/**
 * Copyright (c) 2011, Google Inc.
 *
 * 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.mail.utils;

import android.app.SearchManager;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.res.Resources;
import android.database.Cursor;
import android.graphics.Typeface;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.provider.Browser;
import android.text.Html;
import android.text.Spannable;
import android.text.SpannableString;
import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.TextUtils;
import android.text.TextUtils.SimpleStringSplitter;
import android.text.style.CharacterStyle;
import android.text.style.ForegroundColorSpan;
import android.text.style.StyleSpan;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewParent;
import android.view.View.MeasureSpec;
import android.view.ViewGroup;
import android.webkit.WebSettings;
import android.webkit.WebView;

import com.android.mail.R;
import com.android.mail.providers.Account;
import com.android.mail.providers.Conversation;
import com.android.mail.providers.Folder;
import com.android.mail.providers.UIProvider;
import com.android.mail.providers.UIProvider.EditSettingsExtras;
import com.google.android.common.html.parser.HtmlDocument;
import com.google.android.common.html.parser.HtmlParser;
import com.google.android.common.html.parser.HtmlTree;
import com.google.android.common.html.parser.HtmlTreeBuilder;
import com.google.common.collect.Maps;

import org.json.JSONObject;

import java.util.Locale;
import java.util.Map;

public class Utils {
    /**
     * longest extension we recognize is 4 characters (e.g. "html", "docx")
     */
    private static final int FILE_EXTENSION_MAX_CHARS = 4;
    private static final Map<Integer, Integer> sPriorityToLength = Maps.newHashMap();
    public static final String SENDER_LIST_TOKEN_ELIDED = "e";
    public static final String SENDER_LIST_TOKEN_NUM_MESSAGES = "n";
    public static final String SENDER_LIST_TOKEN_NUM_DRAFTS = "d";
    public static final String SENDER_LIST_TOKEN_LITERAL = "l";
    public static final String SENDER_LIST_TOKEN_SENDING = "s";
    public static final String SENDER_LIST_TOKEN_SEND_FAILED = "f";
    public static final Character SENDER_LIST_SEPARATOR = '\n';
    public static final SimpleStringSplitter sSenderListSplitter = new SimpleStringSplitter(
            SENDER_LIST_SEPARATOR);
    public static String[] sSenderFragments = new String[8];

    public static final String EXTRA_ACCOUNT = "account";
    public static final String EXTRA_ACCOUNT_URI = "accountUri";
    public static final String EXTRA_FOLDER_URI = "folderUri";
    public static final String EXTRA_COMPOSE_URI = "composeUri";
    public static final String EXTRA_CONVERSATION = "conversationUri";
    public static final String EXTRA_FOLDER = "folder";
    /*
     * Notifies that changes happened. Certain UI components, e.g., widgets, can
     * register for this {@link Intent} and update accordingly. However, this
     * can be very broad and is NOT the preferred way of getting notification.
     */
    // TODO: UI Provider has this notification URI?
    public static final String ACTION_NOTIFY_DATASET_CHANGED =
            "com.android.mail.ACTION_NOTIFY_DATASET_CHANGED";

    /** Parameter keys for context-aware help. */
    private static final String SMART_HELP_LINK_PARAMETER_NAME = "p";

    private static final String SMART_LINK_APP_VERSION = "version";
    private static String sVersionCode = null;

    private static final String LOG_TAG = LogTag.getLogTag();

    public static boolean isRunningJellybeanOrLater() {
        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN;
    }

    /**
     * Sets WebView in a restricted mode suitable for email use.
     *
     * @param webView The WebView to restrict
     */
    public static void restrictWebView(WebView webView) {
        WebSettings webSettings = webView.getSettings();
        webSettings.setSavePassword(false);
        webSettings.setSaveFormData(false);
        webSettings.setJavaScriptEnabled(true);
        webSettings.setSupportZoom(false);
    }

    /**
     * Format a plural string.
     *
     * @param resource The identity of the resource, which must be a R.plurals
     * @param count The number of items.
     */
    public static String formatPlural(Context context, int resource, int count) {
        CharSequence formatString = context.getResources().getQuantityText(resource, count);
        return String.format(formatString.toString(), count);
    }

