package utils;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Collections;
import java.util.List;

import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.extensions.java6.auth.oauth2.AuthorizationCodeInstalledApp;
import com.google.api.client.extensions.jetty.auth.oauth2.LocalServerReceiver;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.http.AbstractInputStreamContent;
import com.google.api.client.http.FileContent;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.client.util.store.FileDataStoreFactory;
import com.google.api.services.drive.Drive;
import com.google.api.services.drive.DriveScopes;
import com.google.api.services.drive.model.File;
import java.io.BufferedReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Arrays;
import java.util.logging.Level;
import java.util.logging.Logger;

public class GoogleDriveUtils {

    private static final String APPLICATION_NAME = "SWD Workspace synchronizer";

    private static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();

    // Directory to store user credentials for this application.
    private static final java.io.File CREDENTIALS_FOLDER //
            = new java.io.File("src/main/resources");

    private static final String CLIENT_SECRET_FILE_NAME = "credentials.json";

    static final String[] scopes = {"email", DriveScopes.DRIVE};

    private static final List<String> SCOPES = Arrays.asList(scopes);

    // Global instance of the {@link FileDataStoreFactory}.
    private static FileDataStoreFactory DATA_STORE_FACTORY;

    // Global instance of the HTTP transport.
    private static HttpTransport HTTP_TRANSPORT;

    private static Drive driveService;

    static {
        try {
            HTTP_TRANSPORT = GoogleNetHttpTransport.newTrustedTransport();
            DATA_STORE_FACTORY = new FileDataStoreFactory(CREDENTIALS_FOLDER);
            driveService = getDriveService();
        } catch (Throwable t) {
            t.printStackTrace();
            System.exit(1);
        }
    }

    private static Credential getCredentials() throws IOException {

        java.io.File clientSecretFilePath = new java.io.File(CREDENTIALS_FOLDER, CLIENT_SECRET_FILE_NAME);

        if (!clientSecretFilePath.exists()) {
            throw new FileNotFoundException("Please copy " + CLIENT_SECRET_FILE_NAME //
                    + " to folder: " + CREDENTIALS_FOLDER.getAbsolutePath());
        }

        InputStream in = new FileInputStream(clientSecretFilePath);

        GoogleClientSecrets clientSecrets = GoogleClientSecrets.load(JSON_FACTORY, new InputStreamReader(in));

        // Build flow and trigger user authorization request.
        GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(HTTP_TRANSPORT, JSON_FACTORY,
                clientSecrets, SCOPES).setDataStoreFactory(DATA_STORE_FACTORY).setAccessType("offline").build();
        Credential credential = new AuthorizationCodeInstalledApp(flow, new LocalServerReceiver()).authorize("user");
        String accessToken = credential.getAccessToken();
        getUserInfo(accessToken);
        return credential;
    }

    private static void getUserInfo(String accessToken){
        try {
            String url = "https://openidconnect.googleapis.com/v1/userinfo";
            URL obj = new URL(url);
            HttpURLConnection conn = (HttpURLConnection) obj.openConnection();
            conn.setRequestProperty("Authorization", "Bearer " + accessToken);

            BufferedReader in = new BufferedReader(
                    new InputStreamReader(conn.getInputStream()));
            String inputLine;
            StringBuilder response = new StringBuilder();

            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
            in.close();

            //print result
            System.out.println(response.toString());
        } catch (Exception ex) {
            Logger.getLogger(GoogleDriveUtils.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public static Drive getDriveService() throws IOException {
        if (driveService != null) {
            return driveService;
        }
        Credential credential = getCredentials();
        //
        driveService = new Drive.Builder(HTTP_TRANSPORT, JSON_FACTORY, credential) //
                .setApplicationName(APPLICATION_NAME).build();
        return driveService;
    }

    public static final File createGoogleFolder(String folderName, String retmoteParentId) throws IOException {
        // Create a folder in google drive using id of parent folder
        // Arguments:
        //    - remoteParentId (String): id of parent folder in drive
        //    - folderName (String): name of folder to be created
        // Returns:
        //    - com.google.api.services.drive.model.File object representing created folder
        File fileMetadata = new File();

        fileMetadata.setName(folderName);
        fileMetadata.setMimeType("application/vnd.google-apps.folder");

        if (retmoteParentId != null) {
            List<String> parents = Arrays.asList(retmoteParentId);
            fileMetadata.setParents(parents);
        }

        // Create a Folder.
        // Returns File object with id & name fields will be assigned values
        File file = driveService.files().create(fileMetadata).setFields("id, name").execute();

        return file;
    }

    // PRIVATE
    private static File _createGoogleFile(String googleFolderIdParent,
            String customFileName, AbstractInputStreamContent uploadStreamContent) throws IOException {

        File fileMetadata = new File();
        fileMetadata.setName(customFileName);

        List<String> parents = Arrays.asList(googleFolderIdParent);
        fileMetadata.setParents(parents);

        File file = driveService.files().create(fileMetadata, uploadStreamContent)
                .setFields("id, webContentLink, webViewLink, parents").execute();

        System.out.println("Also delete file with ID: " + file.getId());
        return file;
    }

    public static File uploadFile(String filePath, String remoteParentId) throws IOException {
        // Create a file in google drive from local file under a folder in drive
        // Arguments:
        //    - remoteParentId (String): id of parent folder in drive
        //    - folderName (String): name of folder to be created
        // Returns:
        //    - com.google.api.services.drive.model.File object representing created folder
        File fileMetadata = new File();
        java.io.File uploadFile = new java.io.File(filePath);

        // set mimeType
        fileMetadata.setName(uploadFile.getName());
        fileMetadata.setMimeType("application/vnd.google-apps.file");

        // set parent
        List<String> parents = Arrays.asList(remoteParentId);
        fileMetadata.setParents(parents);

        FileContent mediaContent = new FileContent(fileMetadata.getMimeType(), uploadFile);
        File file = driveService.files().create(fileMetadata, mediaContent)
                .setFields("id, webContentLink, webViewLink, parents")
                .execute();
        System.out.println("File ID: " + file.getId());

        return file;
    }

    public static void deleteFile(String remoteFileId) throws IOException {
        driveService.files().delete(remoteFileId).execute();
    }
}