/*
 * Copyright (C) 2019 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.launcher3.icons;

import static android.content.Intent.ACTION_DATE_CHANGED;
import static android.content.Intent.ACTION_TIMEZONE_CHANGED;
import static android.content.Intent.ACTION_TIME_CHANGED;
import static android.content.res.Resources.ID_NULL;

import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.ActivityInfo;
import android.content.pm.LauncherActivityInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.res.Resources;
import android.content.res.XmlResourceParser;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.os.Handler;
import android.os.PatternMatcher;
import android.os.Process;
import android.os.UserHandle;
import android.os.UserManager;
import android.text.TextUtils;
import android.util.ArrayMap;
import android.util.Log;

import com.android.launcher3.icons.ThemedIconDrawable.ThemeData;
import com.android.launcher3.util.SafeCloseable;

import org.xmlpull.v1.XmlPullParser;

import java.util.Calendar;
import java.util.Collections;
import java.util.Map;
import java.util.function.Supplier;

/**
 * Class to handle icon loading from different packages
 */
public class IconProvider {

    private final String ACTION_OVERLAY_CHANGED = "android.intent.action.OVERLAY_CHANGED";
    private static final int CONFIG_ICON_MASK_RES_ID = Resources.getSystem().getIdentifier(
            "config_icon_mask", "string", "android");

    private static final String TAG_ICON = "icon";
    private static final String ATTR_PACKAGE = "package";
    private static final String ATTR_DRAWABLE = "drawable";

    private static final String TAG = "IconProvider";
    private static final boolean DEBUG = false;

    private static final String ICON_METADATA_KEY_PREFIX = ".dynamic_icons";

    private static final String SYSTEM_STATE_SEPARATOR = " ";
    private static final String THEMED_ICON_MAP_FILE = "grayscale_icon_map";

    private static final Map<String, ThemeData> DISABLED_MAP = Collections.emptyMap();

    private Map<String, ThemeData> mThemedIconMap;

    private final Context mContext;
    private final ComponentName mCalendar;
    private final ComponentName mClock;

    static final int ICON_TYPE_DEFAULT = 0;
    static final int ICON_TYPE_CALENDAR = 1;
    static final int ICON_TYPE_CLOCK = 2;

    public IconProvider(Context context) {
        this(context, false);
    }

    public IconProvider(Context context, boolean supportsIconTheme) {
        mContext = context;
        mCalendar = parseComponentOrNull(context, R.string.calendar_component_name);
        mClock = parseComponentOrNull(context, R.string.clock_component_name);
        if (!supportsIconTheme) {
            // Initialize an empty map if theming is not supported
            mThemedIconMap = DISABLED_MAP;
        }
    }

    /**
     * Enables or disables icon theme support
     */
    public void setIconThemeSupported(boolean isSupported) {
        mThemedIconMap = isSupported ? null : DISABLED_MAP;
    }

    /**
     * Adds any modification to the provided systemState for dynamic icons. This system state
     * is used by caches to check for icon invalidation.
     */
    public String getSystemStateForPackage(String systemState, String packageName) {
        if (mCalendar != null && mCalendar.getPackageName().equals(packageName)) {
            return systemState + SYSTEM_STATE_SEPARATOR + getDay();
        } else {
            return systemState;
        }
    }

    /**
     * Loads the icon for the provided LauncherActivityInfo
     */
    public Drawable getIcon(LauncherActivityInfo info, int iconDpi) {
        return getIconWithOverrides(info.getApplicationInfo().packageName, info.getUser(), iconDpi,
                () -> info.getIcon(iconDpi));
    }

    /**
     * Loads the icon for the provided activity info
     */
    public Drawable getIcon(ActivityInfo info) {
        return getIcon(info, mContext.getResources().getConfiguration().densityDpi);
    }

