package logic

import (
	"encoding/json"
	"errors"
	"fmt"
	"sort"
	"time"

	"github.com/go-playground/validator/v10"
	"github.com/gravitl/netmaker/database"
	"github.com/gravitl/netmaker/logger"
	"github.com/gravitl/netmaker/models"
	"github.com/gravitl/netmaker/validation"
)

// GetNetworkNodes - gets the nodes of a network
func GetNetworkNodes(network string) ([]models.Node, error) {
	var nodes []models.Node
	collection, err := database.FetchRecords(database.NODES_TABLE_NAME)
	if err != nil {
		if database.IsEmptyRecord(err) {
			return []models.Node{}, nil
		}
		return nodes, err
	}
	for _, value := range collection {

		var node models.Node
		err := json.Unmarshal([]byte(value), &node)
		if err != nil {
			continue
		}
		if node.Network == network {
			nodes = append(nodes, node)
		}
	}
	return nodes, nil
}

// GetSortedNetworkServerNodes - gets nodes of a network, except sorted by update time
func GetSortedNetworkServerNodes(network string) ([]models.Node, error) {
	var nodes []models.Node
	collection, err := database.FetchRecords(database.NODES_TABLE_NAME)
	if err != nil {
		if database.IsEmptyRecord(err) {
			return []models.Node{}, nil
		}
		return nodes, err
	}
	for _, value := range collection {

		var node models.Node
		err := json.Unmarshal([]byte(value), &node)
		if err != nil {
			continue
		}
		if node.Network == network && node.IsServer == "yes" {
			nodes = append(nodes, node)
		}
	}
	sort.Sort(models.NodesArray(nodes))
	return nodes, nil
}

// UncordonNode - approves a node to join a network
func UncordonNode(network, macaddress string) (models.Node, error) {
	node, err := GetNodeByMacAddress(network, macaddress)
	if err != nil {
		return models.Node{}, err
	}
	node.SetLastModified()
	node.IsPending = "no"
	node.PullChanges = "yes"
	data, err := json.Marshal(&node)
	if err != nil {
		return node, err
	}
	key, err := GetRecordKey(node.MacAddress, node.Network)
	if err != nil {
		return node, err
	}

	err = database.Insert(key, string(data), database.NODES_TABLE_NAME)
	return node, err
}

// GetPeers - gets the peers of a given node
func GetPeers(node *models.Node) ([]models.Node, error) {
	if IsLeader(node) {
		SetNetworkServerPeers(node)
	}
	excludeIsRelayed := node.IsRelay != "yes"
	var relayedNode string
	if node.IsRelayed == "yes" {
		relayedNode = node.Address
	}
	peers, err := GetPeersList(node.Network, excludeIsRelayed, relayedNode)
	if err != nil {
		return nil, err
	}
	return peers, nil
}

// IsLeader - determines if a given server node is a leader
func IsLeader(node *models.Node) bool {
	nodes, err := GetSortedNetworkServerNodes(node.Network)
	if err != nil {
		logger.Log(0, "ERROR: COULD NOT RETRIEVE SERVER NODES. THIS WILL BREAK HOLE PUNCHING.")
		return false
	}
	for _, n := range nodes {
		if n.LastModified > time.Now().Add(-1*time.Minute).Unix() {
			return n.Address == node.Address
		}
	}
	return len(nodes) <= 1 || nodes[1].Address == node.Address
}

// == DB related functions ==

// UpdateNode - takes a node and updates another node with it's values
func UpdateNode(currentNode *models.Node, newNode *models.Node) error {
	newNode.Fill(currentNode)
	if err := ValidateNode(newNode, true); err != nil {
		return err
	}
	newNode.SetID()
	if newNode.ID == currentNode.ID {
		newNode.SetLastModified()
		if data, err := json.Marshal(newNode); err != nil {
			return err
		} else {
			return database.Insert(newNode.ID, string(data), database.NODES_TABLE_NAME)
		}
	}
	return fmt.Errorf("failed to update node " + newNode.MacAddress + ", cannot change macaddress.")
}

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

// ValidateNode - validates node values
func ValidateNode(node *models.Node, isUpdate bool) error {
	v := validator.New()
	_ = v.RegisterValidation("macaddress_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("in_charset", func(fl validator.FieldLevel) bool {
		isgood := node.NameInNodeCharSet()
		return isgood
	})
	_ = v.RegisterValidation("checkyesorno", func(fl validator.FieldLevel) bool {
		return validation.CheckYesOrNo(fl)
	})
	err := v.Struct(node)

	return err
}

// GetAllNodes - returns all nodes in the DB
func GetAllNodes() ([]models.Node, error) {
	var nodes []models.Node

