/*
 * Copyright (C) 2006 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.calendar;

import static android.provider.Calendar.EVENT_BEGIN_TIME;

import android.content.AsyncQueryHandler;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.database.MatrixCursor;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.GradientDrawable;
import android.net.Uri;
import android.text.TextUtils;
import android.text.format.DateUtils;
import android.text.format.Time;
import android.util.Log;
import android.view.animation.AlphaAnimation;
import android.widget.ViewFlipper;

import java.util.Calendar;
import java.util.Formatter;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;

public class Utils {
    private static final boolean DEBUG = true;
    private static final String TAG = "CalUtils";
    private static final int CLEAR_ALPHA_MASK = 0x00FFFFFF;
    private static final int HIGH_ALPHA = 255 << 24;
    private static final int MED_ALPHA = 180 << 24;
    private static final int LOW_ALPHA = 150 << 24;

    protected static final String OPEN_EMAIL_MARKER = " <";
    protected static final String CLOSE_EMAIL_MARKER = ">";
    /* The corner should be rounded on the top right and bottom right */
    private static final float[] CORNERS = new float[] {0, 0, 5, 5, 5, 5, 0, 0};

    // TODO switch these to use Calendar.java when it gets added
    private static final String TIMEZONE_COLUMN_KEY = "key";
    private static final String TIMEZONE_COLUMN_VALUE = "value";
    private static final String TIMEZONE_KEY_TYPE = "timezoneType";
    private static final String TIMEZONE_KEY_INSTANCES = "timezoneInstances";
    private static final String TIMEZONE_KEY_INSTANCES_PREVIOUS = "timezoneInstancesPrevious";
    private static final String TIMEZONE_TYPE_AUTO = "auto";
    private static final String TIMEZONE_TYPE_HOME = "home";
    private static final String[] TIMEZONE_POJECTION = new String[] {
        TIMEZONE_COLUMN_KEY,
        TIMEZONE_COLUMN_VALUE,
    };
    // Uri.parse("content://" + AUTHORITY + "/reminders");
    private static final Uri TIMEZONE_URI =
            Uri.parse("content://" + android.provider.Calendar.AUTHORITY + "/properties");
    private static final String TIMEZONE_UPDATE_WHERE = "key=?";


    private static StringBuilder mSB = new StringBuilder(50);
    private static Formatter mF = new Formatter(mSB, Locale.getDefault());
    private volatile static boolean mFirstTZRequest = true;
    private volatile static boolean mTZQueryInProgress = false;

    private volatile static boolean mUseHomeTZ = false;
    private volatile static String mHomeTZ = Time.getCurrentTimezone();

    private static HashSet<Runnable> mTZCallbacks = new HashSet<Runnable>();
    private static int mToken = 1;
    private static AsyncTZHandler mHandler;

    private static class AsyncTZHandler extends AsyncQueryHandler {
        public AsyncTZHandler(ContentResolver cr) {
            super(cr);
        }

        @Override
        protected void onQueryComplete(int token, Object cookie, Cursor cursor) {
            synchronized (mTZCallbacks) {
                boolean writePrefs = false;
                // Check the values in the db
                while(cursor.moveToNext()) {
                    int keyColumn = cursor.getColumnIndexOrThrow(TIMEZONE_COLUMN_KEY);
                    int valueColumn = cursor.getColumnIndexOrThrow(TIMEZONE_COLUMN_VALUE);
                    String key = cursor.getString(keyColumn);
                    String value = cursor.getString(valueColumn);
                    if (TextUtils.equals(key, TIMEZONE_KEY_TYPE)) {
                        boolean useHomeTZ = !TextUtils.equals(value, TIMEZONE_TYPE_AUTO);
                        if (useHomeTZ != mUseHomeTZ) {
                            writePrefs = true;
                            mUseHomeTZ = useHomeTZ;
                        }
                    } else if (TextUtils.equals(key, TIMEZONE_KEY_INSTANCES_PREVIOUS)) {
                        if (!TextUtils.isEmpty(value) && !TextUtils.equals(mHomeTZ, value)) {
                            writePrefs = true;
                            mHomeTZ = value;
                        }
                    }
                }
                if (writePrefs) {
                    // Write the prefs
                    setSharedPreference((Context)cookie,
                            CalendarPreferenceActivity.KEY_HOME_TZ_ENABLED, mUseHomeTZ);
                    setSharedPreference((Context)cookie,
                            CalendarPreferenceActivity.KEY_HOME_TZ, mHomeTZ);
                }

                mTZQueryInProgress = false;
                for (Runnable callback : mTZCallbacks) {
                    if (callback != null) {
                        callback.run();
                    }
                }
                mTZCallbacks.clear();
            }
        }
    }

    public static void startActivity(Context context, String className, long time) {
        Intent intent = new Intent(Intent.ACTION_VIEW);

        intent.setClassName(context, className);
        intent.putExtra(EVENT_BEGIN_TIME, time);
        intent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT | Intent.FLAG_ACTIVITY_SINGLE_TOP);

        context.startActivity(intent);
    }

    static String getSharedPreference(Context context, String key, String defaultValue) {
        SharedPreferences prefs = CalendarPreferenceActivity.getSharedPreferences(context);
        return prefs.getString(key, defaultValue);
    }

