import { db } from '../../lib/db';
import { policySettings } from '../../lib/db/schema/policySettings';
import type { NewPolicySetting } from '../../lib/db/schema/policySettings';
import type { FlattenedSetting } from './policyParser';
import logger from '../logging';

/**
 * Upsert policy settings to database with conflict resolution
 */
export async function upsertPolicySettings(
  tenantId: string,
  settings: FlattenedSetting[]
): Promise<{ inserted: number; updated: number }> {
  if (settings.length === 0) {
    logger.info({ event: 'dbUpsert:skip', reason: 'no settings to upsert' });
    return { inserted: 0, updated: 0 };
  }

  const now = new Date();
  
  // Convert to database insert format
  const records: NewPolicySetting[] = settings.map((setting) => ({
    tenantId,
    policyName: setting.policyName,
    policyType: setting.policyType,
    settingName: setting.settingName,
    settingValue: setting.settingValue,
    graphPolicyId: setting.graphPolicyId,
    lastSyncedAt: now,
  }));

  try {
    // Batch upsert with conflict resolution
    // Uses the unique constraint: (tenantId, graphPolicyId, settingName)
    const result = await db
      .insert(policySettings)
      .values(records)
      .onConflictDoUpdate({
        target: [
          policySettings.tenantId,
          policySettings.graphPolicyId,
          policySettings.settingName,
        ],
        set: {
          policyName: policySettings.policyName,
          policyType: policySettings.policyType,
          settingValue: policySettings.settingValue,
          lastSyncedAt: now,
        },
      });

    // Drizzle doesn't return row counts in all cases, so we estimate
    const total = records.length;
    logger.info({ 
      event: 'dbUpsert:success', 
      total, 
      tenantId,
      policies: [...new Set(settings.map(s => s.graphPolicyId))].length
    });

    return { inserted: total, updated: 0 };
  } catch (error) {
    logger.error({ 
      event: 'dbUpsert:error', 
      error: error instanceof Error ? error.message : String(error),
      tenantId,
      settingsCount: settings.length
    });
    throw error;
  }
}

export default upsertPolicySettings;