	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
		if err := json.Unmarshal([]byte(value), &node); err != nil {
			return []models.Node{}, err
		}
		// add node to our array
		nodes = append(nodes, node)
	}

	return nodes, nil
}

// CheckIsServer - check if a node is the server node
func CheckIsServer(node *models.Node) bool {
	nodeData, err := database.FetchRecords(database.NODES_TABLE_NAME)
	if err != nil && !database.IsEmptyRecord(err) {
		return false
	}
	for _, value := range nodeData {
		var tmpNode models.Node
		if err := json.Unmarshal([]byte(value), &tmpNode); err != nil {
			continue
		}
		if tmpNode.Network == node.Network && tmpNode.MacAddress != node.MacAddress {
			return false
		}
	}
	return true
}

// 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) {

	//TODO: Maybe I should make Network a part of the node struct. Then we can just query the Network object for stuff.
	parentNetwork, _ := GetNetworkByNode(node)

	node.ExpirationDateTime = time.Now().Unix() + models.TEN_YEARS_IN_SECONDS

	if node.ListenPort == 0 {
		node.ListenPort = parentNetwork.DefaultListenPort
	}
	if node.SaveConfig == "" {
		if parentNetwork.DefaultSaveConfig != "" {
			node.SaveConfig = parentNetwork.DefaultSaveConfig
		} else {
			node.SaveConfig = "yes"
		}
	}
	if node.Interface == "" {
		node.Interface = parentNetwork.DefaultInterface
	}
	if node.PersistentKeepalive == 0 {
		node.PersistentKeepalive = parentNetwork.DefaultKeepalive
	}
	if node.PostUp == "" {
		postup := parentNetwork.DefaultPostUp
		node.PostUp = postup
	}
	if node.PostDown == "" {
		postdown := parentNetwork.DefaultPostDown
		node.PostDown = postdown
	}
	if node.IsStatic == "" {
		node.IsStatic = "no"
	}
	if node.UDPHolePunch == "" {
		node.UDPHolePunch = parentNetwork.DefaultUDPHolePunch
		if node.UDPHolePunch == "" {
			node.UDPHolePunch = "yes"
		}
	}
	// == Parent Network settings ==
	if node.IsDualStack == "" {
		node.IsDualStack = parentNetwork.IsDualStack
	}
	if node.MTU == 0 {
		node.MTU = parentNetwork.DefaultMTU
	}
	// == node defaults if not set by parent ==
	node.SetIPForwardingDefault()
	node.SetDNSOnDefault()
	node.SetIsLocalDefault()
	node.SetIsDualStackDefault()
	node.SetLastModified()
	node.SetDefaultName()
	node.SetLastCheckIn()
	node.SetLastPeerUpdate()
	node.SetRoamingDefault()
	node.SetPullChangesDefault()
	node.SetDefaultAction()
	node.SetID()
	node.SetIsServerDefault()
	node.SetIsStaticDefault()
	node.SetDefaultEgressGateway()
	node.SetDefaultIngressGateway()
	node.SetDefaulIsPending()
	node.SetDefaultMTU()
	node.SetDefaultIsRelayed()
	node.SetDefaultIsRelay()
	node.KeyUpdateTimeStamp = time.Now().Unix()
}

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

// GetNodeByMacAddress - gets a node by mac address
func GetNodeByMacAddress(network string, macaddress string) (models.Node, error) {

	var node models.Node

	key, err := GetRecordKey(macaddress, network)
	if err != nil {
		return node, err
	}

	record, err := database.FetchRecord(database.NODES_TABLE_NAME, key)
	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
}

// GetDeletedNodeByMacAddress - get a deleted node
func GetDeletedNodeByMacAddress(network string, macaddress string) (models.Node, error) {

	var node models.Node

	key, err := GetRecordKey(macaddress, network)
	if err != nil {
		return node, err
	}

	record, err := database.FetchRecord(database.DELETED_NODES_TABLE_NAME, key)
	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
}

// GetNodeRelay - gets the relay node of a given network
func GetNodeRelay(network string, relayedNodeAddr string) (models.Node, error) {
	collection, err := database.FetchRecords(database.NODES_TABLE_NAME)
	var relay models.Node
	if err != nil {
		if database.IsEmptyRecord(err) {
			return relay, nil
		}
		logger.Log(2, err.Error())
		return relay, err
	}
	for _, value := range collection {
		err := json.Unmarshal([]byte(value), &relay)
		if err != nil {
			logger.Log(2, err.Error())
			continue
		}
		if relay.IsRelay == "yes" {
			for _, addr := range relay.RelayAddrs {
				if addr == relayedNodeAddr {
					return relay, nil
				}
			}
		}
	}
	return relay, errors.New("could not find relay for node " + relayedNodeAddr)
}