/*
 * Copyright (C) 2014 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.systemui.statusbar.policy;

import android.app.ActivityManager;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.UserHandle;
import android.text.format.DateFormat;
import android.util.AttributeSet;
import android.widget.LinearLayout;
import android.widget.TextClock;

import com.android.systemui.R;

/**
 * Container for a clock which has two separate views for the clock itself and AM/PM indicator. This
 * is used to scale the clock independently of AM/PM.
 */
public class SplitClockView extends LinearLayout {

    private TextClock mTimeView;
    private TextClock mAmPmView;

    private BroadcastReceiver mIntentReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            final String action = intent.getAction();
            if (Intent.ACTION_TIME_CHANGED.equals(action)
                    || Intent.ACTION_TIMEZONE_CHANGED.equals(action)
                    || Intent.ACTION_LOCALE_CHANGED.equals(action)
                    || Intent.ACTION_CONFIGURATION_CHANGED.equals(action)
                    || Intent.ACTION_USER_SWITCHED.equals(action)) {
                updatePatterns();
            }
        }
    };

    public SplitClockView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
        mTimeView = (TextClock) findViewById(R.id.time_view);
        mAmPmView = (TextClock) findViewById(R.id.am_pm_view);
        mTimeView.setShowCurrentUserTime(true);
        mAmPmView.setShowCurrentUserTime(true);
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();

        IntentFilter filter = new IntentFilter();
        filter.addAction(Intent.ACTION_TIME_CHANGED);
        filter.addAction(Intent.ACTION_TIMEZONE_CHANGED);
        filter.addAction(Intent.ACTION_LOCALE_CHANGED);
        filter.addAction(Intent.ACTION_CONFIGURATION_CHANGED);
        filter.addAction(Intent.ACTION_USER_SWITCHED);
        getContext().registerReceiverAsUser(mIntentReceiver, UserHandle.ALL, filter, null, null);

        updatePatterns();
    }

    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        getContext().unregisterReceiver(mIntentReceiver);
    }

    private void updatePatterns() {
        String formatString = DateFormat.getTimeFormatString(getContext(),
                ActivityManager.getCurrentUser());
        int index = getAmPmPartEndIndex(formatString);
        String timeString;
        String amPmString;
        if (index == -1) {
            timeString = formatString;
            amPmString = "";
        } else {
            timeString = formatString.substring(0, index);
            amPmString = formatString.substring(index);
        }
        mTimeView.setFormat12Hour(timeString);
        mTimeView.setFormat24Hour(timeString);
        mAmPmView.setFormat12Hour(amPmString);
        mAmPmView.setFormat24Hour(amPmString);
    }

    /**
     * @return the index where the AM/PM part starts at the end in {@code formatString} including
     *         leading white spaces or {@code -1} if no AM/PM part is found or {@code formatString}
     *         doesn't end with AM/PM part
     */
    private static int getAmPmPartEndIndex(String formatString) {
        boolean hasAmPm = false;
        int length = formatString.length();
        for (int i = length - 1; i >= 0; i--) {
            char c = formatString.charAt(i);
            boolean isAmPm = c == 'a';
            boolean isWhitespace = Character.isWhitespace(c);
            if (isAmPm) {
                hasAmPm = true;
            }
            if (isAmPm || isWhitespace) {
                continue;
            }
            if (i == length - 1) {

                // First character was not AM/PM and not whitespace, so it's not ending with AM/PM.
                return -1;
            } else {

                // If we have AM/PM at all, return last index, or -1 to indicate that it's not
                // ending with AM/PM.
                return hasAmPm ? i + 1 : -1;
            }
        }

        // Only AM/PM and whitespaces? The whole string is AM/PM. Else: Only whitespaces in the
        // string.
        return hasAmPm ? 0 : -1;
    }

}