/*
 * Copyright (C) 2014 Bluetooth Connection Template
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.hardcopy.btchat.bluetooth;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.Timer;
import java.util.TimerTask;
import java.util.UUID;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;

/**
 * This class does all the work for setting up and managing Bluetooth
 * connections with other devices. It has a thread that listens for
 * incoming connections, a thread for connecting with a device, and a
 * thread for performing data transmissions when connected.
 */
public class BluetoothManager {
	
    // Debugging
    private static final String TAG = "BluetoothManager";

    // Constants that indicate the current connection state
    public static final int STATE_NONE = 0;       // we're doing nothing
    public static final int STATE_LISTEN = 1;     // now listening for incoming connections
    public static final int STATE_CONNECTING = 2; // now initiating an outgoing connection
    public static final int STATE_CONNECTED = 3;  // now connected to a remote device
    
    // Message types sent from the BluetoothManager to Handler
    public static final int MESSAGE_STATE_CHANGE = 1;
    public static final int MESSAGE_READ = 2;
    public static final int MESSAGE_WRITE = 3;
    public static final int MESSAGE_DEVICE_NAME = 4;
    public static final int MESSAGE_TOAST = 5;
    
    // 
	public static final String SERVICE_HANDLER_MSG_KEY_DEVICE_NAME = "device_name";
	public static final String SERVICE_HANDLER_MSG_KEY_DEVICE_ADDRESS = "device_address";
	public static final String SERVICE_HANDLER_MSG_KEY_TOAST = "toast";
    
    
    
    // Name for the SDP record when creating server socket
    private static final String NAME = "BluetoothManager";

    // Unique UUID for this application
    private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

    // Member fields
    private final BluetoothAdapter mAdapter;
    private final Handler mHandler;
    private AcceptThread mAcceptThread;
    private ConnectThread mConnectThread;
    private ConnectedThread mConnectedThread;
    private int mState;

    private static final long RECONNECT_DELAY_MAX = 60*60*1000;
    
    private long mReconnectDelay = 15*1000;
    private Timer mConnectTimer = null;
    private boolean mIsServiceStopped = false;
    

    /**
     * Constructor. Prepares a new BluetoothChat session.
     * @param context  The UI Activity Context
     * @param handler  A Handler to send messages back to the UI Activity
     */
    public BluetoothManager(Context context, Handler handler) {
        mAdapter = BluetoothAdapter.getDefaultAdapter();
        mState = STATE_NONE;
        mHandler = handler;
    }

    /**
     * Set the current state of the chat connection
     * @param state  An integer defining the current connection state
     */
    private synchronized void setState(int state) {
        Log.d(TAG, "setState() " + mState + " -> " + state);
        mState = state;
        
        if(mState == STATE_CONNECTED)
        	cancelRetryConnect();

        // Give the new state to the Handler so the UI Activity can update
        mHandler.obtainMessage(MESSAGE_STATE_CHANGE, state, -1).sendToTarget();
    }

    /**
     * Return the current connection state. */
    public synchronized int getState() {
        return mState;
    }

    /**
     * Start the chat service. Specifically start AcceptThread to begin a
     * session in listening (server) mode. Called by the Activity onResume() */
    public synchronized void start() {
        Log.d(TAG, "Starting BluetoothManager...");

        // Cancel any thread attempting to make a connection
        if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}

        // Cancel any thread currently running a connection
        if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}

        // Start the thread to listen on a BluetoothServerSocket
        if (mAcceptThread == null) {
            mAcceptThread = new AcceptThread();
            mAcceptThread.start();
        }
        setState(STATE_LISTEN);
        mIsServiceStopped = false;
    }

    /**
     * Start the ConnectThread to initiate a connection to a remote device.
     * @param device  The BluetoothDevice to connect
     */
    public synchronized void connect(BluetoothDevice device) {
        Log.d(TAG, "Connecting to: " + device);
        
        if (mState == STATE_CONNECTED)
        	return;

        // Cancel any thread attempting to make a connection
        if (mState == STATE_CONNECTING) {
            if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}
        }

        // Cancel any thread currently running a connection
        if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}

        // Start the thread to connect with the given device
        mConnectThread = new ConnectThread(device);
        mConnectThread.start();
        setState(STATE_CONNECTING);
    }

    /**
     * Start the ConnectedThread to begin managing a Bluetooth connection
     * @param socket  The BluetoothSocket on which the connection was made
     * @param device  The BluetoothDevice that has been connected
     */
    public synchronized void connected(BluetoothSocket socket, BluetoothDevice device) {
    	Log.d(TAG, "connected");

        // Cancel the thread that completed the connection
        if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}

        // Cancel any thread currently running a connection
        if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}

        // Cancel the accept thread because we only want to connect to one device
        if (mAcceptThread != null) {mAcceptThread.cancel(); mAcceptThread = null;}

        // Start the thread to manage the connection and perform transmissions
        mConnectedThread = new ConnectedThread(socket);
        mConnectedThread.start();

