package de.thedevstack.conversationsplus.utils;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

import java.net.MalformedURLException;
import java.net.URL;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import de.thedevstack.conversationsplus.ConversationsPlusApplication;
import de.thedevstack.conversationsplus.entities.Conversation;
import de.thedevstack.conversationsplus.entities.DownloadableFile;
import de.thedevstack.conversationsplus.entities.FileParams;
import de.thedevstack.conversationsplus.entities.Message;
import de.thedevstack.conversationsplus.entities.Transferable;
import de.thedevstack.conversationsplus.enums.FileStatus;
import de.thedevstack.conversationsplus.persistance.DatabaseBackend;
import de.thedevstack.conversationsplus.persistance.FileBackend;

/**
 * Utility class to work with messages.
 */
public final class MessageUtil {

    public static void extractFileParamsFromBody(Message message) {
        if (null == message) {
            return;
        }

        // Ensure that for every message the fileParams are set after calling this method
        FileParams fileParams = message.getFileParams();
        if (null == fileParams) {
            fileParams = new FileParams();
            message.setFileParams(fileParams);
        }

        String body = message.getBody();
        /**
         * there are a few cases where spaces result in an unwanted behavior, e.g.
         * "http://example.com/image.jpg" text that will not be shown /abc.png"
         * or more than one image link in one message.
         */
        if (null == body || body.isEmpty() || body.contains(" ")) {
            return;
        }

        try {
            URL url = new URL(body);
            if (!url.getProtocol().equalsIgnoreCase("http") && !url.getProtocol().equalsIgnoreCase("https")) {
                message.setTreatAsDownloadable(Message.Decision.NEVER);
                return;
            }
            String extension = FileUtils.getRelevantExtension(url);
            if (message.isHttpUploaded()) {
                fileParams.setUrl(url.toString());
                if (null != extension
                        && (Transferable.WELL_KNOWN_EXTENSIONS.contains(extension.toLowerCase()) || Transferable.VALID_IMAGE_EXTENSIONS.contains(extension.toLowerCase()))) {
                    message.setTreatAsDownloadable(Message.Decision.MUST);
                } else {
                    message.setTreatAsDownloadable(Message.Decision.NEVER);
                    fileParams.setFileStatus(FileStatus.UNDEFINED);
                }

                extractFilename(message, url.toString());
                return;
            }

            if (extension == null) {
                message.setTreatAsDownloadable(Message.Decision.NEVER);
                return;
            }
            byte[] ivAndKey = UrlUtil.getIvAndKeyFromURL(url);

            if (null != ivAndKey) {
                if (MimeUtils.guessMimeTypeFromExtension(extension) != null) {
                    message.setTreatAsDownloadable(Message.Decision.MUST);
                    fileParams.setKeyAndIv(ivAndKey);
                } else {
                    message.setTreatAsDownloadable(Message.Decision.NEVER);
                }
            } else if (Transferable.VALID_IMAGE_EXTENSIONS.contains(extension)
                    || Transferable.WELL_KNOWN_EXTENSIONS.contains(extension)) {
                message.setTreatAsDownloadable(Message.Decision.SHOULD);
            } else {
                message.setTreatAsDownloadable(Message.Decision.NEVER);
            }

            if (message.treatAsDownloadable() == Message.Decision.MUST
                    || message.treatAsDownloadable() == Message.Decision.SHOULD) {
                fileParams.setUrl(url.toString());
                extractFilename(message, url.toString());
            }
        } catch (MalformedURLException e) {
            message.setTreatAsDownloadable(Message.Decision.NEVER);
        }
    }

    private static void extractFilename(Message message, String url) {
        String originalFilename = FileUtils.getFilenameFromPath(url);
        final String lowerCaseFilename = originalFilename.toLowerCase();
        final String lastPart = FileUtils.getLastExtension(lowerCaseFilename);

        detectAndSetEncryption(lastPart, message);

        String filenameExtension;
        if (!lastPart.isEmpty() && Transferable.VALID_CRYPTO_EXTENSIONS.contains(lastPart)) {
            filenameExtension = FileUtils.getSecondToLastExtension(lowerCaseFilename);
            originalFilename = originalFilename.replace("." + lastPart, "");
        } else {
            filenameExtension = lastPart;
        }
        message.setRelativeFilePath(message.getUuid() + "." + filenameExtension);

        message.getFileParams().setOriginalFilename(originalFilename);
    }

    private static void detectAndSetEncryption(String lastPart, Message message) {
        if (!lastPart.isEmpty() && ("pgp".equals(lastPart) || "gpg".equals(lastPart))) {
            message.setEncryption(Message.ENCRYPTION_PGP);
        } else if (message.getEncryption() != Message.ENCRYPTION_OTR
                && message.getEncryption() != Message.ENCRYPTION_AXOLOTL) {
            message.setEncryption(Message.ENCRYPTION_NONE);
        } else if ((message.getEncryption() == Message.ENCRYPTION_OTR
                || message.getEncryption() == Message.ENCRYPTION_AXOLOTL)
                && message.getFileParams() != null && message.getFileParams().getKey() == null) {
            // If an encryption is set for the message, but no key given -> decryption not possible
            message.setEncryption(Message.ENCRYPTION_NONE);
        }
    }

