/*
 *   Nextcloud Android client application
 *
 *   @author Bartosz Przybylski
 *   Copyright (C) 2016  Bartosz Przybylski <bart.p.pl@gmail.com>
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License version 2,
 *   as published by the Free Software Foundation.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

package com.owncloud.android.providers;

import android.accounts.Account;
import android.accounts.AuthenticatorException;
import android.accounts.OperationCanceledException;
import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.AssetFileDescriptor;
import android.database.Cursor;
import android.graphics.Point;
import android.os.Build;
import android.os.CancellationSignal;
import android.os.Handler;
import android.os.Looper;
import android.os.ParcelFileDescriptor;
import android.preference.PreferenceManager;
import android.provider.DocumentsProvider;
import android.util.Log;
import android.widget.Toast;

import com.owncloud.android.MainApp;
import com.owncloud.android.R;
import com.owncloud.android.authentication.AccountUtils;
import com.owncloud.android.datamodel.FileDataStorageManager;
import com.owncloud.android.datamodel.OCFile;
import com.owncloud.android.files.services.FileDownloader;
import com.owncloud.android.lib.common.OwnCloudAccount;
import com.owncloud.android.lib.common.OwnCloudClient;
import com.owncloud.android.lib.common.OwnCloudClientManagerFactory;
import com.owncloud.android.lib.common.operations.RemoteOperationResult;
import com.owncloud.android.lib.common.utils.Log_OC;
import com.owncloud.android.operations.CreateFolderOperation;
import com.owncloud.android.operations.SynchronizeFileOperation;
import com.owncloud.android.ui.activity.ConflictsResolveActivity;
import com.owncloud.android.ui.activity.Preferences;
import com.owncloud.android.utils.FileStorageUtils;

import org.nextcloud.providers.cursors.FileCursor;
import org.nextcloud.providers.cursors.RootCursor;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@TargetApi(Build.VERSION_CODES.KITKAT)
public class DocumentsStorageProvider extends DocumentsProvider {

    private static final String TAG = "DocumentsStorageProvider";

    private FileDataStorageManager currentStorageManager;
    private Map<Long, FileDataStorageManager> rootIdToStorageManager;
    private OwnCloudClient client;

    @Override
    public Cursor queryRoots(String[] projection) throws FileNotFoundException {

        SharedPreferences appPrefs = PreferenceManager.getDefaultSharedPreferences(MainApp.getAppContext());
        if (Preferences.LOCK_PASSCODE.equals(appPrefs.getString(Preferences.PREFERENCE_LOCK, "")) ||
            Preferences.LOCK_DEVICE_CREDENTIALS.equals(appPrefs.getString(Preferences.PREFERENCE_LOCK, ""))) {
            return new FileCursor();
        }

        initiateStorageMap();

        final RootCursor result = new RootCursor(projection);

        for (Account account : AccountUtils.getAccounts(getContext())) {
            result.addRoot(account, getContext());
        }

        return result;
    }

    @Override
    public Cursor queryDocument(String documentId, String[] projection) throws FileNotFoundException {
        final long docId = Long.parseLong(documentId);
        updateCurrentStorageManagerIfNeeded(docId);

        final FileCursor result = new FileCursor(projection);
        if (currentStorageManager == null) {

            for (Map.Entry<Long, FileDataStorageManager> entry : rootIdToStorageManager.entrySet()) {
                if (entry.getValue().getFileById(docId) != null) {
                    currentStorageManager = entry.getValue();
                    break;
                }
            }
        }

        if (currentStorageManager == null) {
            throw new FileNotFoundException("File with " + documentId + " not found");
        }

