import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.security.GeneralSecurityException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

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.javanet.NetHttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.client.util.DateTime;
import com.google.api.client.util.store.FileDataStoreFactory;
import com.google.api.services.calendar.Calendar;
import com.google.api.services.calendar.CalendarScopes;
import com.google.api.services.calendar.model.CalendarListEntry;
import com.google.api.services.calendar.model.Event;
import com.google.api.services.calendar.model.Events;

public class CalendarQuickstart {
    private static final String APPLICATION_NAME = "Google Calendar API Java Quickstart";
    private static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();
    private static final String TOKENS_DIRECTORY_PATH = "tokens";

    /**
     * Global instance of the scopes required by this quickstart.
     * If modifying these scopes, delete your previously saved tokens/ folder.
     */
    private static final List<String> SCOPES = Collections.singletonList(CalendarScopes.CALENDAR);
    private static final String CREDENTIALS_FILE_PATH = "/credentials.json";
    
    
    private static HashMap<String, String> colorMap;
    
    static {
    	colorMap = new HashMap<String, String>();
    	colorMap.put("1", "7986cb"); // Lavendel
    	colorMap.put("2", "33b679"); // Salbei
    	colorMap.put("3", "8e24aa"); // Weintraube
    	colorMap.put("4", "e67c73"); // Flamingo
    	colorMap.put("5", "f6bf26"); // Banane
    	colorMap.put("6", "f4511e"); // Mandarine
    	colorMap.put("7", "039be5"); // Pfau
    	colorMap.put("8", "616161"); // Grafit
    	colorMap.put("9", "3f51b5"); // Heidelbeere
    	colorMap.put("10", "0b8043"); // Basilikum
    	colorMap.put("11", "d50000"); // Tomate
    }

    /**
     * Creates an authorized Credential object.
     * @param HTTP_TRANSPORT The network HTTP Transport.
     * @return An authorized Credential object.
     * @throws IOException If the credentials.json file cannot be found.
     */
    private static Credential getCredentials(final NetHttpTransport HTTP_TRANSPORT) throws IOException {
        // Load client secrets.
        InputStream in = CalendarQuickstart.class.getResourceAsStream(CREDENTIALS_FILE_PATH);
        if (in == null) {
            throw new FileNotFoundException("Resource not found: " + CREDENTIALS_FILE_PATH);
        }
        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(new FileDataStoreFactory(new java.io.File(TOKENS_DIRECTORY_PATH)))
//                .setAccessType("offline")
                .build();
        LocalServerReceiver receiver = new LocalServerReceiver.Builder().setPort(8888).build();
        return new AuthorizationCodeInstalledApp(flow, receiver).authorize("user");
    }

    public static void main(String... args) throws IOException, GeneralSecurityException {
        // Build a new authorized API client service.
        final NetHttpTransport HTTP_TRANSPORT = GoogleNetHttpTransport.newTrustedTransport();
        Calendar service = new Calendar.Builder(HTTP_TRANSPORT, JSON_FACTORY, getCredentials(HTTP_TRANSPORT))
                .setApplicationName(APPLICATION_NAME)
                .build();
        
        System.out.println("The list:");
        com.google.api.services.calendar.model.CalendarList calList = service.calendarList().list().execute();
        
        System.out.println("size: " + calList.size());
        for (CalendarListEntry entry : calList.getItems()) {
        	System.out.println("ID " + entry.getId() + ", Description " + entry.getDescription() + ", Summary: " + entry.getSummary());
        }

        
        System.out.println("\nEvents:");
        int ct = 0;
        int colCt = 0;
        int hitCt = 0;
        int pageCt = 0;
        int cngCt = 0;
        
        String srcId = "tero23q0dqqfc45r4jjcecl7bs@group.calendar.google.com";
        String trgId = "rpg91b8ls4e437a2gu63jhmlfk@group.calendar.google.com";
        
        Events events = null;
        List<Event> srcItems = null;
        
        do {
        	String nextPage = null;
        	if (events != null) {
        		nextPage = events.getNextPageToken();
        		events = service.events().list(srcId)
//        				.setSingleEvents(true)
        				.setPageToken(nextPage)
                        .execute();
        	}
        	else {
        		events = service.events().list(srcId)
//        				.setMaxResults(2450)
//        				.setTimeMin(new DateTime(1230800400000l)) // 1230800400000l 1497690000000l
//        				.setOrderBy("startTime")
//        				.setShowDeleted(false)
//        				.setOrderBy("updated")
//        				.setUpdatedMin(new DateTime(1559379600000l))
//        				.setSingleEvents(true)
        				.execute();
        	}
        	
        	if (srcItems == null)
        		srcItems = events.getItems();
        	else
        		srcItems.addAll(events.getItems());
        	
        	pageCt++;
        } while (events.getNextPageToken() != null);
        
        
        
        List<Event> trgItems = null;
        
        do {
        	String nextPage = null;
        	if (events != null) {
        		nextPage = events.getNextPageToken();
        		events = service.events().list(srcId)
        				.setPageToken(nextPage)
                        .execute();
        	}
        	else {
        		events = service.events().list(srcId).execute();
        	}
        	
        	if (trgItems == null)
        		trgItems = events.getItems();
        	else
        		trgItems.addAll(events.getItems());
        } while (events.getNextPageToken() != null);
        
        
        if (srcItems.isEmpty()) {
            System.out.println("No upcoming events found.");
        } else {
        	
        	System.out.println("# src items: " + srcItems.size());
        	
            for (Event event : srcItems) {
            	
            	ct++;
            	
            	// XXX Restart from number
//            	if (ct < 1300)
//            		continue;
            	
            	// XXX This event is not updatable for some reason
            	if (event.getId().equals("6cqj2d3265h34bb574qj4b9kcgr36bb2ckrjebb160rj4e3465imcdr26g"))
            		continue;
            	
            	if (event.getColorId() != null) {
            		
            		colCt++;
            	
	            	String startStr = null;
	            	if (event.getStart() != null && event.getStart().getDateTime() != null)
	            		startStr = event.getStart().getDateTime().toString();
	            	
	            	System.out.println("ID: " + event.getId()
	            	+ ", CREATED: " + event.getCreated()
	            	+ ", UPDATED: " + event.getUpdated()
	            	+ ", COLOR: " + event.getColorId()
	            	+ ", START: " + startStr
	            	+ ", " + ct
	            	+ ", DESCRIPTION: " + event.getDescription()
	            	+ ", SUMMARY: " + event.getSummary());
           		
            		for (Event trgEvent : trgItems) {
            			if (trgEvent.getId().equals(event.getId())) {
            				
            				Event currentEvent = service.events().get(trgId, trgEvent.getId()).execute();
            				trgEvent.setSequence(currentEvent.getSequence());
            				
            				trgEvent.setColorId(event.getColorId());
            				service.events().update(trgId, trgEvent.getId(), trgEvent).execute();
            				cngCt++;
            				
            				break;
            			}
            		}
            	}
            }
        }
    	
        
        System.out.println("Page count: " + pageCt);
        System.out.println("Colored source events: " + colCt);
        System.out.println("Target hits: " + hitCt);
        System.out.println("Change count: " + cngCt);
        
    }
}