/*
 * Copyright (C) 2023 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.graphics;


import static com.android.launcher3.graphics.ThemeManager.PREF_ICON_SHAPE;
import static com.android.launcher3.util.Executors.MAIN_EXECUTOR;
import static com.android.launcher3.util.Executors.UI_HELPER_EXECUTOR;

import static java.util.Objects.requireNonNullElse;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.MatrixCursor;
import android.net.Uri;
import android.os.Binder;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder.DeathRecipient;
import android.os.Message;
import android.os.Messenger;
import android.text.TextUtils;
import android.util.Log;

import androidx.annotation.NonNull;

import com.android.launcher3.InvariantDeviceProfile;
import com.android.launcher3.InvariantDeviceProfile.GridOption;
import com.android.launcher3.LauncherAppState;
import com.android.launcher3.LauncherModel;
import com.android.launcher3.LauncherPrefs;
import com.android.launcher3.dagger.ApplicationContext;
import com.android.launcher3.dagger.LauncherAppSingleton;
import com.android.launcher3.model.BgDataModel;
import com.android.launcher3.shapes.IconShapeModel;
import com.android.launcher3.shapes.ShapesProvider;
import com.android.launcher3.util.ContentProviderProxy.ProxyProvider;
import com.android.launcher3.util.DaggerSingletonTracker;
import com.android.launcher3.util.Executors;
import com.android.launcher3.util.Preconditions;
import com.android.launcher3.util.RunnableList;
import com.android.systemui.shared.Flags;

import java.lang.ref.WeakReference;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutionException;

import javax.inject.Inject;

/**
 * Exposes various launcher grid options and allows the caller to change them.
 * APIs:
 *      /shape_options: List of various available shape options, where each has following fields
 *          shape_key: key of the shape option
 *          title: translated title of the shape option
 *          path: path of the shape, assuming drawn on 100x100 view port
 *          is_default: true if this shape option is currently set to the system
 *
 *      /list_options: List the various available grid options, where each has following fields
 *          name: key of the grid option
 *          rows: number of rows in the grid
 *          cols: number of columns in the grid
 *          preview_count: number of previews available for this grid option. The preview uri
 *                         looks like /preview/[grid-name]/[preview index starting with 0]
 *          is_default: true if this grid option is currently set to the system
 *
 *     /get_preview: Open a file stream for the grid preview
 *
 *     /default_grid: Call update to set the current shape and grid, with values
 *          shape_key: key of the shape to apply
 *          name: key of the grid to apply
 */
@LauncherAppSingleton
public class GridCustomizationsProxy implements ProxyProvider {

    private static final String TAG = "GridCustomizationsProvider";

    // KEY_NAME is the name of the grid used internally while the KEY_GRID_TITLE is the translated
    // string title of the grid.
    private static final String KEY_NAME = "name";
    private static final String KEY_GRID_TITLE = "grid_title";
    private static final String KEY_ROWS = "rows";
    private static final String KEY_COLS = "cols";
    private static final String KEY_GRID_ICON_ID = "grid_icon_id";
    private static final String KEY_PREVIEW_COUNT = "preview_count";
    // is_default means if a certain option is currently set to the system
    private static final String KEY_IS_DEFAULT = "is_default";
    private static final String KEY_SHAPE_KEY = "shape_key";
    private static final String KEY_SHAPE_TITLE = "shape_title";
    private static final String KEY_PATH = "path";

    // list_options is the key for grid option list
    private static final String KEY_LIST_OPTIONS = "/list_options";
    private static final String KEY_SHAPE_OPTIONS = "/shape_options";
    // default_grid is for setting grid and shape to system settings
    private static final String KEY_DEFAULT_GRID = "/default_grid";
    private static final String SET_SHAPE = "/shape";

    private static final String METHOD_GET_PREVIEW = "get_preview";

    private static final String GET_ICON_THEMED = "/get_icon_themed";
    private static final String SET_ICON_THEMED = "/set_icon_themed";
    private static final String ICON_THEMED = "/icon_themed";
    private static final String BOOLEAN_VALUE = "boolean_value";

    private static final String KEY_SURFACE_PACKAGE = "surface_package";
    private static final String KEY_CALLBACK = "callback";
    public static final String KEY_HIDE_BOTTOM_ROW = "hide_bottom_row";
    public static final String KEY_GRID_NAME = "grid_name";

    private static final int MESSAGE_ID_UPDATE_PREVIEW = 1337;
    private static final int MESSAGE_ID_UPDATE_SHAPE = 2586;
    private static final int MESSAGE_ID_UPDATE_GRID = 7414;
    private static final int MESSAGE_ID_UPDATE_COLOR = 856;
    private static final int MESSAGE_ID_UPDATE_ICON_THEMED = 311;