    /**
     * Writes a new home time zone to the db.
     *
     * Updates the home time zone in the db asynchronously and updates
     * the local cache. Sending a time zone of **tbd** will cause it to
     * be set to the device's time zone. null or empty tz will be ignored.
     *
     * @param context The calling activity
     * @param timeZone The time zone to set Calendar to, or **tbd**
     */
    public static void setTimeZone(Context context, String timeZone) {
        if (TextUtils.isEmpty(timeZone)) {
            if (DEBUG) {
                Log.d(TAG, "Empty time zone, nothing to be done.");
            }
            return;
        }
        boolean updatePrefs = false;
        synchronized (mTZCallbacks) {
            if (CalendarPreferenceActivity.LOCAL_TZ.equals(timeZone)) {
                if (mUseHomeTZ) {
                    updatePrefs = true;
                }
                mUseHomeTZ = false;
            } else {
                if (!mUseHomeTZ || !TextUtils.equals(mHomeTZ, timeZone)) {
                    updatePrefs = true;
                }
                mUseHomeTZ = true;
                mHomeTZ = timeZone;
            }
        }
        if (updatePrefs) {
            // Write the prefs
            setSharedPreference(context, CalendarPreferenceActivity.KEY_HOME_TZ_ENABLED,
                    mUseHomeTZ);
            setSharedPreference(context, CalendarPreferenceActivity.KEY_HOME_TZ, mHomeTZ);

            // Update the db
            ContentValues values = new ContentValues();
            if (mHandler == null) {
                mHandler = new AsyncTZHandler(context.getContentResolver());
            }

            mHandler.cancelOperation(mToken);

            // skip 0 so query can use it
            if (++mToken == 0) {
                mToken = 1;
            }

            String[] selArgs = new String[] {TIMEZONE_KEY_TYPE};
            values.put(TIMEZONE_COLUMN_VALUE, mUseHomeTZ ? TIMEZONE_TYPE_HOME : TIMEZONE_TYPE_AUTO);
            mHandler.startUpdate(mToken, null, TIMEZONE_URI, values, TIMEZONE_UPDATE_WHERE,
                    selArgs);

            if (mUseHomeTZ) {
                selArgs[0] = TIMEZONE_KEY_INSTANCES;
                values.clear();
                values.put(TIMEZONE_COLUMN_VALUE, mHomeTZ);
                mHandler.startUpdate(mToken, null, TIMEZONE_URI, values, TIMEZONE_UPDATE_WHERE,
                        selArgs);
            }
        }
    }

    /**
     * Gets the time zone that Calendar should be displayed in
     *
     * This is a helper method to get the appropriate time zone for Calendar. If this
     * is the first time this method has been called it will initiate an asynchronous
     * query to verify that the data in preferences is correct. The callback supplied
     * will only be called if this query returns a value other than what is stored in
     * preferences and should cause the calling activity to refresh anything that
     * depends on calling this method.
     *
     * @param context The calling activity
     * @param callback The runnable that should execute if a query returns new values
     * @return The string value representing the time zone Calendar should display
     */
    public static String getTimeZone(Context context, Runnable callback) {
        synchronized (mTZCallbacks){
            if (mFirstTZRequest) {
                mTZQueryInProgress = true;
                mFirstTZRequest = false;

                SharedPreferences prefs = CalendarPreferenceActivity.getSharedPreferences(context);
                mUseHomeTZ = prefs.getBoolean(
                        CalendarPreferenceActivity.KEY_HOME_TZ_ENABLED, false);
                mHomeTZ = prefs.getString(
                        CalendarPreferenceActivity.KEY_HOME_TZ, Time.getCurrentTimezone());

                // When the async query returns it should synchronize on
                // mTZCallbacks, update mUseHomeTZ, mHomeTZ, and the
                // preferences, set mTZQueryInProgress to false, and call all
                // the runnables in mTZCallbacks.
                if (mHandler == null) {
                    mHandler = new AsyncTZHandler(context.getContentResolver());
                }
                mHandler.startQuery(0, context, TIMEZONE_URI, TIMEZONE_POJECTION, null, null, null);
            }
            if (mTZQueryInProgress) {
                mTZCallbacks.add(callback);
            }
        }
        return mUseHomeTZ ? mHomeTZ : Time.getCurrentTimezone();
    }

