package auth

import (
	"fmt"
	"github.com/gravitl/netmaker/database"
	"github.com/gravitl/netmaker/logger"
	"github.com/gravitl/netmaker/logic"
	"github.com/gravitl/netmaker/models"
	"github.com/gravitl/netmaker/pro/idp"
	"github.com/gravitl/netmaker/pro/idp/azure"
	"github.com/gravitl/netmaker/pro/idp/google"
	proLogic "github.com/gravitl/netmaker/pro/logic"
	"strings"
	"time"
)

var syncTicker *time.Ticker

func StartSyncHook() {
	syncTicker = time.NewTicker(logic.GetIDPSyncInterval())

	for range syncTicker.C {
		err := SyncFromIDP()
		if err != nil {
			logger.Log(0, "failed to sync from idp: ", err.Error())
		} else {
			logger.Log(0, "sync from idp complete")
		}
	}
}

func ResetIDPSyncHook() {
	if syncTicker != nil {
		syncTicker.Stop()
		if logic.IsSyncEnabled() {
			go StartSyncHook()
		}
	}
}

func SyncFromIDP() error {
	settings := logic.GetServerSettings()

	var idpClient idp.Client
	var idpUsers []idp.User
	var idpGroups []idp.Group
	var err error

	switch settings.AuthProvider {
	case "google":
		idpClient, err = google.NewGoogleWorkspaceClient()
		if err != nil {
			return err
		}
	case "azure-ad":
		idpClient = azure.NewAzureEntraIDClient()
	default:
		if settings.AuthProvider != "" {
			return fmt.Errorf("invalid auth provider: %s", settings.AuthProvider)
		}
	}

	if settings.AuthProvider != "" && idpClient != nil {
		idpUsers, err = idpClient.GetUsers()
		if err != nil {
			return err
		}

		idpGroups, err = idpClient.GetGroups()
		if err != nil {
			return err
		}
	}

	err = syncUsers(idpUsers)
	if err != nil {
		return err
	}

	return syncGroups(idpGroups)
}

func syncUsers(idpUsers []idp.User) error {
	dbUsers, err := logic.GetUsersDB()
	if err != nil && !database.IsEmptyRecord(err) {
		return err
	}

	password, err := logic.FetchPassValue("")
	if err != nil {
		return err
	}

	idpUsersMap := make(map[string]struct{})
	for _, user := range idpUsers {
		idpUsersMap[user.Username] = struct{}{}
	}

	dbUsersMap := make(map[string]models.User)
	for _, user := range dbUsers {
		dbUsersMap[user.UserName] = user
	}

	filters := logic.GetServerSettings().UserFilters

	for _, user := range idpUsers {
		var found bool
		for _, filter := range filters {
			if strings.HasPrefix(user.Username, filter) {
				found = true
				break
			}
		}

		// if there are filters but none of them match, then skip this user.
		if len(filters) > 0 && !found {
			continue
		}

		dbUser, ok := dbUsersMap[user.Username]
		if !ok {
			// create the user only if it doesn't exist.
			err = logic.CreateUser(&models.User{
				UserName:                   user.Username,
				ExternalIdentityProviderID: user.ID,
				DisplayName:                user.DisplayName,
				AccountDisabled:            user.AccountDisabled,
				Password:                   password,
				AuthType:                   models.OAuth,
				PlatformRoleID:             models.ServiceUser,
			})
			if err != nil {
				return err
			}
		} else if dbUser.AuthType == models.OAuth {
			if dbUser.AccountDisabled != user.AccountDisabled ||
				dbUser.DisplayName != user.DisplayName ||
				dbUser.ExternalIdentityProviderID != user.ID {

				dbUser.AccountDisabled = user.AccountDisabled
				dbUser.DisplayName = user.DisplayName
				dbUser.ExternalIdentityProviderID = user.ID

