/*
 * Copyright (C) 2015 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.widget;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.InsetDrawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView.State;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

import com.android.launcher3.BaseContainerView;
import com.android.launcher3.BaseRecyclerView;
import com.android.launcher3.CellLayout;
import com.android.launcher3.DeleteDropTarget;
import com.android.launcher3.DeviceProfile;
import com.android.launcher3.DragController;
import com.android.launcher3.DragSource;
import com.android.launcher3.DropTarget.DragObject;
import com.android.launcher3.Folder;
import com.android.launcher3.IconCache;
import com.android.launcher3.ItemInfo;
import com.android.launcher3.Launcher;
import com.android.launcher3.LauncherAppState;
import com.android.launcher3.PendingAddItemInfo;
import com.android.launcher3.R;
import com.android.launcher3.Utilities;
import com.android.launcher3.WidgetPreviewLoader;
import com.android.launcher3.Workspace;
import com.android.launcher3.model.WidgetsModel;
import com.android.launcher3.util.Thunk;

/**
 * The widgets list view container.
 */
public class WidgetsContainerView extends BaseContainerView
        implements View.OnLongClickListener, View.OnClickListener, DragSource{

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

    /* Coefficient multiplied to the screen height for preloading widgets. */
    private static final int PRELOAD_SCREEN_HEIGHT_MULTIPLE = 1;

    /* Global instances that are used inside this container. */
    @Thunk Launcher mLauncher;
    private DragController mDragController;
    private IconCache mIconCache;

    /* Recycler view related member variables */
    private View mContent;
    private WidgetsRecyclerView mView;
    private WidgetsListAdapter mAdapter;

    /* Touch handling related member variables. */
    private Toast mWidgetInstructionToast;

    /* Rendering related. */
    private WidgetPreviewLoader mWidgetPreviewLoader;

    private Rect mPadding = new Rect();

    public WidgetsContainerView(Context context) {
        this(context, null);
    }

    public WidgetsContainerView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public WidgetsContainerView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        mLauncher = (Launcher) context;
        mDragController = mLauncher.getDragController();
        mAdapter = new WidgetsListAdapter(context, this, this, mLauncher);
        mIconCache = (LauncherAppState.getInstance()).getIconCache();
        if (DEBUG) {
            Log.d(TAG, "WidgetsContainerView constructor");
        }
    }

    @Override
    protected void onFinishInflate() {
        mContent = findViewById(R.id.content);
        mView = (WidgetsRecyclerView) findViewById(R.id.widgets_list_view);
        mView.setAdapter(mAdapter);

        // This extends the layout space so that preloading happen for the {@link RecyclerView}
        mView.setLayoutManager(new LinearLayoutManager(getContext()) {
            @Override
            protected int getExtraLayoutSpace(State state) {
                DeviceProfile grid = mLauncher.getDeviceProfile();
                return super.getExtraLayoutSpace(state)
                        + grid.availableHeightPx * PRELOAD_SCREEN_HEIGHT_MULTIPLE;
            }
        });
        mPadding.set(getPaddingLeft(), getPaddingTop(), getPaddingRight(),
                getPaddingBottom());
        setScroller();
        updateBackgroundAndPaddings();
    }

    public void reset() {
        updateScrubber();
        updateBackgroundAndPaddings();
    }

    private void updateScrubber() {
        if (useScroller() && useScrubber()) {
            mScrubber.updateSections();
        }
    }

    //
    // Returns views used for launcher transitions.
    //

    public View getContentView() {
        return mView;
    }

    public void setScrubberVisibility(int visibility) {
        if (mScrubberContainerView != null) {
            mScrubberContainerView.setVisibility(visibility);
        }
    }

    public View getRevealView() {
        // TODO(hyunyoungs): temporarily use apps view transition.
        return findViewById(R.id.widgets_reveal_view);
    }

    public void scrollToTop() {
        mView.scrollToPosition(0);
    }

    //
    // Touch related handling.
    //

    @Override
    public void onClick(View v) {
        // When we have exited widget tray or are in transition, disregard clicks
        if (!mLauncher.isWidgetsViewVisible()
                || mLauncher.getWorkspace().isSwitchingState()
                || !(v instanceof WidgetCell)) return;

        // Let the user know that they have to long press to add a widget
        if (mWidgetInstructionToast != null) {
            mWidgetInstructionToast.cancel();
        }
        mWidgetInstructionToast = Toast.makeText(getContext(),R.string.long_press_widget_to_add,
                Toast.LENGTH_SHORT);
        mWidgetInstructionToast.show();
    }

