package com.example.meinwald.ui.map;

import android.Manifest;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.location.Location;
import android.os.Bundle;
import android.os.IBinder;
import android.preference.PreferenceManager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;
import android.widget.Toast;

import com.example.meinwald.BuildConfig;
import com.example.meinwald.R;
import com.example.meinwald.ui.area.AreaReference;
import com.example.meinwald.ui.area.OwnArea;
import com.example.meinwald.ui.task.OwnTask;
import com.google.android.gms.common.util.Hex;
import com.google.android.gms.dynamic.IObjectWrapper;
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.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptor;
import com.google.android.gms.maps.model.CameraPosition;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.Polygon;
import com.google.android.gms.maps.model.PolygonOptions;
import com.google.android.gms.maps.model.Polyline;
import com.google.android.gms.maps.model.PolylineOptions;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.maps.android.SphericalUtil;

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

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

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

import static com.example.meinwald.R.layout.fragment_map;

public class MapsFragment extends Fragment implements OnMapReadyCallback {

    /**
     * ______________________________________________________________________________________________
     * MAPS
     */
    // A default location and default zoom to use when location permission is not granted.
    private static final LatLng M_DEFAULT_LOCATION = new LatLng(49.5, 11.0); //Nuremberg
    private static final int DEFAULT_ZOOM = 1;
    private static final float MAX_ZOOM = (float) 20.0;


    private static final int PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 1;
    private static final String TAG = MapsFragment.class.getSimpleName();
    // Keys for storing activity state.
    private static final String KEY_CAMERA_POSITION = "camera_position";
    private static final String KEY_LOCATION = "location";

    private GoogleMap mMap;
    private CameraPosition mCameraPosition;

    /**
     * The entry point to the Fused Location Provider.
     */
    private FusedLocationProviderClient mFusedLocationProviderClient;
    private boolean mLocationPermissionGranted;
    /**
     * The geographical location where the device is currently located.
     * That is the last-known location retrieved by the Fused Location Provider.
     */
    private Location mLastKnownLocation;

    /**
     * ______________________________________________________________________________________________
     * TASKS
     */
    private List<OwnTask> allTasks;
    private static final String KEY_ALL_TASKS = "allTasks";

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

    /**
     * ______________________________________________________________________________________________
     * AREA
     */
    private List<OwnArea> allAreas;
    private static final String KEY_AREA_REFERENCES = "areaReferences";
    private List<AreaReference> areaReferences;

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

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

    /**
     * Is called when the MapsFragment view is created. Initializes all service connections, the location client and map itself.
     * @param inflater Calling LayoutInflater
     * @param container ViewGroup
     * @param savedInstanceState Applications savedInstanceState
     * @return
     */
    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        //get view to inflate
        View root = inflater.inflate(fragment_map, container, false);

        //get storage permission
        getReadStoragePermission();

        //get tasks
        allTasks = readTasksFromPreferences();

        //get areas
        //instantiate area lists
        allAreas = new ArrayList<>();

        //get saved areas
        allAreas = loadAreasFromPreferences();

        //display map fragment
        SupportMapFragment mapFragment = new SupportMapFragment();
        FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
        transaction.add(R.id.map, mapFragment).commit();

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

        //wait for map is ready
        mapFragment.getMapAsync(new OnMapReadyCallback()
        {
            @Override
            public void onMapReady(GoogleMap googleMap) {
                //save map instance locally
                mMap = googleMap;
                //set max zoom level
                mMap.setMaxZoomPreference(MAX_ZOOM);
                mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
                mMap.setOnMarkerClickListener(new GoogleMap.OnMarkerClickListener() {
                    @Override
                    public boolean onMarkerClick(Marker marker) {

                        if (mMap.getCameraPosition().zoom < 17.5)
                        {
                            mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(marker.getPosition().latitude, marker.getPosition().longitude),(float)17.5));
                        }
                        else
                        {
                            mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(marker.getPosition().latitude, marker.getPosition().longitude),mMap.getCameraPosition().zoom));
                        }

                        return false;
                    }
                });

                //retrieve saved instance state
                mCameraPosition  = parseCameraPosition(PreferenceManager.getDefaultSharedPreferences(getContext()).getString(KEY_CAMERA_POSITION, new CameraPosition(new LatLng(45.0,11.0), (float) 1.0, (float) 0.0,(float) 0.0).toString()));
                mLastKnownLocation  = new Location(PreferenceManager.getDefaultSharedPreferences(getContext()).getString(KEY_LOCATION, new LatLng(45.0,11.0).toString()));
                mCameraPosition  = parseCameraPosition(PreferenceManager.getDefaultSharedPreferences(getContext()).getString(KEY_CAMERA_POSITION, new CameraPosition(new LatLng(45.0,11.0), (float) 1.0, (float) 0.0,(float) 0.0).toString()));

