreadyDeleted := node.PendingDelete || node.Action == models.NODE_DELETE
	node.Action = models.NODE_DELETE
	//delete ext clients if node is ingress gw
	if node.IsIngressGateway {
		if err := DeleteGatewayExtClients(node.ID.String(), node.Network); err != nil {
			slog.Error("failed to delete ext clients", "nodeid", node.ID.String(), "error", err.Error())
		}
	}
	if node.IsRelayed {
		// cleanup node from relayednodes on relay node
		relayNode, err := GetNodeByID(node.RelayedBy)
		if err == nil {
			relayedNodes := []string{}
			for _, relayedNodeID := range relayNode.RelayedNodes {
				if relayedNodeID == node.ID.String() {
					continue
				}
				relayedNodes = append(relayedNodes, relayedNodeID)
			}
			relayNode.RelayedNodes = relayedNodes
			UpsertNode(&relayNode)
		}
	}
	if node.FailedOverBy != uuid.Nil {
		ResetFailedOverPeer(node)
	}
	if node.IsRelay {
		// unset all the relayed nodes
		SetRelayedNodes(false, node.ID.String(), node.RelayedNodes)
	}
	if node.InternetGwID != "" {
		inetNode, err := GetNodeByID(node.InternetGwID)
		if err == nil {
			clientNodeIDs := []string{}
			for _, inetNodeClientID := range inetNode.InetNodeReq.InetNodeClientIDs {
				if inetNodeClientID == node.ID.String() {
					continue
				}
				clientNodeIDs = append(clientNodeIDs, inetNodeClientID)
			}
			inetNode.InetNodeReq.InetNodeClientIDs = clientNodeIDs
			UpsertNode(&inetNode)
		}
	}
	if node.IsInternetGateway {
		UnsetInternetGw(node)
	}
	if !purge && !alreadyDeleted {
		newnode := *node
		newnode.PendingDelete = true
		if err := UpdateNode(node, &newnode); err != nil {
			return err
		}
		newZombie <- node.ID
		return nil
	}
	if alreadyDeleted {
		logger.Log(1, "forcibly deleting node", node.ID.String())
	}
	host, err := GetHost(node.HostID.String())
	if err != nil {
		logger.Log(1, "no host found for node", node.ID.String(), "deleting..")
		if delErr := DeleteNodeByID(node); delErr != nil {
			logger.Log(0, "failed to delete node", node.ID.String(), delErr.Error())
		}
		return err
	}
	if err := DissasociateNodeFromHost(node, host); err != nil {
		return err
	}

	return nil
}

// GetNodeByHostRef - gets the node by host id and network
func GetNodeByHostRef(hostid, network string) (node models.Node, err error) {
	nodes, err := GetNetworkNodes(network)
	if err != nil {
		return models.Node{}, err
	}
	for _, node := range nodes {
		if node.HostID.String() == hostid && node.Network == network {
			return node, nil
		}
	}
	return models.Node{}, errors.New("node not found")
}

// DeleteNodeByID - deletes a node from database
func DeleteNodeByID(node *models.Node) error {
	var err error
	var key = node.ID.String()
	if err = database.DeleteRecord(database.NODES_TABLE_NAME, key); err != nil {
		if !database.IsEmptyRecord(err) {
			return err
		}
	}
	if servercfg.CacheEnabled() {
		deleteNodeFromCache(node.ID.String())
	}
	if servercfg.IsDNSMode() {
		SetDNS()
	}
	_, err = nodeacls.RemoveNodeACL(nodeacls.NetworkID(node.Network), nodeacls.NodeID(node.ID.String()))
	if err != nil {
		// ignoring for now, could hit a nil pointer if delete called twice
		logger.Log(2, "attempted to remove node ACL for node", node.ID.String())
	}
	// removeZombie <- node.ID
	if err = DeleteMetrics(node.ID.String()); err != nil {
		logger.Log(1, "unable to remove metrics from DB for node", node.ID.String(), err.Error())
	}
	return nil
}

// IsNodeIDUnique - checks if node id is unique
func IsNodeIDUnique(node *models.Node) (bool, error) {
	_, err := database.FetchRecord(database.NODES_TABLE_NAME, node.ID.String())
	return database.IsEmptyRecord(err), err
}

// ValidateNode - validates node values
func ValidateNode(node *models.Node, isUpdate bool) error {
	v := validator.New()
	_ = v.RegisterValidation("id_unique", func(fl validator.FieldLevel) bool {
		if isUpdate {
			return true
		}
		isFieldUnique, _ := IsNodeIDUnique(node)
		return isFieldUnique
	})
	_ = v.RegisterValidation("network_exists", func(fl validator.FieldLevel) bool {
		_, err := GetNetworkByNode(node)
		return err == nil
	})
	_ = v.RegisterValidation("checkyesornoorunset", func(f1 validator.FieldLevel) bool {
		return validation.CheckYesOrNoOrUnset(f1)
	})
	err := v.Struct(node)
	return err
}

