/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

package com.mohtada.nestedscrollview;

import android.view.View;
import android.view.ViewGroup;

import com.facebook.react.bridge.JSApplicationIllegalArgumentException;
import android.os.SystemClock;
import com.facebook.react.views.scroll.ScrollEvent;
import com.facebook.react.views.scroll.ScrollEventType;
import com.facebook.react.bridge.ReactContext;
import com.facebook.react.uimanager.UIManagerModule;

/**
 * Helper class that deals with emitting Scroll Events.
 *
 * Forked from https://github.com/facebook/react-native/blob/v0.42.0/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollViewHelper.java
 */
public class ReactNestedScrollViewHelper {

    public static final long MOMENTUM_DELAY = 20;
    public static final String OVER_SCROLL_ALWAYS = "always";
    public static final String AUTO = "auto";
    public static final String OVER_SCROLL_NEVER = "never";

    /**
     * Shared by {@link ReactScrollView} and {@link ReactHorizontalScrollView}.
     */
    public static void emitScrollEvent(ViewGroup scrollView) {
        emitScrollEvent(scrollView, ScrollEventType.SCROLL);
    }

    public static void emitScrollBeginDragEvent(ViewGroup scrollView) {
        emitScrollEvent(scrollView, ScrollEventType.BEGIN_DRAG);
    }

    public static void emitScrollEndDragEvent(ViewGroup scrollView) {
        emitScrollEvent(scrollView, ScrollEventType.END_DRAG);
    }

    public static void emitScrollMomentumBeginEvent(ViewGroup scrollView) {
        emitScrollEvent(scrollView, ScrollEventType.MOMENTUM_BEGIN);
    }

    public static void emitScrollMomentumEndEvent(ViewGroup scrollView) {
        emitScrollEvent(scrollView, ScrollEventType.MOMENTUM_END);
    }

    private static void emitScrollEvent(ViewGroup scrollView, ScrollEventType scrollEventType) {
        View contentView = scrollView.getChildAt(0);

        if (contentView == null) {
            return;
        }

        ReactContext reactContext = (ReactContext) scrollView.getContext();
        reactContext.getNativeModule(UIManagerModule.class).getEventDispatcher().dispatchEvent(
            ScrollEvent.obtain(
                scrollView.getId(),
                scrollEventType,
                scrollView.getScrollX(),
                scrollView.getScrollY(),
                contentView.getWidth(),
                contentView.getHeight(),
                scrollView.getWidth(),
                scrollView.getHeight()));
    }

    public static int parseOverScrollMode(String jsOverScrollMode) {
        if (jsOverScrollMode == null || jsOverScrollMode.equals(AUTO)) {
            return View.OVER_SCROLL_IF_CONTENT_SCROLLS;
        } else if (jsOverScrollMode.equals(OVER_SCROLL_ALWAYS)) {
            return View.OVER_SCROLL_ALWAYS;
        } else if (jsOverScrollMode.equals(OVER_SCROLL_NEVER)) {
            return View.OVER_SCROLL_NEVER;
        } else {
            throw new JSApplicationIllegalArgumentException("wrong overScrollMode: " + jsOverScrollMode);
        }
    }
}