
from werkzeug.datastructures import FileStorage

from wtforms import ValidationError, fields
from wtforms.widgets import HTMLString, html_params
from flask.ext.babelpkg import gettext
from .filemanager import ImageManager, FileManager

try:
    from wtforms.fields.core import _unset_value as unset_value
except ImportError:
    from wtforms.utils import unset_value
    

"""
    Based and thanks to https://github.com/mrjoes/flask-admin/blob/master/flask_admin/form/upload.py
"""

class BS3FileUploadFieldWidget(object):
    
    empty_template = ('<div class="input-group">'
                    '<span class="input-group-addon"><i class="fa fa-upload"></i>'
                    '</span>'
                    '<input class="form-control" %(file)s/>'
        '</div>'
        )
    
    data_template = ('<div>'
                     ' <input %(text)s>'
                     ' <input type="checkbox" name="%(marker)s">Delete</input>'
                     '</div>'
                     '<div class="input-group">'
                    '<span class="input-group-addon"><i class="fa fa-upload"></i>'
                    '</span>'
                    '<input class="form-control" %(file)s/>'
        '</div>'
        )

    def __call__(self, field, **kwargs):
        kwargs.setdefault('id', field.id)
        kwargs.setdefault('name', field.name)
        
        args = {
            'file': html_params(type='file',
                                **kwargs),
            'marker': '_%s-delete' % field.name
        }
        
        template = self.data_template if field.data else self.empty_template

        return HTMLString(template % {
            'text': html_params(type='text',
                                value=field.data),
            'file': html_params(type='file',
                                **kwargs),
            'marker': '_%s-delete' % field.name
        })
        

class BS3ImageUploadFieldWidget(object):
    
    empty_template = ('<div class="input-group">'
                    '<span class="input-group-addon"><span class="glyphicon glyphicon-upload"></span>'
                    '</span>'
                    '<input class="form-control" %(file)s/>'
        '</div>'
        )
    
    data_template = ('<div class="thumbnail">'
                     ' <img %(image)s>'
                     ' <input type="checkbox" name="%(marker)s">Delete</input>'
                     '</div>'
                     '<div class="input-group">'
                    '<span class="input-group-addon"><span class="glyphicon glyphicon-upload"></span>'
                    '</span>'
                    '<input class="form-control" %(file)s/>'
                    '</div>'
        )

    def __call__(self, field, **kwargs):
        kwargs.setdefault('id', field.id)
        kwargs.setdefault('name', field.name)
        
        args = {
            'file': html_params(type='file',
                                **kwargs),
            'marker': '_%s-delete' % field.name
        }
        
        if field.data:
            url = self.get_url(field)
            args['image'] = html_params(src=url)
            template = self.data_template
            
        else: 
            template = self.empty_template

        return HTMLString(template % args)

    def get_url(self, field):
        im = ImageManager()
        return im.get_url(field.data)


# Fields
class FileUploadField(fields.TextField):
    """
        Customizable file-upload field.

        Saves file to configured path, handles updates and deletions. Inherits from `TextField`,
        resulting filename will be stored as string.
    """
    widget = BS3FileUploadFieldWidget()

    def __init__(self, label=None, validators=None,
                 filemanager = None,
                 **kwargs):
        """
            Constructor.

            :param label:
                Display label
            :param validators:
                Validators
        """
        
        self.filemanager = filemanager or FileManager()
        self._should_delete = False

        super(FileUploadField, self).__init__(label, validators, **kwargs)

    def pre_validate(self, form):
        if (self.data and
                isinstance(self.data, FileStorage) and
                not self.filemanager.is_file_allowed(self.data.filename)):
            raise ValidationError(gettext('Invalid file extension'))

    def process(self, formdata, data=unset_value):
        if formdata:
            marker = '_%s-delete' % self.name
            if marker in formdata:
                self._should_delete = True
        return super(FileUploadField, self).process(formdata, data)

    def populate_obj(self, obj, name):
        field = getattr(obj, name, None)
        if field:
            # If field should be deleted, clean it up
            if self._should_delete:
                self.filemanager.delete_file(field)
                setattr(obj, name, None)
                return

        if self.data and isinstance(self.data, FileStorage):
            if field:
                self.filemanager.delete_file(field)

            filename = self.filemanager.generate_name(obj, self.data)
            filename = self.filemanager.save_file(self.data, filename)

            setattr(obj, name, filename)



class ImageUploadField(fields.TextField):
    """
        Image upload field.
    """
    widget = BS3ImageUploadFieldWidget()

    def __init__(self, label=None, validators=None,
                 imagemanager = None,
                 **kwargs):
        
        self.imagemanager = imagemanager or ImageManager()
        self._should_delete = False
        super(ImageUploadField, self).__init__(label, validators, **kwargs)


    def pre_validate(self, form):
        if (self.data and
                isinstance(self.data, FileStorage) and
                not self.imagemanager.is_file_allowed(self.data.filename)):
            raise ValidationError(gettext('Invalid file extension'))

    def process(self, formdata, data=unset_value):
        if formdata:
            marker = '_%s-delete' % self.name
            if marker in formdata:
                self._should_delete = True
        return super(ImageUploadField, self).process(formdata, data)


    def populate_obj(self, obj, name):
        field = getattr(obj, name, None)
        if field:
            # If field should be deleted, clean it up
            if self._should_delete:
                self.imagemanager.delete_file(field)
                setattr(obj, name, None)
                return

        if self.data and isinstance(self.data, FileStorage):
            if field:
                self.imagemanager.delete_file(field)

            filename = self.imagemanager.generate_name(obj, self.data)
            filename = self.imagemanager.save_file(self.data, filename)

            setattr(obj, name, filename)
    