    /**
     * @return an ellipsized String that's at most maxCharacters long. If the
     *         text passed is longer, it will be abbreviated. If it contains a
     *         suffix, the ellipses will be inserted in the middle and the
     *         suffix will be preserved.
     */
    public static String ellipsize(String text, int maxCharacters) {
        int length = text.length();
        if (length < maxCharacters)
            return text;

        int realMax = Math.min(maxCharacters, length);
        // Preserve the suffix if any
        int index = text.lastIndexOf(".");
        String extension = "\u2026"; // "...";
        if (index >= 0) {
            // Limit the suffix to dot + four characters
            if (length - index <= FILE_EXTENSION_MAX_CHARS + 1) {
                extension = extension + text.substring(index + 1);
            }
        }
        realMax -= extension.length();
        if (realMax < 0)
            realMax = 0;
        return text.substring(0, realMax) + extension;
    }

    /**
     * Ensures that the given string starts and ends with the double quote
     * character. The string is not modified in any way except to add the double
     * quote character to start and end if it's not already there. sample ->
     * "sample" "sample" -> "sample" ""sample"" -> "sample"
     * "sample"" -> "sample" sa"mp"le -> "sa"mp"le" "sa"mp"le" -> "sa"mp"le"
     * (empty string) -> "" " -> ""
     */
    public static String ensureQuotedString(String s) {
        if (s == null) {
            return null;
        }
        if (!s.matches("^\".*\"$")) {
            return "\"" + s + "\"";
        } else {
            return s;
        }
    }

    // TODO: Move this to the UI Provider.
    private static CharacterStyle sUnreadStyleSpan = null;
    private static CharacterStyle sReadStyleSpan;
    private static CharacterStyle sDraftsStyleSpan;
    private static CharSequence sMeString;
    private static CharSequence sDraftSingularString;
    private static CharSequence sDraftPluralString;
    private static CharSequence sSendingString;
    private static CharSequence sSendFailedString;

    private static int sMaxUnreadCount = -1;
    private static String sUnreadText;
    private static int sDefaultFolderBackgroundColor = -1;

    public static void getStyledSenderSnippet(Context context, String senderInstructions,
            SpannableStringBuilder senderBuilder, SpannableStringBuilder statusBuilder,
            int maxChars, boolean forceAllUnread, boolean forceAllRead, boolean allowDraft) {
        Resources res = context.getResources();
        if (sUnreadStyleSpan == null) {
            sUnreadStyleSpan = new StyleSpan(Typeface.BOLD);
            sReadStyleSpan = new StyleSpan(Typeface.NORMAL);
            sDraftsStyleSpan = new ForegroundColorSpan(res.getColor(R.color.drafts));

            sMeString = context.getText(R.string.me);
            sDraftSingularString = res.getQuantityText(R.plurals.draft, 1);
            sDraftPluralString = res.getQuantityText(R.plurals.draft, 2);
            SpannableString sendingString = new SpannableString(context.getText(R.string.sending));
            sendingString.setSpan(CharacterStyle.wrap(sDraftsStyleSpan), 0, sendingString.length(),
                    0);
            sSendingString = sendingString;
            sSendFailedString = context.getText(R.string.send_failed);
        }

        getSenderSnippet(senderInstructions, senderBuilder, statusBuilder, maxChars,
                sUnreadStyleSpan, sReadStyleSpan, sDraftsStyleSpan, sMeString,
                sDraftSingularString, sDraftPluralString, sSendingString, sSendFailedString,
                forceAllUnread, forceAllRead, allowDraft);
    }

    /**
     * Uses sender instructions to build a formatted string.
     * <p>
     * Sender list instructions contain compact information about the sender
     * list. Most work that can be done without knowing how much room will be
     * availble for the sender list is done when creating the instructions.
     * <p>
     * The instructions string consists of tokens separated by
     * SENDER_LIST_SEPARATOR. Here are the tokens, one per line:
     * <ul>
     * <li><tt>n</tt></li>
     * <li><em>int</em>, the number of non-draft messages in the conversation</li>
     * <li><tt>d</tt</li>
     * <li><em>int</em>, the number of drafts in the conversation</li>
     * <li><tt>l</tt></li>
     * <li><em>literal html to be included in the output</em></li>
     * <li><tt>s</tt> indicates that the message is sending (in the outbox
     * without errors)</li>
     * <li><tt>f</tt> indicates that the message failed to send (in the outbox
     * with errors)</li>
     * <li><em>for each message</em>
     * <ul>
     * <li><em>int</em>, 0 for read, 1 for unread</li>
     * <li><em>int</em>, the priority of the message. Zero is the most important
     * </li>
     * <li><em>text</em>, the sender text or blank for messages from 'me'</li>
     * </ul>
     * </li>
     * <li><tt>e</tt> to indicate that one or more messages have been elided</li>
     * <p>
     * The instructions indicate how many messages and drafts are in the
     * conversation and then describe the most important messages in order,
     * indicating the priority of each message and whether the message is
     * unread.
     *
     * @param instructions instructions as described above
     * @param senderBuilder the SpannableStringBuilder to append to for sender
     *            information
     * @param statusBuilder the SpannableStringBuilder to append to for status
     * @param maxChars the number of characters available to display the text
     * @param unreadStyle the CharacterStyle for unread messages, or null
     * @param draftsStyle the CharacterStyle for draft messages, or null
     * @param sendingString the string to use when there are messages scheduled
     *            to be sent
     * @param sendFailedString the string to use when there are messages that
     *            mailed to send
     * @param meString the string to use for messages sent by this user
     * @param draftString the string to use for "Draft"
     * @param draftPluralString the string to use for "Drafts"
     */
    public static synchronized void getSenderSnippet(String instructions,
            SpannableStringBuilder senderBuilder, SpannableStringBuilder statusBuilder,
            int maxChars, CharacterStyle unreadStyle, CharacterStyle readStyle,
            CharacterStyle draftsStyle, CharSequence meString, CharSequence draftString,
            CharSequence draftPluralString, CharSequence sendingString,
            CharSequence sendFailedString, boolean forceAllUnread, boolean forceAllRead,
            boolean allowDraft) {
        assert !(forceAllUnread && forceAllRead);
        boolean unreadStatusIsForced = forceAllUnread || forceAllRead;
        boolean forcedUnreadStatus = forceAllUnread;