    // Set of all active previews used to track duplicate memory allocations
    private final Set<PreviewLifecycleObserver> mActivePreviews =
            Collections.newSetFromMap(new ConcurrentHashMap<>());

    private final Context mContext;
    private final ThemeManager mThemeManager;
    private final LauncherPrefs mPrefs;
    private final InvariantDeviceProfile mIdp;

    @Inject
    protected GridCustomizationsProxy(
            @ApplicationContext Context context,
            ThemeManager themeManager,
            LauncherPrefs prefs,
            InvariantDeviceProfile idp,
            DaggerSingletonTracker lifeCycle
    ) {
        mContext = context;
        mThemeManager = themeManager;
        mPrefs = prefs;
        mIdp = idp;
        lifeCycle.addCloseable(() -> mActivePreviews.forEach(PreviewLifecycleObserver::binderDied));
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection,
            String[] selectionArgs, String sortOrder) {
        String path = uri.getPath();
        if (path == null) {
            return null;
        }

        switch (path) {
            case KEY_SHAPE_OPTIONS: {
                if (Flags.newCustomizationPickerUi()) {
                    MatrixCursor cursor = new MatrixCursor(new String[]{
                            KEY_SHAPE_KEY, KEY_SHAPE_TITLE, KEY_PATH, KEY_IS_DEFAULT});
                    String currentShapePath = mThemeManager.getIconState().getIconMask();
                    Optional<? extends IconShapeModel> selectedShape = ShapesProvider.IconShape.getEntries().stream().filter(
                                    shape -> shape.getPathString().equals(currentShapePath)
                    ).findFirst();
                    // Handle default for when current shape doesn't match new shapes.
                    if (selectedShape.isEmpty())
                        selectedShape = Optional.of(ShapesProvider.IconShape.getEntries().stream().findFirst().get());

                    var resources = mContext.getResources();
                    for (var shape : ShapesProvider.IconShape.getEntries()) cursor.newRow()
                            .add(KEY_SHAPE_KEY, shape.name())
                            .add(KEY_SHAPE_TITLE, resources.getString(shape.getTitle()))
                            .add(KEY_PATH, shape.getPathString())
                            .add(KEY_IS_DEFAULT, shape.equals(selectedShape.get()));
                    return cursor;
                } else  {
                    return null;
                }
            }
            case KEY_LIST_OPTIONS: {
                MatrixCursor cursor = new MatrixCursor(new String[]{
                        KEY_NAME, KEY_GRID_TITLE, KEY_ROWS, KEY_COLS, KEY_PREVIEW_COUNT,
                        KEY_IS_DEFAULT, KEY_GRID_ICON_ID});
                List<GridOption> gridOptionList = mIdp.parseAllGridOptions(mContext);
                if (com.android.launcher3.Flags.oneGridSpecs()) {
                    gridOptionList.sort(Comparator
                            .comparingInt((GridOption option) -> option.numColumns)
                            .reversed());
                }
                for (GridOption gridOption : gridOptionList) {
                    cursor.newRow()
                            .add(KEY_NAME, gridOption.name)
                            .add(KEY_GRID_TITLE, gridOption.gridTitle)
                            .add(KEY_ROWS, gridOption.numRows)
                            .add(KEY_COLS, gridOption.numColumns)
                            .add(KEY_PREVIEW_COUNT, 1)
                            .add(KEY_IS_DEFAULT, mIdp.numColumns == gridOption.numColumns
                                    && mIdp.numRows == gridOption.numRows)
                            .add(KEY_GRID_ICON_ID, gridOption.gridIconId);
                }
                return cursor;
            }
            case GET_ICON_THEMED:
            case ICON_THEMED: {
                MatrixCursor cursor = new MatrixCursor(new String[]{BOOLEAN_VALUE});
                cursor.newRow().add(BOOLEAN_VALUE, mThemeManager.isMonoThemeEnabled() ? 1 : 0);
                return cursor;
            }
            default:
                return null;
        }
    }