    /**
     * Formats a date or a time range according to the local conventions.
     *
     * @param context the context is required only if the time is shown
     * @param startMillis the start time in UTC milliseconds
     * @param endMillis the end time in UTC milliseconds
     * @param flags a bit mask of options See
     * {@link #formatDateRange(Context, Formatter, long, long, int, String) formatDateRange}
     * @return a string containing the formatted date/time range.
     */
    public static String formatDateRange(Context context, long startMillis,
            long endMillis, int flags) {
        String date;
        synchronized (mSB) {
            mSB.setLength(0);
            date = DateUtils.formatDateRange(context, mF, startMillis, endMillis, flags,
                    getTimeZone(context, null)).toString();
        }
        return date;
    }

    static void setSharedPreference(Context context, String key, String value) {
        SharedPreferences prefs = CalendarPreferenceActivity.getSharedPreferences(context);
        SharedPreferences.Editor editor = prefs.edit();
        editor.putString(key, value);
        editor.commit();
    }

    static void setSharedPreference(Context context, String key, boolean value) {
        SharedPreferences prefs = CalendarPreferenceActivity.getSharedPreferences(context);
        SharedPreferences.Editor editor = prefs.edit();
        editor.putBoolean(key, value);
        editor.commit();
    }

    static void setDefaultView(Context context, int viewId) {
        String activityString = CalendarApplication.ACTIVITY_NAMES[viewId];

        SharedPreferences prefs = CalendarPreferenceActivity.getSharedPreferences(context);
        SharedPreferences.Editor editor = prefs.edit();
        if (viewId == CalendarApplication.AGENDA_VIEW_ID ||
                viewId == CalendarApplication.DAY_VIEW_ID) {
            // Record the (new) detail start view only for Agenda and Day
            editor.putString(CalendarPreferenceActivity.KEY_DETAILED_VIEW, activityString);
        }

        // Record the (new) start view
        editor.putString(CalendarPreferenceActivity.KEY_START_VIEW, activityString);
        editor.commit();
    }

    public static final Time timeFromIntent(Intent intent) {
        Time time = new Time();
        time.set(timeFromIntentInMillis(intent));
        return time;
    }

    public static MatrixCursor matrixCursorFromCursor(Cursor cursor) {
        MatrixCursor newCursor = new MatrixCursor(cursor.getColumnNames());
        int numColumns = cursor.getColumnCount();
        String data[] = new String[numColumns];
        cursor.moveToPosition(-1);
        while (cursor.moveToNext()) {
            for (int i = 0; i < numColumns; i++) {
                data[i] = cursor.getString(i);
            }
            newCursor.addRow(data);
        }
        return newCursor;
    }

    /**
     * Compares two cursors to see if they contain the same data.
     *
     * @return Returns true of the cursors contain the same data and are not null, false
     * otherwise
     */
    public static boolean compareCursors(Cursor c1, Cursor c2) {
        if(c1 == null || c2 == null) {
            return false;
        }

        int numColumns = c1.getColumnCount();
        if (numColumns != c2.getColumnCount()) {
            return false;
        }

        if (c1.getCount() != c2.getCount()) {
            return false;
        }

        c1.moveToPosition(-1);
        c2.moveToPosition(-1);
        while(c1.moveToNext() && c2.moveToNext()) {
            for(int i = 0; i < numColumns; i++) {
                if(!TextUtils.equals(c1.getString(i), c2.getString(i))) {
                    return false;
                }
            }
        }

        return true;
    }

    /**
     * If the given intent specifies a time (in milliseconds since the epoch),
     * then that time is returned. Otherwise, the current time is returned.
     */
    public static final long timeFromIntentInMillis(Intent intent) {
        // If the time was specified, then use that.  Otherwise, use the current time.
        Uri data = intent.getData();
        long millis = intent.getLongExtra(EVENT_BEGIN_TIME, -1);
        if (millis == -1 && data != null && data.isHierarchical()) {
            List<String> path = data.getPathSegments();
            if(path.size() == 2 && path.get(0).equals("time")) {
                try {
                    millis = Long.valueOf(data.getLastPathSegment());
                } catch (NumberFormatException e) {
                    Log.i("Calendar", "timeFromIntentInMillis: Data existed but no valid time " +
                            "found. Using current time.");
                }
            }
        }
        if (millis <= 0) {
            millis = System.currentTimeMillis();
        }
        return millis;
    }

    public static final void applyAlphaAnimation(ViewFlipper v) {
        AlphaAnimation in = new AlphaAnimation(0.0f, 1.0f);

        in.setStartOffset(0);
        in.setDuration(500);

