-- Migration 011: Add billing frequency support to invoices
-- Adds due_months and due_day to assessment_groups
-- Adds period_start, period_end, assessment_group_id to invoices

DO $$
DECLARE
  v_schema TEXT;
BEGIN
  FOR v_schema IN
    SELECT schema_name FROM information_schema.schemata
    WHERE schema_name LIKE 'tenant_%'
  LOOP
    -- Add due_months and due_day to assessment_groups
    EXECUTE format('
      ALTER TABLE %I.assessment_groups
        ADD COLUMN IF NOT EXISTS due_months INTEGER[] DEFAULT ''{1,2,3,4,5,6,7,8,9,10,11,12}'',
        ADD COLUMN IF NOT EXISTS due_day INTEGER DEFAULT 1
    ', v_schema);

    -- Add period tracking and assessment group link to invoices
    EXECUTE format('
      ALTER TABLE %I.invoices
        ADD COLUMN IF NOT EXISTS period_start DATE,
        ADD COLUMN IF NOT EXISTS period_end DATE,
        ADD COLUMN IF NOT EXISTS assessment_group_id UUID
    ', v_schema);

    -- Backfill due_months based on existing frequency values
    EXECUTE format('
      UPDATE %I.assessment_groups
      SET due_months = CASE frequency
        WHEN ''quarterly'' THEN ''{1,4,7,10}''::INTEGER[]
        WHEN ''annual'' THEN ''{1}''::INTEGER[]
        ELSE ''{1,2,3,4,5,6,7,8,9,10,11,12}''::INTEGER[]
      END
      WHERE due_months IS NULL OR due_months = ''{1,2,3,4,5,6,7,8,9,10,11,12}''
        AND frequency != ''monthly''
    ', v_schema);

    -- Backfill period_start/period_end for existing invoices (all monthly)
    EXECUTE format('
      UPDATE %I.invoices
      SET period_start = invoice_date,
          period_end = (invoice_date + INTERVAL ''1 month'' - INTERVAL ''1 day'')::DATE
      WHERE period_start IS NULL AND invoice_type = ''regular_assessment''
    ', v_schema);

    -- Backfill assessment_group_id on existing invoices from units
    EXECUTE format('
      UPDATE %I.invoices i
      SET assessment_group_id = u.assessment_group_id
      FROM %I.units u
      WHERE i.unit_id = u.id AND i.assessment_group_id IS NULL
    ', v_schema, v_schema);

  END LOOP;
END $$;