        // Send the name of the connected device back to the UI Activity
        Message msg = mHandler.obtainMessage(MESSAGE_DEVICE_NAME);
        Bundle bundle = new Bundle();
        bundle.putString(SERVICE_HANDLER_MSG_KEY_DEVICE_ADDRESS, device.getAddress());
        bundle.putString(SERVICE_HANDLER_MSG_KEY_DEVICE_NAME, device.getName());
        msg.setData(bundle);
        mHandler.sendMessage(msg);

        setState(STATE_CONNECTED);
    }

    /**
     * Stop all threads
     */
    public synchronized void stop() {
        Log.d(TAG, "stop");
        if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}
        if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}
        if (mAcceptThread != null) {mAcceptThread.cancel(); mAcceptThread = null;}
        setState(STATE_NONE);
        
        mIsServiceStopped = true;
        cancelRetryConnect();
    }

    /**
     * Write to the ConnectedThread in an unsynchronized manner
     * @param out The bytes to write
     * @see ConnectedThread#write(byte[])
     */
    public void write(byte[] out) {
        // Create temporary object
        ConnectedThread r;
        // Synchronize a copy of the ConnectedThread
        synchronized (this) {
            if (mState != STATE_CONNECTED) return;
            r = mConnectedThread;
        }
        // Perform the write unsynchronized
        r.write(out);
    }

    /**
     * Indicate that the connection attempt failed and notify the UI Activity.
     */
    private void connectionFailed() {
    	Log.d(TAG, "BluetoothManager :: connectionFailed()");
        setState(STATE_LISTEN);

        // Send a failure message back to the Activity
        /*
        Message msg = mHandler.obtainMessage(MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(SERVICE_HANDLER_MSG_KEY_TOAST, "Unable to connect device");
        msg.setData(bundle);
        mHandler.sendMessage(msg);
        */
        
        // Reserve re-connect timer
        reserveRetryConnect();
    }

    /**
     * Indicate that the connection was lost and notify the UI Activity.
     */
    private void connectionLost() {
    	Log.d(TAG, "BluetoothManager :: connectionLost()");
        setState(STATE_LISTEN);

        // Send a failure message back to the Activity
        // WARNING: This makes too many toast.
        /*
        Message msg = mHandler.obtainMessage(MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(SERVICE_HANDLER_MSG_KEY_TOAST, "Device connection was lost");
        msg.setData(bundle);
        mHandler.sendMessage(msg);
        */
        
        // Reserve re-connect timer
        reserveRetryConnect();
    }
    
    /**
     * Automatically retry bluetooth connection.
     */
    private void reserveRetryConnect() {
    	if(mIsServiceStopped)
    		return;
    	
        mReconnectDelay = mReconnectDelay * 2;
        if(mReconnectDelay > RECONNECT_DELAY_MAX)
        	mReconnectDelay = RECONNECT_DELAY_MAX;
        
		if(mConnectTimer != null) {
			try {
				mConnectTimer.cancel();
			} catch (IllegalStateException e) {
				e.printStackTrace();
			}
		}
		mConnectTimer = new Timer();
		mConnectTimer.schedule(new ConnectTimerTask(), mReconnectDelay);
    }
    
    private void cancelRetryConnect() {
    	if(mConnectTimer != null) {
			try {
				mConnectTimer.cancel();
				mConnectTimer.purge();
			} catch (IllegalStateException e) {
				e.printStackTrace();
			}
			mConnectTimer = null;
			mReconnectDelay = 15*1000;
    	}
    }

    /**
     * This thread runs while listening for incoming connections. It behaves
     * like a server-side client. It runs until a connection is accepted
     * (or until cancelled).
     */
    private class AcceptThread extends Thread {
        // The local server socket
        private final BluetoothServerSocket mmServerSocket;

        public AcceptThread() {
            BluetoothServerSocket tmp = null;

            // Create a new listening server socket
            try {
                tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID);
            } catch (IOException e) {
                Log.e(TAG, "listen() failed" + e.toString());
            }
            mmServerSocket = tmp;
        }

        public void run() {
            Log.d(TAG, "BEGIN mAcceptThread" + this);
            setName("AcceptThread");
            BluetoothSocket socket = null;

            // Listen to the server socket if we're not connected
            while (mState != STATE_CONNECTED) {
                try {
                    // This is a blocking call and will only return on a
                    // successful connection or an exception
                	if(mmServerSocket != null)
                		socket = mmServerSocket.accept();
                } catch (IOException e) {
                    Log.e(TAG, "accept() failed", e);
                    break;
                }

                // If a connection was accepted
                if (socket != null) {
                    synchronized (BluetoothManager.this) {
                        switch (mState) {
                        case STATE_LISTEN:
                        case STATE_CONNECTING:
                            // Situation normal. Start the connected thread.
                            connected(socket, socket.getRemoteDevice());
                            break;
                        case STATE_NONE:
                        case STATE_CONNECTED:
                            // Either not ready or already connected. Terminate new socket.
                            try {
                                socket.close();
                            } catch (IOException e) {
                                Log.e(TAG, "Could not close unwanted socket", e);
                            }
                            break;
                        }
                    }
                }
            }
            Log.i(TAG, "END mAcceptThread");
        }

        public void cancel() {
            Log.d(TAG, "cancel " + this);
            try {
            	if(mmServerSocket != null)
            		mmServerSocket.close();
            } catch (IOException e) {
                Log.e(TAG, "close() of server failed" + e.toString());
            }
        }
    }	// End of class AcceptThread