				err = logic.UpsertUser(dbUser)
				if err != nil {
					return err
				}
			}
		} else {
			logger.Log(0, "user with username "+user.Username+" already exists, skipping creation")
			continue
		}
	}

	for _, user := range dbUsersMap {
		if user.ExternalIdentityProviderID == "" {
			continue
		}
		if _, ok := idpUsersMap[user.UserName]; !ok {
			// delete the user if it has been deleted on idp.
			err = logic.DeleteUser(user.UserName)
			if err != nil {
				return err
			}
		}
	}

	return nil
}

func syncGroups(idpGroups []idp.Group) error {
	dbGroups, err := proLogic.ListUserGroups()
	if err != nil && !database.IsEmptyRecord(err) {
		return err
	}

	dbUsers, err := logic.GetUsersDB()
	if err != nil && !database.IsEmptyRecord(err) {
		return err
	}

	idpGroupsMap := make(map[string]struct{})
	for _, group := range idpGroups {
		idpGroupsMap[group.ID] = struct{}{}
	}

	dbGroupsMap := make(map[string]models.UserGroup)
	for _, group := range dbGroups {
		if group.ExternalIdentityProviderID != "" {
			dbGroupsMap[group.ExternalIdentityProviderID] = group
		}
	}

	dbUsersMap := make(map[string]models.User)
	for _, user := range dbUsers {
		if user.ExternalIdentityProviderID != "" {
			dbUsersMap[user.ExternalIdentityProviderID] = user
		}
	}

	modifiedUsers := make(map[string]struct{})

	filters := logic.GetServerSettings().GroupFilters

	for _, group := range idpGroups {
		var found bool
		for _, filter := range filters {
			if strings.HasPrefix(group.Name, filter) {
				found = true
				break
			}
		}

		// if there are filters but none of them match, then skip this group.
		if len(filters) > 0 && !found {
			continue
		}

		dbGroup, ok := dbGroupsMap[group.ID]
		if !ok {
			err := proLogic.CreateUserGroup(models.UserGroup{
				ExternalIdentityProviderID: group.ID,
				Default:                    false,
				Name:                       group.Name,
			})
			if err != nil {
				return err
			}
		} else {
			dbGroup.Name = group.Name
			err = proLogic.UpdateUserGroup(dbGroup)
			if err != nil {
				return err
			}
		}

		groupMembersMap := make(map[string]struct{})
		for _, member := range group.Members {
			groupMembersMap[member] = struct{}{}
		}

		for _, user := range dbUsers {
			// use dbGroup.Name because the group name may have been changed on idp.
			_, inNetmakerGroup := user.UserGroups[models.UserGroupID(dbGroup.Name)]
			_, inIDPGroup := groupMembersMap[user.ExternalIdentityProviderID]

			if inNetmakerGroup && !inIDPGroup {
				// use dbGroup.Name because the group name may have been changed on idp.
				delete(dbUsersMap[user.ExternalIdentityProviderID].UserGroups, models.UserGroupID(dbGroup.Name))
				modifiedUsers[user.ExternalIdentityProviderID] = struct{}{}
			}

			if !inNetmakerGroup && inIDPGroup {
				// use dbGroup.Name because the group name may have been changed on idp.
				dbUsersMap[user.ExternalIdentityProviderID].UserGroups[models.UserGroupID(dbGroup.Name)] = struct{}{}
				modifiedUsers[user.ExternalIdentityProviderID] = struct{}{}
			}
		}
	}

	for userID := range modifiedUsers {
		err = logic.UpsertUser(dbUsersMap[userID])
		if err != nil {
			return err
		}
	}

	for _, group := range dbGroups {
		if group.ExternalIdentityProviderID != "" {
			if _, ok := idpGroupsMap[group.ExternalIdentityProviderID]; !ok {
				// delete the group if it has been deleted on idp.
				err = proLogic.DeleteUserGroup(group.ID)
				if err != nil {
					return err
				}
			}
		}
	}

	return nil
}