        OCFile file = currentStorageManager.getFileById(docId);
        if (file != null) {
            result.addFile(file);
        }

        return result;
    }

    @Override
    public Cursor queryChildDocuments(String parentDocumentId, String[] projection, String sortOrder) {

        final long folderId = Long.parseLong(parentDocumentId);
        updateCurrentStorageManagerIfNeeded(folderId);

        final FileCursor result = new FileCursor(projection);

        final OCFile browsedDir = currentStorageManager.getFileById(folderId);
        for (OCFile file : currentStorageManager.getFolderContent(browsedDir, false)) {
            result.addFile(file);
        }

        return result;
    }

    @SuppressLint("LongLogTag")
    @Override
    public ParcelFileDescriptor openDocument(String documentId, String mode, CancellationSignal cancellationSignal)
            throws FileNotFoundException {
        final long docId = Long.parseLong(documentId);
        updateCurrentStorageManagerIfNeeded(docId);

        OCFile file = currentStorageManager.getFileById(docId);

        if (file == null) {
            throw new FileNotFoundException("File with id " + documentId + " not found!");
        }

        Account account = currentStorageManager.getAccount();
        Context context = getContext();

        if (context == null) {
            throw new FileNotFoundException("Context may not be null!");
        }

        if (!file.isDown()) {

            Intent i = new Intent(getContext(), FileDownloader.class);
            i.putExtra(FileDownloader.EXTRA_ACCOUNT, account);
            i.putExtra(FileDownloader.EXTRA_FILE, file);
            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
                context.startForegroundService(i);
            } else {
                context.startService(i);
            }

            do {
                if (!waitOrGetCancelled(cancellationSignal)) {
                    throw new FileNotFoundException("File with id " + documentId + " not found!");
                }
                file = currentStorageManager.getFileById(docId);

                if (file == null) {
                    throw new FileNotFoundException("File with id " + documentId + " not found!");
                }
            } while (!file.isDown());
        } else {
            OCFile finalFile = file;
            Thread syncThread = new Thread(() -> {
                try {
                    FileDataStorageManager storageManager =
                            new FileDataStorageManager(account, context.getContentResolver());
                    SynchronizeFileOperation sfo =
                            new SynchronizeFileOperation(finalFile, null, account, true, context);
                    RemoteOperationResult result = sfo.execute(storageManager, context);
                    if (result.getCode() == RemoteOperationResult.ResultCode.SYNC_CONFLICT) {
                        // ISSUE 5: if the user is not running the app (this is a service!),
                        // this can be very intrusive; a notification should be preferred
                        Intent i = new Intent(context, ConflictsResolveActivity.class);
                        i.setFlags(i.getFlags() | Intent.FLAG_ACTIVITY_NEW_TASK);
                        i.putExtra(ConflictsResolveActivity.EXTRA_FILE, finalFile);
                        i.putExtra(ConflictsResolveActivity.EXTRA_ACCOUNT, account);
                        context.startActivity(i);
                    } else {
                        FileStorageUtils.checkIfFileFinishedSaving(finalFile);
                        if (!result.isSuccess()) {
                            showToast();
                        }
                    }
                } catch (Exception exception) {
                    showToast();
                }
            });

            syncThread.start();
            try {
                syncThread.join();
            } catch (InterruptedException e) {
                Log.e(TAG, "Failed to wait for thread to finish");
            }
        }

        return ParcelFileDescriptor.open(new File(file.getStoragePath()), ParcelFileDescriptor.parseMode(mode));
    }

    private void showToast() {
        Handler handler = new Handler(Looper.getMainLooper());
        handler.post(() -> Toast.makeText(MainApp.getAppContext(),
                R.string.file_not_synced,
                Toast.LENGTH_SHORT).show());
    }

    @Override
    public boolean onCreate() {
        return true;
    }

    @Override
    public AssetFileDescriptor openDocumentThumbnail(String documentId,
                                                     Point sizeHint,
                                                     CancellationSignal signal)
            throws FileNotFoundException {
        long docId = Long.parseLong(documentId);
        updateCurrentStorageManagerIfNeeded(docId);

        OCFile file = currentStorageManager.getFileById(docId);

        if (file == null) {
            throw new FileNotFoundException("File with id " + documentId + " not found!");
        }

        File realFile = new File(file.getStoragePath());

        return new AssetFileDescriptor(
                ParcelFileDescriptor.open(realFile, ParcelFileDescriptor.MODE_READ_ONLY),
                0,
                AssetFileDescriptor.UNKNOWN_LENGTH);
    }