        // Measure each fragment. It's ok to iterate over the entire set of
        // fragments because it is
        // never a long list, even if there are many senders.
        final Map<Integer, Integer> priorityToLength = sPriorityToLength;
        priorityToLength.clear();

        int maxFoundPriority = Integer.MIN_VALUE;
        int numMessages = 0;
        int numDrafts = 0;
        CharSequence draftsFragment = "";
        CharSequence sendingFragment = "";
        CharSequence sendFailedFragment = "";

        sSenderListSplitter.setString(instructions);
        int numFragments = 0;
        String[] fragments = sSenderFragments;
        int currentSize = fragments.length;
        while (sSenderListSplitter.hasNext()) {
            fragments[numFragments++] = sSenderListSplitter.next();
            if (numFragments == currentSize) {
                sSenderFragments = new String[2 * currentSize];
                System.arraycopy(fragments, 0, sSenderFragments, 0, currentSize);
                currentSize *= 2;
                fragments = sSenderFragments;
            }
        }

        for (int i = 0; i < numFragments;) {
            String fragment0 = fragments[i++];
            if ("".equals(fragment0)) {
                // This should be the final fragment.
            } else if (SENDER_LIST_TOKEN_ELIDED.equals(fragment0)) {
                // ignore
            } else if (SENDER_LIST_TOKEN_NUM_MESSAGES.equals(fragment0)) {
                numMessages = Integer.valueOf(fragments[i++]);
            } else if (SENDER_LIST_TOKEN_NUM_DRAFTS.equals(fragment0)) {
                String numDraftsString = fragments[i++];
                numDrafts = Integer.parseInt(numDraftsString);
                draftsFragment = numDrafts == 1 ? draftString : draftPluralString + " ("
                        + numDraftsString + ")";
            } else if (SENDER_LIST_TOKEN_LITERAL.equals(fragment0)) {
                senderBuilder.append(Html.fromHtml(fragments[i++]));
                return;
            } else if (SENDER_LIST_TOKEN_SENDING.equals(fragment0)) {
                sendingFragment = sendingString;
            } else if (SENDER_LIST_TOKEN_SEND_FAILED.equals(fragment0)) {
                sendFailedFragment = sendFailedString;
            } else {
                String priorityString = fragments[i++];
                CharSequence nameString = fragments[i++];
                if (nameString.length() == 0)
                    nameString = meString;
                int priority = Integer.parseInt(priorityString);
                priorityToLength.put(priority, nameString.length());
                maxFoundPriority = Math.max(maxFoundPriority, priority);
            }
        }
        String numMessagesFragment = (numMessages != 0) ? " \u00A0"
                + Integer.toString(numMessages + numDrafts) : "";