        AlphaAnimation out = new AlphaAnimation(1.0f, 0.0f);

        out.setStartOffset(0);
        out.setDuration(500);

        v.setInAnimation(in);
        v.setOutAnimation(out);
    }

    public static Drawable getColorChip(int color) {
        /*
         * We want the color chip to have a nice gradient using
         * the color of the calendar. To do this we use a GradientDrawable.
         * The color supplied has an alpha of FF so we first do:
         * color & 0x00FFFFFF
         * to clear the alpha. Then we add our alpha to it.
         * We use 3 colors to get a step effect where it starts off very
         * light and quickly becomes dark and then a slow transition to
         * be even darker.
         */
        color &= CLEAR_ALPHA_MASK;
        int startColor = color | HIGH_ALPHA;
        int middleColor = color | MED_ALPHA;
        int endColor = color | LOW_ALPHA;
        int[] colors = new int[] {startColor, middleColor, endColor};
        GradientDrawable d = new GradientDrawable(GradientDrawable.Orientation.LEFT_RIGHT, colors);
        d.setCornerRadii(CORNERS);
        return d;
    }

    /**
     * Formats the given Time object so that it gives the month and year
     * (for example, "September 2007").
     *
     * @param time the time to format
     * @return the string containing the weekday and the date
     */
    public static String formatMonthYear(Context context, Time time) {
        return time.format(context.getResources().getString(R.string.month_year));
    }

    // TODO: replace this with the correct i18n way to do this
    public static final String englishNthDay[] = {
        "", "1st", "2nd", "3rd", "4th", "5th", "6th", "7th", "8th", "9th",
        "10th", "11th", "12th", "13th", "14th", "15th", "16th", "17th", "18th", "19th",
        "20th", "21st", "22nd", "23rd", "24th", "25th", "26th", "27th", "28th", "29th",
        "30th", "31st"
    };

    public static String formatNth(int nth) {
        return "the " + englishNthDay[nth];
    }

    /**
     * Returns a list joined together by the provided delimiter, for example,
     * ["a", "b", "c"] could be joined into "a,b,c"
     *
     * @param things the things to join together
     * @param delim the delimiter to use
     * @return a string contained the things joined together
     */
    public static String join(List<?> things, String delim) {
        StringBuilder builder = new StringBuilder();
        boolean first = true;
        for (Object thing : things) {
            if (first) {
                first = false;
            } else {
                builder.append(delim);
            }
            builder.append(thing.toString());
        }
        return builder.toString();
    }

    /**
     * Sets the time to the beginning of the day (midnight) by clearing the
     * hour, minute, and second fields.
     */
    static void setTimeToStartOfDay(Time time) {
        time.second = 0;
        time.minute = 0;
        time.hour = 0;
    }

    /**
     * Get first day of week as android.text.format.Time constant.
     * @return the first day of week in android.text.format.Time
     */
    public static int getFirstDayOfWeek() {
        int startDay = Calendar.getInstance().getFirstDayOfWeek();
        if (startDay == Calendar.SATURDAY) {
            return Time.SATURDAY;
        } else if (startDay == Calendar.MONDAY) {
            return Time.MONDAY;
        } else {
            return Time.SUNDAY;
        }
    }

    /**
     * Determine whether the column position is Saturday or not.
     * @param column the column position
     * @param firstDayOfWeek the first day of week in android.text.format.Time
     * @return true if the column is Saturday position
     */
    public static boolean isSaturday(int column, int firstDayOfWeek) {
        return (firstDayOfWeek == Time.SUNDAY && column == 6)
            || (firstDayOfWeek == Time.MONDAY && column == 5)
            || (firstDayOfWeek == Time.SATURDAY && column == 0);
    }

    /**
     * Determine whether the column position is Sunday or not.
     * @param column the column position
     * @param firstDayOfWeek the first day of week in android.text.format.Time
     * @return true if the column is Sunday position
     */
    public static boolean isSunday(int column, int firstDayOfWeek) {
        return (firstDayOfWeek == Time.SUNDAY && column == 0)
            || (firstDayOfWeek == Time.MONDAY && column == 6)
            || (firstDayOfWeek == Time.SATURDAY && column == 1);
    }

    /**
     * Scan through a cursor of calendars and check if names are duplicated.
     *
     * This travels a cursor containing calendar display names and fills in the provided map with
     * whether or not each name is repeated.
     * @param isDuplicateName The map to put the duplicate check results in.
     * @param cursor The query of calendars to check
     * @param nameIndex The column of the query that contains the display name
     */
    public static void checkForDuplicateNames(Map<String, Boolean> isDuplicateName, Cursor cursor,
            int nameIndex) {
        isDuplicateName.clear();
        cursor.moveToPosition(-1);
        while (cursor.moveToNext()) {
            String displayName = cursor.getString(nameIndex);
            // Set it to true if we've seen this name before, false otherwise
            if (displayName != null) {
                isDuplicateName.put(displayName, isDuplicateName.containsKey(displayName));
            }
        }
    }
}