/*
 * 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;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.content.res.TypedArray;
import android.content.res.XmlResourceParser;
import android.graphics.Point;
import android.util.DisplayMetrics;
import android.util.Pair;
import android.util.Xml;
import android.view.Display;
import android.view.WindowManager;

import com.android.launcher3.config.FeatureFlags;
import com.android.launcher3.util.Thunk;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

public class InvariantDeviceProfile {

    // This is a static that we use for the default icon size on a 4/5-inch phone
    private static float DEFAULT_ICON_SIZE_DP = 60;

    private static final float ICON_SIZE_DEFINED_IN_APP_DP = 48;

    private static final String KEY_GRID_SIZE = "pref_grid_size";
    private static final String KEY_GRID_CUSTOM = "pref_grid_custom";

    // Constants that affects the interpolation curve between statically defined device profile
    // buckets.
    private static float KNEARESTNEIGHBOR = 3;
    private static float WEIGHT_POWER = 5;

    // used to offset float not being able to express extremely small weights in extreme cases.
    private static float WEIGHT_EFFICIENT = 100000f;

    // Profile-defining invariant properties
    String name;
    float minWidthDps;
    float minHeightDps;

    /**
     * Number of icons per row and column in the workspace.
     */
    public int numRows;
    public int numColumns;

    /**
     * Number of icons per row in the drawer
     */
    public int numColumnsDrawer;

    /**
     * The minimum number of predicted apps in all apps.
     */
    @Deprecated
    int minAllAppsPredictionColumns;

    /**
     * Number of icons per row and column in the folder.
     */
    public int numFolderRows;
    public int numFolderColumns;
    public float iconSize;
    public float landscapeIconSize;
    public int iconBitmapSize;
    public int fillResIconDpi;
    public float iconTextSize;

    /**
     * Number of icons inside the hotseat area.
     */
    public int numHotseatIcons;

    int defaultLayoutId;
    int demoModeLayoutId;

    public DeviceProfile landscapeProfile;
    public DeviceProfile portraitProfile;

    public Point defaultWallpaperSize;

    public InvariantDeviceProfile() {
    }

    public InvariantDeviceProfile(Context context, InvariantDeviceProfile p) {
        this(context, p.name, p.minWidthDps, p.minHeightDps, p.numRows, p.numColumns, p.numColumnsDrawer,
                p.numFolderRows, p.numFolderColumns, p.minAllAppsPredictionColumns,
                p.iconSize, p.landscapeIconSize, p.iconTextSize, p.numHotseatIcons,
                p.defaultLayoutId, p.demoModeLayoutId);
    }

    InvariantDeviceProfile(Context context, String n, float w, float h, int r, int c, int cd,
                           int fr, int fc, int maapc, float is, float lis, float its, int hs,
                           int dlId, int dmlId) {
        name = n;
        minWidthDps = w;
        minHeightDps = h;
        numRows = r;
        numColumns = c;
        numColumnsDrawer = cd;
        numFolderRows = fr;
        numFolderColumns = fc;
        minAllAppsPredictionColumns = maapc;
        iconSize = is;
        landscapeIconSize = lis;
        iconTextSize = its;
        numHotseatIcons = hs;
        defaultLayoutId = dlId;
        demoModeLayoutId = dmlId;

        setGridSize(context);
    }

    @TargetApi(23)
    InvariantDeviceProfile(Context context) {
        WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
        Display display = wm.getDefaultDisplay();
        DisplayMetrics dm = new DisplayMetrics();
        display.getMetrics(dm);

        Point smallestSize = new Point();
        Point largestSize = new Point();
        display.getCurrentSizeRange(smallestSize, largestSize);

        // This guarantees that width < height
        minWidthDps = Utilities.dpiFromPx(Math.min(smallestSize.x, smallestSize.y), dm);
        minHeightDps = Utilities.dpiFromPx(Math.min(largestSize.x, largestSize.y), dm);

