package com.mapbox.mapboxsdk.maps;

import android.graphics.Bitmap;
import android.util.DisplayMetrics;

import com.mapbox.mapboxsdk.annotations.Icon;
import com.mapbox.mapboxsdk.annotations.IconFactory;
import com.mapbox.mapboxsdk.annotations.Marker;
import com.mapbox.mapboxsdk.annotations.MarkerView;
import com.mapbox.mapboxsdk.exceptions.IconBitmapChangedException;

import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;

/**
 * Responsible for managing icons added to the Map.
 * <p>
 * Maintains a {@link List} of {@link Icon} and  is responsible for initialising default markers and
 * setting up {@link MarkerView} annotation ghosting.
 * </p>
 * <p>
 * Keep track of icons added and the resulting average icon size. This is used internally by our
 * gestures detection to calculate the size of a touch target.
 * </p>
 */
class IconManager {

    private NativeMapView nativeMapView;
    private List<Icon> icons;

    private int averageIconHeight;
    private int averageIconWidth;

    IconManager(NativeMapView nativeMapView) {
        this.nativeMapView = nativeMapView;
        this.icons = new ArrayList<>();
        // load transparent icon for MarkerView to trace actual markers, see #6352
        loadIcon(IconFactory.recreate(IconFactory.ICON_MARKERVIEW_ID, IconFactory.ICON_MARKERVIEW_BITMAP));
    }

    Icon loadIconForMarker(Marker marker) {
        Icon icon = marker.getIcon();

        // calculating average before adding
        int iconSize = icons.size() + 1;

        // TODO replace former if case with anchor implementation,
        // current workaround for having extra pixels is diving height by 2
        if (icon == null) {
            icon = IconFactory.getInstance(nativeMapView.getContext()).defaultMarker();
            Bitmap bitmap = icon.getBitmap();
            averageIconHeight = averageIconHeight + (bitmap.getHeight() / 2 - averageIconHeight) / iconSize;
            averageIconWidth = averageIconWidth + (bitmap.getWidth() - averageIconWidth) / iconSize;
            marker.setIcon(icon);
        } else {
            Bitmap bitmap = icon.getBitmap();
            averageIconHeight = averageIconHeight + (bitmap.getHeight() - averageIconHeight) / iconSize;
            averageIconWidth = averageIconWidth + (bitmap.getWidth() - averageIconWidth) / iconSize;
        }

        if (!icons.contains(icon)) {
            icons.add(icon);
            loadIcon(icon);
        } else {
            Icon oldIcon = icons.get(icons.indexOf(icon));
            if (!oldIcon.getBitmap().sameAs(icon.getBitmap())) {
                throw new IconBitmapChangedException();
            }
        }
        return icon;
    }

    Icon loadIconForMarkerView(MarkerView marker) {
        Icon icon = marker.getIcon();
        int iconSize = icons.size() + 1;
        if (icon == null) {
            icon = IconFactory.getInstance(nativeMapView.getContext()).defaultMarkerView();
            marker.setIcon(icon);
        }
        Bitmap bitmap = icon.getBitmap();
        averageIconHeight = averageIconHeight + (bitmap.getHeight() - averageIconHeight) / iconSize;
        averageIconWidth = averageIconWidth + (bitmap.getWidth() - averageIconWidth) / iconSize;
        if (!icons.contains(icon)) {
            icons.add(icon);
        } else {
            Icon oldIcon = icons.get(icons.indexOf(icon));
            if (!oldIcon.getBitmap().sameAs(icon.getBitmap())) {
                throw new IconBitmapChangedException();
            }
        }
        return icon;
    }

    int getTopOffsetPixelsForIcon(Icon icon) {
        return (int) (nativeMapView.getTopOffsetPixelsForAnnotationSymbol(icon.getId()) * nativeMapView.getPixelRatio());
    }

    void loadIcon(Icon icon) {
        Bitmap bitmap = icon.getBitmap();
        String id = icon.getId();
        if (bitmap.getConfig() != Bitmap.Config.ARGB_8888) {
            bitmap = bitmap.copy(Bitmap.Config.ARGB_8888, false);
        }
        ByteBuffer buffer = ByteBuffer.allocate(bitmap.getRowBytes() * bitmap.getHeight());
        bitmap.copyPixelsToBuffer(buffer);

        float density = bitmap.getDensity();
        if (density == Bitmap.DENSITY_NONE) {
            density = DisplayMetrics.DENSITY_DEFAULT;
        }
        float scale = density / DisplayMetrics.DENSITY_DEFAULT;
        nativeMapView.addAnnotationIcon(
                id,
                bitmap.getWidth(),
                bitmap.getHeight(),
                scale, buffer.array());
    }

    void reloadIcons() {
        int count = icons.size();
        for (int i = 0; i < count; i++) {
            Icon icon = icons.get(i);
            loadIcon(icon);
        }
    }

    void ensureIconLoaded(Marker marker, MapboxMap mapboxMap) {
        Icon icon = marker.getIcon();
        if (icon == null) {
            icon = IconFactory.getInstance(nativeMapView.getContext()).defaultMarker();
            marker.setIcon(icon);
        }
        if (!icons.contains(icon)) {
            icons.add(icon);
            loadIcon(icon);
        } else {
            Icon oldIcon = icons.get(icons.indexOf(icon));
            if (!oldIcon.getBitmap().sameAs(icon.getBitmap())) {
                throw new IconBitmapChangedException();
            }
        }

        // this seems to be a costly operation according to the profiler so I'm trying to save some calls
        Marker previousMarker = marker.getId() != -1 ? (Marker) mapboxMap.getAnnotation(marker.getId()) : null;
        if (previousMarker == null || previousMarker.getIcon() == null || previousMarker.getIcon() != marker.getIcon()) {
            marker.setTopOffsetPixels(getTopOffsetPixelsForIcon(icon));
        }
    }

    int getAverageIconHeight() {
        return averageIconHeight;
    }

    int getAverageIconWidth() {
        return averageIconWidth;
    }
}