        // Don't allocate fixedFragment unless we need it
        SpannableStringBuilder fixedFragment = null;
        int fixedFragmentLength = 0;
        if (draftsFragment.length() != 0 && allowDraft) {
            if (fixedFragment == null) {
                fixedFragment = new SpannableStringBuilder();
            }
            fixedFragment.append(draftsFragment);
            if (draftsStyle != null) {
                fixedFragment.setSpan(CharacterStyle.wrap(draftsStyle), 0, fixedFragment.length(),
                        Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
            }
        }
        if (sendingFragment.length() != 0) {
            if (fixedFragment == null) {
                fixedFragment = new SpannableStringBuilder();
            }
            if (fixedFragment.length() != 0)
                fixedFragment.append(", ");
            fixedFragment.append(sendingFragment);
        }
        if (sendFailedFragment.length() != 0) {
            if (fixedFragment == null) {
                fixedFragment = new SpannableStringBuilder();
            }
            if (fixedFragment.length() != 0)
                fixedFragment.append(", ");
            fixedFragment.append(sendFailedFragment);
        }

        if (fixedFragment != null) {
            fixedFragmentLength = fixedFragment.length();
        }
        maxChars -= fixedFragmentLength;

        int maxPriorityToInclude = -1; // inclusive
        int numCharsUsed = numMessagesFragment.length();
        int numSendersUsed = 0;
        while (maxPriorityToInclude < maxFoundPriority) {
            if (priorityToLength.containsKey(maxPriorityToInclude + 1)) {
                int length = numCharsUsed + priorityToLength.get(maxPriorityToInclude + 1);
                if (numCharsUsed > 0)
                    length += 2;
                // We must show at least two senders if they exist. If we don't
                // have space for both
                // then we will truncate names.
                if (length > maxChars && numSendersUsed >= 2) {
                    break;
                }
                numCharsUsed = length;
                numSendersUsed++;
            }
            maxPriorityToInclude++;
        }

        int numCharsToRemovePerWord = 0;
        if (numCharsUsed > maxChars) {
            numCharsToRemovePerWord = (numCharsUsed - maxChars) / numSendersUsed;
        }

        String lastFragment = null;
        CharacterStyle lastStyle = null;
        for (int i = 0; i < numFragments;) {
            String fragment0 = fragments[i++];
            if ("".equals(fragment0)) {
                // This should be the final fragment.
            } else if (SENDER_LIST_TOKEN_ELIDED.equals(fragment0)) {
                if (lastFragment != null) {
                    addStyledFragment(senderBuilder, lastFragment, lastStyle, false);
                    senderBuilder.append(" ");
                    addStyledFragment(senderBuilder, "..", lastStyle, true);
                    senderBuilder.append(" ");
                }
                lastFragment = null;
            } else if (SENDER_LIST_TOKEN_NUM_MESSAGES.equals(fragment0)) {
                i++;
            } else if (SENDER_LIST_TOKEN_NUM_DRAFTS.equals(fragment0)) {
                i++;
            } else if (SENDER_LIST_TOKEN_SENDING.equals(fragment0)) {
            } else if (SENDER_LIST_TOKEN_SEND_FAILED.equals(fragment0)) {
            } else {
                final String unreadString = fragment0;
                final String priorityString = fragments[i++];
                String nameString = fragments[i++];
                if (nameString.length() == 0) {
                    nameString = meString.toString();
                } else {
                    nameString = Html.fromHtml(nameString).toString();
                }
                if (numCharsToRemovePerWord != 0) {
                    nameString = nameString.substring(0,
                            Math.max(nameString.length() - numCharsToRemovePerWord, 0));
                }
                final boolean unread = unreadStatusIsForced ? forcedUnreadStatus : Integer
                        .parseInt(unreadString) != 0;
                final int priority = Integer.parseInt(priorityString);
                if (priority <= maxPriorityToInclude) {
                    if (lastFragment != null && !lastFragment.equals(nameString)) {
                        addStyledFragment(senderBuilder, lastFragment.concat(","), lastStyle,
                                false);
                        senderBuilder.append(" ");
                    }
                    lastFragment = nameString;
                    lastStyle = unread ? unreadStyle : readStyle;
                } else {
                    if (lastFragment != null) {
                        addStyledFragment(senderBuilder, lastFragment, lastStyle, false);
                        // Adjacent spans can cause the TextView in Gmail widget
                        // confused and leads to weird behavior on scrolling.
                        // Our workaround here is to separate the spans by
                        // spaces.
                        senderBuilder.append(" ");
                        addStyledFragment(senderBuilder, "..", lastStyle, true);
                        senderBuilder.append(" ");
                    }
                    lastFragment = null;
                }
            }
        }
        if (lastFragment != null) {
            addStyledFragment(senderBuilder, lastFragment, lastStyle, false);
        }
        senderBuilder.append(numMessagesFragment);
        if (fixedFragmentLength != 0) {
            statusBuilder.append(fixedFragment);
        }
    }