    /**
     * Checks if an attached file is an image or not.
     * Prerequisite for calling this method: The check if a file is attached is done before.
     * @param message
     * @return
     */
    public static boolean isAttachedFileAnImage(Message message) {
        final FileParams fileParams = message.getFileParams();
        String mimeType = (null != fileParams) ? fileParams.getMimeType() : null;
        return message.getType() == Message.TYPE_IMAGE
                || (fileParams != null && fileParams.getWidth() > 0)
                || (null != mimeType && mimeType.startsWith("image/"));
    }

    public static boolean isTypeFileAndDecrypted(Message message) {
        return message.getType() == Message.TYPE_FILE
                && message.getEncryption() != Message.ENCRYPTION_PGP
                && message.getEncryption() != Message.ENCRYPTION_DECRYPTION_FAILED;
    }

    public static boolean isDecrypted(Message message) {
        return message.getEncryption() != Message.ENCRYPTION_PGP && message.getEncryption() != Message.ENCRYPTION_DECRYPTION_FAILED;
    }

    /**
     * Checks if the file status of an message is <b>NOT</b> one of:
     * <ul>
     *     <li>FileStatus#NOT_FOUND</li>
     *     <li>FileStatus#DELETED</li>
     * </ul>
     * The file status does not guarantee that a file is really available or not.
     * @param message
     * @return
     */
    public static boolean mayFileRemoteAvailable(Message message) {
        FileStatus fileStatus = (null != message.getFileParams()) ? message.getFileParams().getFileStatus() : null;
        return null != fileStatus
                && FileStatus.NOT_FOUND != fileStatus
                && FileStatus.DELETED != fileStatus;
    }

    public static boolean needsDownload(Message message) {
        FileStatus fileStatus = (null != message.getFileParams()) ? message.getFileParams().getFileStatus() : null;
        return (null == fileStatus
                || (null != fileStatus && (fileStatus == FileStatus.NEEDS_DOWNLOAD || fileStatus == FileStatus.UNDEFINED)))
                && message.treatAsDownloadable() != Message.Decision.NEVER;
    }

    public static boolean isMessageSent(Message message) {
        switch (message.getStatus()) {
            case Message.STATUS_SEND:
            case Message.STATUS_SEND_DISPLAYED:
            case Message.STATUS_SEND_RECEIVED:
                return true;
            default:
                return false;
        }
    }

    public static void setAndSaveFileStatus(Message message, FileStatus fileStatus) {
        message.getFileParams().setFileStatus(fileStatus);
        DatabaseBackend.getInstance().updateMessage(message);
        UiUpdateHelper.updateConversationUi();
    }

    public static boolean markMessage(Conversation conversation, String uuid, int status) {
        if (uuid == null) {
            return false;
        } else {
            Message message = conversation.findSentMessageWithUuid(uuid);
            if (message != null) {
                markMessage(message, status);
                return true;
            } else {
                return false;
            }
        }
    }

    public static void markMessage(Message message, int status) {
        if (status == Message.STATUS_SEND_FAILED
                && (message.getStatus() == Message.STATUS_SEND_RECEIVED || message
                .getStatus() == Message.STATUS_SEND_DISPLAYED)) {
            return;
        }
        message.setStatus(status);
        DatabaseBackend.getInstance(ConversationsPlusApplication.getAppContext()).updateMessage(message);
        UiUpdateHelper.updateConversationUi();
    }

    public static boolean wasHighlightedOrPrivate(final Message message) {
        final String nick = message.getConversation().getMucOptions().getActualNick();
        final Pattern highlight = generateNickHighlightPattern(nick);
        if (message.getBody() == null || nick == null) {
            return false;
        }
        final Matcher m = highlight.matcher(message.getBody());
        return (m.find() || message.getType() == Message.TYPE_PRIVATE);
    }

    private static Pattern generateNickHighlightPattern(final String nick) {
        // We expect a word boundary, i.e. space or start of string, followed by
        // the
        // nick (matched in case-insensitive manner), followed by optional
        // punctuation (for example "bob: i disagree" or "how are you alice?"),
        // followed by another word boundary.
        return Pattern.compile("\\b" + Pattern.quote(nick) + "\\p{Punct}?\\b",
                Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);
    }

    public static void updateMessageWithImageDetails(Message message, String filePath, long size, int imageWidth, int imageHeight) {
        message.setRelativeFilePath(filePath);
        MessageUtil.updateMessageWithFileParams(message, null, size, imageWidth, imageHeight);
    }

    public static void updateFileParams(Message message) {
        updateFileParams(message, null);
    }

    public static void updateFileParams(Message message, URL url) {
        DownloadableFile file = FileBackend.getFile(message);
        int imageWidth = -1;
        int imageHeight = -1;
        if (message.getType() == Message.TYPE_IMAGE || file.getMimeType().startsWith("image/")) {
            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inJustDecodeBounds = true;
            Bitmap bmp = BitmapFactory.decodeFile(file.getAbsolutePath(), options);
            imageHeight = options.outHeight;
            imageWidth = options.outWidth;
            if (null != bmp) {
                bmp.recycle();
            }
        }

        MessageUtil.updateMessageWithFileParams(message, url, file.getSize(), imageWidth, imageHeight);
    }

    private static void updateMessageWithFileParams(Message message, URL url, long size, int imageWidth, int imageHeight) {
        FileParams fileParams = message.getFileParams();
        if (null == fileParams) {
            fileParams = new FileParams();
            message.setFileParams(fileParams);
        }
        fileParams.setSize(size);
        if (null != url) {
            fileParams.setUrl(url.toString());
        }
        if (-1 < imageWidth) {
            fileParams.setWidth(imageWidth);
        }
        if (-1 < imageHeight) {
            fileParams.setHeight(imageHeight);
        }
        String relativeFilePathFromMessage = message.getRelativeFilePath();
        if (null != relativeFilePathFromMessage && relativeFilePathFromMessage.startsWith("/")) {
            fileParams.setPath(relativeFilePathFromMessage);
        }
    }

    private MessageUtil() {
        // Static helper class
    }
}