    @Override
    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
        String path = uri.getPath();
        if (path == null) {
            return 0;
        }
        switch (path) {
            case KEY_DEFAULT_GRID: {
                if (Flags.newCustomizationPickerUi()) {
                    mPrefs.put(PREF_ICON_SHAPE,
                            requireNonNullElse(values.getAsString(KEY_SHAPE_KEY), ""));
                }
                String gridName = values.getAsString(KEY_NAME);
                // Verify that this is a valid grid option
                GridOption match = null;
                for (GridOption option : mIdp.parseAllGridOptions(mContext)) {
                    String name = option.name;
                    if (name != null && name.equals(gridName)) {
                        match = option;
                        break;
                    }
                }
                if (match == null) {
                    return 0;
                }

                mIdp.setCurrentGrid(mContext, gridName);
                if (Flags.newCustomizationPickerUi()) {
                    try {
                        // Wait for device profile to be fully reloaded and applied to the launcher
                        loadModelSync(mContext);
                    } catch (ExecutionException | InterruptedException e) {
                        Log.e(TAG, "Fail to load model", e);
                    }
                }
                mContext.getContentResolver().notifyChange(uri, null);
                return 1;
            }
            case SET_SHAPE:
                if (Flags.newCustomizationPickerUi()) {
                    mPrefs.put(PREF_ICON_SHAPE,
                            requireNonNullElse(values.getAsString(KEY_SHAPE_KEY), ""));
                }
                return 1;
            case ICON_THEMED:
            case SET_ICON_THEMED: {
                mThemeManager.setMonoThemeEnabled(values.getAsBoolean(BOOLEAN_VALUE));
                mContext.getContentResolver().notifyChange(uri, null);
                return 1;
            }
            default:
                return 0;
        }
    }

    /**
     * Loads the model in memory synchronously
     */
    private void loadModelSync(Context context) throws ExecutionException, InterruptedException {
        Preconditions.assertNonUiThread();
        BgDataModel.Callbacks emptyCallbacks = new BgDataModel.Callbacks() { };
        LauncherModel launcherModel = LauncherAppState.getInstance(context).getModel();
        MAIN_EXECUTOR.submit(
                () -> launcherModel.addCallbacksAndLoad(emptyCallbacks)
        ).get();

        Executors.MODEL_EXECUTOR.submit(() -> { }).get();
        MAIN_EXECUTOR.submit(
                () -> launcherModel.removeCallbacks(emptyCallbacks)
        ).get();
    }

    @Override
    public Bundle call(@NonNull String method, String arg, Bundle extras) {
        if (METHOD_GET_PREVIEW.equals(method)) {
            return getPreview(extras);
        } else {
            return null;
        }
    }

    private synchronized Bundle getPreview(Bundle request) {
        RunnableList lifeCycleTracker = new RunnableList();
        try {
            PreviewSurfaceRenderer renderer = new PreviewSurfaceRenderer(
                    mContext, lifeCycleTracker, request, Binder.getCallingPid());
            PreviewLifecycleObserver observer =
                    new PreviewLifecycleObserver(lifeCycleTracker, renderer);

            // Destroy previous renderers to avoid any duplicate memory
            mActivePreviews.stream().filter(observer::isSameRenderer).forEach(o ->
                    MAIN_EXECUTOR.execute(o.lifeCycleTracker::executeAllAndDestroy));

            renderer.loadAsync();
            lifeCycleTracker.add(() -> renderer.getHostToken().unlinkToDeath(observer, 0));
            renderer.getHostToken().linkToDeath(observer, 0);

            Bundle result = new Bundle();
            result.putParcelable(KEY_SURFACE_PACKAGE, renderer.getSurfacePackage());

            mActivePreviews.add(observer);
            lifeCycleTracker.add(() -> mActivePreviews.remove(observer));