                //move camera to last position
                mMap.moveCamera(CameraUpdateFactory.newCameraPosition(mCameraPosition));

                //get permission
                getLocationPermission();

                //turn on the My Location layer and the related control on the map.
                updateLocationUI();

                // Get the current location of the device and set the position of the map.
                getDeviceLocation();
            }
        });

        return root;
    }

    @Override
    public void onPause() {

        //save current location and camera position to shared preferences
        if (mMap.getCameraPosition() != null && mLastKnownLocation != null) {
            PreferenceManager.getDefaultSharedPreferences(getContext()).edit().putString(KEY_CAMERA_POSITION, mMap.getCameraPosition().toString()).commit();
            PreferenceManager.getDefaultSharedPreferences(getContext()).edit().putString(KEY_LOCATION, mLastKnownLocation.toString()).commit();
        }

        super.onPause();
    }

    private void drawAreas()
    {
        for (OwnArea area: allAreas)
        {
            if (area.getLocations() != null && area.getLocations().size()>0)
            {
                PolygonOptions options = new PolygonOptions().clickable(true);

                if (BuildConfig.DEBUG)
                {
                    Log.d(TAG, "Color: " + getAreaColor(area.getLastChecked()));
                    Log.d(TAG, "Color: " + String.valueOf(getAreaColor(area.getLastChecked() & 0x00FFFFFF) | 0x60000000));
                    Log.d(TAG, "Area: " + SphericalUtil.computeArea(area.getLocations()));
                }
                options.strokeColor(getAreaColor(area.getLastChecked()));
                options.fillColor((options.getStrokeColor() & 0x00FFFFFF) | 0x60000000);

                for (LatLng location: area.getLocations())
                {
                    options.add(location);

                    if (BuildConfig.DEBUG)
                    {
                        Log.d(TAG, "Position: " + location.toString());
                    }
                }

                options.add(area.getLocations().get(0));

                mMap.addPolygon(options);
            }
        }
    }

    /**
     * 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)));
                }
            }
            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;
    }

    /**
     * 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);
            }
            br.close();
        }
        catch (IOException e) {
            if (BuildConfig.DEBUG)
            {
                Log.e(TAG, "Failed read from external storage: " + e.toString());
            }
        }

        return text.toString();
    }

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

    /**
     * Parses a string and creates a new CameraPosition from it.
     * Use CameraPosition.toString() to get corresponding string.
     * @param posString String which includes a camera position.
     * @return The parsed position of type CameraPosition.
     */
    private CameraPosition parseCameraPosition(String posString) {
        //parse string from shared preferences (CameraPosition.toString())
        String[] stringsplit = posString.split(" ");
        float lat = Float.parseFloat(stringsplit[1].split(",")[0].substring(1));
        float lng = Float.parseFloat(stringsplit[1].split(",")[1].substring(0,stringsplit[1].split(",")[1].length()-1));
        float zoom = Float.parseFloat(stringsplit[2].split("=")[1].substring(0,stringsplit[2].split("=")[1].length()-1));
        float tilt = Float.parseFloat(stringsplit[3].split("=")[1].substring(0,stringsplit[3].split("=")[1].length()-1));
        float bearing = Float.parseFloat(stringsplit[4].split("=")[1].substring(0,stringsplit[4].split("=")[1].length()-1));

        return new CameraPosition(new LatLng(lat,lng),zoom,tilt,bearing);
    }

    /**
     * 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);
        }
    }

    /**
     * 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)
    {
        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)
                {
                    updateLocationUI();
                    mLocationPermissionGranted = true;
                }
            }
            case READ_EXTERNAL_STORAGE_CODE: {

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

    /**
     * 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.
                            mLastKnownLocation = task.getResult();
                            if (BuildConfig.DEBUG) {

                                if (task.getResult() != null)
                                {
                                    Log.d(TAG, "getDeviceLocation " + task.getResult().toString());

