package example.zxing;


import android.os.Bundle;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentPagerAdapter;
import androidx.fragment.app.FragmentTransaction;
import androidx.legacy.app.FragmentStatePagerAdapter;
import androidx.viewpager.widget.PagerAdapter;
import androidx.viewpager.widget.ViewPager;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.journeyapps.barcodescanner.CameraPreview;
import com.journeyapps.barcodescanner.DecoratedBarcodeView;

public class TabbedScanning extends AppCompatActivity implements ActionBar.TabListener {

    /**
     * The {@link PagerAdapter} that will provide
     * fragments for each of the sections. We use a
     * {@link FragmentPagerAdapter} derivative, which will keep every
     * loaded fragment in memory. If this becomes too memory intensive, it
     * may be best to switch to a
     * {@link FragmentStatePagerAdapter}.
     */
    private SectionsPagerAdapter mSectionsPagerAdapter;


    /**
     * The {@link ViewPager} that will host the section contents.
     */
    private ViewPager mViewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_tabbed_scanning);
        // Create the adapter that will return a fragment for each of the three
        // primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

        // Set up the ViewPager with the sections adapter.
        mViewPager = findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);

        // Set up the action bar.
        final ActionBar actionBar = getSupportActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        // When swiping between different sections, select the corresponding
        // tab. We can also use ActionBar.Tab#select() to do this if we have
        // a reference to the Tab.
        mViewPager.setOffscreenPageLimit(0);
        mViewPager.addOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
            @Override
            public void onPageSelected(int position) {
                actionBar.setSelectedNavigationItem(position);
            }
        });

        // For each of the sections in the app, add a tab to the action bar.
        for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
            // Create a tab with text corresponding to the page title defined by
            // the adapter. Also specify this Activity object, which implements
            // the TabListener interface, as the callback (listener) for when
            // this tab is selected.
            actionBar.addTab(
                    actionBar.newTab()
                            .setText(mSectionsPagerAdapter.getPageTitle(i))
                            .setTabListener(this));
        }

    }

    @Override
    public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
        // When the given tab is selected, switch to the corresponding page in
        // the ViewPager.
        mViewPager.setCurrentItem(tab.getPosition());
    }

    @Override
    public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
    }

    @Override
    public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class ScanFragment extends Fragment {
        DecoratedBarcodeView barcodeView;

        public ScanFragment() {
        }

        /**
         * Returns a new instance of this fragment for the given section
         * number.
         */
        public static ScanFragment newInstance() {
            return new ScanFragment();
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_tabbed_scanning, container, false);
            barcodeView = rootView.findViewById(R.id.barcode_view);
            return rootView;
        }


        @Override
        public void setUserVisibleHint(boolean isVisibleToUser) {
            super.setUserVisibleHint(isVisibleToUser);
            if(barcodeView != null) {
                if (isVisibleToUser) {
                    barcodeView.resume();
                } else {
                    barcodeView.pauseAndWait();
                }
            }
        }

        @Override
        public void onPause() {
            super.onPause();
            barcodeView.pauseAndWait();
        }

        @Override
        public void onResume() {
            super.onResume();
            barcodeView.resume();
        }
    }


    /**
     * A placeholder fragment containing a simple view.
     */
    public static class CameraFragment extends Fragment {

        private CameraPreview cameraPreview;

        public CameraFragment() {
        }

        /**
         * Returns a new instance of this fragment for the given section
         * number.
         */
        public static CameraFragment newInstance() {
            return new CameraFragment();
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_tabbed_camera, container, false);
            cameraPreview = rootView.findViewById(R.id.camera_preview);
            return rootView;
        }

        @Override
        public void setUserVisibleHint(boolean isVisibleToUser) {
            super.setUserVisibleHint(isVisibleToUser);

            if (cameraPreview != null) {
                if (isVisibleToUser) {
                    cameraPreview.resume();
                } else {
                    cameraPreview.pauseAndWait();
                }
            }
        }

        @Override
        public void onPause() {
            super.onPause();
            cameraPreview.pauseAndWait();
        }

        @Override
        public void onResume() {
            super.onResume();
        }
    }



    /**
     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
     * one of the sections/tabs/pages.
     */
    public class SectionsPagerAdapter extends FragmentPagerAdapter {

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            if(position == 0) {
                return ScanFragment.newInstance();
            } else {
                return CameraFragment.newInstance();
            }

        }

        @Override
        public int getCount() {
            return 2;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            switch (position) {
                case 0:
                    return "Scan";
                case 1:
                    return "Camera";
            }
            return null;
        }
    }
}