//  FileStack extension for App Inventor by Marco Perrone

package FileStack;

import com.google.appinventor.components.runtime.*;
import android.app.Activity;
import android.content.Intent;
			
import com.google.appinventor.components.annotations.DesignerComponent;
import com.google.appinventor.components.annotations.DesignerProperty;
import com.google.appinventor.components.annotations.PropertyCategory;
import com.google.appinventor.components.annotations.SimpleFunction;
import com.google.appinventor.components.annotations.SimpleEvent;
import com.google.appinventor.components.annotations.SimpleObject;
import com.google.appinventor.components.annotations.SimpleProperty;
import com.google.appinventor.components.annotations.UsesPermissions;
import com.google.appinventor.components.annotations.UsesActivities;
import com.google.appinventor.components.annotations.UsesLibraries;
import com.google.appinventor.components.annotations.UsesActivityMetadata;
import com.google.appinventor.components.annotations.androidmanifest.*;
import com.google.appinventor.components.common.ComponentCategory;
import com.google.appinventor.components.common.PropertyTypeConstants;
import com.google.appinventor.components.common.YaVersion;
import com.google.appinventor.components.runtime.util.GingerbreadUtil;
import com.google.appinventor.components.runtime.util.SdkLevel;
import com.google.appinventor.components.runtime.util.AsynchUtil;

import java.io.IOException;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.DataOutputStream;
import java.io.BufferedReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Scanner;
import java.net.CookieHandler;

import java.util.Base64;
import java.util.Date;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;


import java.io.FileWriter;
import java.io.BufferedWriter;
import java.io.StringWriter;
import java.io.PrintWriter;



@SimpleObject(external=true)
@UsesPermissions(permissionNames = "android.permission.INTERNET,android.permission.READ_EXTERNAL_STORAGE,android.permission.WRITE_EXTERNAL_STORAGE")

@DesignerComponent(version = YaVersion.WEB_COMPONENT_VERSION,
    description = "<p>Non-visible component to manage files to FileStack.", 
    category = ComponentCategory.EXTENSION,
    nonVisible = true,
    iconName = "images/nearfield.png")
	
public class FileStack extends AndroidNonvisibleComponent implements Component {

	private final Activity activity;
	private final CookieHandler cookieHandler;
	private String twoHyphens = "--";
	private String boundary =  "*****"+Long.toString(System.currentTimeMillis())+"*****";
	private String lineEnd = "\r\n";
	private URL url;
	
	@SimpleEvent(description = "Get FileStack Response")
	public void GetFileStackResponse(int responseCode, String response, String handle) {
    
		EventDispatcher.dispatchEvent(this, "GetFileStackResponse", responseCode, response, handle);
	}
	
	@SimpleEvent(description = "Get Policy and Signature ")
	public void GetPolicyAndSignature(String policy, String signature) {
    
		EventDispatcher.dispatchEvent(this, "GetPolicyAndSignature", policy, signature);
	}
  
	@SimpleFunction(description = "Upload File to FileStack.")
	public void UploadToFileStack(final String objectLocation, final String fileType,  final String apiKey) {
	  
	  AsynchUtil.runAsynchronously(new Runnable() {
      @Override
      public void run() {
        try {
			
			UploadToFilestack_Exec(objectLocation, fileType, apiKey, "");
		}
		catch(IOException e) {
			e.printStackTrace();
		}	  
      }
	  });
	}
	
	@SimpleFunction(description = "Upload File to FileStack with Secret Key.")
	public void UploadToFileStackWithSecretKey(final String objectLocation,  final String fileType,  final String apiKey,  final String secretKey) {
	  
	  AsynchUtil.runAsynchronously(new Runnable() {
      @Override
      public void run() {
        try {
			UploadToFilestack_Exec(objectLocation, fileType, apiKey, secretKey);
		}
		catch(IOException e) {
			e.printStackTrace();
		}	  
      }
	  }); 
	}
	
	@SimpleFunction(description = "Overwrite File to FileStack with Secret Key.")
	public void OverwriteFileStackWithSecretKey(final String objectLocation,  final String handle, final String fileType,  final String apiKey,  final String secretKey) {
	  
	  AsynchUtil.runAsynchronously(new Runnable() {
      @Override
      public void run() {
        try {
			OverwriteToFilestack(objectLocation, handle, fileType, apiKey, secretKey);
		}
		catch(IOException e) {
			e.printStackTrace();
		}	  
      }
	  }); 
	}
	
	@SimpleFunction(description = "Delete File to FileStack with Secret Key.")
	public void DeleteToFileStackWithSecretKey(final String handle, final String apiKey,  final String secretKey) {
	  
	  AsynchUtil.runAsynchronously(new Runnable() {
      @Override
      public void run() {
        try {
			DeleteToFilestack(handle, apiKey, secretKey);
		}
		catch(IOException e) {
			e.printStackTrace();
		}	  
      }
	  }); 
	}
	
