/*
 * Copyright (C) 2008 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;

import com.android.launcher3.backup.BackupProtos;

import android.app.ActivityManager;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.drawable.Drawable;
import android.text.TextUtils;
import android.util.Log;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map.Entry;

import com.android.launcher3.settings.SettingsProvider;

/**
 * Cache of application icons.  Icons can be made from any thread.
 */
public class IconCache {
    @SuppressWarnings("unused")
    private static final String TAG = "Launcher.IconCache";

    private static final int INITIAL_ICON_CACHE_CAPACITY = 50;
    private static final String RESOURCE_FILE_PREFIX = "icon_";

    private static final boolean DEBUG = true;

    private IconPackHelper mIconPackHelper;

    private static class CacheEntry {
        public Bitmap icon;
        public String title;
    }

    private final Bitmap mDefaultIcon;
    private final Context mContext;
    private final PackageManager mPackageManager;
    private final HashMap<ComponentName, CacheEntry> mCache =
            new HashMap<ComponentName, CacheEntry>(INITIAL_ICON_CACHE_CAPACITY);
    private int mIconDpi;

    public IconCache(Context context) {
        ActivityManager activityManager =
                (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);

        mContext = context;
        mPackageManager = context.getPackageManager();
        mIconDpi = activityManager.getLauncherLargeIconDensity();

        // need to set mIconDpi before getting default icon
        mDefaultIcon = makeDefaultIcon();

        mIconPackHelper = new IconPackHelper(context);
        loadIconPack();
    }

    public Drawable getFullResDefaultActivityIcon() {
        return getFullResIcon(Resources.getSystem(),
                android.R.mipmap.sym_def_app_icon);
    }

    public Drawable getFullResIcon(Resources resources, int iconId) {
        Drawable d;
        try {
            d = resources.getDrawableForDensity(iconId, mIconDpi);
        } catch (Resources.NotFoundException e) {
            d = null;
        }

        return (d != null) ? d : getFullResDefaultActivityIcon();
    }

    public Drawable getFullResIcon(String packageName, int iconId) {
        Resources resources;
        try {
            resources = mPackageManager.getResourcesForApplication(packageName);
        } catch (PackageManager.NameNotFoundException e) {
            resources = null;
        }
        if (resources != null) {
            if (iconId != 0) {
                return getFullResIcon(resources, iconId);
            }
        }
        return getFullResDefaultActivityIcon();
    }

    public Drawable getFullResIcon(ResolveInfo info) {
        return getFullResIcon(info.activityInfo);
    }

    public Drawable getFullResIcon(ActivityInfo info) {

        Resources resources;
        try {
            resources = mPackageManager.getResourcesForApplication(
                    info.applicationInfo);
        } catch (PackageManager.NameNotFoundException e) {
            resources = null;
        }
        if (resources != null) {
            int iconId = 0;
            if (mIconPackHelper != null && mIconPackHelper.isIconPackLoaded()) {
                iconId = mIconPackHelper.getResourceIdForActivityIcon(info);
                if (iconId != 0) {
                    return getFullResIcon(mIconPackHelper.getIconPackResources(), iconId);
                }
            }
            iconId = info.getIconResource();
            if (iconId != 0) {
                return getFullResIcon(resources, iconId);
            }
        }

        return getFullResDefaultActivityIcon();
    }

    private Bitmap makeDefaultIcon() {
        Drawable d = getFullResDefaultActivityIcon();
        Bitmap b = Bitmap.createBitmap(Math.max(d.getIntrinsicWidth(), 1),
                Math.max(d.getIntrinsicHeight(), 1),
                Bitmap.Config.ARGB_8888);
        Canvas c = new Canvas(b);
        d.setBounds(0, 0, b.getWidth(), b.getHeight());
        d.draw(c);
        c.setBitmap(null);
        return b;
    }

    private void loadIconPack() {
        mIconPackHelper.unloadIconPack();
        String iconPack = SettingsProvider.getStringCustomDefault(mContext,
                SettingsProvider.SETTINGS_UI_GENERAL_ICONS_ICON_PACK, "");
        if (!TextUtils.isEmpty(iconPack) && !mIconPackHelper.loadIconPack(iconPack)) {
            SettingsProvider.putString(mContext,
                    SettingsProvider.SETTINGS_UI_GENERAL_ICONS_ICON_PACK, "");
        }
    }

    /**
     * Remove any records for the supplied ComponentName.
     */
    public void remove(ComponentName componentName) {
        synchronized (mCache) {
            mCache.remove(componentName);
        }
    }