            // Wrap the callback in a weak reference. This ensures that the callback is not kept
            // alive due to the Messenger's IBinder
            Messenger messenger = new Messenger(new Handler(
                    UI_HELPER_EXECUTOR.getLooper(),
                    new WeakCallbackWrapper(observer)));

            Message msg = Message.obtain();
            msg.replyTo = messenger;
            result.putParcelable(KEY_CALLBACK, msg);
            return result;
        } catch (Exception e) {
            Log.e(TAG, "Unable to generate preview", e);
            MAIN_EXECUTOR.execute(lifeCycleTracker::executeAllAndDestroy);
            return null;
        }
    }

    private static class PreviewLifecycleObserver implements Handler.Callback, DeathRecipient {

        public final RunnableList lifeCycleTracker;
        public final PreviewSurfaceRenderer renderer;
        public boolean destroyed = false;

        PreviewLifecycleObserver(
                RunnableList lifeCycleTracker,
                PreviewSurfaceRenderer renderer) {
            this.lifeCycleTracker = lifeCycleTracker;
            this.renderer = renderer;
            lifeCycleTracker.add(() -> destroyed = true);
        }

        @Override
        public boolean handleMessage(Message message) {
            if (destroyed) {
                return true;
            }

            switch (message.what) {
                case MESSAGE_ID_UPDATE_PREVIEW:
                    renderer.hideBottomRow(message.getData().getBoolean(KEY_HIDE_BOTTOM_ROW));
                    break;
                case MESSAGE_ID_UPDATE_SHAPE:
                    if (Flags.newCustomizationPickerUi()
                            && com.android.launcher3.Flags.enableLauncherIconShapes()) {
                        String shapeKey = message.getData().getString(KEY_SHAPE_KEY);
                        if (!TextUtils.isEmpty(shapeKey)) {
                            renderer.updateShape(shapeKey);
                        }
                    }
                    break;
                case MESSAGE_ID_UPDATE_GRID:
                    String gridName = message.getData().getString(KEY_GRID_NAME);
                    if (!TextUtils.isEmpty(gridName)) {
                        renderer.updateGrid(gridName);
                    }
                    break;
                case MESSAGE_ID_UPDATE_COLOR:
                    if (Flags.newCustomizationPickerUi()) {
                        renderer.previewColor(message.getData());
                    }
                    break;
                case MESSAGE_ID_UPDATE_ICON_THEMED:
                    if (Flags.newCustomizationPickerUi()) {
                        Boolean iconThemed = message.getData().getBoolean(BOOLEAN_VALUE);
                        // TODO Update icon themed in the preview
                    }
                    break;
                default:
                    // Unknown command, destroy lifecycle
                    Log.d(TAG, "Unknown preview command: " + message.what + ", destroying preview");
                    MAIN_EXECUTOR.execute(lifeCycleTracker::executeAllAndDestroy);
                    break;
            }

            return true;
        }

        @Override
        public void binderDied() {
            MAIN_EXECUTOR.execute(lifeCycleTracker::executeAllAndDestroy);
        }

        /**
         * Two renderers are considered same if they have the same host token and display Id
         */
        public boolean isSameRenderer(PreviewLifecycleObserver plo) {
            return plo != null
                    && plo.renderer.getHostToken().equals(renderer.getHostToken())
                    && plo.renderer.getDisplayId() == renderer.getDisplayId();
        }
    }

    /**
     * A WeakReference wrapper around Handler.Callback to avoid passing hard-reference over IPC
     * when using a Messenger
     */
    private static class WeakCallbackWrapper implements Handler.Callback {

        private final WeakReference<Handler.Callback> mActual;
        private final Message mCleanupMessage;

        WeakCallbackWrapper(Handler.Callback actual) {
            mActual = new WeakReference<>(actual);
            mCleanupMessage = new Message();
        }

        @Override
        public boolean handleMessage(Message message) {
            Handler.Callback actual = mActual.get();
            return actual != null && actual.handleMessage(message);
        }

        @Override
        protected void finalize() throws Throwable {
            super.finalize();
            Handler.Callback actual = mActual.get();
            if (actual != null) {
                actual.handleMessage(mCleanupMessage);
            }
        }
    }
}
