package http

import (
	"encoding/json"
	"net/http"
	"unicode/utf8"

	"github.com/gorilla/mux"

	"github.com/netbirdio/netbird/management/server"
	"github.com/netbirdio/netbird/management/server/http/api"
	"github.com/netbirdio/netbird/management/server/http/util"
	"github.com/netbirdio/netbird/management/server/jwtclaims"
	"github.com/netbirdio/netbird/management/server/status"
	"github.com/netbirdio/netbird/route"
)

// RoutesHandler is the routes handler of the account
type RoutesHandler struct {
	accountManager  server.AccountManager
	claimsExtractor *jwtclaims.ClaimsExtractor
}

// NewRoutesHandler returns a new instance of RoutesHandler handler
func NewRoutesHandler(accountManager server.AccountManager, authCfg AuthCfg) *RoutesHandler {
	return &RoutesHandler{
		accountManager: accountManager,
		claimsExtractor: jwtclaims.NewClaimsExtractor(
			jwtclaims.WithAudience(authCfg.Audience),
			jwtclaims.WithUserIDClaim(authCfg.UserIDClaim),
		),
	}
}

// GetAllRoutes returns the list of routes for the account
func (h *RoutesHandler) GetAllRoutes(w http.ResponseWriter, r *http.Request) {
	claims := h.claimsExtractor.FromRequestContext(r)
	account, user, err := h.accountManager.GetAccountFromToken(claims)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	routes, err := h.accountManager.ListRoutes(account.Id, user.Id)
	if err != nil {
		util.WriteError(err, w)
		return
	}
	apiRoutes := make([]*api.Route, 0)
	for _, r := range routes {
		apiRoutes = append(apiRoutes, toRouteResponse(r))
	}

	util.WriteJSONObject(w, apiRoutes)
}

// CreateRoute handles route creation request
func (h *RoutesHandler) CreateRoute(w http.ResponseWriter, r *http.Request) {
	claims := h.claimsExtractor.FromRequestContext(r)
	account, user, err := h.accountManager.GetAccountFromToken(claims)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	var req api.PostApiRoutesJSONRequestBody
	err = json.NewDecoder(r.Body).Decode(&req)
	if err != nil {
		util.WriteErrorResponse("couldn't parse JSON request", http.StatusBadRequest, w)
		return
	}

	_, newPrefix, err := route.ParseNetwork(req.Network)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	if utf8.RuneCountInString(req.NetworkId) > route.MaxNetIDChar || req.NetworkId == "" {
		util.WriteError(status.Errorf(status.InvalidArgument, "identifier should be between 1 and %d",
			route.MaxNetIDChar), w)
		return
	}

	newRoute, err := h.accountManager.CreateRoute(account.Id, newPrefix.String(), req.Peer, req.Description, req.NetworkId, req.Masquerade, req.Metric, req.Groups, req.Enabled, user.Id)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	resp := toRouteResponse(newRoute)

	util.WriteJSONObject(w, &resp)
}

// UpdateRoute handles update to a route identified by a given ID
func (h *RoutesHandler) UpdateRoute(w http.ResponseWriter, r *http.Request) {
	claims := h.claimsExtractor.FromRequestContext(r)
	account, user, err := h.accountManager.GetAccountFromToken(claims)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	vars := mux.Vars(r)
	routeID := vars["id"]
	if len(routeID) == 0 {
		util.WriteError(status.Errorf(status.InvalidArgument, "invalid route ID"), w)
		return
	}

