Initial commit: HOA Financial Intelligence Platform MVP

Multi-tenant financial management platform for homeowner associations featuring:
- NestJS backend with 16 modules (auth, accounts, transactions, budgets, units,
  invoices, payments, vendors, reserves, investments, capital projects, reports)
- React + Mantine frontend with dashboard, CRUD pages, and financial reports
- Schema-per-tenant PostgreSQL isolation with JWT-based tenant resolution
- Docker Compose infrastructure (nginx, backend, frontend, postgres, redis)
- Comprehensive seed data for Sunrise Valley HOA demo
- 39 API endpoints with Swagger documentation
- Double-entry bookkeeping with journal entries
- Budget vs actual reporting and Sankey cash flow visualization

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/src/modules/accounts/accounts.service.ts

@@ -0,0 +1,107 @@
+import { Injectable, NotFoundException, BadRequestException } from '@nestjs/common';
+import { TenantService } from '../../database/tenant.service';
+import { CreateAccountDto } from './dto/create-account.dto';
+import { UpdateAccountDto } from './dto/update-account.dto';
+
+@Injectable()
+export class AccountsService {
+  constructor(private tenant: TenantService) {}
+
+  async findAll(fundType?: string) {
+    let sql = 'SELECT * FROM accounts WHERE is_active = true';
+    const params: any[] = [];
+    if (fundType) {
+      sql += ' AND fund_type = $1';
+      params.push(fundType);
+    }
+    sql += ' ORDER BY account_number';
+    return this.tenant.query(sql, params);
+  }
+
+  async findOne(id: string) {
+    const rows = await this.tenant.query('SELECT * FROM accounts WHERE id = $1', [id]);
+    if (!rows.length) throw new NotFoundException('Account not found');
+    return rows[0];
+  }
+
+  async create(dto: CreateAccountDto) {
+    const existing = await this.tenant.query(
+      'SELECT id FROM accounts WHERE account_number = $1',
+      [dto.accountNumber],
+    );
+    if (existing.length) {
+      throw new BadRequestException(`Account number ${dto.accountNumber} already exists`);
+    }
+
+    const rows = await this.tenant.query(
+      `INSERT INTO accounts (account_number, name, description, account_type, fund_type, parent_account_id, is_1099_reportable)
+       VALUES ($1, $2, $3, $4, $5, $6, $7)
+       RETURNING *`,
+      [
+        dto.accountNumber,
+        dto.name,
+        dto.description || null,
+        dto.accountType,
+        dto.fundType,
+        dto.parentAccountId || null,
+        dto.is1099Reportable || false,
+      ],
+    );
+    return rows[0];
+  }
+
+  async update(id: string, dto: UpdateAccountDto) {
+    const account = await this.findOne(id);
+    if (account.is_system && dto.accountType && dto.accountType !== account.account_type) {
+      throw new BadRequestException('Cannot change type of system account');
+    }
+
+    const sets: string[] = [];
+    const params: any[] = [];
+    let idx = 1;
+
+    if (dto.name !== undefined) { sets.push(`name = $${idx++}`); params.push(dto.name); }
+    if (dto.description !== undefined) { sets.push(`description = $${idx++}`); params.push(dto.description); }
+    if (dto.is1099Reportable !== undefined) { sets.push(`is_1099_reportable = $${idx++}`); params.push(dto.is1099Reportable); }
+    if (dto.isActive !== undefined) { sets.push(`is_active = $${idx++}`); params.push(dto.isActive); }
+
+    if (!sets.length) return account;
+
+    sets.push(`updated_at = NOW()`);
+    params.push(id);
+
+    const rows = await this.tenant.query(
+      `UPDATE accounts SET ${sets.join(', ')} WHERE id = $${idx} RETURNING *`,
+      params,
+    );
+    return rows[0];
+  }
+
+  async getTrialBalance(asOfDate?: string) {
+    const dateFilter = asOfDate
+      ? `AND je.entry_date <= $1`
+      : '';
+    const params = asOfDate ? [asOfDate] : [];
+
+    const sql = `
+      SELECT
+        a.id, a.account_number, a.name, a.account_type, a.fund_type,
+        COALESCE(SUM(jel.debit), 0) as total_debits,
+        COALESCE(SUM(jel.credit), 0) as total_credits,
+        CASE
+          WHEN a.account_type IN ('asset', 'expense')
+            THEN COALESCE(SUM(jel.debit), 0) - COALESCE(SUM(jel.credit), 0)
+          ELSE COALESCE(SUM(jel.credit), 0) - COALESCE(SUM(jel.debit), 0)
+        END as balance
+      FROM accounts a
+      LEFT JOIN journal_entry_lines jel ON jel.account_id = a.id
+      LEFT JOIN journal_entries je ON je.id = jel.journal_entry_id
+        AND je.is_posted = true AND je.is_void = false
+        ${dateFilter}
+      WHERE a.is_active = true
+      GROUP BY a.id, a.account_number, a.name, a.account_type, a.fund_type
+      ORDER BY a.account_number
+    `;
+    return this.tenant.query(sql, params);
+  }
+}