letter rates go up by 5p as of 1st october 2019

migrations/versions/0306_letter_rates_price_rise.py

@@ -0,0 +1,70 @@
+"""
+All prices going up 5p
+
+1 sheet (double-sided) increases from 30p to 35p (plus VAT)
+2 sheets (double-sided) increases from 35p to 40p (plus VAT)
+3 sheets (double-sided) increases from 40p to 45p (plus VAT)
+4 sheets (double-sided) increases from 45p to 50p (plus VAT)
+5 sheets (double-sided) increases from 50p to 55p (plus VAT)
+First class letters:
+
+1 sheet (double-sided) increases from 56p to 61p (plus VAT)
+2 sheets (double-sided) increases from 61p to 66p (plus VAT)
+3 sheets (double-sided) increases from 66p to 71p (plus VAT)
+4 sheets (double-sided) increases from 71p to 76p (plus VAT)
+5 sheets (double-sided) increases from 76p to 81p (plus VAT)
+
+Revision ID: 0306_letter_rates_price_rise
+Revises: 0305_add_gp_org_type
+Create Date: 2019-09-25 15:43:09.388251
+
+"""
+import itertools
+import uuid
+from datetime import datetime
+
+from alembic import op
+from sqlalchemy.sql import text
+
+from app.models import LetterRate
+
+
+revision = '0306_letter_rates_price_rise'
+down_revision = '0305_add_gp_org_type'
+
+
+CHANGEOVER_DATE = datetime(2019, 9, 30, 23, 0)
+
+
+def upgrade():
+    # all old rates are going in the bin
+    conn = op.get_bind()
+    conn.execute(text("UPDATE letter_rates SET end_date = :start WHERE end_date IS NULL"), start=CHANGEOVER_DATE)
+
+    base_prices = {
+        'second': 30,
+        'first': 56,
+    }
+    op.bulk_insert(LetterRate.__table__, [
+        {
+            'id': uuid.uuid4(),
+            'start_date': CHANGEOVER_DATE,
+            'end_date': None,
+            'sheet_count': sheet_count,
+            'rate': (base_prices[post_class] + (5 * sheet_count)) / 100.0,
+            'crown': crown,
+            'post_class': post_class,
+        }
+        for sheet_count, crown, post_class in itertools.product(
+            range(1, 6),
+            [True, False],
+            ['first', 'second']
+        )
+    ])
+
+
+def downgrade():
+    # Make sure you've thought about billing implications etc before downgrading!
+    conn = op.get_bind()
+    conn.execute(text("DELETE FROM letter_rates WHERE start_date = :start"), start=CHANGEOVER_DATE)
+    conn.execute(text("UPDATE letter_rates SET end_date = NULL WHERE end_date = :start"), start=CHANGEOVER_DATE)