	@SimpleFunction(description = "Calculate Policy and Signature.")
	public void CalculatePolicyAndSignature(final String secretKey) {
	  
	  AsynchUtil.runAsynchronously(new Runnable() {
      @Override
      public void run() {
        try {
			CalculatePolicySignature(secretKey);
		}
		catch(IOException e) {
			e.printStackTrace();
		}	  
      }
	  }); 
	}
  
  public FileStack(ComponentContainer container) {
    super(container.$form());
    activity = container.$context();
    cookieHandler = (SdkLevel.getLevel() >= SdkLevel.LEVEL_GINGERBREAD)
        ? GingerbreadUtil.newCookieManager()
        : null;
  }

void UploadToFilestack_Exec(String OBJECT_LOCATION, String FILETYPE, String APIKEY, String SECRETKEY) throws IOException {
	try
	{
		Path path = Paths.get(URI.create(OBJECT_LOCATION));
		byte[] buffer = java.nio.file.Files.readAllBytes(path);
		String Policy = "";
		String Signature = "";
		
		if (SECRETKEY.compareTo("") != 0)
		{
			Policy = getPolicy();
			Signature = getSignature(SECRETKEY,Policy);
			
			url = new URL("https://www.filestackapi.com/api/store/S3?key="+APIKEY+"&policy="+Policy+"&signature="+Signature);	
		}
		else
		{
			url = new URL("https://www.filestackapi.com/api/store/S3?key="+APIKEY);	
		}
		
		ConnectToFileStack(FILETYPE, buffer);
		
	}
	catch (IOException e) {
		e.printStackTrace();
		StringWriter errors = new StringWriter();
		e.printStackTrace(new PrintWriter(errors));
		appendLog(errors.toString());
	}
}

void OverwriteToFilestack(String OBJECT_LOCATION, String HANDLE, String FILETYPE, String APIKEY, String SECRETKEY) throws IOException {
	try
	{
		Path path = Paths.get(URI.create(OBJECT_LOCATION));
		byte[] buffer = java.nio.file.Files.readAllBytes(path);
		String Policy = "";
		String Signature = "";
		Policy = getPolicy();
		Signature = getSignature(SECRETKEY,Policy);
		url = new URL("https://www.filestackapi.com/api/file/"+HANDLE+"?policy="+Policy+"&signature="+Signature);	
		
		ConnectToFileStack(FILETYPE, buffer);
		
	}
	catch (IOException e) {
		e.printStackTrace();
		StringWriter errors = new StringWriter();
		e.printStackTrace(new PrintWriter(errors));
		appendLog(errors.toString());
	}
}

void DeleteToFilestack(String HANDLE, String APIKEY, String SECRETKEY) throws IOException {
	try
	{		
		String Policy = "";
		String Signature = "";
		Policy = getPolicy();
		Signature = getSignature(SECRETKEY,Policy);
		url = new URL("https://www.filestackapi.com/api/file/"+HANDLE+"?key="+APIKEY+"&policy="+Policy+"&signature="+Signature);	
		DeleteFile();
	}
	catch (IOException e) {
		e.printStackTrace();
		StringWriter errors = new StringWriter();
		e.printStackTrace(new PrintWriter(errors));
		appendLog(errors.toString());
	}
}

void CalculatePolicySignature(String SECRETKEY) throws IOException {
	
		final String Policy = getPolicy();
	    final String Signature = getSignature(SECRETKEY,Policy);	
		// Dispatch the event.
			activity.runOnUiThread(new Runnable() {
				@Override
				public void run() {
					GetPolicyAndSignature(Policy, Signature);
				}
			});
	
}

public void DeleteFile()
{
	HttpURLConnection connection = null;
	InputStream inputStream = null;
	try
	{
		connection = (HttpURLConnection) url.openConnection();
		connection.setDoInput(true);
		connection.setDoOutput(true);
		connection.setUseCaches(false);
		connection.setRequestMethod("DELETE");
		connection.setRequestProperty("Connection", "Keep-Alive");
		connection.setRequestProperty("User-Agent", "Android Multipart HTTP Client 1.0");
		connection.connect();
		inputStream = connection.getInputStream();
		final int status = connection.getResponseCode();
		if (status == HttpURLConnection.HTTP_OK) {
			BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
			String inputLine;
			final StringBuffer response = new StringBuffer();
			while ((inputLine = in.readLine()) != null) {
				response.append(inputLine);
			}
			inputStream.close();
			connection.disconnect();
			final String responseStr = response.toString();
			final String handleFin = ""; 
			// Dispatch the event.
			activity.runOnUiThread(new Runnable() {
				@Override
				public void run() {
					GetFileStackResponse(status, responseStr, handleFin);
				}
			});
	
		} else {	
				// Dispatch the event.
					activity.runOnUiThread(new Runnable() {
						@Override
						public void run() {
							GetFileStackResponse(status, "Error!", "");
						}
					});
				