    /**
     * Adds a fragment with given style to a string builder.
     *
     * @param builder the current string builder
     * @param fragment the fragment to be added
     * @param style the style of the fragment
     * @param withSpaces whether to add the whole fragment or to divide it into
     *            smaller ones
     */
    private static void addStyledFragment(SpannableStringBuilder builder, String fragment,
            CharacterStyle style, boolean withSpaces) {
        if (withSpaces) {
            int pos = builder.length();
            builder.append(fragment);
            builder.setSpan(CharacterStyle.wrap(style), pos, builder.length(),
                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
        } else {
            int start = 0;
            while (true) {
                int pos = fragment.substring(start).indexOf(' ');
                if (pos == -1) {
                    addStyledFragment(builder, fragment.substring(start), style, true);
                    break;
                } else {
                    pos += start;
                    if (start < pos) {
                        addStyledFragment(builder, fragment.substring(start, pos), style, true);
                        builder.append(' ');
                    }
                    start = pos + 1;
                    if (start >= fragment.length()) {
                        break;
                    }
                }
            }
        }
    }

    /**
     * Returns a boolean indicating whether the table UI should be shown.
     */
    public static boolean useTabletUI(Context context) {
        return context.getResources().getInteger(R.integer.use_tablet_ui) != 0;
    }

    /**
     * Returns displayable text from the provided HTML string.
     *
     * @param htmlText HTML string
     * @return Plain text string representation of the specified Html string
     */
    public static String convertHtmlToPlainText(String htmlText) {
        return getHtmlTree(htmlText).getPlainText();
    }

    /**
     * Returns a {@link HtmlTree} representation of the specified HTML string.
     */
    public static HtmlTree getHtmlTree(String htmlText) {
        final HtmlParser parser = new HtmlParser();
        final HtmlDocument doc = parser.parse(htmlText);
        final HtmlTreeBuilder builder = new HtmlTreeBuilder();
        doc.accept(builder);

        return builder.getTree();
    }


    /**
     * Perform a simulated measure pass on the given child view, assuming the
     * child has a ViewGroup parent and that it should be laid out within that
     * parent with a matching width but variable height. Code largely lifted
     * from AnimatedAdapter.measureChildHeight().
     *
     * @param child a child view that has already been placed within its parent
     *            ViewGroup
     * @param parent the parent ViewGroup of child
     * @return measured height of the child in px
     */
    public static int measureViewHeight(View child, ViewGroup parent) {
        int parentWSpec = MeasureSpec.makeMeasureSpec(parent.getWidth(), MeasureSpec.EXACTLY);
        int wSpec = ViewGroup.getChildMeasureSpec(parentWSpec,
                parent.getPaddingLeft() + parent.getPaddingRight(),
                ViewGroup.LayoutParams.MATCH_PARENT);
        int hSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
        child.measure(wSpec, hSpec);
        return child.getMeasuredHeight();
    }

    /**
     * Encode the string in HTML.
     *
     * @param removeEmptyDoubleQuotes If true, also remove any occurrence of ""
     *            found in the string
     */
    public static Object cleanUpString(String string, boolean removeEmptyDoubleQuotes) {
        return !TextUtils.isEmpty(string) ? TextUtils.htmlEncode(removeEmptyDoubleQuotes ? string
                .replace("\"\"", "") : string) : "";
    }

    /**
     * Returns comma seperated strings as an array.
     */
    public static String[] splitCommaSeparatedString(String str) {
        return TextUtils.isEmpty(str) ? new String[0] : TextUtils.split(str, ",");
    }

    /**
     * Get the correct display string for the unread count of a folder.
     */
    public static String getUnreadCountString(Context context, int unreadCount) {
        String unreadCountString;
        Resources resources = context.getResources();
        if (sMaxUnreadCount == -1) {
            sMaxUnreadCount = resources.getInteger(R.integer.maxUnreadCount);
        }
        if (unreadCount > sMaxUnreadCount) {
            if (sUnreadText == null) {
                sUnreadText = resources.getString(R.string.widget_large_unread_count);
            }
            unreadCountString = String.format(sUnreadText, sMaxUnreadCount);
        } else if (unreadCount <= 0) {
            unreadCountString = "";
        } else {
            unreadCountString = String.valueOf(unreadCount);
        }
        return unreadCountString;
    }

    /**
     * Get text matching the last sync status.
     */
    public static CharSequence getSyncStatusText(Context context, int status) {
        String[] errors = context.getResources().getStringArray(R.array.sync_status);
        if (status >= errors.length) {
            return "";
        }
        return errors[status];
    }

    /**
     * Create an intent to show a conversation.
     * @param conversation Conversation to open.
     * @param folder
     * @param account
     * @return
     */
    public static Intent createViewConversationIntent(Conversation conversation, Folder folder,
            Account account) {
        final Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK |
                Intent.FLAG_ACTIVITY_TASK_ON_HOME);
        intent.setDataAndType(conversation.uri, account.mimeType);
        intent.putExtra(Utils.EXTRA_ACCOUNT, account.serialize());
        intent.putExtra(Utils.EXTRA_FOLDER, Folder.toString(folder));
        intent.putExtra(Utils.EXTRA_CONVERSATION, conversation);
        return intent;
    }