    /**
     * This thread runs while attempting to make an outgoing connection
     * with a device. It runs straight through; the connection either
     * succeeds or fails.
     */
    private class ConnectThread extends Thread {
        private final BluetoothSocket mmSocket;
        private final BluetoothDevice mmDevice;

        public ConnectThread(BluetoothDevice device) {
            mmDevice = device;
            BluetoothSocket tmp = null;

            // Get a BluetoothSocket for a connection with the
            // given BluetoothDevice
            try {
                tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
            } catch (IOException e) {
                Log.e(TAG, "create() failed", e);
            }
            mmSocket = tmp;
        }

        public void run() {
            Log.i(TAG, "BEGIN mConnectThread");
            setName("ConnectThread");

            // Always cancel discovery because it will slow down a connection
            mAdapter.cancelDiscovery();

            // Make a connection to the BluetoothSocket
            try {
                // This is a blocking call and will only return on a
                // successful connection or an exception
                mmSocket.connect();
            } catch (IOException e) {
                connectionFailed();
                // Close the socket
                try {
                    mmSocket.close();
                } catch (IOException e2) {
                    Log.e(TAG, "unable to close() socket during connection failure", e2);
                }
                // Start the service over to restart listening mode
                BluetoothManager.this.start();
                return;
            }

            // Reset the ConnectThread because we're done
            synchronized (BluetoothManager.this) {
                mConnectThread = null;
            }

            // Start the connected thread
            connected(mmSocket, mmDevice);
        }

        public void cancel() {
            try {
                mmSocket.close();
            } catch (IOException e) {
                Log.e(TAG, "close() of connect socket failed", e);
            }
        }
    }	// End of class ConnectThread

    /**
     * This thread runs during a connection with a remote device.
     * It handles all incoming and outgoing transmissions.
     */
    private class ConnectedThread extends Thread {
        private final BluetoothSocket mmSocket;
        private final InputStream mmInStream;
        private final OutputStream mmOutStream;

        public ConnectedThread(BluetoothSocket socket) {
            Log.d(TAG, "create ConnectedThread");
            mmSocket = socket;
            InputStream tmpIn = null;
            OutputStream tmpOut = null;

            // Get the BluetoothSocket input and output streams
            try {
                tmpIn = socket.getInputStream();
                tmpOut = socket.getOutputStream();
            } catch (IOException e) {
                Log.e(TAG, "temp sockets not created", e);
            }

            mmInStream = tmpIn;
            mmOutStream = tmpOut;
        }

        public void run() {
            Log.i(TAG, "BEGIN mConnectedThread");
            int bytes;

            // Keep listening to the InputStream while connected
            while (true) {
                try {
                    // Read from the InputStream
                    byte[] buffer = new byte[128];
                    Arrays.fill(buffer, (byte)0x00);
                    bytes = mmInStream.read(buffer);

                    // Send the obtained bytes to the main thread
                    mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer)
                            .sendToTarget();
                } catch (IOException e) {
                    Log.e(TAG, "disconnected", e);
                    connectionLost();
                    break;
                }
            }
        }

        /**
         * Write to the connected OutStream.
         * @param buffer  The bytes to write
         */
        public void write(byte[] buffer) {
            try {
                mmOutStream.write(buffer);

                // Disabled: Share the sent message back to the main thread
                // mHandler.obtainMessage(Constants.MESSAGE_WRITE, -1, -1, buffer)
                //        .sendToTarget();
            } catch (IOException e) {
                Log.e(TAG, "Exception during write");
            }
        }

        public void cancel() {
            try {
                mmSocket.close();
            } catch (IOException e) {
                Log.e(TAG, "close() of connect socket failed");
            }
        }
        
    }	// End of class ConnectedThread
    
    /**
     * Auto connect timer
     */
	private class ConnectTimerTask extends TimerTask {
		public ConnectTimerTask() {}
		
		public void run() {
	    	if(mIsServiceStopped)
	    		return;
			
			mHandler.post(new Runnable() {
				public void run() {
			    	if(getState() == STATE_CONNECTED || getState() == STATE_CONNECTING)
			    		return;
			    	
			    	Log.d(TAG, "ConnectTimerTask :: Retry connect()");
			    	
					ConnectionInfo cInfo = ConnectionInfo.getInstance(null);
					if(cInfo != null) {
						String addrs = cInfo.getDeviceAddress();
						BluetoothAdapter ba = BluetoothAdapter.getDefaultAdapter();
						if(ba != null && addrs != null) {
							BluetoothDevice device = ba.getRemoteDevice(addrs);
							
							if(device != null) {
								connect(device);
							}
						}
					}
				}	// End of run()
			});
		}
	}
    
}