    @Override
    public Cursor querySearchDocuments(String rootId, String query, String[] projection) {
        updateCurrentStorageManagerIfNeeded(rootId);

        OCFile root = currentStorageManager.getFileByPath("/");
        FileCursor result = new FileCursor(projection);

        for (OCFile f : findFiles(root, query)) {
            result.addFile(f);
        }

        return result;
    }

    @Override
    public String createDocument(String documentId, String mimeType, String displayName) throws FileNotFoundException {
        long docId = Long.parseLong(documentId);
        updateCurrentStorageManagerIfNeeded(docId);

        OCFile parent = currentStorageManager.getFileById(docId);

        if (parent == null) {
            throw new FileNotFoundException("Parent file not found");
        }

        CreateFolderOperation createFolderOperation = new CreateFolderOperation(parent.getRemotePath() + displayName
                                                                                    + "/", true);
        RemoteOperationResult result = createFolderOperation.execute(client, currentStorageManager);


        if (!result.isSuccess()) {
            throw new FileNotFoundException("Failed to create document with name " +
                                                displayName + " and documentId " + documentId);
        }


        String newDirPath = parent.getRemotePath() + displayName + "/";
        OCFile newFolder = currentStorageManager.getFileByPath(newDirPath);

        return String.valueOf(newFolder.getFileId());
    }

    @SuppressLint("LongLogTag")
    private void updateCurrentStorageManagerIfNeeded(long docId) {
        if (rootIdToStorageManager == null) {
            try {
                queryRoots(FileCursor.DEFAULT_DOCUMENT_PROJECTION);
            } catch (FileNotFoundException e) {
                Log.e(TAG, "Failed to query roots");
            }
        }

        if (currentStorageManager == null ||
            rootIdToStorageManager.containsKey(docId) && currentStorageManager != rootIdToStorageManager.get(docId)) {
            currentStorageManager = rootIdToStorageManager.get(docId);
        }

        try {
            Account account = currentStorageManager.getAccount();
            OwnCloudAccount ocAccount = new OwnCloudAccount(account, MainApp.getAppContext());
            client = OwnCloudClientManagerFactory.getDefaultSingleton().getClientFor(ocAccount, getContext());
        } catch (OperationCanceledException | IOException | AuthenticatorException |
            com.owncloud.android.lib.common.accounts.AccountUtils.AccountNotFoundException e) {
            Log_OC.e(TAG, "Failed to set client", e);
        }
    }

    private void updateCurrentStorageManagerIfNeeded(String rootId) {
        for (FileDataStorageManager data : rootIdToStorageManager.values()) {
            if (data.getAccount().name.equals(rootId)) {
                currentStorageManager = data;
            }
        }
    }

    @SuppressLint("UseSparseArrays")
    private void initiateStorageMap() throws FileNotFoundException {

        rootIdToStorageManager = new HashMap<>();

        Context context = getContext();

        if (context == null) {
            throw new FileNotFoundException("Context may not be null!");
        }

        ContentResolver contentResolver = context.getContentResolver();

        for (Account account : AccountUtils.getAccounts(getContext())) {
            final FileDataStorageManager storageManager = new FileDataStorageManager(account, contentResolver);
            final OCFile rootDir = storageManager.getFileByPath("/");
            rootIdToStorageManager.put(rootDir.getFileId(), storageManager);
        }
    }

    private boolean waitOrGetCancelled(CancellationSignal cancellationSignal) {
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            return false;
        }

        return !(cancellationSignal != null && cancellationSignal.isCanceled());
    }

    List<OCFile> findFiles(OCFile root, String query) {
        List<OCFile> result = new ArrayList<>();
        for (OCFile f : currentStorageManager.getFolderContent(root, false)) {
            if (f.isFolder()) {
                result.addAll(findFiles(f, query));
            } else if (f.getFileName().contains(query)) {
                result.add(f);
            }
        }
        return result;
    }
}