    /**
     * Create an intent to open a folder.
     *
     * @param folderUri Folder uri.
     * @param account
     * @param folder Folder to open.
     * @return
     */
    public static Intent createViewFolderIntent(Folder folder, Account account) {
        final Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK
                | Intent.FLAG_ACTIVITY_TASK_ON_HOME);
        intent.setDataAndType(folder.uri, account.mimeType);
        intent.putExtra(Utils.EXTRA_ACCOUNT, account.serialize());
        if (folder != null) {
            intent.putExtra(Utils.EXTRA_FOLDER, Folder.toString(folder));
        }
        return intent;
    }

    /**
     * Helper method to show context-aware Gmail help.
     *
     * @param context Context to be used to open the help.
     * @param fromWhere Information about the activity the user was in
     * when they requested help.
     */
    public static void showHelp(Context context, Account account, String fromWhere) {
        final String urlString = (account != null && account.helpIntentUri != null) ?
                account.helpIntentUri.toString() : null;
        if (TextUtils.isEmpty(urlString) ) {
            LogUtils.e(LOG_TAG, "unable to show help for account: %s", account);
            return;
        }
        final Uri uri = addParamsToUrl(context, urlString);
        Uri.Builder builder = uri.buildUpon();
        // Add the activity specific information parameter.
        if (!TextUtils.isEmpty(fromWhere)) {
            builder = builder.appendQueryParameter(SMART_HELP_LINK_PARAMETER_NAME, fromWhere);
        }

        openUrl(context, builder.build());
    }

    /**
     * Helper method to open a link in a browser.
     *
     * @param context Context
     * @param uri Uri to open.
     */
    private static void openUrl(Context context, Uri uri) {
        if(uri == null || TextUtils.isEmpty(uri.toString())) {
            LogUtils.wtf(LOG_TAG, "invalid url in Utils.openUrl(): %s", uri);
            return;
        }
        Intent intent = new Intent(Intent.ACTION_VIEW, uri);
        intent.putExtra(Browser.EXTRA_APPLICATION_ID, context.getPackageName());
        context.startActivity(intent);
    }


    private static Uri addParamsToUrl(Context context, String url) {
        url = replaceLocale(url);
        Uri.Builder builder = Uri.parse(url).buildUpon();
        final String versionCode = getVersionCode(context);
        if (versionCode != null) {
            builder = builder.appendQueryParameter(SMART_LINK_APP_VERSION, versionCode);
        }

        return builder.build();
    }

    /**
     * Replaces the language/country of the device into the given string.  The pattern "%locale%"
     * will be replaced with the <language_code>_<country_code> value.
     *
     * @param str the string to replace the language/country within
     *
     * @return the string with replacement
     */
    private static String replaceLocale(String str) {
        // Substitute locale if present in string
        if (str.contains("%locale%")) {
            Locale locale = Locale.getDefault();
            String tmp = locale.getLanguage() + "_" + locale.getCountry().toLowerCase();
            str = str.replace("%locale%", tmp);
        }
        return str;
    }

    /**
     * Returns the version code for the package, or null if it cannot be retrieved.
     */
    public static String getVersionCode(Context context) {
        if (sVersionCode == null) {
            try {
                sVersionCode = String.valueOf(context.getPackageManager()
                        .getPackageInfo(context.getPackageName(), 0 /* flags */)
                        .versionCode);
            } catch (NameNotFoundException e) {
                LogUtils.e(Utils.LOG_TAG, "Error finding package %s",
                        context.getApplicationInfo().packageName);
            }
        }
        return sVersionCode;
    }

    /**
     * Show the settings screen for the supplied account.
     */
    public static void showSettings(Context context, Account account) {
        if (account == null) {
            LogUtils.e(LOG_TAG, "Invalid attempt to show setting screen with null account");
            return;
        }
        final Intent settingsIntent = new Intent(Intent.ACTION_EDIT, account.settingsIntentUri);
        context.startActivity(settingsIntent);
    }