                                }
                            }
                        } else {
                            if (BuildConfig.DEBUG) {
                                Log.d(TAG, "Current location is null. Using defaults.");
                                Log.e(TAG, "Exception: %s", task.getException());
                            }
                            mMap.moveCamera(CameraUpdateFactory
                                    .newLatLngZoom(M_DEFAULT_LOCATION, DEFAULT_ZOOM));
                            //mMap.getUiSettings().setMyLocationButtonEnabled(false);
                            if (BuildConfig.DEBUG) {
                                Log.d(TAG, "getDeviceLocation: task not successful");
                            }
                        }
                    }
                });
            }
        } catch (SecurityException e)  {
            if (BuildConfig.DEBUG) {
                Log.e(TAG, "Exception occurred: ");
                e.printStackTrace();
            }
        }
    }

    private void updateLocationUI() {
        if (mMap == null) {
            if (BuildConfig.DEBUG) {
                Log.d(TAG, "Permission: Map not ready!");
            }
            return;
        }
        try {
            if (mLocationPermissionGranted) {
                mMap.setMyLocationEnabled(true);
                mMap.getUiSettings().setMapToolbarEnabled(true);
                mMap.getUiSettings().setMyLocationButtonEnabled(true);
                mMap.getUiSettings().setCompassEnabled(true);
                mMap.getUiSettings().setZoomControlsEnabled(true);

                if (BuildConfig.DEBUG) {
                    Log.d(TAG, "Permission: Granted!");
                }
            } else {
                mMap.setMyLocationEnabled(false);
                mMap.getUiSettings().setMyLocationButtonEnabled(false);
                mMap.getUiSettings().setZoomControlsEnabled(false);
                mMap.getUiSettings().setCompassEnabled(false);
                mMap.getUiSettings().setMapToolbarEnabled(false);
                mLastKnownLocation = null;

                if (BuildConfig.DEBUG) {
                    Log.d(TAG, "Permission: Denied!");
                }

                getLocationPermission();
            }
        } catch (SecurityException e)  {
            if (BuildConfig.DEBUG) {
                Log.e(TAG, "Exception occurred: ");
                e.printStackTrace();
            }
        }

        for (OwnTask task: allTasks)
        {
            MarkerOptions marker = new MarkerOptions();

            //set options
            marker.position(new LatLng(task.getLocation().getLatitude(), task.getLocation().getLongitude()));
            marker.title(task.getTitle());

            mMap.addMarker(marker);
        }

        drawAreas();
    }

    /**
     * Decides color of area based on the time passed since last ckeck update.
     *
     * @param time difference in milliseconds between last check and now
     * @return color number
     */
    private int getAreaColor(long time) {
        //set transparency related to time difference
        if(time > -1)
        {
            long timeDiff = new Date().getTime() - time;

            //less than a week
            if (timeDiff < 7*24*60*60*1000L)
            {
                return  Color.parseColor("#57a639");
            }
            //less than two weeks
            else if (timeDiff < 14*24*60*60*1000L)
            {
                return  Color.parseColor("#819b45");
            }
            //less than three weeks
            else if (timeDiff < 21*24*60*60*1000L)
            {
                return  Color.parseColor("#d3d30c");
            }
            //less than four weeks
            else if (timeDiff < 28*24*60*60*1000L)
            {
                return  Color.parseColor("#df9600");
            }
            //less than 6 weeks
            else if (timeDiff < 42*24*60*60*1000L)
            {
                return  Color.parseColor("#df3d00");
            }
            //longer than four weeks
            else
            {
                return  Color.parseColor("#f70000");
            }
        }
        else
        {
            return  Color.parseColor("#f70000");
        }
    }

    /**
     * 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);
        }
    }

    /**
     * Reads tasks saved in preferences as jsonStrings
     *
     * @return list of OwnTask
     */
    private List<OwnTask> readTasksFromPreferences() {
        List<OwnTask> tasks = new ArrayList<>();

        try {
            String jsonString = PreferenceManager.getDefaultSharedPreferences(getContext()).getString(KEY_ALL_TASKS, "error");
            if(!"error".equalsIgnoreCase(jsonString)) {
                JSONArray jsonObjects = new JSONArray(jsonString);

                for (int i = 0; i<jsonObjects.length();i++) {
                    tasks.add(new OwnTask(jsonObjects.getJSONObject(i)));

                    if (BuildConfig.DEBUG) {
                        Log.d(TAG, "Task loaded from shared preferences: " + tasks.get(i).toString());
                    }

                    Bitmap image = BitmapFactory.decodeFile(tasks.get(i).getPathImage() + File.separator + tasks.get(i).getId() + ".jpeg");
                    if (BuildConfig.DEBUG) {
                        Log.d(TAG, "Image loaded from shared preferences: " + image.getByteCount());
                    }
                    tasks.get(i).setImage(image);
                }
            }
        }  catch (JSONException e) {
            if (BuildConfig.DEBUG) {
                Log.e(TAG, "Error while parsing tasks as jsonObjects from preferences");
                e.printStackTrace();
            }
        }

        return tasks;
    }

    @Override
    public void onMapReady(GoogleMap googleMap) { }
}