'''framework.py

Library that implements a template (Template) class for classes that
loads data into GenX. Also included here is a DataLoaderController which
takes care of the use of the DataLoaders. 
'''
import wx, os, io, traceback

from .utils import PluginHandler
from genx.gui_logging import iprint

head, tail = os.path.split(__file__)
# Look only after the file name and not the ending since
# the file ending can be pyc if compiled... 
__FILENAME__ = tail.split('.')[0]
# This assumes that plugin is under the current dir may need 
# changing
__MODULE_DIR__ = head
if __MODULE_DIR__ != '/':
    __MODULE_DIR__ += '/'


class Template:
    def __init__(self, parent):
        self.parent = parent
        # This is made for the virtual datalist controller...
        self.data = self.parent.data_cont.get_data()
        self.Register()
        
    def Register(self):
        '''Register(self) --> None
        
        Register the data loader with the parent
        '''
        self.parent.data_loader = self
        
    def SetData(self, data):
        '''SetData(self, data) --> None
        
        Sets the data connection to the plugin.
        '''
        self.data = data
        
    def UpdateDataList(self):
        '''UpdateDataList(self) --> None
        
        Forces the data list to update. This is only necessary if new
        data sets have been added when the data has been loaded
        '''
        # Just a force update of the data_list
        self.parent.SetItemCount(\
            self.parent.data_cont.get_count())
        # Updating the imagelist as well
        self.parent._UpdateImageList()
        
    def SetStatusText(self, text):
        '''SetStatusText(self, text) --> None
        
        Set a status text in the main frame for user information 
        '''
        self.parent.SetStatusText(text)
    
    def LoadDataFile(self, selected_items):
        '''LoadDataFile(self, seleceted_items) --> None
        
        Selected items is the selcted items in the items in the current DataList
        into which data from file(s) should be loaded. Note that the default
        implementation only allows the loading of a single file! 
        Overriding this function in subclasses can of course change this 
        behaviour. This function calls the LoadData function which implements 
        the io function by it self. The LoadData has to be overloaded in
        order to have a working plugin.
        '''
        n_selected = len(selected_items)
        if n_selected == 1:
            dlg = wx.FileDialog(self.parent, message = "Choose your Datafile"
                    , defaultFile = "", wildcard = "All files (*.*)|*.*"
                    , style=wx.FD_OPEN | wx.FD_CHANGE_DIR)
                    
            if dlg.ShowModal() == wx.ID_OK:
                self.LoadData(selected_items[0], dlg.GetPath())
                return True
            dlg.Destroy()
        else:
            if n_selected > 1:
                dlg = wx.MessageDialog(self.parent,\
                    'Please select only one dataset'\
                    , caption = 'Too many selections'
                    , style = wx.OK|wx.ICON_INFORMATION)
            else:
                dlg = wx.MessageDialog(self.parent, 'Please select a dataset'
                    , caption = 'No active dataset'
                    , style = wx.OK|wx.ICON_INFORMATION)
            dlg.ShowModal()
            dlg.Destroy()
        
        return False
    
    def LoadData(self, data_item, file_path):
        '''LoadData(self, data_item, file_path) --> None
        
        This file should load a single data file into data object of
        the model. Please overide this function. It is called by the 
        LoadFile function.
        '''
        pass
        
    def SettingsDialog(self):
        '''SettingsDialog(self) --> None
        
        This function should - if necessary implement a dialog box
        that allows the user set import settings for example.
        '''
        pass
    
    def SendUpdateDataEvent(self):
        '''SendUpdateDataEvent(self) --> None
        
        Sends an event that new data has been loaded and 
        things such as plotting should be updated.
        '''
        self.parent._UpdateData('New data added')
        
    def Remove(self):
        '''Remove(self) --> None
        
        Removes the plugin from knowledge of the parent.
        '''
        self.parent.data_loader = None
        
class PluginController:
    def __init__(self, parent):
        self.plugin_handler = PluginHandler(parent, __MODULE_DIR__ \
                            , 'data_loaders')
        self.parent = parent
        self.plugin_handler.load_plugin('default')
        
    def load_default(self):
        try:
            plugin_name = self.parent.config.get('data handling', 'data loader')
            self.LoadPlugin(plugin_name)
        except Exception as S:
            iprint('Could not locate the data loader parameter or the data loader. Error:')
            iprint(S.__str__())
            iprint('Proceeding with laoding the default data loader.')
            self.LoadPlugin('default')
        
