Initial schema iteration

db/migrate/20250719121103_add_start_end_columns_to_balances.rb

@@ -0,0 +1,158 @@
+class AddStartEndColumnsToBalances < ActiveRecord::Migration[7.2]
+  def up
+    # Rename existing columns to deprecated versions
+    # rename_column :balances, :balance, :balance_deprecated
+    # rename_column :balances, :cash_balance, :cash_balance_deprecated
+
+    # Add new columns for balance tracking
+    add_column :balances, :start_cash_balance, :decimal, precision: 19, scale: 4, null: false, default: 0.0
+    add_column :balances, :start_non_cash_balance, :decimal, precision: 19, scale: 4, null: false, default: 0.0
+
+    # Flow tracking columns (absolute values)
+    add_column :balances, :cash_inflows, :decimal, precision: 19, scale: 4, null: false, default: 0.0
+    add_column :balances, :cash_outflows, :decimal, precision: 19, scale: 4, null: false, default: 0.0
+    add_column :balances, :non_cash_inflows, :decimal, precision: 19, scale: 4, null: false, default: 0.0
+    add_column :balances, :non_cash_outflows, :decimal, precision: 19, scale: 4, null: false, default: 0.0
+
+    # Market value changes
+    add_column :balances, :net_market_flows, :decimal, precision: 19, scale: 4, null: false, default: 0.0
+
+    # Manual adjustments from valuations
+    add_column :balances, :cash_adjustments, :decimal, precision: 19, scale: 4, null: false, default: 0.0
+    add_column :balances, :non_cash_adjustments, :decimal, precision: 19, scale: 4, null: false, default: 0.0
+
+    # Add generated columns
+    change_table :balances do |t|
+      t.virtual :start_balance, type: :decimal, precision: 19, scale: 4, stored: true,
+        as: "start_cash_balance + start_non_cash_balance"
+
+      t.virtual :end_cash_balance, type: :decimal, precision: 19, scale: 4, stored: true,
+        as: "start_cash_balance + cash_inflows - cash_outflows + cash_adjustments"
+
+      t.virtual :end_non_cash_balance, type: :decimal, precision: 19, scale: 4, stored: true,
+        as: "start_non_cash_balance + non_cash_inflows - non_cash_outflows + net_market_flows + non_cash_adjustments"
+
+      # Postgres doesn't support generated columns depending on other generated columns,
+      # but we want the integrity of the data to happen at the DB level, so this is the full formula.
+      # Formula: (cash components) + (non-cash components)
+      t.virtual :end_balance, type: :decimal, precision: 19, scale: 4, stored: true,
+        as: <<~SQL.squish
+          (
+            start_cash_balance +
+            cash_inflows -
+            cash_outflows +
+            cash_adjustments
+          ) + (
+            start_non_cash_balance +
+            non_cash_inflows -
+            non_cash_outflows +
+            net_market_flows +
+            non_cash_adjustments
+          )
+        SQL
+    end
+
+    # Migrate existing data
+
+    # Step 1: Set start values using LOCF (Last Observation Carried Forward)
+    execute <<~SQL
+      UPDATE balances b1
+      SET
+        start_cash_balance = COALESCE(prev.cash_balance, 0),
+        start_non_cash_balance = COALESCE(prev.balance - prev.cash_balance, 0)
+      FROM balances b1_inner
+      LEFT JOIN LATERAL (
+        SELECT
+          b2.cash_balance,
+          b2.balance
+        FROM balances b2
+        WHERE b2.account_id = b1_inner.account_id
+        AND b2.currency = b1_inner.currency
+        AND b2.date < b1_inner.date
+        ORDER BY b2.date DESC
+        LIMIT 1
+      ) prev ON true
+      WHERE b1.id = b1_inner.id
+    SQL
+
+    # Step 2: Calculate net flows as inflows (can be negative)
+    # We use net change as inflows, outflows stay 0 for historical data
+    execute <<~SQL
+      UPDATE balances SET
+        cash_inflows = cash_balance - start_cash_balance,
+        cash_outflows = 0,
+        non_cash_inflows = (balance - cash_balance) - start_non_cash_balance,
+        non_cash_outflows = 0,
+        net_market_flows = 0
+    SQL
+
+    # Step 3: Initialize adjustments to 0
+    execute <<~SQL
+      UPDATE balances SET
+        cash_adjustments = 0,
+        non_cash_adjustments = 0
+    SQL
+
+    # Step 4: Calculate adjustments from valuation entries
+    execute <<~SQL
+      WITH valuation_data AS (
+        SELECT#{' '}
+          e.account_id,
+          e.date,
+          e.amount as valuation_amount,
+          e.currency,
+          a.accountable_type
