package controller

import (
	"encoding/json"
	"errors"
	"fmt"
	"net"
	"net/http"
	"strings"

	"github.com/google/uuid"
	"github.com/gorilla/mux"
	"golang.org/x/exp/slog"

	"github.com/gravitl/netmaker/database"
	"github.com/gravitl/netmaker/logger"
	"github.com/gravitl/netmaker/logic"
	"github.com/gravitl/netmaker/logic/acls"
	"github.com/gravitl/netmaker/models"
	"github.com/gravitl/netmaker/mq"
	"github.com/gravitl/netmaker/servercfg"
)

func networkHandlers(r *mux.Router) {
	r.HandleFunc("/api/networks", logic.SecurityCheck(true, http.HandlerFunc(getNetworks))).Methods(http.MethodGet)
	r.HandleFunc("/api/networks", logic.SecurityCheck(true, checkFreeTierLimits(limitChoiceNetworks, http.HandlerFunc(createNetwork)))).Methods(http.MethodPost)
	r.HandleFunc("/api/networks/{networkname}", logic.SecurityCheck(true, http.HandlerFunc(getNetwork))).Methods(http.MethodGet)
	r.HandleFunc("/api/networks/{networkname}", logic.SecurityCheck(true, http.HandlerFunc(deleteNetwork))).Methods(http.MethodDelete)
	r.HandleFunc("/api/networks/{networkname}", logic.SecurityCheck(true, http.HandlerFunc(updateNetwork))).Methods(http.MethodPut)
	// ACLs
	r.HandleFunc("/api/networks/{networkname}/acls", logic.SecurityCheck(true, http.HandlerFunc(updateNetworkACL))).Methods(http.MethodPut)
	r.HandleFunc("/api/networks/{networkname}/acls/v2", logic.SecurityCheck(true, http.HandlerFunc(updateNetworkACLv2))).Methods(http.MethodPut)
	r.HandleFunc("/api/networks/{networkname}/acls", logic.SecurityCheck(true, http.HandlerFunc(getNetworkACL))).Methods(http.MethodGet)
}

// swagger:route GET /api/networks networks getNetworks
//
// Lists all networks.
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: getNetworksSliceResponse
func getNetworks(w http.ResponseWriter, r *http.Request) {

	var err error

	allnetworks, err := logic.GetNetworks()
	if err != nil && !database.IsEmptyRecord(err) {
		slog.Error("failed to fetch networks", "error", err.Error())
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}

	logger.Log(2, r.Header.Get("user"), "fetched networks.")
	logic.SortNetworks(allnetworks[:])
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(allnetworks)
}

// swagger:route GET /api/networks/{networkname} networks getNetwork
//
// Get a network.
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: networkBodyResponse
func getNetwork(w http.ResponseWriter, r *http.Request) {
	// set header.
	w.Header().Set("Content-Type", "application/json")
	var params = mux.Vars(r)
	netname := params["networkname"]
	network, err := logic.GetNetwork(netname)
	if err != nil {
		logger.Log(0, r.Header.Get("user"), fmt.Sprintf("failed to fetch network [%s] info: %v",
			netname, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}

	logger.Log(2, r.Header.Get("user"), "fetched network", netname)
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(network)
}

// swagger:route PUT /api/networks/{networkname}/acls networks updateNetworkACL
//
// Update a network ACL (Access Control List).
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: aclContainerResponse
func updateNetworkACL(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	var params = mux.Vars(r)
	netname := params["networkname"]
	var networkACLChange acls.ACLContainer
	networkACLChange, err := networkACLChange.Get(acls.ContainerID(netname))
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to fetch ACLs for network [%s]: %v", netname, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	err = json.NewDecoder(r.Body).Decode(&networkACLChange)
	if err != nil {
		logger.Log(0, r.Header.Get("user"), "error decoding request body: ",
			err.Error())
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}
	newNetACL, err := networkACLChange.Save(acls.ContainerID(netname))
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to update ACLs for network [%s]: %v", netname, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}
	logger.Log(1, r.Header.Get("user"), "updated ACLs for network", netname)

