# -*- coding: utf-8 -*-
# Part of Odoo. See LICENSE file for full copyright and licensing details.
from hashlib import sha256
from json import dumps, loads
import logging

from odoo import models, api, fields, release, _
from odoo.exceptions import UserError

_logger = logging.getLogger(__name__)


class pos_config(models.Model):
    _inherit = 'pos.config'

    def open_ui(self):
        for config in self:
            if not config.company_id.country_id:
                raise UserError(_("You have to set a country in your company setting."))
            if config.company_id._is_accounting_unalterable():
                if config.current_session_id:
                    config.current_session_id._check_session_timing()
        return super(pos_config, self).open_ui()


class pos_session(models.Model):
    _inherit = 'pos.session'

    def _check_session_timing(self):
        self.ensure_one()
        return True

    def open_frontend_cb(self):
        sessions_to_check = self.filtered(lambda s: s.config_id.company_id._is_accounting_unalterable())
        sessions_to_check.filtered(lambda s: s.state == 'opening_control').start_at = fields.Datetime.now()
        for session in sessions_to_check:
            session._check_session_timing()
        return super(pos_session, self).open_frontend_cb()


ORDER_FIELDS_BEFORE_17_4 = ['date_order', 'user_id', 'lines', 'payment_ids', 'pricelist_id', 'session_id', 'pos_reference', 'sale_journal', 'fiscal_position_id', 'partner_id']
ORDER_FIELDS_FROM_17_4 = ['date_order', 'user_id', 'lines', 'payment_ids', 'pricelist_id', 'session_id', 'pos_reference', 'sale_journal', 'fiscal_position_id', 'pos_version']
LINE_FIELDS = ['notice', 'product_id', 'qty', 'price_unit', 'discount', 'tax_ids', 'tax_ids_after_fiscal_position']


class pos_order(models.Model):
    _inherit = 'pos.order'

    l10n_fr_hash = fields.Char(string="Inalteralbility Hash", readonly=True, copy=False)
    l10n_fr_secure_sequence_number = fields.Integer(string="Inalteralbility No Gap Sequence #", readonly=True, copy=False)
    l10n_fr_string_to_hash = fields.Char(compute='_compute_string_to_hash', readonly=True, store=False)
    previous_order_id = fields.Many2one('pos.order', string='Previous Order', readonly=True, compute='_compute_previous_order', store=True, copy=False)
    pos_version = fields.Char(help="Version of Odoo that created the order", readonly=True, copy=False)

    @api.depends('l10n_fr_secure_sequence_number')
    def _compute_previous_order(self):
        for order in self:
            prev_order = self.search([('state', 'in', ['paid', 'done', 'invoiced']),
                                                ('company_id', '=', order.company_id.id),
                                                ('l10n_fr_secure_sequence_number', '!=', 0),
                                                ('l10n_fr_secure_sequence_number', '=', order.l10n_fr_secure_sequence_number - 1)])
            if prev_order and len(prev_order) != 1:
                raise UserError(
                    _('An error occurred when computing the inalterability. Impossible to get the unique previous posted point of sale order.'))
            elif prev_order:
                order.previous_order_id = prev_order

    def _get_new_hash(self):
        """ Returns the hash to write on pos orders when they get posted"""
        self.ensure_one()
        # build and return the hash
        computed_hash = self._compute_hash(self.previous_order_id.l10n_fr_hash if self.previous_order_id else '')
        _logger.info(
            'Computed hash for order ID %s: %s \n String to hash: %s \n Previous hash: %s',
            self.id,
            computed_hash,
            dumps(loads(self.l10n_fr_string_to_hash), indent=2),
            self.previous_order_id.l10n_fr_hash
        )
        return computed_hash

    def _compute_hash(self, previous_hash):
        """ Computes the hash of the browse_record given as self, based on the hash
        of the previous record in the company's securisation sequence given as parameter"""
        self.ensure_one()
        hash_string = sha256((previous_hash + self.l10n_fr_string_to_hash).encode('utf-8'))
        return hash_string.hexdigest()