				}
		
	}
	catch (IOException e) {
		e.printStackTrace();
		StringWriter errors = new StringWriter();
		e.printStackTrace(new PrintWriter(errors));
		appendLog(errors.toString());
	}
}
public void ConnectToFileStack(String FileType, byte[] buffer)
{
		HttpURLConnection connection = null;
		DataOutputStream outputStream = null;
		InputStream inputStream = null;
		int bufferSize;
		
	try
	{	
		connection = (HttpURLConnection) url.openConnection();
		connection.setDoInput(true);
		connection.setDoOutput(true);
		connection.setUseCaches(false);
		connection.setRequestMethod("POST");
		connection.setRequestProperty("Connection", "Keep-Alive");
		connection.setRequestProperty("User-Agent", "Android Multipart HTTP Client 1.0");
		connection.setRequestProperty("Content-Type", FileType);
		try
		{
			outputStream = new DataOutputStream(connection.getOutputStream());
		}
		catch (IOException e) {
			e.printStackTrace();
			StringWriter errors = new StringWriter();
			e.printStackTrace(new PrintWriter(errors));
			appendLog(errors.toString());
		}	
		bufferSize = buffer.length;
		try
		{
			outputStream.write(buffer, 0, bufferSize);
		}
		catch (IOException e) {
			e.printStackTrace();
			StringWriter errors = new StringWriter();
			e.printStackTrace(new PrintWriter(errors));
			appendLog(errors.toString());
		}
		outputStream.writeBytes(lineEnd);
		outputStream.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
		inputStream = connection.getInputStream();
		final int status = connection.getResponseCode();
		String handle = "";
		if (status == HttpURLConnection.HTTP_OK) {
			BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
			String inputLine;
			final StringBuffer response = new StringBuffer();
			while ((inputLine = in.readLine()) != null) {
				response.append(inputLine);
			}
			inputStream.close();
			connection.disconnect();
			//fileInputStream.close();
			outputStream.flush();
			outputStream.close();
			final String responseStr = response.toString();
			if (responseStr.indexOf("cdn.filestackcontent.com") != -1)
			{
				handle = responseStr.substring(responseStr.indexOf("cdn.filestackcontent.com"));
				handle = handle.substring(handle.indexOf("/")+1);
				handle = handle.substring(0,handle.indexOf(",")-1);
			}
			final String handleFin = handle; 
			// Dispatch the event.
			activity.runOnUiThread(new Runnable() {
				@Override
				public void run() {
					GetFileStackResponse(status, responseStr, handleFin);
				}
			});
	
		} else {	
				// Dispatch the event.
					activity.runOnUiThread(new Runnable() {
						@Override
						public void run() {
							GetFileStackResponse(status, "Error!", "");
						}
					});
				
				}
	}
	catch (IOException e) {
		e.printStackTrace();
		StringWriter errors = new StringWriter();
		e.printStackTrace(new PrintWriter(errors));
		appendLog(errors.toString());
	}
}

public String getPolicy()
{ 
	Long data = System.currentTimeMillis() + 86400000; //Add 1 day to have a valid policy for the date
	String dataStr = data.toString();
	dataStr = "{\"expiry\":"+dataStr+"}"; 
	String Policy = Base64.getUrlEncoder().encodeToString(dataStr.getBytes());
	return Policy;
}
public String getSignature(String SecretKey, String Policy)
{ 
	String Signature = "";
	try 
	{
		SecretKeySpec signingKey = new SecretKeySpec(SecretKey.getBytes(StandardCharsets.UTF_8), "HmacSHA256");
		Mac mac = Mac.getInstance("HmacSHA256");
		mac.init(signingKey);
		byte[] rawHmac = mac.doFinal(Policy.getBytes(StandardCharsets.UTF_8));
		byte[] hexArray = {(byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f'};
		byte[] hexChars = new byte[rawHmac.length * 2];
		for ( int j = 0; j < rawHmac.length; j++ ) {
			int v = rawHmac[j] & 0xFF;
			hexChars[j * 2] = hexArray[v >>> 4];
			hexChars[j * 2 + 1] = hexArray[v & 0x0F];
		}
		Signature = new String(hexChars);
	}
	catch (Exception e) {
		throw new RuntimeException(e);
	}
	return Signature;
}
public void appendLog(String text)
{       
   File logFile = new File("sdcard/FileStackLog.txt");
   if (!logFile.exists())
   {
      try
      {
         logFile.createNewFile();
      } 
      catch (IOException e)
      {
         // TODO Auto-generated catch block
         e.printStackTrace();
      }
   }
   try
   {
      //BufferedWriter for performance, true to set append to file flag
      BufferedWriter buf = new BufferedWriter(new FileWriter(logFile, true)); 
      buf.append(text);
      buf.newLine();
	  buf.flush();
      buf.close();
   }
   catch (IOException e)
   {
      // TODO Auto-generated catch block
      e.printStackTrace();
   }
}
}