from odoo import models, _
from odoo.tools import float_is_zero

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

    def _create_account_move(self, balancing_account=False, amount_to_balance=0, bank_payment_method_diffs=None):
        """
        Extend _create_account_move to generate additional journal entry lines
        for 100% discount orders (where total amount is 0).
        """
        # Call super to generate the standard move
        data = super(PosSession, self)._create_account_move(balancing_account, amount_to_balance, bank_payment_method_diffs)

        if not self.config_id.discount_100_income_account_id or not self.config_id.discount_100_expense_account_id:
            return data

        # Identify orders with 0 absolute paid amount but non-zero gross amount
        # We look for orders where amount_total is near zero.
        # Note: 100% discount orders have amount_total = 0.
        
        MoveLine = data.get('MoveLine')
        if not MoveLine:
            # Depending on Odoo 19's internal structure changes, fallback / ensure MoveLine exists. Odoo 17 returns a dict with 'MoveLine'.
            MoveLine = self.env['account.move.line']

        income_account = self.config_id.discount_100_income_account_id
        expense_account = self.config_id.discount_100_expense_account_id
        
        # Helper to convert amount to company currency if needed, similar to Odoo's internals
        def _get_amounts(amount, date):
            return self._update_amounts({'amount': 0, 'amount_converted': 0}, {'amount': amount}, date)

        zero_value_moves = []
        
        for order in self._get_closed_orders():
            if float_is_zero(order.amount_total, precision_rounding=self.currency_id.rounding):
                # Calculate the exact discount amount applied by loyalty rewards
                discount_amount = sum(
                    abs(line.price_subtotal) 
                    for line in order.lines 
                    if line.price_subtotal < 0 and (getattr(line, 'is_reward_line', False) or getattr(line, 'reward_id', False))
                )
                
                if float_is_zero(discount_amount, precision_rounding=self.currency_id.rounding):
                    continue

                amounts = _get_amounts(discount_amount, order.date_order)
                
                # Create Credit Line (Income)
                # We use _credit_amounts helper logic style manually
                credit_vals = {
                    'name': _('100%% Discount Income: %s') % order.name,
                    'account_id': income_account.id,
                    'move_id': self.move_id.id,
                    'partner_id': order.partner_id.id or False,
                }
                credit_vals.update(self._credit_amounts(credit_vals, amounts['amount'], amounts['amount_converted']))
                zero_value_moves.append(credit_vals)

                # Create Debit Line (Expense/Discount)
                debit_vals = {
                    'name': _('100%% Discount Expense: %s') % order.name,
                    'account_id': expense_account.id,
                    'move_id': self.move_id.id,
                    'partner_id': order.partner_id.id or False,
                }
                debit_vals.update(self._debit_amounts(debit_vals, amounts['amount'], amounts['amount_converted']))
                zero_value_moves.append(debit_vals)

        if zero_value_moves and self.move_id:
            MoveLine.with_context(check_move_validity=False).create(zero_value_moves)

        return data