    def _compute_string_to_hash(self):
        def _getattrstring(obj, field_str):
            field_value = obj[field_str]
            if obj._fields[field_str].type == 'many2one':
                field_value = field_value.id
            if obj._fields[field_str].type in ['many2many', 'one2many']:
                field_value = field_value.sorted().ids
            return str(field_value)

        for order in self:
            values = {}
            if order.pos_version:
                order_fields = ORDER_FIELDS_FROM_17_4
            else:
                order_fields = ORDER_FIELDS_BEFORE_17_4
            for field in order_fields:
                values[field] = _getattrstring(order, field)

            for line in order.lines:
                for field in LINE_FIELDS:
                    k = 'line_%d_%s' % (line.id, field)
                    values[k] = _getattrstring(line, field)
            #make the json serialization canonical
            #  (https://tools.ietf.org/html/draft-staykov-hu-json-canonical-form-00)
            order.l10n_fr_string_to_hash = dumps(values, sort_keys=True,
                                                ensure_ascii=True, indent=None,
                                                separators=(',',':'))

    @api.model_create_multi
    def create(self, vals_list):
        for vals in vals_list:
            vals['pos_version'] = release.version
        return super().create(vals_list)

    def write(self, vals):
        has_been_posted = False
        for order in self:
            if order.company_id._is_accounting_unalterable():
                # write the hash and the secure_sequence_number when posting or invoicing an pos.order
                if vals.get('state') in ['paid', 'done', 'invoiced']:
                    has_been_posted = True

                # restrict the operation in case we are trying to write a forbidden field
                if order.pos_version:
                    ORDER_FIELDS = ORDER_FIELDS_FROM_17_4
                else:
                    ORDER_FIELDS = ORDER_FIELDS_BEFORE_17_4
                if (order.state in ['paid', 'done', 'invoiced'] and set(vals).intersection(ORDER_FIELDS)):
                    raise UserError(_('According to the French law, you cannot modify a point of sale order. Forbidden fields: %s.') % ', '.join(ORDER_FIELDS))
                # restrict the operation in case we are trying to overwrite existing hash
                if (order.l10n_fr_hash and 'l10n_fr_hash' in vals) or (order.l10n_fr_secure_sequence_number and 'l10n_fr_secure_sequence_number' in vals):
                    raise UserError(_('You cannot overwrite the values ensuring the inalterability of the point of sale.'))
        res = super(pos_order, self).write(vals)
        # write the hash and the secure_sequence_number when posting or invoicing a pos order
        if has_been_posted:
            for order in self.filtered(lambda o: o.company_id._is_accounting_unalterable() and
                                                not (o.l10n_fr_secure_sequence_number or o.l10n_fr_hash)):
                new_number = order.company_id.l10n_fr_pos_cert_sequence_id.next_by_id()
                res |= super(pos_order, order).write({'l10n_fr_secure_sequence_number': new_number})
                res |= super(pos_order, order).write({'l10n_fr_hash': order._get_new_hash()})
        return res

    @api.ondelete(at_uninstall=True)
    def _unlink_except_pos_so(self):
        for order in self:
            if order.company_id._is_accounting_unalterable():
                raise UserError(_("According to French law, you cannot delete a point of sale order."))

class PosOrderLine(models.Model):
    _inherit = "pos.order.line"

    def write(self, vals):
        # restrict the operation in case we are trying to write a forbidden field
        if set(vals).intersection(LINE_FIELDS):
            if any(l.company_id._is_accounting_unalterable() and l.order_id.state in ['done', 'invoiced'] for l in self):
                raise UserError(_('According to the French law, you cannot modify a point of sale order line. Forbidden fields: %s.') % ', '.join(LINE_FIELDS))
        return super(PosOrderLine, self).write(vals)
