From bdf8e4441a9486d7ab40e75d07d5c5749820f0b8 Mon Sep 17 00:00:00 2001
From: Sylvain Calador <sylvain.calador@akretion.com>
Date: Wed, 1 Apr 2015 11:12:02 +0200
Subject: [PATCH] [IMP] Module constraint install and uninstall

---
 pos_product_category/README.rst  |  7 ++++
 pos_product_category/__init__.py |  1 +
 pos_product_category/module.py   | 59 ++++++++++++++++++++++++++++++++
 pos_product_category/product.py  | 11 +++++-
 4 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 pos_product_category/module.py

diff --git a/pos_product_category/README.rst b/pos_product_category/README.rst
index a0380b6d..83fe6d6a 100644
--- a/pos_product_category/README.rst
+++ b/pos_product_category/README.rst
@@ -6,6 +6,13 @@ POS Product Category
 
 This module was written to replace POS categories by product categories.
 
+Important notes:
+- When the module is installed the link beetween products and POS categories
+  is **overwritten** by a link beetween product categories
+  (the link is the field pos_categ_id in the table product_template)
+- When the module is uninstalled the link beetween products and POS categories
+  is restored in an **empty** state (NULL values)
+
 Installation
 ============
 
diff --git a/pos_product_category/__init__.py b/pos_product_category/__init__.py
index 468e5ccb..5f45a17f 100644
--- a/pos_product_category/__init__.py
+++ b/pos_product_category/__init__.py
@@ -20,3 +20,4 @@
 ##############################################################################
 
 from . import product
+from . import module
diff --git a/pos_product_category/module.py b/pos_product_category/module.py
new file mode 100644
index 00000000..bcabab40
--- /dev/null
+++ b/pos_product_category/module.py
@@ -0,0 +1,59 @@
+# -*- coding: utf-8 -*-
+##############################################################################
+#
+#    OpenERP, Open Source Management Solution
+#    Copyright (C) 2015-TODAY Akretion (<http://www.akretion.com>).
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU Affero 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 Affero General Public License for more details.
+#
+#    You should have received a copy of the GNU Affero General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+##############################################################################
+
+from openerp import models
+
+
+class Module(models.Model):
+
+    _inherit = 'ir.module.module'
+
+    def module_uninstall(self, cr, uid, ids, context=None):
+
+        context = context or {}
+
+        for module in self.browse(cr, uid, ids, context=context):
+            if module.name == 'pos_product_category':
+
+                # As we have loose previous POS categs restore them
+                # in a sane empty state
+
+                cr.execute('UPDATE product_template SET pos_categ_id=NULL')
+
+                # And restore original constraint
+                cr.execute('''
+                    ALTER TABLE product_template
+                    DROP CONSTRAINT IF EXISTS
+                    product_template_pos_categ_id_fkey
+                ''')
+
+                cr.execute('''
+                    ALTER TABLE product_template ADD CONSTRAINT
+                    "product_template_pos_categ_id_fkey"
+                    FOREIGN KEY (pos_categ_id)
+                    REFERENCES pos_category(id) ON DELETE SET NULL;
+                ''')
+
+                break
+
+        return super(Module, self).module_uninstall(
+            cr, uid, ids, context=context
+        )
diff --git a/pos_product_category/product.py b/pos_product_category/product.py
index f660d9e4..4e0cd4cb 100644
--- a/pos_product_category/product.py
+++ b/pos_product_category/product.py
@@ -19,6 +19,7 @@
 #
 ##############################################################################
 
+import sys
 from openerp import models, fields, api
 
 
@@ -50,8 +51,10 @@ def _auto_end(self, cr, context=None):
     context = context or {}
     module = context['module']
     foreign_keys = []
+    patched = 'openerp.addons.pos_product_category' in sys.modules
+
     for t, k, r, d in self._foreign_keys:
-        if (t, k) == ('product_template', 'pos_categ_id'):
+        if patched and (t, k) == ('product_template', 'pos_categ_id'):
             if module == 'pos_product_category':
                 cr.execute('''
                     ALTER TABLE product_template
@@ -62,6 +65,12 @@ def _auto_end(self, cr, context=None):
                     UPDATE product_template
                     SET pos_categ_id = categ_id;
                 ''')
+                cr.execute('''
+                    ALTER TABLE product_template ADD CONSTRAINT
+                    "product_template_pos_categ_id_fkey"
+                    FOREIGN KEY (pos_categ_id)
+                    REFERENCES product_category(id) ON DELETE SET NULL;
+                ''')
             continue
         foreign_keys.append((t, k, r, d))
     self._foreign_keys = foreign_keys