        ArrayList<InvariantDeviceProfile> closestProfiles = findClosestDeviceProfiles(
                minWidthDps, minHeightDps, getPredefinedDeviceProfiles(context));
        InvariantDeviceProfile interpolatedDeviceProfileOut =
                invDistWeightedInterpolate(context, minWidthDps,  minHeightDps, closestProfiles);

        InvariantDeviceProfile closestProfile = closestProfiles.get(0);
        numRows = closestProfile.numRows;
        numColumns = closestProfile.numColumns;
        numColumnsDrawer = closestProfile.numColumnsDrawer;
        numHotseatIcons = closestProfile.numHotseatIcons;
        defaultLayoutId = closestProfile.defaultLayoutId;
        demoModeLayoutId = closestProfile.demoModeLayoutId;
        numFolderRows = closestProfile.numFolderRows;
        numFolderColumns = closestProfile.numFolderColumns;
        minAllAppsPredictionColumns = closestProfile.minAllAppsPredictionColumns;

        iconSize = interpolatedDeviceProfileOut.iconSize;
        landscapeIconSize = interpolatedDeviceProfileOut.landscapeIconSize;
        iconBitmapSize = Utilities.pxFromDp(iconSize, dm);
        iconTextSize = interpolatedDeviceProfileOut.iconTextSize;
        fillResIconDpi = getLauncherIconDensity(iconBitmapSize);

        // If the partner customization apk contains any grid overrides, apply them
        // Supported overrides: numRows, numColumns, iconSize
        applyPartnerDeviceProfileOverrides(context, dm);

        Point realSize = new Point();
        display.getRealSize(realSize);
        // The real size never changes. smallSide and largeSide will remain the
        // same in any orientation.
        int smallSide = Math.min(realSize.x, realSize.y);
        int largeSide = Math.max(realSize.x, realSize.y);

        landscapeProfile = new DeviceProfile(context, this, smallestSize, largestSize,
                largeSide, smallSide, true /* isLandscape */);
        portraitProfile = new DeviceProfile(context, this, smallestSize, largestSize,
                smallSide, largeSide, false /* isLandscape */);

        // We need to ensure that there is enough extra space in the wallpaper
        // for the intended parallax effects
        if (context.getResources().getConfiguration().smallestScreenWidthDp >= 720) {
            defaultWallpaperSize = new Point(
                    (int) (largeSide * wallpaperTravelToScreenWidthRatio(largeSide, smallSide)),
                    largeSide);
        } else {
            defaultWallpaperSize = new Point(Math.max(smallSide * 2, largeSide), largeSide);
        }
    }

    ArrayList<InvariantDeviceProfile> getPredefinedDeviceProfiles(Context context) {
        ArrayList<InvariantDeviceProfile> profiles = new ArrayList<>();
        try (XmlResourceParser parser = context.getResources().getXml(R.xml.device_profiles)) {
            final int depth = parser.getDepth();
            int type;