	_, err = h.accountManager.GetRoute(account.Id, routeID, user.Id)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	var req api.PutApiRoutesIdJSONRequestBody
	err = json.NewDecoder(r.Body).Decode(&req)
	if err != nil {
		util.WriteErrorResponse("couldn't parse JSON request", http.StatusBadRequest, w)
		return
	}

	prefixType, newPrefix, err := route.ParseNetwork(req.Network)
	if err != nil {
		util.WriteError(status.Errorf(status.InvalidArgument, "couldn't parse update prefix %s for route ID %s",
			req.Network, routeID), w)
		return
	}

	if utf8.RuneCountInString(req.NetworkId) > route.MaxNetIDChar || req.NetworkId == "" {
		util.WriteError(status.Errorf(status.InvalidArgument,
			"identifier should be between 1 and %d", route.MaxNetIDChar), w)
		return
	}

	newRoute := &route.Route{
		ID:          routeID,
		Network:     newPrefix,
		NetID:       req.NetworkId,
		NetworkType: prefixType,
		Masquerade:  req.Masquerade,
		Peer:        req.Peer,
		Metric:      req.Metric,
		Description: req.Description,
		Enabled:     req.Enabled,
		Groups:      req.Groups,
	}

	err = h.accountManager.SaveRoute(account.Id, user.Id, newRoute)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	resp := toRouteResponse(newRoute)

	util.WriteJSONObject(w, &resp)
}

// PatchRoute handles patch updates to a route identified by a given ID
func (h *RoutesHandler) PatchRoute(w http.ResponseWriter, r *http.Request) {
	claims := h.claimsExtractor.FromRequestContext(r)
	account, user, err := h.accountManager.GetAccountFromToken(claims)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	vars := mux.Vars(r)
	routeID := vars["id"]
	if len(routeID) == 0 {
		util.WriteError(status.Errorf(status.InvalidArgument, "invalid route ID"), w)
		return
	}

	_, err = h.accountManager.GetRoute(account.Id, routeID, user.Id)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	var req api.PatchApiRoutesIdJSONRequestBody
	err = json.NewDecoder(r.Body).Decode(&req)
	if err != nil {
		util.WriteErrorResponse("couldn't parse JSON request", http.StatusBadRequest, w)
		return
	}

	if len(req) == 0 {
		util.WriteError(status.Errorf(status.InvalidArgument, "no patch instruction received"), w)
		return
	}

	var operations []server.RouteUpdateOperation

	for _, patch := range req {
		switch patch.Path {
		case api.RoutePatchOperationPathNetwork:
			if patch.Op != api.RoutePatchOperationOpReplace {
				util.WriteError(status.Errorf(status.InvalidArgument,
					"network field only accepts replace operation, got %s", patch.Op), w)
				return
			}
			operations = append(operations, server.RouteUpdateOperation{
				Type:   server.UpdateRouteNetwork,
				Values: patch.Value,
			})
		case api.RoutePatchOperationPathDescription:
			if patch.Op != api.RoutePatchOperationOpReplace {
				util.WriteError(status.Errorf(status.InvalidArgument,
					"description field only accepts replace operation, got %s", patch.Op), w)
				return
			}
			operations = append(operations, server.RouteUpdateOperation{
				Type:   server.UpdateRouteDescription,
				Values: patch.Value,
			})
		case api.RoutePatchOperationPathNetworkId:
			if patch.Op != api.RoutePatchOperationOpReplace {
				util.WriteError(status.Errorf(status.InvalidArgument,
					"network Identifier field only accepts replace operation, got %s", patch.Op), w)
				return
			}
			operations = append(operations, server.RouteUpdateOperation{
				Type:   server.UpdateRouteNetworkIdentifier,
				Values: patch.Value,
			})
		case api.RoutePatchOperationPathPeer:
			if patch.Op != api.RoutePatchOperationOpReplace {
				util.WriteError(status.Errorf(status.InvalidArgument,
					"peer field only accepts replace operation, got %s", patch.Op), w)
				return
			}
			if len(patch.Value) > 1 {
				util.WriteError(status.Errorf(status.InvalidArgument,
					"value field only accepts 1 value, got %d", len(patch.Value)), w)
				return
			}
			operations = append(operations, server.RouteUpdateOperation{
				Type:   server.UpdateRoutePeer,
				Values: patch.Value,
			})
		case api.RoutePatchOperationPathMetric:
			if patch.Op != api.RoutePatchOperationOpReplace {
				util.WriteError(status.Errorf(status.InvalidArgument,
					"metric field only accepts replace operation, got %s", patch.Op), w)

