/*
 *  Copyright 2024 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.cms.repository.mentions;

import java.util.HashSet;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.avalon.framework.component.Component;
import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.avalon.framework.service.Serviceable;

import org.ametys.core.user.User;
import org.ametys.core.user.UserIdentity;
import org.ametys.core.user.UserManager;
import org.ametys.core.util.I18nUtils;
import org.ametys.runtime.i18n.I18nizableText;
import org.ametys.runtime.plugin.component.AbstractLogEnabled;

/**
 * Utils for Mentions
 */
public class MentionUtils extends AbstractLogEnabled implements Component, Serviceable
{
    /** Avalon role */
    public static final String ROLE = MentionUtils.class.getName();

    /** Regex used to extract mentions from a text. A mention is inside a @() */
    public static final String EXTRACT_MENTIONS_REGEX_SIMPLE_TEXT = "@\\(([^()]+)\\)";

    /** Regex used to extract mentions from a text. A mention is inside a @() */
    public static final String EXTRACT_MENTIONS_REGEX_RICH_TEXT = "data-ametys-mention-user=\"([^\"]+)\"";
    
    /** A prefix to have before full name of a mentioned user */
    public static final String MENTIONED_USER_PREFIX = "@";

    /** The user manager */
    protected UserManager _userManager;

    /** The i18n utils. */
    protected I18nUtils _i18nUtils;
    
    public void service(ServiceManager manager) throws ServiceException
    {
        _userManager = (UserManager) manager.lookup(UserManager.ROLE);
        _i18nUtils = (I18nUtils) manager.lookup(I18nUtils.ROLE);
    }

    /**
     * Extract mentioned users from simple text content
     * @param content the simple text content
     * @return the set of mentioned users
     */
    public static Set<UserIdentity> extractMentionedUsersFromSimpleText(String content)
    {
        Set<UserIdentity> mentionendUsers = new HashSet<>();
        if (content != null)
        {
            Pattern pattern = Pattern.compile(EXTRACT_MENTIONS_REGEX_SIMPLE_TEXT);
            Matcher matcher = pattern.matcher(content);
            
            while (matcher.find())
            {
                String userIdentityAsString = matcher.group(1);
                UserIdentity userIdentity = UserIdentity.stringToUserIdentity(userIdentityAsString);
                mentionendUsers.add(userIdentity);
            }
        }
        return mentionendUsers;
    }
    
    /**
     * Extract mentioned users from rich text content
     * @param content the rich text content
     * @return the set of mentioned users
     */
    public Set<UserIdentity> extractMentionedUsersFromRichText(String content)
    {
        Set<UserIdentity> mentionedUsers = new HashSet<>();
        Pattern pattern = Pattern.compile("data-ametys-mention-user=\"([^\"]+)\"");
        Matcher matcher = pattern.matcher(content);

        while (matcher.find())
        {
            String userIdentityAsString = matcher.group(1);
            UserIdentity userIdentity = UserIdentity.stringToUserIdentity(userIdentityAsString);
            mentionedUsers.add(userIdentity);
        }
        return mentionedUsers;
    }

    /**
     * Transform syntax text of a rich text to display text using a regex to find the parts to transform and a function to transform them
     * @param syntaxText the syntax text
     * @param recipient the recipient of the mail, for mail purposes
     * @return the transformed text with colors according to the recipient
     */
    public String transformRichTextToReadableText(String syntaxText, UserIdentity recipient)
    {
        String readableText = syntaxText;

        if (syntaxText != null)
        {
            Pattern pattern = Pattern.compile(EXTRACT_MENTIONS_REGEX_RICH_TEXT);
            Matcher matcher = pattern.matcher(syntaxText);
            StringBuffer sb = new StringBuffer();

            while (matcher.find())
            {
                String mentionBackgroundColor = _getMentionColor(recipient, matcher);
                
                StringBuilder replaceBy = new StringBuilder("style=\"background: ").append(mentionBackgroundColor).append("; color: #1264a3\"");
                
                matcher.appendReplacement(sb, Matcher.quoteReplacement(replaceBy.toString()));
            }
            matcher.appendTail(sb);
            readableText = sb.toString();
        }
        return readableText;
    }
    
    /**
     * Transform syntax text of a simple text to display text using a regex to find the parts to transform and a function to transform them
     * @param syntaxText the syntax text
     * @param recipient the recipient of the mail, for mail purposes, can be null for any other purposes
     * @return the transformed text with colors according to the recipient if not null, with full name in plain text otherwise
     */
    public String transformTextToReadableText(String syntaxText, UserIdentity recipient)
    {
        String readableText = syntaxText;

        if (syntaxText != null)
        {
            Pattern pattern = Pattern.compile(EXTRACT_MENTIONS_REGEX_SIMPLE_TEXT);
            Matcher matcher = pattern.matcher(syntaxText);
            StringBuffer sb = new StringBuffer();

            while (matcher.find())
            {
                String userIdentityAsString = matcher.group(1);
                UserIdentity mentionedUserIdentity = UserIdentity.stringToUserIdentity(userIdentityAsString);
                User mentionedUser = _userManager.getUser(mentionedUserIdentity);
                String mentionedUserName = mentionedUser != null ? (MENTIONED_USER_PREFIX + mentionedUser.getFullName()) : _i18nUtils.translate(new I18nizableText("plugin.core", "PLUGINS_CORE_USERS_UNKNOWN_USER"));
                
                StringBuilder replaceBy = new StringBuilder(mentionedUserName);
                if (recipient != null)
                {
                    String mentionBackgroundColor = _getMentionColor(recipient, matcher);
                    
                    replaceBy = new StringBuilder("<span style=\"background: ").append(mentionBackgroundColor).append("; color: #1264a3\">")
                            .append(mentionedUserName)
                            .append("</span>");
                }
                
                matcher.appendReplacement(sb, Matcher.quoteReplacement(replaceBy.toString()));
            }
            matcher.appendTail(sb);
            readableText = sb.toString();
        }
        return readableText;
    }

    private String _getMentionColor(UserIdentity recipient, Matcher matcher)
    {
        String userIdentityAsString = matcher.group(1);
        UserIdentity mentionedUserIdentity = UserIdentity.stringToUserIdentity(userIdentityAsString);

        String mentionBackgroundColor = "rgba(29, 155, 209, 0.1)";
        if (mentionedUserIdentity.equals(recipient))
        {
            mentionBackgroundColor = "rgba(255, 198, 0, 0.18)";
        }
        return mentionBackgroundColor;
    }

}