Initial commit

Fusion Accounting/models/loan_line.py

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+"""
+Fusion Accounting - Loan Amortization Line
+
+Each record represents a single installment in a loan's amortization
+schedule, tracking principal, interest, remaining balance, and the
+link to the corresponding journal entry once paid.
+"""
+
+from odoo import api, Command, fields, models, _
+from odoo.exceptions import UserError
+from odoo.tools import float_round
+
+
+class FusionLoanLine(models.Model):
+    """Single installment of a loan amortization schedule.
+
+    Created in bulk by :meth:`fusion.loan.compute_amortization_schedule`
+    and individually paid via :meth:`action_create_entry` which posts
+    a journal entry debiting the loan liability and interest expense,
+    and crediting the bank / payment account.
+    """
+    _name = 'fusion.loan.line'
+    _description = 'Loan Amortization Line'
+    _order = 'sequence, id'
+
+    # ------------------------------------------------------------------
+    # Parent link
+    # ------------------------------------------------------------------
+    loan_id = fields.Many2one(
+        'fusion.loan',
+        string='Loan',
+        required=True,
+        ondelete='cascade',
+        index=True,
+    )
+
+    # ------------------------------------------------------------------
+    # Schedule fields
+    # ------------------------------------------------------------------
+    sequence = fields.Integer(
+        string='#',
+        required=True,
+        help="Installment number in the amortization schedule.",
+    )
+    date = fields.Date(
+        string='Due Date',
+        required=True,
+    )
+    principal_amount = fields.Monetary(
+        string='Principal',
+        currency_field='currency_id',
+        help="Portion of the payment that reduces the outstanding balance.",
+    )
+    interest_amount = fields.Monetary(
+        string='Interest',
+        currency_field='currency_id',
+        help="Interest charged for this period.",
+    )
+    total_payment = fields.Monetary(
+        string='Total Payment',
+        currency_field='currency_id',
+        help="Sum of principal and interest for this installment.",
+    )
+    remaining_balance = fields.Monetary(
+        string='Remaining Balance',
+        currency_field='currency_id',
+        help="Outstanding principal after this installment.",
+    )
+
+    # ------------------------------------------------------------------
+    # Status
+    # ------------------------------------------------------------------
+    is_paid = fields.Boolean(
+        string='Paid',
+        default=False,
+        copy=False,
+    )
+    move_id = fields.Many2one(
+        'account.move',
+        string='Journal Entry',
+        copy=False,
+        readonly=True,
+        help="The posted journal entry recording this installment payment.",
+    )
+
+    # ------------------------------------------------------------------
+    # Related / helper
+    # ------------------------------------------------------------------
+    currency_id = fields.Many2one(
+        related='loan_id.currency_id',
+        store=True,
+    )
+    company_id = fields.Many2one(
+        related='loan_id.company_id',
+        store=True,
+    )
+    loan_state = fields.Selection(
+        related='loan_id.state',
+        string='Loan Status',
+    )
+
+    # ==================== Business Methods ====================
+
+    def action_create_entry(self):
+        """Create and post the journal entry for this loan installment.
+
+        Debits:
+            - Loan liability account  (principal portion)
+            - Interest expense account (interest portion)
+        Credits:
+            - Journal default account / bank (total payment)
+        """
+        self.ensure_one()
+        if self.is_paid:
+            raise UserError(
+                _("Installment #%s is already paid.", self.sequence)
+            )
+        if self.loan_id.state != 'running':
+            raise UserError(
+                _("Entries can only be created for running loans.")
+            )
+
+        loan = self.loan_id
+        move_vals = {
+            'journal_id': loan.journal_id.id,
+            'date': self.date,
+            'ref': _('%(loan)s - Installment #%(seq)s',
+                     loan=loan.name, seq=self.sequence),
+            'fusion_loan_id': loan.id,
+            'line_ids': [
+                # Debit: reduce loan liability
+                Command.create({
+                    'account_id': loan.loan_account_id.id,
+                    'debit': self.principal_amount,
+                    'credit': 0.0,
+                    'partner_id': loan.partner_id.id,
+                    'name': _('%(loan)s - Principal #%(seq)s',
+                             loan=loan.name, seq=self.sequence),
+                }),
+                # Debit: interest expense
+                Command.create({
+                    'account_id': loan.interest_account_id.id,
+                    'debit': self.interest_amount,
+                    'credit': 0.0,
+                    'partner_id': loan.partner_id.id,
+                    'name': _('%(loan)s - Interest #%(seq)s',
+                             loan=loan.name, seq=self.sequence),
+                }),
+                # Credit: bank / payment
+                Command.create({
+                    'account_id': loan.journal_id.default_account_id.id,
+                    'debit': 0.0,
+                    'credit': self.total_payment,
+                    'partner_id': loan.partner_id.id,
+                    'name': _('%(loan)s - Payment #%(seq)s',
+                             loan=loan.name, seq=self.sequence),
+                }),
+            ],
+        }
+        move = self.env['account.move'].create(move_vals)
+        move.action_post()
+
+        self.write({
+            'is_paid': True,
+            'move_id': move.id,
+        })
+        return True