    @Override
    public boolean onLongClick(View v) {
        if (DEBUG) {
            Log.d(TAG, String.format("onLonglick [v=%s]", v));
        }
        // Return early if this is not initiated from a touch
        if (!v.isInTouchMode()) return false;
        // When we have exited all apps or are in transition, disregard long clicks
        if (!mLauncher.isWidgetsViewVisible() ||
                mLauncher.getWorkspace().isSwitchingState()) return false;
        // Return if global dragging is not enabled
        Log.d(TAG, String.format("onLonglick dragging enabled?.", v));
        if (!mLauncher.isDraggingEnabled()) return false;

        boolean status = beginDragging(v);
        if (status && v.getTag() instanceof PendingAddWidgetInfo) {
            WidgetHostViewLoader hostLoader = new WidgetHostViewLoader(mLauncher, v);
            boolean preloadStatus = hostLoader.preloadWidget();
            if (DEBUG) {
                Log.d(TAG, String.format("preloading widget [status=%s]", preloadStatus));
            }
            mLauncher.getDragController().addDragListener(hostLoader);
        }
        return status;
    }

    private boolean beginDragging(View v) {
        if (v instanceof WidgetCell) {
            if (!beginDraggingWidget((WidgetCell) v)) {
                return false;
            }
        } else {
            Log.e(TAG, "Unexpected dragging view: " + v);
        }

        // We don't enter spring-loaded mode if the drag has been cancelled
        if (mLauncher.getDragController().isDragging()) {
            // Go into spring loaded mode (must happen before we startDrag())
            mLauncher.enterSpringLoadedDragMode();
        }

        return true;
    }

    private boolean beginDraggingWidget(WidgetCell v) {
        // Get the widget preview as the drag representation
        WidgetImageView image = (WidgetImageView) v.findViewById(R.id.widget_preview);
        PendingAddItemInfo createItemInfo = (PendingAddItemInfo) v.getTag();

        // If the ImageView doesn't have a drawable yet, the widget preview hasn't been loaded and
        // we abort the drag.
        if (image.getBitmap() == null) {
            return false;
        }

        // Compose the drag image
        Bitmap preview;
        float scale = 1f;
        final Rect bounds = image.getBitmapBounds();

        if (createItemInfo instanceof PendingAddWidgetInfo) {
            // This can happen in some weird cases involving multi-touch. We can't start dragging
            // the widget if this is null, so we break out.

            PendingAddWidgetInfo createWidgetInfo = (PendingAddWidgetInfo) createItemInfo;
            int[] size = mLauncher.getWorkspace().estimateItemSize(createWidgetInfo, true);

            Bitmap icon = image.getBitmap();
            float minScale = 1.25f;
            int maxWidth = Math.min((int) (icon.getWidth() * minScale), size[0]);

            int[] previewSizeBeforeScale = new int[1];
            preview = getWidgetPreviewLoader().generateWidgetPreview(mLauncher,
                    createWidgetInfo.info, maxWidth, null, previewSizeBeforeScale, null);

            if (previewSizeBeforeScale[0] < icon.getWidth()) {
                // The icon has extra padding around it.
                int padding = (icon.getWidth() - previewSizeBeforeScale[0]) / 2;
                if (icon.getWidth() > image.getWidth()) {
                    padding = padding * image.getWidth() / icon.getWidth();
                }

                bounds.left += padding;
                bounds.right -= padding;
            }
            scale = bounds.width() / (float) preview.getWidth();
        } else {
            PendingAddShortcutInfo createShortcutInfo = (PendingAddShortcutInfo) v.getTag();
            Drawable icon = mIconCache.getFullResIcon(createShortcutInfo.activityInfo);
            preview = Utilities.createIconBitmap(icon, mLauncher);
            createItemInfo.spanX = createItemInfo.spanY = 1;
            scale = ((float) mLauncher.getDeviceProfile().iconSizePx) / preview.getWidth();
        }

        // Don't clip alpha values for the drag outline if we're using the default widget preview
        boolean clipAlpha = !(createItemInfo instanceof PendingAddWidgetInfo &&
                (((PendingAddWidgetInfo) createItemInfo).previewImage == 0));

        // Start the drag
        mLauncher.lockScreenOrientation();
        mLauncher.getWorkspace().onDragStartedWithItem(createItemInfo, preview, clipAlpha);
        mDragController.startDrag(image, preview, this, createItemInfo,
                bounds, DragController.DRAG_ACTION_COPY, scale);

        preview.recycle();
        return true;
    }

    //
    // Drag related handling methods that implement {@link DragSource} interface.
    //

    @Override
    public boolean supportsFlingToDelete() {
        return false;
    }

    @Override
    public boolean supportsAppInfoDropTarget() {
        return true;
    }

