feat: creates backend for the project

backend/src/db/migrate.ts

@@ -0,0 +1,142 @@
+import { pool } from './pool';
+
+const migrations: { name: string; sql: string }[] = [
+  {
+    name: '001_create_tables',
+    sql: `
+      CREATE TABLE IF NOT EXISTS accounts (
+        id             BIGSERIAL PRIMARY KEY,
+        bank           TEXT NOT NULL,
+        account_number TEXT NOT NULL,
+        currency       TEXT NOT NULL,
+        alias          TEXT
+      );
+      CREATE UNIQUE INDEX IF NOT EXISTS ux_accounts_bank_number
+        ON accounts(bank, account_number);
+
+      CREATE TABLE IF NOT EXISTS categories (
+        id        BIGSERIAL PRIMARY KEY,
+        name      TEXT NOT NULL,
+        type      TEXT NOT NULL,
+        is_active BOOLEAN NOT NULL DEFAULT TRUE
+      );
+      ALTER TABLE categories DROP CONSTRAINT IF EXISTS chk_categories_type;
+      ALTER TABLE categories
+        ADD CONSTRAINT chk_categories_type
+        CHECK (type IN ('expense', 'income', 'transfer'));
+
+      CREATE TABLE IF NOT EXISTS transactions (
+        id                     BIGSERIAL PRIMARY KEY,
+        account_id             BIGINT NOT NULL REFERENCES accounts(id),
+        operation_at           TIMESTAMPTZ NOT NULL,
+        amount_signed          BIGINT NOT NULL,
+        commission             BIGINT NOT NULL,
+        description            TEXT NOT NULL,
+        direction              TEXT NOT NULL,
+        fingerprint            TEXT NOT NULL,
+        category_id            BIGINT REFERENCES categories(id),
+        is_category_confirmed  BOOLEAN NOT NULL DEFAULT FALSE,
+        comment                TEXT,
+        created_at             TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+        updated_at             TIMESTAMPTZ NOT NULL DEFAULT NOW()
+      );
+      CREATE UNIQUE INDEX IF NOT EXISTS ux_transactions_account_fingerprint
+        ON transactions(account_id, fingerprint);
+      ALTER TABLE transactions DROP CONSTRAINT IF EXISTS chk_transactions_direction;
+      ALTER TABLE transactions
+        ADD CONSTRAINT chk_transactions_direction
+        CHECK (direction IN ('income', 'expense', 'transfer'));
+
+      CREATE TABLE IF NOT EXISTS category_rules (
+        id                     BIGSERIAL PRIMARY KEY,
+        pattern                TEXT NOT NULL,
+        match_type             TEXT NOT NULL,
+        category_id            BIGINT NOT NULL REFERENCES categories(id),
+        priority               INT NOT NULL DEFAULT 0,
+        requires_confirmation  BOOLEAN NOT NULL DEFAULT FALSE,
+        is_active              BOOLEAN NOT NULL DEFAULT TRUE,
+        created_at             TIMESTAMPTZ NOT NULL DEFAULT NOW()
+      );
+
+      CREATE TABLE IF NOT EXISTS sessions (
+        id               TEXT PRIMARY KEY,
+        created_at       TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+        last_activity_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+        is_active        BOOLEAN NOT NULL DEFAULT TRUE
+      );
+    `,
+  },
+  {
+    name: '002_seed_categories',
+    sql: `
+      INSERT INTO categories (name, type) VALUES
+        ('Продукты',     'expense'),
+        ('Авто',         'expense'),
+        ('Здоровье',     'expense'),
+        ('Арчи',         'expense'),
+        ('ЖКХ',          'expense'),
+        ('Дом',          'expense'),
+        ('Проезд',       'expense'),
+        ('Одежда',       'expense'),
+        ('Химия',        'expense'),
+        ('Косметика',    'expense'),
+        ('Инвестиции',   'transfer'),
+        ('Развлечения',  'expense'),
+        ('Общепит',      'expense'),
+        ('Штрафы',       'expense'),
+        ('Налоги',       'expense'),
+        ('Подписки',     'expense'),
+        ('Перевод',      'transfer'),
+        ('Наличные',     'expense'),
+        ('Подарки',      'expense'),
+        ('Спорт',        'expense'),
+        ('Отпуск',       'expense'),
+        ('Техника',      'expense'),
+        ('Поступления',  'income')
+      ON CONFLICT DO NOTHING;
+    `,
+  },
+];
+
+export async function runMigrations(): Promise<void> {
+  await pool.query(`
+    CREATE TABLE IF NOT EXISTS _migrations (
+      name TEXT PRIMARY KEY,
+      applied_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+    )
+  `);
+
+  for (const m of migrations) {
+    const { rows } = await pool.query(
+      'SELECT 1 FROM _migrations WHERE name = $1',
+      [m.name],
+    );
+    if (rows.length > 0) continue;
+
+    const client = await pool.connect();
+    try {
+      await client.query('BEGIN');
+      await client.query(m.sql);
+      await client.query('INSERT INTO _migrations (name) VALUES ($1)', [m.name]);
+      await client.query('COMMIT');
+      console.log(`Migration applied: ${m.name}`);
+    } catch (err) {
+      await client.query('ROLLBACK');
+      throw err;
+    } finally {
+      client.release();
+    }
+  }
+}
+
+if (require.main === module) {
+  runMigrations()
+    .then(() => {
+      console.log('All migrations applied');
+      process.exit(0);
+    })
+    .catch((err) => {
+      console.error('Migration failed:', err);
+      process.exit(1);
+    });
+}

backend/src/db/pool.ts

@@ -0,0 +1,10 @@
+import { Pool } from 'pg';
+import { config } from '../config';
+
+export const pool = new Pool({
+  host: config.db.host,
+  port: config.db.port,
+  database: config.db.database,
+  user: config.db.user,
+  password: config.db.password,
+});