/*
 *  Copyright 2017 Anyware Services
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.ametys.plugins.workspaces.project.notification;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;

import javax.mail.MessagingException;

import org.ametys.core.group.Group;
import org.ametys.core.group.GroupIdentity;
import org.ametys.core.observation.Event;
import org.ametys.core.user.User;
import org.ametys.core.user.UserIdentity;
import org.ametys.core.util.mail.SendMailHelper;
import org.ametys.plugins.workspaces.ObservationConstants;
import org.ametys.plugins.workspaces.members.JCRProjectMember;
import org.ametys.plugins.workspaces.members.JCRProjectMember.MemberType;
import org.ametys.plugins.workspaces.members.ProjectMemberManager.ProjectMember;
import org.ametys.plugins.workspaces.project.objects.Project;
import org.ametys.runtime.config.Config;
import org.ametys.runtime.i18n.I18nizableText;

/**
 * Notifier to send mail to a newly added member of a workspace.
 */
public class AddMemberMailNotifierObserver extends AbstractMemberMailNotifierObserver
{
    @Override
    public boolean supports(Event event)
    {
        return event.getId().equals(ObservationConstants.EVENT_MEMBER_ADDED);
    }

    @Override
    public void observe(Event event, Map<String, Object> transientVars) throws Exception
    {
        // Check feature enabled
        boolean notification = Config.getInstance().getValue("workspaces.member.added.send.notification");
        if (!notification)
        {
            return;
        }
        
        Map<String, Object> args = event.getArguments();
        
        // Retrieve newly added member
        String newMemberId = (String) args.get(ObservationConstants.ARGS_MEMBER_ID);
        JCRProjectMember newMember = _resolver.resolveById(newMemberId);

        // Retrieve project
        String projectId = (String) args.get(ObservationConstants.ARGS_PROJECT_ID);
        Project project = _resolver.resolveById(projectId);
        
        // Compute subject and body
        String subject = _i18nUtils.translate(getSubjectI18nizableText(project, newMember));
        String textBody = _i18nUtils.translate(getBodyI18nizableText(project, newMember));
        
        List<User> newUsersInProject = new ArrayList<>();
        if (MemberType.USER == newMember.getType())
        {
            newUsersInProject.add(_userManager.getUser(newMember.getUser()));
        }
        else if (MemberType.GROUP == newMember.getType())
        {
            GroupIdentity groupIdentity = newMember.getGroup();
            Group group = _groupManager.getGroup(groupIdentity);
            if (group != null && project != null)
            {
                newUsersInProject = _projectMemberManager.getGroupUsersFromProject(group, project, (currentProject, identity) -> _isMemberNewToTheProject(currentProject, identity, groupIdentity));
            }
        }
        
        // Retrieve mail sender
        String sender = Config.getInstance().getValue("smtp.mail.from");
        
        for (String memberMail : getUsersEmail(newUsersInProject))
        {
            try
            {
                SendMailHelper.sendMail(subject, null, textBody, memberMail, sender);
            }
            catch (MessagingException e)
            {
                getLogger().warn("Could not send a notification e-mail to " + memberMail, e);
            }
        }
    }
    
    private boolean _isMemberNewToTheProject(Project project, UserIdentity userIdentity, GroupIdentity newGroupToIgnore)
    {
        Collection<ProjectMember> projectMembers = _projectMemberManager.getProjectMembers(project, false, false);
        boolean isUserOfProject = projectMembers.stream()
                .filter(member -> MemberType.USER == member.getType())
                .map(ProjectMember::getUser)
                .map(User::getIdentity)
                .filter(userIdentity::equals)
                .findAny()
                .isPresent();
        
        if (isUserOfProject)
        {
            // User from group was already part of the project, as a member of type "user"
            return false;
        }
        
        return projectMembers.stream()
                .filter(member -> MemberType.GROUP == member.getType())
                .map(ProjectMember::getGroup)
                .filter(group -> !newGroupToIgnore.equals(group.getIdentity()))
                .filter(Objects::nonNull)
                .map(Group::getUsers)
                .flatMap(Set::stream)
                .filter(userIdentity::equals)
                .findAny()
                .isEmpty(); // User was not found in any group of the project, apart from the ignored group
    }
    
    /**
     * Gets the {@link I18nizableText} for subject of the mail
     * @param project the project
     * @param member the member
     * @return the subject
     */
    protected I18nizableText getSubjectI18nizableText(Project project, JCRProjectMember member)
    {
        return new I18nizableText("plugin." + _pluginName, getSubjectI18nKey(), getSubjectParams(project, member));
    }
    
    /**
     * Gets the i18n subject key
     * @return the i18n subject key
     */
    protected String getSubjectI18nKey()
    {
        return "PROJECT_MAIL_NOTIFICATION_SUBJECT_MEMBER_ADDED";
    }
    
    /**
     * Gets the i18n parameters for subject key
     * @param project the project
     * @param member the member
     * @return the i18n parameters
     */
    protected List<String> getSubjectParams(Project project, JCRProjectMember member)
    {
        return getI18nParams(project.getTitle()); // {0}
    }
    
    /**
     * Gets the {@link I18nizableText} for body of the mail
     * @param project the project
     * @param member the member
     * @return the body
     */
    protected I18nizableText getBodyI18nizableText(Project project, JCRProjectMember member)
    {
        return new I18nizableText("plugin." + _pluginName, getBodyI18nKey(), getBodyParams(project, member));
    }
    
    /**
     * Gets the i18n body key
     * @return the i18n body key
     */
    protected String getBodyI18nKey()
    {
        return "PROJECT_MAIL_NOTIFICATION_BODY_MEMBER_ADDED";
    }
    
    /**
     * Gets the i18n parameters for body key
     * @param project the project
     * @param jcrMember the member
     * @return the i18n parameters
     */
    protected List<String> getBodyParams(Project project, JCRProjectMember jcrMember)
    {
        return getI18nParams(
            project.getTitle(), // {0}
            getProjectUrl(project)); // {1}
    }

}