// Vikunja is a to-do list application to facilitate your life.
// Copyright 2018-2020 Vikunja and contributors. All rights reserved.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package models

import (
	"code.vikunja.io/api/pkg/user"
	"code.vikunja.io/web"
	"xorm.io/builder"
)

// CanUpdate checks if a user can update a label
func (l *Label) CanUpdate(a web.Auth) (bool, error) {
	return l.isLabelOwner(a) // Only owners should be allowed to update a label
}

// CanDelete checks if a user can delete a label
func (l *Label) CanDelete(a web.Auth) (bool, error) {
	return l.isLabelOwner(a) // Only owners should be allowed to delete a label
}

// CanRead checks if a user can read a label
func (l *Label) CanRead(a web.Auth) (bool, error) {
	return l.hasAccessToLabel(a)
}

// CanCreate checks if the user can create a label
// Currently a dummy.
func (l *Label) CanCreate(a web.Auth) (bool, error) {
	if _, is := a.(*LinkSharing); is {
		return false, nil
	}

	return true, nil
}

func (l *Label) isLabelOwner(a web.Auth) (bool, error) {

	if _, is := a.(*LinkSharing); is {
		return false, nil
	}

	lorig, err := getLabelByIDSimple(l.ID)
	if err != nil {
		return false, err
	}
	return lorig.CreatedByID == a.GetID(), nil
}

// Helper method to check if a user can see a specific label
func (l *Label) hasAccessToLabel(a web.Auth) (bool, error) {

	// TODO: add an extra check for link share handling

	// Get all tasks
	taskIDs, err := getUserTaskIDs(&user.User{ID: a.GetID()})
	if err != nil {
		return false, err
	}

	// Get all labels associated with these tasks
	var labels []*Label
	has, err := x.Table("labels").
		Select("labels.*").
		Join("LEFT", "label_task", "label_task.label_id = labels.id").
		Where("label_task.label_id is not null OR labels.created_by_id = ?", a.GetID()).
		Or(builder.In("label_task.task_id", taskIDs)).
		And("labels.id = ?", l.ID).
		Exist(&labels)
	return has, err
}