            while (((type = parser.next()) != XmlPullParser.END_TAG ||
                    parser.getDepth() > depth) && type != XmlPullParser.END_DOCUMENT) {
                if ((type == XmlPullParser.START_TAG) && "profile".equals(parser.getName())) {
                    TypedArray a = context.obtainStyledAttributes(
                            Xml.asAttributeSet(parser), R.styleable.InvariantDeviceProfile);
                    int numRows = a.getInt(R.styleable.InvariantDeviceProfile_numRows, 0);
                    int numColumns = a.getInt(R.styleable.InvariantDeviceProfile_numColumns, 0);
                    float iconSize = a.getFloat(R.styleable.InvariantDeviceProfile_iconSize, 0);
                    profiles.add(new InvariantDeviceProfile(
                            context,
                            a.getString(R.styleable.InvariantDeviceProfile_name),
                            a.getFloat(R.styleable.InvariantDeviceProfile_minWidthDps, 0),
                            a.getFloat(R.styleable.InvariantDeviceProfile_minHeightDps, 0),
                            numRows,
                            numColumns,
                            a.getInt(R.styleable.InvariantDeviceProfile_numColumnsDrawer, numColumns),
                            a.getInt(R.styleable.InvariantDeviceProfile_numFolderRows, numRows),
                            a.getInt(R.styleable.InvariantDeviceProfile_numFolderColumns, numColumns),
                            a.getInt(R.styleable.InvariantDeviceProfile_minAllAppsPredictionColumns, numColumns),
                            iconSize,
                            a.getFloat(R.styleable.InvariantDeviceProfile_landscapeIconSize, iconSize),
                            a.getFloat(R.styleable.InvariantDeviceProfile_iconTextSize, 0),
                            a.getInt(R.styleable.InvariantDeviceProfile_numHotseatIcons, numColumns),
                            a.getResourceId(R.styleable.InvariantDeviceProfile_defaultLayoutId, 0),
                            a.getResourceId(R.styleable.InvariantDeviceProfile_demoModeLayoutId, 0)));
                    a.recycle();
                }
            }
        } catch (IOException|XmlPullParserException e) {
            throw new RuntimeException(e);
        }
        return profiles;
    }

    private int getLauncherIconDensity(int requiredSize) {
        // Densities typically defined by an app.
        int[] densityBuckets = new int[] {
                DisplayMetrics.DENSITY_LOW,
                DisplayMetrics.DENSITY_MEDIUM,
                DisplayMetrics.DENSITY_TV,
                DisplayMetrics.DENSITY_HIGH,
                DisplayMetrics.DENSITY_XHIGH,
                DisplayMetrics.DENSITY_XXHIGH,
                DisplayMetrics.DENSITY_XXXHIGH
        };

        int density = DisplayMetrics.DENSITY_XXXHIGH;
        for (int i = densityBuckets.length - 1; i >= 0; i--) {
            float expectedSize = ICON_SIZE_DEFINED_IN_APP_DP * densityBuckets[i]
                    / DisplayMetrics.DENSITY_DEFAULT;
            if (expectedSize >= requiredSize) {
                density = densityBuckets[i];
            }
        }

        return density;
    }

    /**
     * Apply any Partner customization grid overrides.
     *
     * Currently we support: all apps row / column count.
     */
    private void applyPartnerDeviceProfileOverrides(Context context, DisplayMetrics dm) {
        Partner p = Partner.get(context.getPackageManager());
        if (p != null) {
            p.applyInvariantDeviceProfileOverrides(this, dm);
        }
    }

    @Thunk float dist(float x0, float y0, float x1, float y1) {
        return (float) Math.hypot(x1 - x0, y1 - y0);
    }

    /**
     * Returns the closest device profiles ordered by closeness to the specified width and height
     */
    // Package private visibility for testing.
    ArrayList<InvariantDeviceProfile> findClosestDeviceProfiles(
            final float width, final float height, ArrayList<InvariantDeviceProfile> points) {

        // Sort the profiles by their closeness to the dimensions
        ArrayList<InvariantDeviceProfile> pointsByNearness = points;
        Collections.sort(pointsByNearness, new Comparator<InvariantDeviceProfile>() {
            public int compare(InvariantDeviceProfile a, InvariantDeviceProfile b) {
                return Float.compare(dist(width, height, a.minWidthDps, a.minHeightDps),
                        dist(width, height, b.minWidthDps, b.minHeightDps));
            }
        });

        return pointsByNearness;
    }

    // Package private visibility for testing.
    InvariantDeviceProfile invDistWeightedInterpolate(Context context, float width, float height,
                ArrayList<InvariantDeviceProfile> points) {
        float weights = 0;

        InvariantDeviceProfile p = points.get(0);
        if (dist(width, height, p.minWidthDps, p.minHeightDps) == 0) {
            return p;
        }