				return
			}
			operations = append(operations, server.RouteUpdateOperation{
				Type:   server.UpdateRouteMetric,
				Values: patch.Value,
			})
		case api.RoutePatchOperationPathMasquerade:
			if patch.Op != api.RoutePatchOperationOpReplace {
				util.WriteError(status.Errorf(status.InvalidArgument,
					"masquerade field only accepts replace operation, got %s", patch.Op), w)
				return
			}
			operations = append(operations, server.RouteUpdateOperation{
				Type:   server.UpdateRouteMasquerade,
				Values: patch.Value,
			})
		case api.RoutePatchOperationPathEnabled:
			if patch.Op != api.RoutePatchOperationOpReplace {
				util.WriteError(status.Errorf(status.InvalidArgument,
					"enabled field only accepts replace operation, got %s", patch.Op), w)
				return
			}
			operations = append(operations, server.RouteUpdateOperation{
				Type:   server.UpdateRouteEnabled,
				Values: patch.Value,
			})
		case api.RoutePatchOperationPathGroups:
			if patch.Op != api.RoutePatchOperationOpReplace {
				util.WriteError(status.Errorf(status.InvalidArgument,
					"groups field only accepts replace operation, got %s", patch.Op), w)
				return
			}
			operations = append(operations, server.RouteUpdateOperation{
				Type:   server.UpdateRouteGroups,
				Values: patch.Value,
			})
		default:
			util.WriteError(status.Errorf(status.InvalidArgument, "invalid patch path"), w)
			return
		}
	}

	root, err := h.accountManager.UpdateRoute(account.Id, routeID, operations)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	resp := toRouteResponse(root)

	util.WriteJSONObject(w, &resp)
}

// DeleteRoute handles route deletion request
func (h *RoutesHandler) DeleteRoute(w http.ResponseWriter, r *http.Request) {
	claims := h.claimsExtractor.FromRequestContext(r)
	account, user, err := h.accountManager.GetAccountFromToken(claims)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	routeID := mux.Vars(r)["id"]
	if len(routeID) == 0 {
		util.WriteError(status.Errorf(status.InvalidArgument, "invalid route ID"), w)
		return
	}

	err = h.accountManager.DeleteRoute(account.Id, routeID, user.Id)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	util.WriteJSONObject(w, emptyObject{})
}

// GetRoute handles a route Get request identified by ID
func (h *RoutesHandler) GetRoute(w http.ResponseWriter, r *http.Request) {
	claims := h.claimsExtractor.FromRequestContext(r)
	account, user, err := h.accountManager.GetAccountFromToken(claims)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	routeID := mux.Vars(r)["id"]
	if len(routeID) == 0 {
		util.WriteError(status.Errorf(status.InvalidArgument, "invalid route ID"), w)
		return
	}

	foundRoute, err := h.accountManager.GetRoute(account.Id, routeID, user.Id)
	if err != nil {
		util.WriteError(status.Errorf(status.NotFound, "route not found"), w)
		return
	}

	util.WriteJSONObject(w, toRouteResponse(foundRoute))
}

func toRouteResponse(serverRoute *route.Route) *api.Route {
	return &api.Route{
		Id:          serverRoute.ID,
		Description: serverRoute.Description,
		NetworkId:   serverRoute.NetID,
		Enabled:     serverRoute.Enabled,
		Peer:        serverRoute.Peer,
		Network:     serverRoute.Network.String(),
		NetworkType: serverRoute.NetworkType.String(),
		Masquerade:  serverRoute.Masquerade,
		Metric:      serverRoute.Metric,
		Groups:      serverRoute.Groups,
	}
}