    /**
     * Remove any records for the supplied package name.
     */
    public void remove(String packageName) {
        HashSet<ComponentName> forDeletion = new HashSet<ComponentName>();
        for (ComponentName componentName: mCache.keySet()) {
            if (componentName.getPackageName().equals(packageName)) {
                forDeletion.add(componentName);
            }
        }
        for (ComponentName condemned: forDeletion) {
            remove(condemned);
        }
    }

    /**
     * Empty out the cache.
     */
    public void flush() {
        synchronized (mCache) {
            mCache.clear();
        }
        loadIconPack();
    }

    /**
     * Empty out the cache that aren't of the correct grid size
     */
    public void flushInvalidIcons(DeviceProfile grid) {
        synchronized (mCache) {
            Iterator<Entry<ComponentName, CacheEntry>> it = mCache.entrySet().iterator();
            while (it.hasNext()) {
                final CacheEntry e = it.next().getValue();
                if (e.icon.getWidth() < grid.iconSizePx || e.icon.getHeight() < grid.iconSizePx) {
                    it.remove();
                }
            }
        }
    }

    /**
     * Fill in "application" with the icon and label for "info."
     */
    public void getTitleAndIcon(AppInfo application, ResolveInfo info,
            HashMap<Object, CharSequence> labelCache) {
        synchronized (mCache) {
            CacheEntry entry = cacheLocked(application.componentName, info, labelCache);

            application.title = entry.title;
            application.iconBitmap = entry.icon;
        }
    }

    public Bitmap getIcon(Intent intent) {
        return getIcon(intent, null);
    }

    public Bitmap getIcon(Intent intent, String title) {
        synchronized (mCache) {
            final ResolveInfo resolveInfo = mPackageManager.resolveActivity(intent, 0);
            ComponentName component = intent.getComponent();

            if (component == null) {
                return mDefaultIcon;
            }

            CacheEntry entry = cacheLocked(component, resolveInfo, null);
            if (title != null) {
                entry.title = title;
            }
            return entry.icon;
        }
    }

    public Bitmap getIcon(ComponentName component, ResolveInfo resolveInfo,
            HashMap<Object, CharSequence> labelCache) {
        synchronized (mCache) {
            if (resolveInfo == null || component == null) {
                return null;
            }

            CacheEntry entry = cacheLocked(component, resolveInfo, labelCache);
            return entry.icon;
        }
    }

    public boolean isDefaultIcon(Bitmap icon) {
        return mDefaultIcon == icon;
    }

    private CacheEntry cacheLocked(ComponentName componentName, ResolveInfo info,
            HashMap<Object, CharSequence> labelCache) {
        CacheEntry entry = mCache.get(componentName);
        if (entry == null) {
            entry = new CacheEntry();

            mCache.put(componentName, entry);

            if (info != null) {
                ComponentName key = LauncherModel.getComponentNameFromResolveInfo(info);
                if (labelCache != null && labelCache.containsKey(key)) {
                    entry.title = labelCache.get(key).toString();
                } else {
                    entry.title = info.loadLabel(mPackageManager).toString();
                    if (labelCache != null) {
                        labelCache.put(key, entry.title);
                    }
                }
                if (entry.title == null) {
                    entry.title = info.activityInfo.name;
                }

                entry.icon = Utilities.createIconBitmap(
                        getFullResIcon(info), mContext);
            } else {
                entry.title = "";
                Bitmap preloaded = getPreloadedIcon(componentName);
                if (preloaded != null) {
                    if (DEBUG) Log.d(TAG, "using preloaded icon for " +
                            componentName.toShortString());
                    entry.icon = preloaded;
                } else {
                    if (DEBUG) Log.d(TAG, "using default icon for " +
                            componentName.toShortString());
                    entry.icon = mDefaultIcon;
                }
            }
        }
        return entry;
    }

    public HashMap<ComponentName,Bitmap> getAllIcons() {
        synchronized (mCache) {
            HashMap<ComponentName,Bitmap> set = new HashMap<ComponentName,Bitmap>();
            for (ComponentName cn : mCache.keySet()) {
                final CacheEntry e = mCache.get(cn);
                set.put(cn, e.icon);
            }
            return set;
        }
    }

