/**
 * Migration: Add soft delete mechanism to all tables
 *
 * Fixes: Most tables use CASCADE delete with no way to recover deleted data
 *
 * @type {import('node-pg-migrate').ColumnDefinitions | undefined}
 */
export const shorthands = undefined;

/**
 * All tables that need soft delete support
 */
const TABLES_WITH_SOFT_DELETE = [
  'user_profiles',
  'user_identities',
  'devices',
  'inventory_devices',
  'raw_events',
  'validated_events',
  'analysis_results',
  'weather_stations',
  'weather_observations',
  'weather_forecasts',
  'camera_devices',
  'subscription_plans',
  'user_subscriptions',
  'subscription_history',
  'payment_records',
  'device_configurations',
  'device_certificates',
  'device_security_events',
  'device_registrations',
];

/**
 * @param pgm {import('node-pg-migrate').MigrationBuilder}
 * @param run {() => void | undefined}
 * @returns {Promise<void> | void}
 */
export const up = (pgm) => {
  console.log('Adding soft delete columns to all tables...');

  // Add deleted_at column to all tables
  TABLES_WITH_SOFT_DELETE.forEach((table) => {
    console.log(`  Adding deleted_at to ${table}...`);

    pgm.addColumn(table, {
      deleted_at: {
        type: 'timestamptz',
        notNull: false,
        comment: 'Soft delete timestamp. NULL = not deleted.',
      },
    });

    // Create partial index for efficient filtering of non-deleted records
    pgm.createIndex(table, 'deleted_at', {
      name: `idx_${table}_deleted_at`,
      where: 'deleted_at IS NULL',
    });
  });

  // Create a helper function for soft delete operations
  pgm.sql(`
    -- Function to soft delete a record
    CREATE OR REPLACE FUNCTION soft_delete()
    RETURNS TRIGGER AS $$
    BEGIN
      NEW.deleted_at = CURRENT_TIMESTAMP;
      RETURN NEW;
    END;
    $$ LANGUAGE plpgsql;

    -- Function to check if record is deleted
    CREATE OR REPLACE FUNCTION is_deleted(deleted_at TIMESTAMPTZ)
    RETURNS BOOLEAN AS $$
    BEGIN
      RETURN deleted_at IS NOT NULL;
    END;
    $$ LANGUAGE plpgsql IMMUTABLE;

    -- Function to restore a soft-deleted record
    CREATE OR REPLACE FUNCTION restore_deleted()
    RETURNS TRIGGER AS $$
    BEGIN
      NEW.deleted_at = NULL;
      RETURN NEW;
    END;
    $$ LANGUAGE plpgsql;
  `);

  console.log('Soft delete columns added to all tables successfully.');
};

/**
 * @param pgm {import('node-pg-migrate').MigrationBuilder}
 * @param run {() => void | undefined}
 * @returns {Promise<void> | void}
 */
export const down = (pgm) => {
  console.log('Removing soft delete columns from all tables...');

  // Drop helper functions
  pgm.sql(`
    DROP FUNCTION IF EXISTS soft_delete() CASCADE;
    DROP FUNCTION IF EXISTS is_deleted(TIMESTAMPTZ) CASCADE;
    DROP FUNCTION IF EXISTS restore_deleted() CASCADE;
  `);

  // Remove deleted_at from all tables in reverse order
  [...TABLES_WITH_SOFT_DELETE].reverse().forEach((table) => {
    console.log(`  Removing deleted_at from ${table}...`);

    // Drop index first
    pgm.dropIndex(table, 'deleted_at', {
      name: `idx_${table}_deleted_at`,
      ifExists: true,
    });

    // Drop column
    pgm.dropColumn(table, 'deleted_at', {
      ifExists: true,
    });
  });

  console.log('Soft delete columns removed from all tables.');
};