package com.example.meinwald.ui.area;

import android.Manifest;
import android.annotation.SuppressLint;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.database.DataSetObserver;
import android.location.Location;
import android.os.Bundle;
import android.os.PowerManager;
import android.preference.PreferenceManager;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.fragment.app.Fragment;

import com.example.meinwald.BuildConfig;
import com.example.meinwald.R;
import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.android.material.floatingactionbutton.FloatingActionButton;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

import static android.content.Context.POWER_SERVICE;

public class AreaFragment extends Fragment {

    private static final String TAG = AreaFragment.class.getSimpleName();

    /**
     * ______________________________________________________________________________________________
     * AREA
     */
    private OwnArea newArea = new OwnArea();
    private List<OwnArea> allAreas;
    private ListView areaList;
    private static final String KEY_AREA_REFERENCES = "areaReferences";
    private List<AreaReference> areaReferences;

    /**
     * ______________________________________________________________________________________________
     * LOCATION
     */
    private static final int PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 1;
    /**
     * The geographical location where the device is currently located.
     * That is the last-known location retrieved by the Fused Location Provider.
     */
    private Location mLastKnownLocation;
    /**
     * The entry point to the Fused Location Provider.
     */
    private FusedLocationProviderClient mFusedLocationProviderClient;
    private boolean mLocationPermissionGranted;
    /**
     * The geographical locations which were received from location tracking.
     */
    private List<LatLng> newPositions;

    /**
     * ______________________________________________________________________________________________
     * CAMERA
     */
    private static final int MY_CAMERA_PERMISSION_CODE = 100;
    private boolean mCameraPermissionGranted;
    private static final int CAMERA_REQUEST = 1888;

    /**
     * ______________________________________________________________________________________________
     * STORAGE
     */
    private static final int READ_EXTERNAL_STORAGE_CODE = 200;
    private static final int WRITE_EXTERNAL_STORAGE_CODE = 201;
    private boolean mReadStorageGranted;
    private boolean mWriteStorageGranted;

    PowerManager.WakeLock wakeLock;
    LocationService gps;

    @Override
    public void onCreate (Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        areaReferences = new ArrayList<>();
        areaReferences = readAreaReferencesFromPreferences();
    }


    @SuppressLint("InvalidWakeLockTag")
    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View root = inflater.inflate(R.layout.fragment_areas, container, false);

        //construct a FusedLocationProviderClient.
        mFusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(getActivity());

        //get permissions
        getLocationPermission();
        getReadStoragePermission();

        //instantiate area lists
        areaList = (ListView) root.findViewById(R.id.areaListView);
        allAreas = new ArrayList<>();

        //get saved areas
        allAreas = loadAreasFromPreferences();
        for (int i = 0; i < allAreas.size(); i++)
        {
            allAreas.get(i).setPathFile(areaReferences.get(i).getPath());
        }
        instantiateAreasList();

        PowerManager powerManager = (PowerManager) getContext().getSystemService(POWER_SERVICE);
        wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "MyWakelockTag");
        gps = new LocationService(getContext());

        //instantiate add button
        final FloatingActionButton fab = root.findViewById(R.id.fab_areas);

        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                //permissions
                getLocationPermission();
                getWriteStoragePPermission();

                AlertDialog.Builder builder = new AlertDialog.Builder(getContext());

                newArea = new OwnArea();
                newPositions = new ArrayList<>();

                final View viewInflated = LayoutInflater.from(getContext()).inflate(R.layout.area_input, (ViewGroup) getView(), false);
                builder.setView(viewInflated);

                final Button startTracking = viewInflated.findViewById(R.id.areaStartTracking);
                final Button stopTracking = viewInflated.findViewById(R.id.areaStopTracking);
                final Button addLocation = viewInflated.findViewById(R.id.areaAddGPSPoint);

                startTracking.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {

                        //start tracking
                        startLocationTracking();

                        startTracking.setVisibility(View.INVISIBLE);
                        stopTracking.setVisibility(View.VISIBLE);
                        addLocation.setVisibility(View.INVISIBLE);
                    }
                });

                stopTracking.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {

                        //stop tracking
                        List<LatLng> positionsToAdd = new ArrayList<>();
                        positionsToAdd = gps.getPositions();

                        for (LatLng pos: positionsToAdd)
                        {
                            newPositions.add(pos);
                        }

                        if (BuildConfig.DEBUG)
                        {
                            Log.d(TAG, "Received locations: " + newPositions.size());
                        }

                        wakeLock.release();