    /**
     * Pre-load an icon into the persistent cache.
     *
     * <P>Queries for a component that does not exist in the package manager
     * will be answered by the persistent cache.
     *
     * @param context application context
     * @param componentName the icon should be returned for this component
     * @param icon the icon to be persisted
     * @param dpi the native density of the icon
     */
    public static void preloadIcon(Context context, ComponentName componentName, Bitmap icon,
            int dpi) {
        // TODO rescale to the correct native DPI
        try {
            PackageManager packageManager = context.getPackageManager();
            packageManager.getActivityIcon(componentName);
            // component is present on the system already, do nothing
            return;
        } catch (PackageManager.NameNotFoundException e) {
            // pass
        }

        final String key = componentName.flattenToString();
        FileOutputStream resourceFile = null;
        try {
            resourceFile = context.openFileOutput(getResourceFilename(componentName),
                    Context.MODE_PRIVATE);
            ByteArrayOutputStream os = new ByteArrayOutputStream();
            if (icon.compress(android.graphics.Bitmap.CompressFormat.PNG, 75, os)) {
                byte[] buffer = os.toByteArray();
                resourceFile.write(buffer, 0, buffer.length);
            } else {
                Log.w(TAG, "failed to encode cache for " + key);
                return;
            }
        } catch (FileNotFoundException e) {
            Log.w(TAG, "failed to pre-load cache for " + key, e);
        } catch (IOException e) {
            Log.w(TAG, "failed to pre-load cache for " + key, e);
        } finally {
            if (resourceFile != null) {
                try {
                    resourceFile.close();
                } catch (IOException e) {
                    Log.d(TAG, "failed to save restored icon for: " + key, e);
                }
            }
        }
    }

    /**
     * Read a pre-loaded icon from the persistent icon cache.
     *
     * @param componentName the component that should own the icon
     * @returns a bitmap if one is cached, or null.
     */
    private Bitmap getPreloadedIcon(ComponentName componentName) {
        final String key = componentName.flattenToShortString();

        if (DEBUG) Log.v(TAG, "looking for pre-load icon for " + key);
        Bitmap icon = null;
        FileInputStream resourceFile = null;
        try {
            resourceFile = mContext.openFileInput(getResourceFilename(componentName));
            byte[] buffer = new byte[1024];
            ByteArrayOutputStream bytes = new ByteArrayOutputStream();
            int bytesRead = 0;
            while(bytesRead >= 0) {
                bytes.write(buffer, 0, bytesRead);
                bytesRead = resourceFile.read(buffer, 0, buffer.length);
            }
            if (DEBUG) Log.d(TAG, "read " + bytes.size());
            icon = BitmapFactory.decodeByteArray(bytes.toByteArray(), 0, bytes.size());
            if (icon == null) {
                Log.w(TAG, "failed to decode pre-load icon for " + key);
            }
        } catch (FileNotFoundException e) {
            if (DEBUG) Log.d(TAG, "there is no restored icon for: " + key, e);
        } catch (IOException e) {
            Log.w(TAG, "failed to read pre-load icon for: " + key, e);
        } finally {
            if(resourceFile != null) {
                try {
                    resourceFile.close();
                } catch (IOException e) {
                    Log.d(TAG, "failed to manage pre-load icon file: " + key, e);
                }
            }
        }

        if (icon != null) {
            // TODO: handle alpha mask in the view layer
            Bitmap b = Bitmap.createBitmap(Math.max(icon.getWidth(), 1),
                    Math.max(icon.getHeight(), 1),
                    Bitmap.Config.ARGB_8888);
            Canvas c = new Canvas(b);
            Paint paint = new Paint();
            paint.setAlpha(127);
            c.drawBitmap(icon, 0, 0, paint);
            c.setBitmap(null);
            icon.recycle();
            icon = b;
        }

        return icon;
    }

    /**
     * Remove a pre-loaded icon from the persistent icon cache.
     *
     * @param componentName the component that should own the icon
     * @returns true on success
     */
    public boolean deletePreloadedIcon(ComponentName componentName) {
        if (componentName == null) {
            return false;
        }
        if (mCache.remove(componentName) != null) {
            if (DEBUG) Log.d(TAG, "removed pre-loaded icon from the in-memory cache");
        }
        boolean success = mContext.deleteFile(getResourceFilename(componentName));
        if (DEBUG && success) Log.d(TAG, "removed pre-loaded icon from persistent cache");

        return success;
    }

    private static String getResourceFilename(ComponentName component) {
        String resourceName = component.flattenToShortString();
        String filename = resourceName.replace(File.separatorChar, '_');
        return RESOURCE_FILE_PREFIX + filename;
    }
}