    /**
     * Loads the icon for the provided activity info
     */
    public Drawable getIcon(ActivityInfo info, int iconDpi) {
        return getIconWithOverrides(info.applicationInfo.packageName,
                UserHandle.getUserHandleForUid(info.applicationInfo.uid),
                iconDpi, () -> loadActivityInfoIcon(info, iconDpi));
    }

    private Drawable getIconWithOverrides(String packageName, UserHandle user, int iconDpi,
            Supplier<Drawable> fallback) {
        Drawable icon = null;

        int iconType = ICON_TYPE_DEFAULT;
        if (mCalendar != null && mCalendar.getPackageName().equals(packageName)) {
            icon = loadCalendarDrawable(iconDpi);
            iconType = ICON_TYPE_CALENDAR;
        } else if (mClock != null
                && mClock.getPackageName().equals(packageName)
                && Process.myUserHandle().equals(user)) {
            icon = loadClockDrawable(iconDpi);
            iconType = ICON_TYPE_CLOCK;
        }
        if (icon == null) {
            icon = fallback.get();
            iconType = ICON_TYPE_DEFAULT;
        }

        ThemeData td = getThemedIconMap().get(packageName);
        return td != null ? td.wrapDrawable(icon, iconType) : icon;
    }

    private Drawable loadActivityInfoIcon(ActivityInfo ai, int density) {
        final int iconRes = ai.getIconResource();
        Drawable icon = null;
        // Get the preferred density icon from the app's resources
        if (density != 0 && iconRes != 0) {
            try {
                final Resources resources = mContext.getPackageManager()
                        .getResourcesForApplication(ai.applicationInfo);
                icon = resources.getDrawableForDensity(iconRes, density);
            } catch (NameNotFoundException | Resources.NotFoundException exc) { }
        }
        // Get the default density icon
        if (icon == null) {
            icon = ai.loadIcon(mContext.getPackageManager());
        }
        return icon;
    }

    private Map<String, ThemeData> getThemedIconMap() {
        if (mThemedIconMap != null) {
            return mThemedIconMap;
        }
        ArrayMap<String, ThemeData> map = new ArrayMap<>();
        try {
            Resources res = mContext.getResources();
            int resID = res.getIdentifier(THEMED_ICON_MAP_FILE, "xml", mContext.getPackageName());
            if (resID != 0) {
                XmlResourceParser parser = res.getXml(resID);
                final int depth = parser.getDepth();

                int type;

                while ((type = parser.next()) != XmlPullParser.START_TAG
                        && type != XmlPullParser.END_DOCUMENT);

                while (((type = parser.next()) != XmlPullParser.END_TAG ||
                        parser.getDepth() > depth) && type != XmlPullParser.END_DOCUMENT) {
                    if (type != XmlPullParser.START_TAG) {
                        continue;
                    }
                    if (TAG_ICON.equals(parser.getName())) {
                        String pkg = parser.getAttributeValue(null, ATTR_PACKAGE);
                        int iconId = parser.getAttributeResourceValue(null, ATTR_DRAWABLE, 0);
                        if (iconId != 0 && !TextUtils.isEmpty(pkg)) {
                            map.put(pkg, new ThemeData(res, iconId));
                        }
                    }
                }
            }
        } catch (Exception e) {
            Log.e(TAG, "Unable to parse icon map", e);
        }
        mThemedIconMap = map;
        return mThemedIconMap;
    }

    private Drawable loadCalendarDrawable(int iconDpi) {
        PackageManager pm = mContext.getPackageManager();
        try {
            final Bundle metadata = pm.getActivityInfo(
                    mCalendar,
                    PackageManager.GET_UNINSTALLED_PACKAGES | PackageManager.GET_META_DATA)
                    .metaData;
            final Resources resources = pm.getResourcesForApplication(mCalendar.getPackageName());
            final int id = getDynamicIconId(metadata, resources);
            if (id != ID_NULL) {
                if (DEBUG) Log.d(TAG, "Got icon #" + id);
                return resources.getDrawableForDensity(id, iconDpi, null /* theme */);
            }
        } catch (PackageManager.NameNotFoundException e) {
            if (DEBUG) {
                Log.d(TAG, "Could not get activityinfo or resources for package: "
                        + mCalendar.getPackageName());
            }
        }
        return null;
    }

    private Drawable loadClockDrawable(int iconDpi) {
        return ClockDrawableWrapper.forPackage(mContext, mClock.getPackageName(), iconDpi);
    }