	// send peer updates
	go func() {
		if err = mq.PublishPeerUpdate(false); err != nil {
			logger.Log(0, "failed to publish peer update after ACL update on network:", netname)
		}
	}()

	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(newNetACL)
}

// swagger:route PUT /api/networks/{networkname}/acls/v2 networks updateNetworkACL
//
// Update a network ACL (Access Control List).
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: aclContainerResponse
func updateNetworkACLv2(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	var params = mux.Vars(r)
	netname := params["networkname"]
	var networkACLChange acls.ACLContainer
	networkACLChange, err := networkACLChange.Get(acls.ContainerID(netname))
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to fetch ACLs for network [%s]: %v", netname, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	err = json.NewDecoder(r.Body).Decode(&networkACLChange)
	if err != nil {
		logger.Log(0, r.Header.Get("user"), "error decoding request body: ",
			err.Error())
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}

	// clone req body to use as return data successful update
	retData := make(acls.ACLContainer)
	data, err := json.Marshal(networkACLChange)
	if err != nil {
		slog.Error("failed to marshal networkACLChange whiles cloning", "error", err.Error())
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	err = json.Unmarshal(data, &retData)
	if err != nil {
		slog.Error("failed to unmarshal networkACLChange whiles cloning", "error", err.Error())
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}

	allNodes, err := logic.GetAllNodes()
	if err != nil {
		slog.Error("failed to fetch all nodes", "error", err.Error())
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	networkNodes := make([]models.Node, 0)
	for _, node := range allNodes {
		if node.Network == netname {
			networkNodes = append(networkNodes, node)
		}
	}
	networkNodesIdMap := make(map[string]models.Node)
	for _, node := range networkNodes {
		networkNodesIdMap[node.ID.String()] = node
	}
	networkClients, err := logic.GetNetworkExtClients(netname)
	if err != nil {
		slog.Error("failed to fetch network clients", "error", err.Error())
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	networkClientsMap := make(map[string]models.ExtClient)
	for _, client := range networkClients {
		networkClientsMap[client.ClientID] = client
	}

	// keep track of ingress gateways to disconnect from their clients
	// this is required because PublishPeerUpdate only somehow does not stop communication
	// between blocked clients and their ingress
	assocClientsToDisconnectPerHost := make(map[uuid.UUID][]models.ExtClient)

	// update client acls and then, remove client acls from req data to pass to existing functions
	for id, acl := range networkACLChange {
		// for node acls
		if _, ok := networkNodesIdMap[string(id)]; ok {
			nodeId := string(id)
			// check acl update, then remove client entries
			for id2 := range acl {
				if _, ok := networkNodesIdMap[string(id2)]; !ok {
					// update client acl
					clientId := string(id2)
					if client, ok := networkClientsMap[clientId]; ok {
						if client.DeniedACLs == nil {
							client.DeniedACLs = make(map[string]struct{})
						}
						if acl[acls.AclID(clientId)] == acls.NotAllowed {
							client.DeniedACLs[nodeId] = struct{}{}
						} else {
							delete(client.DeniedACLs, string(nodeId))
						}
						networkClientsMap[clientId] = client
					}
				}
			}
		} else {
			// for client acls
			clientId := string(id)
			for id2 := range acl {
				if _, ok := networkNodesIdMap[string(id2)]; !ok {
					// update client acl
					clientId2 := string(id2)
					if client, ok := networkClientsMap[clientId]; ok {
						if client.DeniedACLs == nil {
							client.DeniedACLs = make(map[string]struct{})
						}
						{
							// TODO: review this when client-to-client acls are supported
							// if acl[acls.AclID(clientId2)] == acls.NotAllowed {
							// 	client.DeniedACLs[clientId2] = struct{}{}
							// } else {
							// 	delete(client.DeniedACLs, clientId2)
							// }
							delete(client.DeniedACLs, clientId2)
						}
						networkClientsMap[clientId] = client
					}
				} else {
					nodeId2 := string(id2)
					if networkClientsMap[clientId].IngressGatewayID == nodeId2 && acl[acls.AclID(nodeId2)] == acls.NotAllowed {
						assocClientsToDisconnectPerHost[networkNodesIdMap[nodeId2].HostID] = append(assocClientsToDisconnectPerHost[networkNodesIdMap[nodeId2].HostID], networkClientsMap[clientId])
					}
				}
			}
		}
	}