                        startTracking.setVisibility(View.VISIBLE);
                        stopTracking.setVisibility(View.INVISIBLE);
                        addLocation.setVisibility(View.VISIBLE);
                    }
                });

                addLocation.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {

                        //get last known location
                        getDeviceLocation();
                    }});

                builder.setPositiveButton("Bestätigen", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {

                        final TextView titleView = viewInflated.findViewById(R.id.areaTitleUserInput);
                        final TextView noticeView = viewInflated.findViewById(R.id.areaManagementNoticeUserInput);

                        if (BuildConfig.DEBUG) {
                            Log.d(TAG, "new title: " + titleView.getText());
                        }

                        if (titleView.getText().length()>0)
                        {
                            //save user input
                            newArea.setTitle(String.valueOf(titleView.getText()));
                            newArea.setNotice(String.valueOf(noticeView.getText()));
                            newArea.setLocations(newPositions);
                            newArea.calculateArea();

                            boolean result =  allAreas.add(newArea);

                            if (BuildConfig.DEBUG)
                            {
                                Log.d(TAG, "new Task: " + newArea.toString());
                                Log.d(TAG, "add new task result: " + result);
                            }

                            newArea.writeToExternalStorage(getContext());
                            areaReferences.add(new AreaReference(newArea.getId(), newArea.getPathFile()));

                            emptyPreferencesAndSaveAreaReferencesToPreferences();

                            //actuate list
                            instantiateAreasList();

                            dialog.dismiss();

                            //confirm added task
                            Toast toast = Toast.makeText(getActivity(), "Grundstück hinzugefügt!", Toast.LENGTH_SHORT);
                            TextView v = (TextView) toast.getView().findViewById(android.R.id.message);
                            if( v != null)
                            {
                                //text align center
                                v.setGravity(Gravity.CENTER);
                            }
                            toast.show();
                        }
                        else
                        {
                            //title needed
                            Toast toast = Toast.makeText(getActivity(), "Grundstückstitel fehlt!", Toast.LENGTH_SHORT);
                            TextView v = (TextView) toast.getView().findViewById(android.R.id.message);
                            if( v != null)
                            {
                                //text align center
                                v.setGravity(Gravity.CENTER);
                            }
                            toast.show();
                        }
                    }
                });

                builder.setNegativeButton("Abbrechen", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which)
                    {
                        //reset variables
                        newArea = new OwnArea();
                        newPositions = new ArrayList<>();

                        dialog.cancel();
                    }
                });

                builder.show();
            }});

        return root;
    }

    /**
     * Get all stored areas and save them temporary.
     */
    public void instantiateAreasList()
    {
        final AreaAdapter adapter = new AreaAdapter(getActivity().getApplicationContext(), allAreas);
        adapter.registerDataSetObserver(new DataSetObserver() {
            @Override
            public void onChanged() {
                super.onChanged();

                if (BuildConfig.DEBUG)
                {
                    Log.d(TAG, "onChanged");
                }

                if (BuildConfig.DEBUG)
                {
                    Log.d(TAG, "dataset size: " + areaList.getAdapter().getCount());
                }

                if (areaList.getAdapter().getCount() > 0)
                {
                    allAreas = new ArrayList<>();
                    areaReferences =new ArrayList<>();

                    for (int i = 0; i < areaList.getAdapter().getCount(); i++)
                    {
                        allAreas.add((OwnArea) areaList.getAdapter().getItem(i));
                        if (BuildConfig.DEBUG)
                        {
                            Log.d(TAG, "dataset added: " + allAreas.get(i).toString());
                        }

                        areaReferences.add(new AreaReference(allAreas.get(i).getId(), allAreas.get(i).getPathFile()));
                    }
                }
            }
        });
        areaList.setAdapter(adapter);

        //initialise onClickListeners
        areaList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

                //for (int j = 0; j < adapterView.getChildCount(); j++)
                //adapterView.getChildAt(j).setBackgroundColor(Color.TRANSPARENT);

                // change the background color of the selected element
                //view.setBackgroundColor(Color.LTGRAY);
                //adapterView.setSelection(i);
            }});
    }


    @Override
    public void onPause() {

        super.onPause();

        //save area references to shared preferences
        emptyPreferencesAndSaveAreaReferencesToPreferences();
    }

    /**
     * Get OwnAreas from a JSONString.
     * @return
     */
    private List<OwnArea> loadAreasFromPreferences()
    {
        if (BuildConfig.DEBUG)
        {
            Log.d(TAG, "loadAreasFromPreferences() reference size: " + areaReferences.size());
        }