// GetAllNodes - returns all nodes in the DB
func GetAllNodes() ([]models.Node, error) {
	var nodes []models.Node
	if servercfg.CacheEnabled() {
		nodes = getNodesFromCache()
		if len(nodes) != 0 {
			return nodes, nil
		}
	}
	nodesMap := make(map[string]models.Node)
	if servercfg.CacheEnabled() {
		defer loadNodesIntoCache(nodesMap)
	}
	collection, err := database.FetchRecords(database.NODES_TABLE_NAME)
	if err != nil {
		if database.IsEmptyRecord(err) {
			return []models.Node{}, nil
		}
		return []models.Node{}, err
	}

	for _, value := range collection {
		var node models.Node
		// ignore legacy nodes in database
		if err := json.Unmarshal([]byte(value), &node); err != nil {
			logger.Log(3, "legacy node detected: ", err.Error())
			continue
		}
		// add node to our array
		nodes = append(nodes, node)
		nodesMap[node.ID.String()] = node
	}

	return nodes, nil
}

// GetNetworkByNode - gets the network model from a node
func GetNetworkByNode(node *models.Node) (models.Network, error) {

	var network = models.Network{}
	networkData, err := database.FetchRecord(database.NETWORKS_TABLE_NAME, node.Network)
	if err != nil {
		return network, err
	}
	if err = json.Unmarshal([]byte(networkData), &network); err != nil {
		return models.Network{}, err
	}
	return network, nil
}

// SetNodeDefaults - sets the defaults of a node to avoid empty fields
func SetNodeDefaults(node *models.Node) {

	parentNetwork, _ := GetNetworkByNode(node)
	_, cidr, err := net.ParseCIDR(parentNetwork.AddressRange)
	if err == nil {
		node.NetworkRange = *cidr
	}
	_, cidr, err = net.ParseCIDR(parentNetwork.AddressRange6)
	if err == nil {
		node.NetworkRange6 = *cidr
	}

	if node.DefaultACL == "" {
		node.DefaultACL = parentNetwork.DefaultACL
	}
	if node.FailOverPeers == nil {
		node.FailOverPeers = make(map[string]struct{})
	}

	node.SetLastModified()
	node.SetLastCheckIn()
	node.SetDefaultConnected()
	node.SetExpirationDateTime()
}

// GetRecordKey - get record key
// depricated
func GetRecordKey(id string, network string) (string, error) {
	if id == "" || network == "" {
		return "", errors.New("unable to get record key")
	}
	return id + "###" + network, nil
}

func GetNodeByID(uuid string) (models.Node, error) {
	if servercfg.CacheEnabled() {
		if node, ok := getNodeFromCache(uuid); ok {
			return node, nil
		}
	}
	var record, err = database.FetchRecord(database.NODES_TABLE_NAME, uuid)
	if err != nil {
		return models.Node{}, err
	}
	var node models.Node
	if err = json.Unmarshal([]byte(record), &node); err != nil {
		return models.Node{}, err
	}
	if servercfg.CacheEnabled() {
		storeNodeInCache(node)
	}
	return node, nil
}

// GetDeletedNodeByID - get a deleted node
func GetDeletedNodeByID(uuid string) (models.Node, error) {

	var node models.Node

	record, err := database.FetchRecord(database.DELETED_NODES_TABLE_NAME, uuid)
	if err != nil {
		return models.Node{}, err
	}

	if err = json.Unmarshal([]byte(record), &node); err != nil {
		return models.Node{}, err
	}

	SetNodeDefaults(&node)

	return node, nil
}

// FindRelay - returns the node that is the relay for a relayed node
func FindRelay(node *models.Node) *models.Node {
	relay, err := GetNodeByID(node.RelayedBy)
	if err != nil {
		logger.Log(0, "FindRelay: "+err.Error())
		return nil
	}
	return &relay
}

// GetAllNodesAPI - get all nodes for api usage
func GetAllNodesAPI(nodes []models.Node) []models.ApiNode {
	apiNodes := []models.ApiNode{}
	for i := range nodes {
		newApiNode := nodes[i].ConvertToAPINode()
		apiNodes = append(apiNodes, *newApiNode)
	}
	return apiNodes[:]
}

// DeleteExpiredNodes - goroutine which deletes nodes which are expired
func DeleteExpiredNodes(ctx context.Context, peerUpdate chan *models.Node) {
	// Delete Expired Nodes Every Hour
	ticker := time.NewTicker(time.Hour)
	for {
		select {
		case <-ctx.Done():
			ticker.Stop()
			return
		case <-ticker.C:
			allnodes, err := GetAllNodes()
			if err != nil {
				slog.Error("failed to retrieve all nodes", "error", err.Error())
				return
			}
			for _, node := range allnodes {
				node := node
				if time.Now().After(node.ExpirationDateTime) {
					peerUpdate <- &node
					slog.Info("deleting expired node", "nodeid", node.ID.String())
				}
			}
		}
	}
}