    /**
     * @param metadata metadata of the default activity of Calendar
     * @param resources from the Calendar package
     * @return the resource id for today's Calendar icon; 0 if resources cannot be found.
     */
    private int getDynamicIconId(Bundle metadata, Resources resources) {
        if (metadata == null) {
            return ID_NULL;
        }
        String key = mCalendar.getPackageName() + ICON_METADATA_KEY_PREFIX;
        final int arrayId = metadata.getInt(key, ID_NULL);
        if (arrayId == ID_NULL) {
            return ID_NULL;
        }
        try {
            return resources.obtainTypedArray(arrayId).getResourceId(getDay(), ID_NULL);
        } catch (Resources.NotFoundException e) {
            if (DEBUG) {
                Log.d(TAG, "package defines '" + key + "' but corresponding array not found");
            }
            return ID_NULL;
        }
    }

    /**
     * @return Today's day of the month, zero-indexed.
     */
    static int getDay() {
        return Calendar.getInstance().get(Calendar.DAY_OF_MONTH) - 1;
    }

    private static ComponentName parseComponentOrNull(Context context, int resId) {
        String cn = context.getString(resId);
        return TextUtils.isEmpty(cn) ? null : ComponentName.unflattenFromString(cn);
    }

    /**
     * Returns a string representation of the current system icon state
     */
    public String getSystemIconState() {
        return (CONFIG_ICON_MASK_RES_ID == ID_NULL
                ? "" : mContext.getResources().getString(CONFIG_ICON_MASK_RES_ID))
                + (mThemedIconMap == DISABLED_MAP ? ",no-theme" : ",with-theme");
    }

    /**
     * Registers a callback to listen for various system dependent icon changes.
     */
    public SafeCloseable registerIconChangeListener(IconChangeListener listener, Handler handler) {
        return new IconChangeReceiver(listener, handler);
    }

    private class IconChangeReceiver extends BroadcastReceiver implements SafeCloseable {

        private final IconChangeListener mCallback;
        private String mIconState;

        IconChangeReceiver(IconChangeListener callback, Handler handler) {
            mCallback = callback;
            mIconState = getSystemIconState();


            IntentFilter packageFilter = new IntentFilter(ACTION_OVERLAY_CHANGED);
            packageFilter.addDataScheme("package");
            packageFilter.addDataSchemeSpecificPart("android", PatternMatcher.PATTERN_LITERAL);
            mContext.registerReceiver(this, packageFilter, null, handler);

            if (mCalendar != null || mClock != null) {
                final IntentFilter filter = new IntentFilter(ACTION_TIMEZONE_CHANGED);
                if (mCalendar != null) {
                    filter.addAction(Intent.ACTION_TIME_CHANGED);
                    filter.addAction(ACTION_DATE_CHANGED);
                }
                mContext.registerReceiver(this, filter, null, handler);
            }
        }

        @Override
        public void onReceive(Context context, Intent intent) {
            switch (intent.getAction()) {
                case ACTION_TIMEZONE_CHANGED:
                    if (mClock != null) {
                        mCallback.onAppIconChanged(mClock.getPackageName(), Process.myUserHandle());
                    }
                    // follow through
                case ACTION_DATE_CHANGED:
                case ACTION_TIME_CHANGED:
                    if (mCalendar != null) {
                        for (UserHandle user
                                : context.getSystemService(UserManager.class).getUserProfiles()) {
                            mCallback.onAppIconChanged(mCalendar.getPackageName(), user);
                        }
                    }
                    break;
                case ACTION_OVERLAY_CHANGED: {
                    String newState = getSystemIconState();
                    if (!mIconState.equals(newState)) {
                        mIconState = newState;
                        mCallback.onSystemIconStateChanged(mIconState);
                    }
                    break;
                }
            }
        }

        @Override
        public void close() {
            mContext.unregisterReceiver(this);
        }
    }

    /**
     * Listener for receiving icon changes
     */
    public interface IconChangeListener {

        /**
         * Called when the icon for a particular app changes
         */
        void onAppIconChanged(String packageName, UserHandle user);

        /**
         * Called when the global icon state changed, which can typically affect all icons
         */
        void onSystemIconStateChanged(String iconState);
    }
}