        List<OwnArea> areas = new ArrayList<>();
        Integer i = 0;

        for (AreaReference reference: areaReferences)
        {
            String jsonString = readAreaFromExternalStorage(reference.getPath());

            areas.add(new OwnArea(jsonString));

            if (BuildConfig.DEBUG)
            {
                Log.d(TAG, "load area from preferences: " + areas.get(i).toString());
            }

            i++;
        }

        return areas;
    }

    /**
     * Read OwnArea from file in external storage and return as a string.
     *
     * @param path File path where the OwnArea is saved.
     * @return
     */
    private String readAreaFromExternalStorage(String path)
    {
        if (BuildConfig.DEBUG)
        {
            Log.d(TAG, "readAreaFromExternalStorage()");
        }

        //Get the text file
        File file = new File(path);

        //Read text from file
        StringBuilder text = new StringBuilder();

        try {
            BufferedReader br = new BufferedReader(new FileReader(file));
            String line;

            while ((line = br.readLine()) != null) {
                text.append(line);
                if (BuildConfig.DEBUG)
                {
                    Log.d(TAG, "Line: " + line);
                }
            }
            br.close();
        }
        catch (IOException e) {
            if (BuildConfig.DEBUG)
            {
                Log.e(TAG, "Failed read from external storage: " + e.toString());
            }
        }

        return text.toString();
}

    /**
     * Converts an OwnArea object into a JSONString object.
     *
     * @param area Area to convert into JSONString
     * @return
     */

    public String areaToString(OwnArea area)
    {
        JSONObject areaObject = newArea.toJSONObject();

        return areaObject.toString();
    }

    /**
     * Reads areaReferences saved in preferences as jsonStrings
     *
     * @return list of AreaReferences
     */
    private List<AreaReference> readAreaReferencesFromPreferences() {

        if (BuildConfig.DEBUG)
        {
            Log.d(TAG, "readAreaReferencesFromPreferences()");
        }

        List<AreaReference> areas = new ArrayList<>();

        try {
            String jsonString = PreferenceManager.getDefaultSharedPreferences(getContext()).getString(KEY_AREA_REFERENCES, "error");
            if(!"error".equalsIgnoreCase(jsonString)) {
                JSONArray jsonObjects = new JSONArray(jsonString);
                for (int i = 0; i<jsonObjects.length();i++)
                {
                    areas.add(new AreaReference(jsonObjects.getJSONObject(i)));

                    // Find the root of the external storage.
                    File root = android.os.Environment.getExternalStorageDirectory();

                    //delete reference if file does not exist
                    File file = new File(getContext().getFilesDir(), "meinWald" + File.pathSeparator + "areas" + File.pathSeparator + areas.get(i).getId() + ".txt");
                    if(file.exists())
                    {
                        areas.remove(i);
                    }
                }
            }
            else
            {
                if (BuildConfig.DEBUG)
                {
                    Log.e(TAG, "read area reference error");
                }
            }
        }  catch (JSONException e) {
            if (BuildConfig.DEBUG) {
                Log.e(TAG, "Error while parsing area references as jsonObjects from preferences");
                e.printStackTrace();
            }
        }

        for (AreaReference reference: areas)
        {
            if (BuildConfig.DEBUG)
            {
                Log.d(TAG, "read reference: " + reference.toString());
            }
        }

        return areas;
    }

    /**
     * Saves areas to preferences
     */
    private void emptyPreferencesAndSaveAreaReferencesToPreferences()
    {
        if (BuildConfig.DEBUG)
        {
            Log.d(TAG, "emptyPreferencesAndSaveAreaReferencesToPreferences()");
        }

        if (!areaReferences.isEmpty()) {
            if (BuildConfig.DEBUG) {
                Log.d(TAG, "areaReferences not empty");
            }

            PreferenceManager.getDefaultSharedPreferences(getContext()).edit().remove(KEY_AREA_REFERENCES).commit();

            JSONArray writeObjects = new JSONArray();


            for (AreaReference reference: areaReferences) {

                JSONObject object = reference.toJSONObject();
                writeObjects.put(object);

                if (BuildConfig.DEBUG) {
                    Log.d(TAG, "area reference is " + object.toString());
                }
            }

            PreferenceManager.getDefaultSharedPreferences(getContext()).edit().putString(KEY_AREA_REFERENCES,  writeObjects.toString()).commit();
        }
        else
        {
            if (BuildConfig.DEBUG) {
                Log.e(TAG, "area references are empty!");
            }
        }
    }