    def LoadPlugin(self, plugin):
        '''LoadPlugin(self, plugin) --> None
        
        Loads a data handler note that there is no UnLoad function
        since only one DataHandler can be plugged in at a time.
        '''
        # Unload the plugins
        names = self.plugin_handler.loaded_plugins.copy()
        try:
            [self.plugin_handler.unload_plugin(pl) for pl in names]
            self.parent.SetStatusText('Unloaded data loader %s'%list(names.keys())[0])
        except:
            outp = io.StringIO()
            traceback.print_exc(200, outp)
            tbtext = outp.getvalue()
            outp.close()
            ShowErrorDialog(self.parent, 'Can NOT unload plugin object'+ \
                list(names.keys())[0] + '\nPython traceback below:\n\n' + tbtext)
        try:
            self.plugin_handler.load_plugin(plugin)
            self.parent.SetStatusText('Loaded data loader: %s'%plugin)
        except:
            outp = io.StringIO()
            traceback.print_exc(200, outp)
            tbtext = outp.getvalue()
            outp.close()
            ShowErrorDialog(self.parent, 'Can NOT load plugin ' + plugin\
             + '\nPython traceback below:\n\n' + tbtext)
        
    def ShowDialog(self):
        '''ShowDialog(self) --> None
        
        Shows a dialog boc for the user to choose a data loader.
        '''
        cur_plugin = list(self.plugin_handler.loaded_plugins.keys())[0]
        plugin_list = self.plugin_handler.get_possible_plugins()
        dlg = PluginDialog(self.parent, plugin_list, cur_plugin,\
                                self.LoadPlugin)
        dlg.ShowModal()
        dlg.Destroy()
        
        
class PluginDialog(wx.Dialog):
    def __init__(self, parent, plugin_list, current_plugin,\
            load_plugin_func = None):
        wx.Dialog.__init__(self, parent, -1, 'Choose a data loader')
        
        self.load_plugin_func = load_plugin_func
        
        choice_sizer = wx.BoxSizer(wx.HORIZONTAL)
        sizer = wx.BoxSizer(wx.VERTICAL)
        
        choice_text = wx.StaticText(self, -1, 'Data loaders: ')
        self.choice_control = wx.Choice(self, -1, choices = plugin_list)
        self.choice_control.SetStringSelection(current_plugin)
        choice_sizer.Add(choice_text, 0, wx.ALIGN_CENTER_VERTICAL)
        choice_sizer.Add(self.choice_control, 0, wx.ALIGN_CENTER_VERTICAL)
        
        # Add the Dialog buttons
        button_sizer = wx.StdDialogButtonSizer()
        okay_button = wx.Button(self, wx.ID_OK)
        okay_button.SetDefault()
        button_sizer.AddButton(okay_button)
        apply_button = wx.Button(self, wx.ID_APPLY)
        apply_button.SetDefault()
        button_sizer.AddButton(apply_button)    
        button_sizer.AddButton(wx.Button(self, wx.ID_CANCEL))
        button_sizer.Realize()
        # Add some eventhandlers
        self.Bind(wx.EVT_BUTTON, self.on_apply, okay_button)
        self.Bind(wx.EVT_BUTTON, self.on_apply, apply_button)
        
        
        sizer.Add((20, 20), 0)
        sizer.Add(choice_sizer, 0, wx.ALIGN_CENTRE|wx.ALL)
        line = wx.StaticLine(self, -1, size=(20,-1), style=wx.LI_HORIZONTAL)
        sizer.Add(line, 0, wx.GROW|wx.ALIGN_CENTER_HORIZONTAL|wx.TOP, 20)
        sizer.Add(button_sizer)
        
        self.SetSizer(sizer)
        
        sizer.Fit(self)
        self.Layout()
        
    def on_apply(self, event):
        if self.load_plugin_func != None:
            self.load_plugin_func(self.choice_control.GetStringSelection())
        event.Skip()

# Utility Dialog functions..
def ShowInfoDialog(frame, message):
    dlg = wx.MessageDialog(frame, message,
                               'Information',
                               wx.OK | wx.ICON_INFORMATION
                               )
    dlg.ShowModal()
    dlg.Destroy()
    
def ShowErrorDialog(frame, message, position = ''):
    dlg = wx.MessageDialog(frame, message,
                               'ERROR',
                               wx.OK | wx.ICON_ERROR
                               )
    dlg.ShowModal()
    dlg.Destroy()

def ShowWarningDialog(frame, message):
    dlg = wx.MessageDialog(frame, message, 'Warning',
                               wx.OK | wx.ICON_ERROR
                               )
    dlg.ShowModal()
    dlg.Destroy()