    /**
     * Show the settings screen for the supplied account.
     */
     public static void showFolderSettings(Context context, Account account, Folder folder) {
         if (account == null || folder == null) {
             LogUtils.e(LOG_TAG, "Invalid attempt to show folder settings. account: %s folder: %s",
                     account, folder);
             return;
         }
         final Intent settingsIntent = new Intent(Intent.ACTION_EDIT, account.settingsIntentUri);

         settingsIntent.putExtra(EditSettingsExtras.EXTRA_ACCOUNT, account);
         settingsIntent.putExtra(EditSettingsExtras.EXTRA_FOLDER, folder);

         context.startActivity(settingsIntent);
    }

    /**
     * Show the settings screen for managing all folders.
     */
     public static void showManageFolder(Context context, Account account) {
         if (account == null) {
             LogUtils.e(LOG_TAG, "Invalid attempt to the manage folders screen with null account");
             return;
         }
         final Intent settingsIntent = new Intent(Intent.ACTION_EDIT, account.settingsIntentUri);

         settingsIntent.putExtra(EditSettingsExtras.EXTRA_ACCOUNT, account);
         settingsIntent.putExtra(EditSettingsExtras.EXTRA_MANAGE_FOLDERS, true);

         context.startActivity(settingsIntent);
    }

    /**
     * Show the feedback screen for the supplied account.
     */
    public static void sendFeedback(Context context, Account account) {
        if (account != null && account.sendFeedbackIntentUri != null) {
            openUrl(context, account.sendFeedbackIntentUri);
        }
    }

    /**
     * Retrieves the mailbox search query associated with an intent (or null if not available),
     * doing proper sanitizing (e.g. trims whitespace).
     */
    public static String mailSearchQueryForIntent(Intent intent) {
        String query = intent.getStringExtra(SearchManager.QUERY);
        return TextUtils.isEmpty(query) ? null : query.trim();
   }

    /**
     * Split out a filename's extension and return it.
     * @param filename a file name
     * @return the file extension (max of 5 chars including period, like ".docx"), or null
     */
    public static String getFileExtension(String filename) {
        String extension = null;
        int index = !TextUtils.isEmpty(filename) ? filename.lastIndexOf('.') : -1;
        // Limit the suffix to dot + four characters
        if (index >= 0 && filename.length() - index <= FILE_EXTENSION_MAX_CHARS + 1) {
            extension = filename.substring(index);
        }
        return extension;
    }

   /**
    * (copied from {@link Intent#normalizeMimeType(String)} for pre-J)
    *
    * Normalize a MIME data type.
    *
    * <p>A normalized MIME type has white-space trimmed,
    * content-type parameters removed, and is lower-case.
    * This aligns the type with Android best practices for
    * intent filtering.
    *
    * <p>For example, "text/plain; charset=utf-8" becomes "text/plain".
    * "text/x-vCard" becomes "text/x-vcard".
    *
    * <p>All MIME types received from outside Android (such as user input,
    * or external sources like Bluetooth, NFC, or the Internet) should
    * be normalized before they are used to create an Intent.
    *
    * @param type MIME data type to normalize
    * @return normalized MIME data type, or null if the input was null
    * @see {@link #setType}
    * @see {@link #setTypeAndNormalize}
    */
   public static String normalizeMimeType(String type) {
       if (type == null) {
           return null;
       }

       type = type.trim().toLowerCase(Locale.US);

       final int semicolonIndex = type.indexOf(';');
       if (semicolonIndex != -1) {
           type = type.substring(0, semicolonIndex);
       }
       return type;
   }

   /**
    * (copied from {@link Uri#normalize()} for pre-J)
    *
    * Return a normalized representation of this Uri.
    *
    * <p>A normalized Uri has a lowercase scheme component.
    * This aligns the Uri with Android best practices for
    * intent filtering.
    *
    * <p>For example, "HTTP://www.android.com" becomes
    * "http://www.android.com"
    *
    * <p>All URIs received from outside Android (such as user input,
    * or external sources like Bluetooth, NFC, or the Internet) should
    * be normalized before they are used to create an Intent.
    *
    * <p class="note">This method does <em>not</em> validate bad URI's,
    * or 'fix' poorly formatted URI's - so do not use it for input validation.
    * A Uri will always be returned, even if the Uri is badly formatted to
    * begin with and a scheme component cannot be found.
    *
    * @return normalized Uri (never null)
    * @see {@link android.content.Intent#setData}
    * @see {@link #setNormalizedData}
    */
   public static Uri normalizeUri(Uri uri) {
       String scheme = uri.getScheme();
       if (scheme == null) return uri;  // give up
       String lowerScheme = scheme.toLowerCase(Locale.US);
       if (scheme.equals(lowerScheme)) return uri;  // no change

       return uri.buildUpon().scheme(lowerScheme).build();
   }

   public static Intent setIntentTypeAndNormalize(Intent intent, String type) {
       return intent.setType(normalizeMimeType(type));
   }

   public static Intent setIntentDataAndTypeAndNormalize(Intent intent, Uri data, String type) {
       return intent.setDataAndType(normalizeUri(data), normalizeMimeType(type));
   }

   public static int getTransparentColor(int color) {
       return 0x00ffffff & color;
   }

    public static void setMenuItemVisibility(Menu menu, int itemId, boolean shouldShow) {
        final MenuItem item = menu.findItem(itemId);
        if (item == null) {
            return;
        }
        item.setVisible(shouldShow);
    }