// createNode - creates a node in database
func createNode(node *models.Node) error {
	// lock because we need unique IPs and having it concurrent makes parallel calls result in same "unique" IPs
	addressLock.Lock()
	defer addressLock.Unlock()

	host, err := GetHost(node.HostID.String())
	if err != nil {
		return err
	}

	if !node.DNSOn {
		if servercfg.IsDNSMode() {
			node.DNSOn = true
		} else {
			node.DNSOn = false
		}
	}

	SetNodeDefaults(node)

	defaultACLVal := acls.Allowed
	parentNetwork, err := GetNetwork(node.Network)
	if err == nil {
		if parentNetwork.DefaultACL != "yes" {
			defaultACLVal = acls.NotAllowed
		}
	}

	if node.DefaultACL == "" {
		node.DefaultACL = "unset"
	}

	if node.Address.IP == nil {
		if parentNetwork.IsIPv4 == "yes" {
			if node.Address.IP, err = UniqueAddress(node.Network, false); err != nil {
				return err
			}
			_, cidr, err := net.ParseCIDR(parentNetwork.AddressRange)
			if err != nil {
				return err
			}
			node.Address.Mask = net.CIDRMask(cidr.Mask.Size())
		}
	} else if !IsIPUnique(node.Network, node.Address.String(), database.NODES_TABLE_NAME, false) {
		return fmt.Errorf("invalid address: ipv4 " + node.Address.String() + " is not unique")
	}
	if node.Address6.IP == nil {
		if parentNetwork.IsIPv6 == "yes" {
			if node.Address6.IP, err = UniqueAddress6(node.Network, false); err != nil {
				return err
			}
			_, cidr, err := net.ParseCIDR(parentNetwork.AddressRange6)
			if err != nil {
				return err
			}
			node.Address6.Mask = net.CIDRMask(cidr.Mask.Size())
		}
	} else if !IsIPUnique(node.Network, node.Address6.String(), database.NODES_TABLE_NAME, true) {
		return fmt.Errorf("invalid address: ipv6 " + node.Address6.String() + " is not unique")
	}
	node.ID = uuid.New()
	//Create a JWT for the node
	tokenString, _ := CreateJWT(node.ID.String(), host.MacAddress.String(), node.Network)
	if tokenString == "" {
		//logic.ReturnErrorResponse(w, r, errorResponse)
		return err
	}
	err = ValidateNode(node, false)
	if err != nil {
		return err
	}
	CheckZombies(node)

	nodebytes, err := json.Marshal(&node)
	if err != nil {
		return err
	}
	err = database.Insert(node.ID.String(), string(nodebytes), database.NODES_TABLE_NAME)
	if err != nil {
		return err
	}
	if servercfg.CacheEnabled() {
		storeNodeInCache(*node)
	}
	_, err = nodeacls.CreateNodeACL(nodeacls.NetworkID(node.Network), nodeacls.NodeID(node.ID.String()), defaultACLVal)
	if err != nil {
		logger.Log(1, "failed to create node ACL for node,", node.ID.String(), "err:", err.Error())
		return err
	}

	if err = UpdateProNodeACLs(node); err != nil {
		logger.Log(1, "failed to apply node level ACLs during creation of node", node.ID.String(), "-", err.Error())
		return err
	}

	if err = UpdateMetrics(node.ID.String(), &models.Metrics{Connectivity: make(map[string]models.Metric)}); err != nil {
		logger.Log(1, "failed to initialize metrics for node", node.ID.String(), err.Error())
	}

	SetNetworkNodesLastModified(node.Network)
	if servercfg.IsDNSMode() {
		err = SetDNS()
	}
	return err
}

// SortApiNodes - Sorts slice of ApiNodes by their ID alphabetically with numbers first
func SortApiNodes(unsortedNodes []models.ApiNode) {
	sort.Slice(unsortedNodes, func(i, j int) bool {
		return unsortedNodes[i].ID < unsortedNodes[j].ID
	})
}

func ValidateParams(nodeid, netid string) (models.Node, error) {
	node, err := GetNodeByID(nodeid)
	if err != nil {
		slog.Error("error fetching node", "node", nodeid, "error", err.Error())
		return node, fmt.Errorf("error fetching node during parameter validation: %v", err)
	}
	if node.Network != netid {
		slog.Error("network url param does not match node id", "url nodeid", netid, "node", node.Network)
		return node, fmt.Errorf("network url param does not match node network")
	}
	return node, nil
}