	// update each client in db for pro servers
	if servercfg.IsPro {
		for _, client := range networkClientsMap {
			client := client
			err := logic.DeleteExtClient(client.Network, client.ClientID)
			if err != nil {
				slog.Error("failed to delete client during update", "client", client.ClientID, "error", err.Error())
				logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
				return
			}
			err = logic.SaveExtClient(&client)
			if err != nil {
				slog.Error("failed to save client during update", "client", client.ClientID, "error", err.Error())
				logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
				return
			}
		}
	}

	_, err = networkACLChange.Save(acls.ContainerID(netname))
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to update ACLs for network [%s]: %v", netname, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}
	logger.Log(1, r.Header.Get("user"), "updated ACLs for network", netname)

	// send peer updates
	go func() {
		if err = mq.PublishPeerUpdate(false); err != nil {
			logger.Log(0, "failed to publish peer update after ACL update on network:", netname)
		}

		// update ingress gateways of associated clients
		hosts, err := logic.GetAllHosts()
		if err != nil {
			slog.Error("failed to fetch hosts after network ACL update. skipping publish extclients ACL", "network", netname)
			return
		}
		hostsMap := make(map[uuid.UUID]models.Host)
		for _, host := range hosts {
			hostsMap[host.ID] = host
		}
		for hostId, clients := range assocClientsToDisconnectPerHost {
			if host, ok := hostsMap[hostId]; ok {
				if err = mq.PublishSingleHostPeerUpdate(&host, allNodes, nil, clients, false); err != nil {
					slog.Error("failed to publish peer update to ingress after ACL update on network", "network", netname, "host", hostId)
				}
			}
		}
	}()

	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(networkACLChange)
}

// swagger:route GET /api/networks/{networkname}/acls networks getNetworkACL
//
// Get a network ACL (Access Control List).
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: aclContainerResponse
func getNetworkACL(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	var params = mux.Vars(r)
	netname := params["networkname"]
	var networkACL acls.ACLContainer
	networkACL, err := networkACL.Get(acls.ContainerID(netname))
	if err != nil {
		if database.IsEmptyRecord(err) {
			networkACL = acls.ACLContainer{}
			w.WriteHeader(http.StatusOK)
			json.NewEncoder(w).Encode(networkACL)
			return
		}
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to fetch ACLs for network [%s]: %v", netname, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	logger.Log(2, r.Header.Get("user"), "fetched acl for network", netname)
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(networkACL)
}

// swagger:route DELETE /api/networks/{networkname} networks deleteNetwork
//
// Delete a network.  Will not delete if there are any nodes that belong to the network.
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: successResponse
func deleteNetwork(w http.ResponseWriter, r *http.Request) {
	// Set header
	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)
	network := params["networkname"]
	err := logic.DeleteNetwork(network)
	if err != nil {
		errtype := "badrequest"
		if strings.Contains(err.Error(), "Node check failed") {
			errtype = "forbidden"
		}
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to delete network [%s]: %v", network, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, errtype))
		return
	}

	logger.Log(1, r.Header.Get("user"), "deleted network", network)
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode("success")
}

