refactor contract handling to support single route per contract and improve reference generation logic

apps/edr-freight-api/src/modules/contracts/contracts.repository.ts

@@ -45,16 +45,23 @@ export class ContractsRepository extends BaseRepository<Contract> {
     return this.repository.findOne({ where: { reference } });
   }
 
-  /** Count contracts created in a specific year. */
-  async countByYear(year: number): Promise<number> {
-    const startDate = new Date(year, 0, 1);
-    const endDate = new Date(year + 1, 0, 1);
-
-    return this.repository
+  /**
+   * Highest NNNNN sequence already issued for `CTR-<year>-…` references.
+   * Includes soft-deleted contracts — their references still occupy the unique
+   * index, so the next number must move past them. (A created-at count drifts
+   * below the issued sequence after any delete and then collides forever.)
+   */
+  async maxReferenceSequence(year: number): Promise<number> {
+    const row = await this.repository
       .createQueryBuilder('contract')
-      .where('contract.created_at >= :startDate', { startDate })
-      .andWhere('contract.created_at < :endDate', { endDate })
-      .getCount();
+      .withDeleted()
+      .select(
+        "COALESCE(MAX(CAST(SUBSTRING(contract.reference FROM '[0-9]+$') AS int)), 0)",
+        'max',
+      )
+      .where('contract.reference LIKE :prefix', { prefix: `CTR-${year}-%` })
+      .getRawOne<{ max: string | number | null }>();
+    return Number(row?.max ?? 0);
   }
 
   /** Find a contract by ID with all child collections, service type, company and files. */