From 6d29b2fad1827ae67c8e2d8e3a614557c8964b8c Mon Sep 17 00:00:00 2001
From: Enric Tobella <etobella@creublanca.es>
Date: Wed, 22 May 2019 10:29:34 +0200
Subject: [PATCH] [IMP] account_loan: Fix rounding issues

---
 account_loan/model/account_loan.py      | 10 +++++++---
 account_loan/model/account_loan_line.py | 18 ++++++++++++++----
 account_loan/tests/test_loan.py         |  6 +++---
 3 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/account_loan/model/account_loan.py b/account_loan/model/account_loan.py
index 2018a194..9a447af2 100644
--- a/account_loan/model/account_loan.py
+++ b/account_loan/model/account_loan.py
@@ -276,7 +276,7 @@ class AccountLoan(models.Model):
         for record in self:
             if record.loan_type == 'fixed-annuity':
                 record.fixed_amount = - record.currency_id.round(numpy.pmt(
-                    record.rate_period / 100,
+                    record.loan_rate() / 100,
                     record.fixed_periods,
                     record.fixed_loan_amount,
                     -record.residual_amount
@@ -307,8 +307,12 @@ class AccountLoan(models.Model):
     @api.depends('rate', 'method_period', 'rate_type')
     def _compute_rate_period(self):
         for record in self:
-            record.rate_period = record.compute_rate(
-                record.rate, record.rate_type, record.method_period)
+            record.rate_period = record.loan_rate()
+
+    def loan_rate(self):
+        return self.compute_rate(
+            self.rate, self.rate_type, self.method_period
+        )
 
     @api.depends('journal_id', 'company_id')
     def _compute_currency(self):
diff --git a/account_loan/model/account_loan_line.py b/account_loan/model/account_loan_line.py
index 50099e3c..3b8fbb04 100644
--- a/account_loan/model/account_loan_line.py
+++ b/account_loan/model/account_loan_line.py
@@ -161,7 +161,7 @@ class AccountLoanLine(models.Model):
             return self.loan_id.fixed_amount
         if self.loan_type == 'fixed-annuity':
             return self.currency_id.round(- numpy.pmt(
-                self.rate / 100,
+                self.loan_id.loan_rate() / 100,
                 self.loan_id.periods - self.sequence + 1,
                 self.pending_principal_amount,
                 -self.loan_id.residual_amount
@@ -174,13 +174,23 @@ class AccountLoanLine(models.Model):
                 'Amount cannot be recomputed if moves or invoices exists '
                 'already'
             ))
-        if not self.loan_id.round_on_end:
+        if (
+            self.sequence == self.loan_id.periods and
+            self.loan_id.round_on_end and
+            self.loan_type == 'fixed-annuity'
+        ):
             self.interests_amount = self.currency_id.round(
-                self.pending_principal_amount * self.rate / 100)
+                self.loan_id.fixed_amount - self.pending_principal_amount +
+                self.loan_id.residual_amount
+            )
+            self.payment_amount = self.currency_id.round(self.compute_amount())
+        elif not self.loan_id.round_on_end:
+            self.interests_amount = self.currency_id.round(
+                self.pending_principal_amount * self.loan_id.loan_rate() / 100)
             self.payment_amount = self.currency_id.round(self.compute_amount())
         else:
             self.interests_amount = (
-                self.pending_principal_amount * self.rate / 100)
+                self.pending_principal_amount * self.loan_id.loan_rate() / 100)
             self.payment_amount = self.compute_amount()
 
     @api.multi
diff --git a/account_loan/tests/test_loan.py b/account_loan/tests/test_loan.py
index d018e991..e05e69a4 100644
--- a/account_loan/tests/test_loan.py
+++ b/account_loan/tests/test_loan.py
@@ -92,9 +92,9 @@ class TestLoan(TransactionCase):
         loan.round_on_end = True
         loan.compute_lines()
         line_1 = loan.line_ids.filtered(lambda r: r.sequence == 1)
-        line_end = loan.line_ids.filtered(lambda r: r.sequence == 60)
-        self.assertNotAlmostEqual(
-            line_1.payment_amount, line_end.payment_amount, 2)
+        for line in loan.line_ids:
+            self.assertAlmostEqual(
+                line_1.payment_amount, line.payment_amount, 2)
         loan.loan_type = 'fixed-principal'
         loan.compute_lines()
         line_1 = loan.line_ids.filtered(lambda r: r.sequence == 1)