    /*
     * Both this method and {@link #supportsFlingToDelete} has to return {@code false} for the
     * {@link DeleteDropTarget} to be invisible.)
     */
    @Override
    public boolean supportsDeleteDropTarget() {
        return false;
    }

    @Override
    public float getIntrinsicIconScaleFactor() {
        return 0;
    }

    @Override
    public void onFlingToDeleteCompleted() {
        // We just dismiss the drag when we fling, so cleanup here
        mLauncher.exitSpringLoadedDragModeDelayed(true,
                Launcher.EXIT_SPRINGLOADED_MODE_SHORT_TIMEOUT, null);
        mLauncher.unlockScreenOrientation(false);
    }

    @Override
    public void onDropCompleted(View target, DragObject d, boolean isFlingToDelete,
            boolean success) {
        if (isFlingToDelete || !success || (target != mLauncher.getWorkspace() &&
                !(target instanceof DeleteDropTarget) && !(target instanceof Folder))) {
            // Exit spring loaded mode if we have not successfully dropped or have not handled the
            // drop in Workspace
            mLauncher.exitSpringLoadedDragModeDelayed(true,
                    Launcher.EXIT_SPRINGLOADED_MODE_SHORT_TIMEOUT, null);
        }
        mLauncher.unlockScreenOrientation(false);

        // Display an error message if the drag failed due to there not being enough space on the
        // target layout we were dropping on.
        if (!success) {
            boolean showOutOfSpaceMessage = false;
            if (target instanceof Workspace) {
                int currentScreen = mLauncher.getCurrentWorkspaceScreen();
                Workspace workspace = (Workspace) target;
                CellLayout layout = (CellLayout) workspace.getChildAt(currentScreen);
                ItemInfo itemInfo = (ItemInfo) d.dragInfo;
                if (layout != null) {
                    showOutOfSpaceMessage =
                            !layout.findCellForSpan(null, itemInfo.spanX, itemInfo.spanY);
                }
            }
            if (showOutOfSpaceMessage) {
                mLauncher.showOutOfSpaceMessage(false);
            }
            d.deferDragViewCleanupPostAnimation = false;
        }
    }

    //
    // Container rendering related.
    //

    @Override
    protected void onUpdateBackgroundAndPaddings(Rect searchBarBounds, Rect padding) {
        boolean isRtl = Utilities.isRtl(getResources());
        // Apply the top-bottom padding to the content itself so that the launcher transition is
        // clipped correctly
        mContent.setPadding(0, padding.top, 0, padding.bottom);

        // TODO: Use quantum_panel_dark instead of quantum_panel_shape_dark.
        InsetDrawable background = new InsetDrawable(
                getResources().getDrawable(R.drawable.quantum_panel_shape_dark), padding.left, 0,
                padding.right, 0);
        Rect bgPadding = new Rect();
        background.getPadding(bgPadding);
        mView.setBackground(background);
        getRevealView().setBackground(background.getConstantState().newDrawable());
        mView.updateBackgroundPadding(bgPadding);

        int startInset = mView.getMaxScrollbarWidth();
        int topBottomPadding =  getPaddingTop();
        final boolean useScrollerScrubber = useScroller() && useScrubber();
        if (isRtl) {
            mView.setPadding(padding.left + mView.getMaxScrollbarWidth(),
                    topBottomPadding, padding.right + startInset, useScrollerScrubber ?
                    mScrubberHeight + topBottomPadding : topBottomPadding);
            if (useScrollerScrubber) {
                mScrubberContainerView.setPadding(padding.left, 0, padding.right, 0);
            }
        } else {
            mView.setPadding(padding.left + startInset, topBottomPadding,
                    padding.right + mView.getMaxScrollbarWidth(), useScrollerScrubber ?
                    mScrubberHeight + topBottomPadding : topBottomPadding);
            if (useScrollerScrubber) {
                mScrubberContainerView.setPadding(padding.left, 0, padding.right, 0);
                mScrubberContainerView.setEnabled(true);
                mScrubberContainerView.bringToFront();
            }
        }
    }

    /**
     * Initialize the widget data model.
     */
    public void addWidgets(WidgetsModel model) {
        mView.setWidgets(model);
        mAdapter.setWidgetsModel(model);
        mAdapter.notifyDataSetChanged();
        updateScrubber();
    }

    public WidgetsModel getWidgets() {
        if (mView != null) {
            return mView.getWidgets();
        }
        return null;
    }

    private WidgetPreviewLoader getWidgetPreviewLoader() {
        if (mWidgetPreviewLoader == null) {
            mWidgetPreviewLoader = LauncherAppState.getInstance().getWidgetCache();
        }
        return mWidgetPreviewLoader;
    }

    @Override
    protected BaseRecyclerView getRecyclerView() {
        return mView;
    }
}