// swagger:route POST /api/networks networks createNetwork
//
// Create a network.
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: networkBodyResponse
func createNetwork(w http.ResponseWriter, r *http.Request) {

	w.Header().Set("Content-Type", "application/json")

	var network models.Network

	// we decode our body request params
	err := json.NewDecoder(r.Body).Decode(&network)
	if err != nil {
		logger.Log(0, r.Header.Get("user"), "error decoding request body: ",
			err.Error())
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}

	if len(network.NetID) > 32 {
		err := errors.New("network name shouldn't exceed 32 characters")
		logger.Log(0, r.Header.Get("user"), "failed to create network: ",
			err.Error())
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}

	if network.AddressRange == "" && network.AddressRange6 == "" {
		err := errors.New("IPv4 or IPv6 CIDR required")
		logger.Log(0, r.Header.Get("user"), "failed to create network: ",
			err.Error())
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}

	// validate address ranges: must be private
	if network.AddressRange != "" {
		_, ipNet, err := net.ParseCIDR(network.AddressRange)
		if err != nil {
			logger.Log(0, r.Header.Get("user"), "failed to create network: ",
				err.Error())
			logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
			return
		}
		if !ipNet.IP.IsPrivate() {
			err := errors.New("address range must be private")
			logger.Log(0, r.Header.Get("user"), "failed to create network: ",
				err.Error())
			logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
			return
		}
	}
	if network.AddressRange6 != "" {
		_, ipNet, err := net.ParseCIDR(network.AddressRange6)
		if err != nil {
			logger.Log(0, r.Header.Get("user"), "failed to create network: ",
				err.Error())
			logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
			return
		}
		if !ipNet.IP.IsPrivate() {
			err := errors.New("address range must be private")
			logger.Log(0, r.Header.Get("user"), "failed to create network: ",
				err.Error())
			logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
			return
		}
	}

	network, err = logic.CreateNetwork(network)
	if err != nil {
		logger.Log(0, r.Header.Get("user"), "failed to create network: ",
			err.Error())
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}
	go func() {
		defaultHosts := logic.GetDefaultHosts()
		for i := range defaultHosts {
			currHost := &defaultHosts[i]
			newNode, err := logic.UpdateHostNetwork(currHost, network.NetID, true)
			if err != nil {
				logger.Log(0, r.Header.Get("user"), "failed to add host to network:", currHost.ID.String(), network.NetID, err.Error())
				logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
				return
			}
			logger.Log(1, "added new node", newNode.ID.String(), "to host", currHost.Name)
			if err = mq.HostUpdate(&models.HostUpdate{
				Action: models.JoinHostToNetwork,
				Host:   *currHost,
				Node:   *newNode,
			}); err != nil {
				logger.Log(0, r.Header.Get("user"), "failed to add host to network:", currHost.ID.String(), network.NetID, err.Error())
			}
			// make  host failover
			logic.CreateFailOver(*newNode)
			// make host remote access gateway
			logic.CreateIngressGateway(network.NetID, newNode.ID.String(), models.IngressRequest{})
		}
	}()

	logger.Log(1, r.Header.Get("user"), "created network", network.NetID)
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(network)
}

// swagger:route PUT /api/networks/{networkname} networks updateNetwork
//
// Update pro settings for a network.
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: networkBodyResponse
func updateNetwork(w http.ResponseWriter, r *http.Request) {

	w.Header().Set("Content-Type", "application/json")

	var payload models.Network

	// we decode our body request params
	err := json.NewDecoder(r.Body).Decode(&payload)
	if err != nil {
		slog.Info("error decoding request body", "user", r.Header.Get("user"), "err", err)
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}

	netOld1, err := logic.GetNetwork(payload.NetID)
	if err != nil {
		slog.Info("error fetching network", "user", r.Header.Get("user"), "err", err)
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}
	// partial update
	netOld2 := netOld1
	_, _, _, err = logic.UpdateNetwork(&netOld1, &netOld2)
	if err != nil {
		slog.Info("failed to update network", "user", r.Header.Get("user"), "err", err)
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}

	slog.Info("updated network", "network", payload.NetID, "user", r.Header.Get("user"))
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(payload)
}