package com.mobify.astro;

import android.app.Activity;
import android.graphics.Rect;
import android.view.View;
import android.view.ViewTreeObserver;
import android.view.WindowManager;
import android.widget.FrameLayout;

public class SoftInputLayoutManager {

    private View mChildOfContent;
    private int usableHeightPrevious;
    private FrameLayout.LayoutParams frameLayoutParams;
    private Activity activity;

    public SoftInputLayoutManager(Activity activity) {
        this.activity = activity;
        this.activity.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE);
    }

    public void addSoftInputLayoutListener() {
        FrameLayout content = activity.findViewById(R.id.main_view_id);
        if (content == null) return;

        mChildOfContent = content.getChildAt(0);
        if (mChildOfContent == null) return;

        mChildOfContent.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                possiblyResizeChildOfContent();
            }
        });

        frameLayoutParams = (FrameLayout.LayoutParams) mChildOfContent.getLayoutParams();
    }

    private void possiblyResizeChildOfContent() {
        int usableHeightNow = computeUsableHeight();
        if (usableHeightNow != usableHeightPrevious) {
            frameLayoutParams.height = usableHeightNow;
            mChildOfContent.requestLayout();
            usableHeightPrevious = usableHeightNow;
        }
    }

    private int computeUsableHeight() {
        Rect r = new Rect();
        mChildOfContent.getWindowVisibleDisplayFrame(r);
        return (r.bottom - r.top);
    }
}