/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * 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 com.android.emailcommon.utility;

import com.android.emailcommon.internet.MimeHeader;
import com.android.emailcommon.internet.MimeUtility;
import com.android.emailcommon.mail.MessagingException;
import com.android.emailcommon.mail.Part;

import android.text.TextUtils;

import java.util.ArrayList;

public class ConversionUtilities {
    /**
     * Helper function to append text to a StringBuffer, creating it if necessary.
     * Optimization:  The majority of the time we are *not* appending - we should have a path
     * that deals with single strings.
     */
    private static StringBuffer appendTextPart(StringBuffer sb, String newText) {
        if (newText == null) {
            return sb;
        }
        else if (sb == null) {
            sb = new StringBuffer(newText);
        } else {
            if (sb.length() > 0) {
                sb.append('\n');
            }
            sb.append(newText);
        }
        return sb;
    }

    /**
     * Plain-Old-Data class to return parsed body data from
     * {@link ConversionUtilities#parseBodyFields}
     */
    public static class BodyFieldData {
        public String textContent;
        public String htmlContent;
        public String snippet;
        public boolean isQuotedReply;
        public boolean isQuotedForward;
    }

    /**
     * Parse body text (plain and/or HTML) from MimeMessage to {@link BodyFieldData}.
     */
    public static BodyFieldData parseBodyFields(ArrayList<Part> viewables)
    throws MessagingException {
        final BodyFieldData data = new BodyFieldData();
        StringBuffer sbHtml = null;
        StringBuffer sbText = null;

        for (Part viewable : viewables) {
            String text = MimeUtility.getTextFromPart(viewable);
            // Deploy text as marked by the various tags
            boolean isHtml = "text/html".equalsIgnoreCase(viewable.getMimeType());

            // Most of the time, just process regular body parts
            if (isHtml) {
                sbHtml = appendTextPart(sbHtml, text);
            } else {
                sbText = appendTextPart(sbText, text);
            }
        }

        // write the combined data to the body part
        if (!TextUtils.isEmpty(sbText)) {
            String text = sbText.toString();
            data.textContent = text;
            data.snippet = TextUtilities.makeSnippetFromPlainText(text);
        }
        if (!TextUtils.isEmpty(sbHtml)) {
            String text = sbHtml.toString();
            data.htmlContent = text;
            if (data.snippet == null) {
                data.snippet = TextUtilities.makeSnippetFromHtmlText(text);
            }
        }
        return data;
    }
}