+        FROM entries e
+        JOIN accounts a ON a.id = e.account_id
+        WHERE e.entryable_type = 'Valuation'
+      )
+      UPDATE balances b
+      SET
+        cash_adjustments = CASE
+          -- For investment accounts: valuation sets total, preserve holdings value
+          WHEN vd.accountable_type = 'Investment' THEN
+            vd.valuation_amount - (b.start_balance + b.cash_inflows + b.non_cash_inflows)
+          -- For loan accounts: adjustment goes to non-cash
+          WHEN vd.accountable_type = 'Loan' THEN
+            0
+          -- For all other accounts: adjustment goes to cash
+          ELSE
+            vd.valuation_amount - (b.start_balance + b.cash_inflows + b.non_cash_inflows)
+        END,
+        non_cash_adjustments = CASE
+          -- Only loan accounts get non-cash adjustments
+          WHEN vd.accountable_type = 'Loan' THEN
+            vd.valuation_amount - (b.start_balance + b.cash_inflows + b.non_cash_inflows)
+        ELSE
+          0
+        END
+      FROM valuation_data vd
+      WHERE b.account_id = vd.account_id
+      AND b.date = vd.date
+      AND b.currency = vd.currency
+    SQL
+  end
+
+  def down
+    # Remove generated columns first (PostgreSQL requirement)
+    remove_column :balances, :start_balance
+    remove_column :balances, :end_cash_balance
+    remove_column :balances, :end_non_cash_balance
+    remove_column :balances, :end_balance
+
+    # Remove new columns
+    remove_column :balances, :start_cash_balance
+    remove_column :balances, :start_non_cash_balance
+    remove_column :balances, :cash_inflows
+    remove_column :balances, :cash_outflows
+    remove_column :balances, :non_cash_inflows
+    remove_column :balances, :non_cash_outflows
+    remove_column :balances, :net_market_flows
+    remove_column :balances, :cash_adjustments
+    remove_column :balances, :non_cash_adjustments
+
+    # Restore original column names
+    # rename_column :balances, :balance_deprecated, :balance
+    # rename_column :balances, :cash_balance_deprecated, :cash_balance
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.2].define(version: 2025_07_18_120146) do
+ActiveRecord::Schema[7.2].define(version: 2025_07_19_121103) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pgcrypto"
   enable_extension "plpgsql"
@@ -115,6 +115,19 @@ ActiveRecord::Schema[7.2].define(version: 2025_07_18_120146) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.decimal "cash_balance", precision: 19, scale: 4, default: "0.0"
+    t.decimal "start_cash_balance", precision: 19, scale: 4, default: "0.0", null: false
+    t.decimal "start_non_cash_balance", precision: 19, scale: 4, default: "0.0", null: false
+    t.decimal "cash_inflows", precision: 19, scale: 4, default: "0.0", null: false
+    t.decimal "cash_outflows", precision: 19, scale: 4, default: "0.0", null: false
+    t.decimal "non_cash_inflows", precision: 19, scale: 4, default: "0.0", null: false
+    t.decimal "non_cash_outflows", precision: 19, scale: 4, default: "0.0", null: false
+    t.decimal "net_market_flows", precision: 19, scale: 4, default: "0.0", null: false
+    t.decimal "cash_adjustments", precision: 19, scale: 4, default: "0.0", null: false
+    t.decimal "non_cash_adjustments", precision: 19, scale: 4, default: "0.0", null: false
+    t.virtual "start_balance", type: :decimal, precision: 19, scale: 4, as: "(start_cash_balance + start_non_cash_balance)", stored: true
+    t.virtual "end_cash_balance", type: :decimal, precision: 19, scale: 4, as: "(((start_cash_balance + cash_inflows) - cash_outflows) + cash_adjustments)", stored: true
+    t.virtual "end_non_cash_balance", type: :decimal, precision: 19, scale: 4, as: "((((start_non_cash_balance + non_cash_inflows) - non_cash_outflows) + net_market_flows) + non_cash_adjustments)", stored: true
+    t.virtual "end_balance", type: :decimal, precision: 19, scale: 4, as: "((((start_cash_balance + cash_inflows) - cash_outflows) + cash_adjustments) + ((((start_non_cash_balance + non_cash_inflows) - non_cash_outflows) + net_market_flows) + non_cash_adjustments))", stored: true
     t.index ["account_id", "date", "currency"], name: "index_account_balances_on_account_id_date_currency_unique", unique: true
     t.index ["account_id", "date"], name: "index_balances_on_account_id_and_date", order: { date: :desc }
     t.index ["account_id"], name: "index_balances_on_account_id"