package http

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

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

	"github.com/rs/xid"

	"github.com/netbirdio/netbird/management/server"
	"github.com/netbirdio/netbird/management/server/jwtclaims"

	"github.com/gorilla/mux"
	log "github.com/sirupsen/logrus"
)

// GroupsHandler is a handler that returns groups of the account
type GroupsHandler struct {
	accountManager  server.AccountManager
	claimsExtractor *jwtclaims.ClaimsExtractor
}

// NewGroupsHandler creates a new GroupsHandler HTTP handler
func NewGroupsHandler(accountManager server.AccountManager, authCfg AuthCfg) *GroupsHandler {
	return &GroupsHandler{
		accountManager: accountManager,
		claimsExtractor: jwtclaims.NewClaimsExtractor(
			jwtclaims.WithAudience(authCfg.Audience),
			jwtclaims.WithUserIDClaim(authCfg.UserIDClaim),
		),
	}
}

// GetAllGroups list for the account
func (h *GroupsHandler) GetAllGroups(w http.ResponseWriter, r *http.Request) {
	claims := h.claimsExtractor.FromRequestContext(r)
	account, _, err := h.accountManager.GetAccountFromToken(claims)
	if err != nil {
		log.Error(err)
		http.Redirect(w, r, "/", http.StatusInternalServerError)
		return
	}

	var groups []*api.Group
	for _, g := range account.Groups {
		groups = append(groups, toGroupResponse(account, g))
	}

	util.WriteJSONObject(w, groups)
}

// UpdateGroup handles update to a group identified by a given ID
func (h *GroupsHandler) UpdateGroup(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)
	groupID, ok := vars["groupId"]
	if !ok {
		util.WriteError(status.Errorf(status.InvalidArgument, "group ID field is missing"), w)
		return
	}
	if len(groupID) == 0 {
		util.WriteError(status.Errorf(status.InvalidArgument, "group ID can't be empty"), w)
		return
	}

	_, ok = account.Groups[groupID]
	if !ok {
		util.WriteError(status.Errorf(status.NotFound, "couldn't find group with ID %s", groupID), w)
		return
	}

	allGroup, err := account.GetGroupAll()
	if err != nil {
		util.WriteError(err, w)
		return
	}
	if allGroup.ID == groupID {
		util.WriteError(status.Errorf(status.InvalidArgument, "updating group ALL is not allowed"), w)
		return
	}

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

	if req.Name == "" {
		util.WriteError(status.Errorf(status.InvalidArgument, "group name shouldn't be empty"), w)
		return
	}

	var peers []string
	if req.Peers == nil {
		peers = make([]string, 0)
	} else {
		peers = *req.Peers
	}
	group := server.Group{
		ID:    groupID,
		Name:  req.Name,
		Peers: peers,
	}

	if err := h.accountManager.SaveGroup(account.Id, user.Id, &group); err != nil {
		log.Errorf("failed updating group %s under account %s %v", groupID, account.Id, err)
		util.WriteError(err, w)
		return
	}

	util.WriteJSONObject(w, toGroupResponse(account, &group))
}

// CreateGroup handles group creation request
func (h *GroupsHandler) CreateGroup(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.PostApiGroupsJSONRequestBody
	err = json.NewDecoder(r.Body).Decode(&req)
	if err != nil {
		util.WriteErrorResponse("couldn't parse JSON request", http.StatusBadRequest, w)
		return
	}

	if req.Name == "" {
		util.WriteError(status.Errorf(status.InvalidArgument, "group name shouldn't be empty"), w)
		return
	}

	var peers []string
	if req.Peers == nil {
		peers = make([]string, 0)
	} else {
		peers = *req.Peers
	}
	group := server.Group{
		ID:    xid.New().String(),
		Name:  req.Name,
		Peers: peers,
	}

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

	util.WriteJSONObject(w, toGroupResponse(account, &group))
}

// DeleteGroup handles group deletion request
func (h *GroupsHandler) DeleteGroup(w http.ResponseWriter, r *http.Request) {
	claims := h.claimsExtractor.FromRequestContext(r)
	account, _, err := h.accountManager.GetAccountFromToken(claims)
	if err != nil {
		util.WriteError(err, w)
		return
	}
	aID := account.Id

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

	allGroup, err := account.GetGroupAll()
	if err != nil {
		util.WriteError(err, w)
		return
	}

	if allGroup.ID == groupID {
		util.WriteError(status.Errorf(status.InvalidArgument, "deleting group ALL is not allowed"), w)
		return
	}

	err = h.accountManager.DeleteGroup(aID, groupID)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	util.WriteJSONObject(w, emptyObject{})
}

// GetGroup returns a group
func (h *GroupsHandler) GetGroup(w http.ResponseWriter, r *http.Request) {
	claims := h.claimsExtractor.FromRequestContext(r)
	account, _, err := h.accountManager.GetAccountFromToken(claims)
	if err != nil {
		util.WriteError(err, w)
		return
	}

	switch r.Method {
	case http.MethodGet:
		groupID := mux.Vars(r)["groupId"]
		if len(groupID) == 0 {
			util.WriteError(status.Errorf(status.InvalidArgument, "invalid group ID"), w)
			return
		}

		group, err := h.accountManager.GetGroup(account.Id, groupID)
		if err != nil {
			util.WriteError(err, w)
			return
		}

		util.WriteJSONObject(w, toGroupResponse(account, group))
	default:
		if err != nil {
			util.WriteError(status.Errorf(status.NotFound, "HTTP method not found"), w)
			return
		}
	}
}

func toGroupResponse(account *server.Account, group *server.Group) *api.Group {
	cache := make(map[string]api.PeerMinimum)
	gr := api.Group{
		Id:         group.ID,
		Name:       group.Name,
		PeersCount: len(group.Peers),
	}

	for _, pid := range group.Peers {
		_, ok := cache[pid]
		if !ok {
			peer, ok := account.Peers[pid]
			if !ok {
				continue
			}
			peerResp := api.PeerMinimum{
				Id:   peer.ID,
				Name: peer.Name,
			}
			cache[pid] = peerResp
			gr.Peers = append(gr.Peers, peerResp)
		}
	}
	return &gr
}