package org.OpenUDID;

import java.math.BigInteger;
import java.security.SecureRandom;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.TreeMap;

import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.content.pm.ResolveInfo;
import android.content.pm.ServiceInfo;
import android.os.IBinder;
import android.os.RemoteException;
import android.provider.Settings.Secure;
import android.util.Log;


public class OpenUDID_manager implements ServiceConnection{
	public final static String PREF_KEY = "openudid";
	public final static String PREFS_NAME = "openudid_prefs";
	public final static String TAG = "OpenUDID";
	
	private final static boolean LOG = true; //Display or not debug message

	private final Context mContext; //Application context
	private List<ResolveInfo> mMatchingIntents; //List of available OpenUDID Intents
	private Map<String, Integer> mReceivedOpenUDIDs; //Map of OpenUDIDs found so far

	private final SharedPreferences mPreferences; //Preferences to store the OpenUDID
	private final Random mRandom;
	
	private OpenUDID_manager(Context context) {
		mPreferences =  context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
		mContext = context;
		mRandom = new Random();
		mReceivedOpenUDIDs = new HashMap<String, Integer>();
	}
	
	@Override
  	public void onServiceConnected(ComponentName className, IBinder service) {
		//Get the OpenUDID from the remote service
		try {
			//Send a random number to the service
			android.os.Parcel data = android.os.Parcel.obtain(); 
			data.writeInt(mRandom.nextInt());
			android.os.Parcel reply = android.os.Parcel.obtain(); 
			service.transact(1, android.os.Parcel.obtain(), reply, 0);
			if (data.readInt() == reply.readInt()) //Check if the service returns us this number
			{
				final String _openUDID = reply.readString();
				if (_openUDID != null) { //if valid OpenUDID, save it
					if (LOG) Log.d(TAG, "Received " + _openUDID);

					if (mReceivedOpenUDIDs.containsKey(_openUDID)) mReceivedOpenUDIDs.put(_openUDID, mReceivedOpenUDIDs.get(_openUDID) + 1);
					else mReceivedOpenUDIDs.put(_openUDID, 1);
						
				}
			}
		} catch (RemoteException e) {if (LOG) Log.e(TAG, "RemoteException: " + e.getMessage());}		    	    			
		mContext.unbindService(this);
		
		startService(); //Try the next one
  	}
	
	@Override
	public void onServiceDisconnected(ComponentName className) {}
	
	private void storeOpenUDID() {
    	final Editor e = mPreferences.edit();
		e.putString(PREF_KEY, OpenUDID);
		e.commit();
	}
	
	/*
	 * Generate a new OpenUDID
	 */
	private void generateOpenUDID() {
		if (LOG) Log.d(TAG, "Generating openUDID");
		//Try to get the ANDROID_ID
		OpenUDID = Secure.getString(mContext.getContentResolver(), Secure.ANDROID_ID); 
		if (OpenUDID == null || OpenUDID.equals("9774d56d682e549c") || OpenUDID.length() < 15 ) {
			//if ANDROID_ID is null, or it's equals to the GalaxyTab generic ANDROID_ID or bad, generates a new one
			final SecureRandom random = new SecureRandom();
			OpenUDID = new BigInteger(64, random).toString(16);
		}
    }
	
	
	/*
	 * Start the oldest service
	 */
	private void startService() {
		if (mMatchingIntents.size() > 0) { //There are some Intents untested
			if (LOG) Log.d(TAG, "Trying service " + mMatchingIntents.get(0).loadLabel(mContext.getPackageManager()));
		
			final ServiceInfo servInfo = mMatchingIntents.get(0).serviceInfo;
            final Intent i = new Intent();
            i.setComponent(new ComponentName(servInfo.applicationInfo.packageName, servInfo.name));
            mContext.bindService(i, this,  Context.BIND_AUTO_CREATE);
            mMatchingIntents.remove(0);
		} else { //No more service to test
			
			getMostFrequentOpenUDID(); //Choose the most frequent
	
			if (OpenUDID == null) //No OpenUDID was chosen, generate one			
				generateOpenUDID();
			if (LOG) Log.d(TAG, "OpenUDID: " + OpenUDID);

			storeOpenUDID();//Store it locally
			mInitialized = true;
		}
	}
	
	private void getMostFrequentOpenUDID() {
		if (mReceivedOpenUDIDs.isEmpty() == false) {
			final TreeMap<String,Integer> sorted_OpenUDIDS = new TreeMap(new ValueComparator());
			sorted_OpenUDIDS.putAll(mReceivedOpenUDIDs);
        
			OpenUDID = sorted_OpenUDIDS.firstKey();
		}
	}
	
	
	private static String OpenUDID = null;
	private static boolean mInitialized = false; 

	/**
	 * The Method to call to get OpenUDID
	 * @return the OpenUDID
	 */
	public static String getOpenUDID() {
		if (!mInitialized) Log.e("OpenUDID", "Initialisation isn't done");
		return OpenUDID;
	}
	
	/**
	 * The Method to call to get OpenUDID
	 * @return the OpenUDID
	 */
	public static boolean isInitialized() {
		return mInitialized;
	}
	
	/**
	 * The Method the call at the init of your app
	 * @param context	you current context
	 */
	public static void sync(Context context) {
		//Initialise the Manager
		OpenUDID_manager manager = new OpenUDID_manager(context);
		
		//Try to get the openudid from local preferences
		OpenUDID = manager.mPreferences.getString(PREF_KEY, null);
		if (OpenUDID == null) //Not found
		{
			//Get the list of all OpenUDID services available (including itself)
			manager.mMatchingIntents = context.getPackageManager().queryIntentServices(new Intent("org.OpenUDID.GETUDID"), 0);
			if (LOG) Log.d(TAG, manager.mMatchingIntents.size() + " services matches OpenUDID");
			
			if (manager.mMatchingIntents != null)
				//Start services one by one
				manager.startService();
		
		} else {//Got it, you can now call getOpenUDID()
			if (LOG) Log.d(TAG, "OpenUDID: " + OpenUDID);
			mInitialized = true;
		}
	}
	
	
	/*
	 * Used to sort the OpenUDIDs collected by occurrence
	 */
	private class ValueComparator implements Comparator {
		public int compare(Object a, Object b) {

			if(mReceivedOpenUDIDs.get(a) < mReceivedOpenUDIDs.get(b)) {
				return 1;
		    } else if(mReceivedOpenUDIDs.get(a) == mReceivedOpenUDIDs.get(b)) {
		    	return 0;
		    } else {
		    	return -1;
		    }
		 }
	}
}