    /**
     * Parse a string (possibly null or empty) into a URI. If the string is null
     * or empty, null is returned back. Otherwise an empty URI is returned.
     *
     * @param uri
     * @return a valid URI, possibly {@link android.net.Uri#EMPTY}
     */
    public static Uri getValidUri(String uri) {
        if (TextUtils.isEmpty(uri) || uri == JSONObject.NULL)
            return Uri.EMPTY;
        return Uri.parse(uri);
    }

    public static boolean isEmpty(Uri uri) {
        return uri == null || uri.equals(Uri.EMPTY);
    }

    public static boolean executeConversationCursorCommand(Cursor cursor, String commandKey,
            boolean value) {
        final Bundle params = new Bundle();
        params.putBoolean(commandKey, value);
        final Bundle response = cursor.respond(params);
        final String result = response.getString(commandKey,
                UIProvider.ConversationCursorCommand.COMMAND_RESPONSE_FAILED);

        return UIProvider.ConversationCursorCommand.COMMAND_RESPONSE_OK.equals(result);
    }

    /**
     * Commands a cursor representing a set of conversations to disable any network requests it may
     * do as clients move through the cursor.
     *
     * @param cursor a conversation cursor
     * @return true iff the provider supports network requests and they were previously enabled
     */
    public static boolean disableConversationCursorNetworkAccess(Cursor cursor) {
        return executeConversationCursorCommand(cursor,
                UIProvider.ConversationCursorCommand.COMMAND_KEY_ALLOW_NETWORK_ACCESS, false);
    }

    /**
     * Commands a cursor representing a set of conversations to [re-]enable any network requests it
     * may do as clients move through the cursor.
     *
     * @param cursor a conversation cursor
     * @return true iff the provider supports network requests and they are successfully enabled
     */
    public static boolean enableConversationCursorNetworkAccess(Cursor cursor) {
        return executeConversationCursorCommand(cursor,
                UIProvider.ConversationCursorCommand.COMMAND_KEY_ALLOW_NETWORK_ACCESS, true);
    }

    /**
     * Commands a cursor representing a set of conversations to set its visibility state.
     *
     * @param cursor a conversation cursor
     */
    public static void setConversationCursorVisibility(Cursor cursor, boolean visible) {
        new MarkConversationCursorVisibleTask(cursor, visible).execute();
    }

    /**
     * Async task for  marking conversations "seen"
     */
    private static class MarkConversationCursorVisibleTask extends AsyncTask<Void, Void, Void> {
        private final Cursor mCursor;
        private final boolean mVisible;

        public MarkConversationCursorVisibleTask(Cursor cursor, boolean visible) {
            mCursor = cursor;
            mVisible = visible;
        }

        @Override
        protected Void doInBackground(Void... params) {
            if (mCursor != null) {
                executeConversationCursorCommand(mCursor,
                        UIProvider.ConversationCursorCommand.COMMAND_KEY_SET_VISIBILITY, mVisible);
            }
            return null;
        }
    }

    /**
     * @return whether to show two pane or single pane search results.
     */
    public static boolean showTwoPaneSearchResults(Context context) {
        return context.getResources().getBoolean(R.bool.show_two_pane_search_results);
    }

    /**
     * Return whether menus should show the disabled archive menu item or just
     * remove it when archive is not available.
     */
    public static boolean shouldShowDisabledArchiveIcon(Context context) {
        return context.getResources().getBoolean(R.bool.show_disabled_archive_menu_item);
    }

    public static int getDefaultFolderBackgroundColor(Context context) {
        if (sDefaultFolderBackgroundColor == -1) {
            sDefaultFolderBackgroundColor = context.getResources().getColor(
                    R.color.default_folder_background_color);
        }
        return sDefaultFolderBackgroundColor;
    }

    /**
     * Hacky method to allow invalidating views all the way up the hierarchy.
     */
    public static void markDirtyTillRoot(String message, View v) {
        LogUtils.d(LOG_TAG, "%s: markingDirtyTillRoot", message);
        v.invalidate();
        ViewParent parent = v.getParent();
        while (parent != null) {
            parent.requestLayout();
            parent = parent.getParent();
        }
    }

}