# low_device_manager module 
# Authors: Nicholas Alexander && Otacilio Lacerda
# Module responsible for management of devices informations. 

import pickle
import os

from PyQt4.QtCore import *

import pcsutils as utils
from pcsdeviceinfo import PcsDeviceInfo
from pcsdeviceutils import *
from ui.tsuigeneralmethods import showMessageBox

USER_HOST = 'root'
HOME = os.path.expanduser("~")
DEVICES_FILE = os.path.join(HOME, ".pcsuite/devices/.ip_list")


class PcsDeviceManager(QObject):
    """Class responsible for devices management such as adding and removing
    devices, get batery, memory and name informations and saving Device objects.

    The DeviceManager holds a list of Devices objects and can save and load this
    list on a file and retrieve information about each Device.

    """
    _currentIp = None
    def __init__(self):
        QObject.__init__(self)
        self._deviceList = []
        
        # FIXME: initialize this in another place
        utils.initDirs()
        self.loadDevices()

        self._currentIp = None

    def _batteryException(self):
        errorMessage = "Could not get device battery status, check if " +\
            "python is installed on your device. To get information about " + \
            "python installation visit: " +\
            "http://pymaemo.garage.maemo.org/installation.html"
        showMessageBox(errorMessage,
                              "Error while collecting device information")

    def _addDevice(self, deviceIp):
        """Add a new device to list connecting to it in the process.
    
        Arguments:
        host_ip -- The IP of the device to connect.
        
        """
        self.loadDevices()
                    
        deviceInfo = PcsDeviceInfo()
        deviceInfo.ip = deviceIp
        (deviceInfo.name, deviceInfo.system,
         deviceInfo.ossoBackup) = queryProductInformation(deviceIp) 
        if deviceInfo.name == "NO INFORMATION":
            return "connectException"
        try:
            deviceInfo.battery = float(queryDeviceBattery(deviceIp))
        except:
            return "batteryException"
    
        if deviceInfo.battery < 0:
            deviceInfo.charging = True
            
        deviceInfo.storage = queryDeviceStorage(deviceIp)
        
        if self.getDevice(deviceIp) != None:
            return deviceInfo
        
        self._deviceList.append(deviceInfo)
        self.saveDevices()
        return deviceInfo

    def removeDevice(self, deviceIp):
        """Remove a Device from list.

        Arguments:
        device_ip -- The IP  of the device to remove

        """
        deviceInfo = self.getDevice(deviceIp)
        if deviceInfo != -1:
            self._deviceList.remove(deviceInfo)
            self.saveDevices()
            return 1
        else:
            raise Exception("No device with that ip was found")

    def getDevices(self):
        """Returns a list with the IP address of all devices in the object's 
        devices list.
        
        """
        ips = []
        for deviceInfo in self._deviceList:
            ips.append(deviceInfo.ip)
        return ips

    def saveDevices(self):
        """Save the list of Device objects in DEVICES_FILE file."""
        obj = self._deviceList
        file = open(DEVICES_FILE, "w")
        pickle.dump(obj, file)
        file.close()

    def loadDevices(self):
        """Loads the list of Device objects from DEVICES_FILE path if possible."""

        if os.path.exists(DEVICES_FILE):
            file = open(DEVICES_FILE)
            self._deviceList = pickle.load(file)
            file.close()

    def getDevice(self, ip):
        # Returns the Device object with the provided ip
        for deviceInfo in self._deviceList:
            if deviceInfo.ip == ip:
                return deviceInfo
        return None

    def setCurrentDevice (self, ip):
        self._currentIp = ip
        
    def getCurrentDevice(self):
        return self.getDevice(self._currentIp)