###################################################################################
#
#    Copyright (c) 2017-2019 MuK IT GmbH.
#
#    This file is part of MuK Utils 
#    (see https://mukit.at).
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU Lesser General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU Lesser General Public License for more details.
#
#    You should have received a copy of the GNU Lesser General Public License
#    along with this program. If not, see <http://www.gnu.org/licenses/>.
#
###################################################################################

import math
import base64
import logging
import mimetypes

from odoo import registry, api, models, _
from odoo.tools.mimetypes import guess_mimetype
from odoo.tools.misc import split_every
from odoo.exceptions import AccessError

_logger = logging.getLogger(__name__)

class IrAttachment(models.Model):
    
    _inherit = 'ir.attachment'
    
    #----------------------------------------------------------
    # Helper
    #----------------------------------------------------------
    
    @api.model
    def _get_datas_inital_vals(self):
        return {
            'store_fname': False,
            'db_datas': False,
        }
    
    @api.model
    def _update_datas_vals(self, vals, attach, bin_data):
        vals.update({
            'file_size': len(bin_data),
            'checksum': self._compute_checksum(bin_data),
            'index_content': self._index(bin_data, attach.datas_fname, attach.mimetype),
        })
        return vals
    
    @api.model
    def _get_datas_clean_vals(self, attach):
        vals = {}
        if attach.store_fname:
            vals['store_fname'] = attach.store_fname
        return vals
    
    @api.model
    def _clean_datas_after_write(self, vals):
        if 'store_fname' in vals:
            self._file_delete(vals['store_fname'])
   
    #----------------------------------------------------------
    # Actions
    #----------------------------------------------------------
    
    @api.multi
    def action_migrate(self):
        self.migrate()
    
    #----------------------------------------------------------
    # Functions
    #----------------------------------------------------------
    
    @api.model
    def storage_locations(self):
        return ['db', 'file']
    
    @api.model
    def force_storage(self):
        if not self.env.user._is_admin():
            raise AccessError(_('Only administrators can execute this action.'))
        storage_domain = {
            'db': ('db_datas', '=', False),
            'file': ('store_fname', '=', False), 
        }
        record_domain = [
            '&', ('type', '=', 'binary'),
            '&', storage_domain[self._storage()], 
            '|', ('res_field', '=', False), ('res_field', '!=', False)
        ]
        self.search(record_domain).migrate(batch_size=100)
        return True
    
    @api.multi
    def migrate(self, batch_size=None):
        commit_on_batch = bool(batch_size)
        batch_size = batch_size or len(self) or 1
        storage_location = self._storage().upper()
        batches = math.ceil(len(self) / batch_size)
        for index, attachment in enumerate(self, start=1):
            _logger.info("Migrate Attachment %s of %s to %s [Batch %s of %s]",
                index % batch_size or batch_size, batch_size, storage_location, 
                math.ceil(index / batch_size), batches
            )
            attachment.with_context(migration=True).write({
                'datas': attachment.datas
            })
            if commit_on_batch and not index % batch_size:
                self.env.cr.commit()     
        
    #----------------------------------------------------------
    # Read
    #----------------------------------------------------------
    
    @api.multi
    def _compute_mimetype(self, values):
        if self.env.context.get('migration') and len(self) == 1:
            return self.mimetype or 'application/octet-stream'
        else:
            return super(IrAttachment, self)._compute_mimetype(values)
        
    #----------------------------------------------------------
    # Create, Write, Delete
    #----------------------------------------------------------
    
    @api.multi
    def _inverse_datas(self):
        location = self._storage()
        for attach in self:
            value = attach.datas
            bin_data = base64.b64decode(value) if value else b''
            vals = self._get_datas_inital_vals()
            vals = self._update_datas_vals(vals, attach, bin_data)
            if value and location != 'db':
                vals['store_fname'] = self._file_write(value, vals['checksum'])
            else:
                vals['db_datas'] = value
            clean_vals = self._get_datas_clean_vals(attach)
            models.Model.write(attach.sudo(), vals)
            self._clean_datas_after_write(clean_vals)