Add a new data model LETTER_BRANDING to store the letters. Add a new data model SERVICE_LETTER_BRANDING to map the service to the letter brand.

This will replace services.dvla_organisation_id and dvla_organisation.

app/models.py

@@ -249,6 +249,23 @@ class DVLAOrganisation(db.Model):
     filename = db.Column(db.String(255), nullable=False)
 
 
+class LetterBranding(db.Model):
+    __tablename__ = 'letter_branding'
+    id = db.Column(UUID(as_uuid=True), primary_key=True)
+    name = db.Column(db.String(255), unique=True, nullable=False)
+    filename = db.Column(db.String(255), unique=True, nullable=False)
+    domain = db.Column(db.Text, unique=True, nullable=True)
+
+
+service_letter_branding = db.Table(
+    'service_letter_branding',
+    db.Model.metadata,
+    # service_id is a primary key as you can only have one letter branding per service
+    db.Column('service_id', UUID(as_uuid=True), db.ForeignKey('services.id'), primary_key=True, nullable=False),
+    db.Column('letter_branding_id', UUID(as_uuid=True), db.ForeignKey('letter_branding.id'), nullable=False),
+)
+
+
 INTERNATIONAL_SMS_TYPE = 'international_sms'
 INBOUND_SMS_TYPE = 'inbound_sms'
 SCHEDULE_NOTIFICATIONS = 'schedule_notifications'

migrations/versions/0251_letter_branding_table.py

@@ -0,0 +1,52 @@
+"""
+
+Revision ID: 0251_letter_branding_table
+Revises: 0250_drop_stats_template_table
+Create Date: 2019-01-17 15:45:33.242955
+
+"""
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+revision = '0251_letter_branding_table'
+down_revision = '0250_drop_stats_template_table'
+
+
+def upgrade():
+    op.create_table('letter_branding',
+                    sa.Column('id', postgresql.UUID(as_uuid=True), nullable=False),
+                    sa.Column('name', sa.String(length=255), nullable=False),
+                    sa.Column('filename', sa.String(length=255), nullable=False),
+                    sa.Column('domain', sa.Text(), nullable=True),
+                    sa.PrimaryKeyConstraint('id'),
+                    sa.UniqueConstraint('domain'),
+                    sa.UniqueConstraint('filename'),
+                    sa.UniqueConstraint('name')
+                    )
+    op.create_table('service_letter_branding',
+                    sa.Column('service_id', postgresql.UUID(as_uuid=True), nullable=False),
+                    sa.Column('letter_branding_id', postgresql.UUID(as_uuid=True), nullable=False),
+                    sa.ForeignKeyConstraint(['letter_branding_id'], ['letter_branding.id'], ),
+                    sa.ForeignKeyConstraint(['service_id'], ['services.id'], ),
+                    sa.PrimaryKeyConstraint('service_id')
+                    )
+
+    op.get_bind()
+
+    op.execute("""INSERT INTO letter_branding (id, name, filename, domain)
+                SELECT uuid_in(md5(random()::text)::cstring), name, filename, null 
+                from dvla_organisation""")
+
+    op.execute("""INSERT INTO service_letter_branding (service_id, letter_branding_id)
+               SELECT S.id, LB.id
+                 FROM services s
+                 JOIN dvla_organisation d on (s.dvla_organisation_id = d.id)
+                 JOIN letter_branding lb on (lb.filename = d.filename)
+                 """)
+
+
+def downgrade():
+    op.drop_table('service_letter_branding')
+    op.drop_table('letter_branding')