    /**
     * DOCU ME!
     * TOOD: What are grant results etc for?
     * @param requestCode
     * @param permissions
     * @param grantResults
     */
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults)
    {
        if (BuildConfig.DEBUG) {
            Log.d(TAG, "onRequestPermissionResult Code: " + requestCode);
        }
        mLocationPermissionGranted = false;
        switch (requestCode) {
            case PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION: {
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED)
                {
                    mLocationPermissionGranted = true;
                }
            }
            case MY_CAMERA_PERMISSION_CODE: {

                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    mCameraPermissionGranted = true;
                }
            }
            case READ_EXTERNAL_STORAGE_CODE: {

                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    mReadStorageGranted = true;
                }
            }
            case WRITE_EXTERNAL_STORAGE_CODE: {

                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    mWriteStorageGranted = true;
                }
            }
        }
    }

    public void getLocation(){

        wakeLock.acquire();

        gps = new LocationService(getContext());

    }

    /**
     * Get the best and most recent location of the device, which may be null in rare
     * cases when a location is not available.
     *
     */
    private void getDeviceLocation() {
        try {
            if (mLocationPermissionGranted) {
                Task<Location> locationResult = mFusedLocationProviderClient.getLastLocation();
                locationResult.addOnCompleteListener(getActivity(), new OnCompleteListener<Location>() {
                    @Override
                    public void onComplete(@NonNull Task<Location> task) {
                        if (task.isSuccessful())
                        {
                            // Set the last known position to the current location of the device and add to tracking stack
                            mLastKnownLocation = task.getResult();
                            newPositions.add(new LatLng(mLastKnownLocation.getLatitude(),mLastKnownLocation.getLongitude()));

                            if (BuildConfig.DEBUG) {

                                if (task.getResult() != null)
                                {
                                    Log.d(TAG, "getDeviceLocation: " + task.getResult().toString());
                                    Log.d(TAG, "Size: " + newPositions.size());
                                }
                            }
                        } else {
                            if (BuildConfig.DEBUG) {
                                Log.d(TAG, "Current location is null. Using defaults.");
                                Log.e(TAG, "Exception: %s", task.getException());
                            }
                        }
                    }
                });
            }
        } catch (SecurityException e)  {
            if (BuildConfig.DEBUG) {
                Log.e(TAG, "Exception occurred: ");
                e.printStackTrace();
            }
        }
    }

    public void startLocationTracking(){

        final Runnable runnable= new Runnable() {
            public void run() {
                // do stuff here
                getLocation();
            }
        };
        runnable.run();
    }

    /**
     * Request location permission, so that we can get the location of the device.
     * The result of the permission request is handled by a callback,
     * onRequestPermissionsResult.
     *
     */
    private void getLocationPermission() {
        if (ContextCompat.checkSelfPermission(getActivity().getApplicationContext(),
                android.Manifest.permission.ACCESS_FINE_LOCATION)
                == PackageManager.PERMISSION_GRANTED) {
            mLocationPermissionGranted = true;
        } else {
            ActivityCompat.requestPermissions(getActivity(),
                    new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION},
                    PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION);
        }
    }

    /**
     * Request read external storage permission, so that we can get saved images from external storage.
     * The result of the permission request is handled by a callback,
     * onRequestPermissionsResult.
     *
     */
    private void getReadStoragePermission() {
        if (ContextCompat.checkSelfPermission(getActivity().getApplicationContext(),
                Manifest.permission.READ_EXTERNAL_STORAGE)
                == PackageManager.PERMISSION_GRANTED) {
            mReadStorageGranted = true;
        } else {
            ActivityCompat.requestPermissions(getActivity(),
                    new String[]{android.Manifest.permission.READ_EXTERNAL_STORAGE},
                    READ_EXTERNAL_STORAGE_CODE);
        }
    }

    /**
     * Request read external storage permission, so that we can get saved images from external storage.
     * The result of the permission request is handled by a callback,
     * onRequestPermissionsResult.
     *
     */
    private void getWriteStoragePPermission() {
        if (ContextCompat.checkSelfPermission(getActivity().getApplicationContext(),
                Manifest.permission.WRITE_EXTERNAL_STORAGE)
                == PackageManager.PERMISSION_GRANTED) {
            mWriteStorageGranted = true;
        } else {
            ActivityCompat.requestPermissions(getActivity(),
                    new String[]{android.Manifest.permission.WRITE_EXTERNAL_STORAGE},
                    WRITE_EXTERNAL_STORAGE_CODE);
        }
    }
}