        InvariantDeviceProfile out = new InvariantDeviceProfile();
        for (int i = 0; i < points.size() && i < KNEARESTNEIGHBOR; ++i) {
            p = new InvariantDeviceProfile(context, points.get(i));
            float w = weight(width, height, p.minWidthDps, p.minHeightDps, WEIGHT_POWER);
            weights += w;
            out.add(p.multiply(w));
        }
        return out.multiply(1.0f/weights);
    }

    private void add(InvariantDeviceProfile p) {
        iconSize += p.iconSize;
        landscapeIconSize += p.landscapeIconSize;
        iconTextSize += p.iconTextSize;
    }

    private InvariantDeviceProfile multiply(float w) {
        iconSize *= w;
        landscapeIconSize *= w;
        iconTextSize *= w;
        return this;
    }

    public int getAllAppsButtonRank() {
        if (FeatureFlags.IS_DOGFOOD_BUILD && FeatureFlags.NO_ALL_APPS_ICON) {
            throw new IllegalAccessError("Accessing all apps rank when all-apps is disabled");
        }
        return numHotseatIcons / 2;
    }

    public boolean isAllAppsButtonRank(int rank) {
        return rank == getAllAppsButtonRank();
    }

    public DeviceProfile getDeviceProfile(Context context) {
        return context.getResources().getConfiguration().orientation
                == Configuration.ORIENTATION_LANDSCAPE ? landscapeProfile : portraitProfile;
    }

    private float weight(float x0, float y0, float x1, float y1, float pow) {
        float d = dist(x0, y0, x1, y1);
        if (Float.compare(d, 0f) == 0) {
            return Float.POSITIVE_INFINITY;
        }
        return (float) (WEIGHT_EFFICIENT / Math.pow(d, pow));
    }

    private void setGridSize(Context context) {
        SharedPreferences prefs = Utilities.getPrefs(context);
        String defaultGridSize = Utilities.getGridValue(numColumns, numRows);
        String properSize = prefs.getString(KEY_GRID_SIZE, defaultGridSize);

        Pair<Integer, Integer> values = Utilities.extractCustomGrid(properSize);
        numColumns = values.first;
        numRows = values.second;
    }

    /**
     * As a ratio of screen height, the total distance we want the parallax effect to span
     * horizontally
     */
    private static float wallpaperTravelToScreenWidthRatio(int width, int height) {
        float aspectRatio = width / (float) height;

        // At an aspect ratio of 16/10, the wallpaper parallax effect should span 1.5 * screen width
        // At an aspect ratio of 10/16, the wallpaper parallax effect should span 1.2 * screen width
        // We will use these two data points to extrapolate how much the wallpaper parallax effect
        // to span (ie travel) at any aspect ratio:

        final float ASPECT_RATIO_LANDSCAPE = 16/10f;
        final float ASPECT_RATIO_PORTRAIT = 10/16f;
        final float WALLPAPER_WIDTH_TO_SCREEN_RATIO_LANDSCAPE = 1.5f;
        final float WALLPAPER_WIDTH_TO_SCREEN_RATIO_PORTRAIT = 1.2f;

        // To find out the desired width at different aspect ratios, we use the following two
        // formulas, where the coefficient on x is the aspect ratio (width/height):
        //   (16/10)x + y = 1.5
        //   (10/16)x + y = 1.2
        // We solve for x and y and end up with a final formula:
        final float x =
                (WALLPAPER_WIDTH_TO_SCREEN_RATIO_LANDSCAPE - WALLPAPER_WIDTH_TO_SCREEN_RATIO_PORTRAIT) /
                        (ASPECT_RATIO_LANDSCAPE - ASPECT_RATIO_PORTRAIT);
        final float y = WALLPAPER_WIDTH_TO_SCREEN_RATIO_PORTRAIT - x * ASPECT_RATIO_PORTRAIT;
        return x * aspectRatio + y;
    }

}