feat(#21): contas bancárias e patrimônio consolidado

CRUD de contas (corrente/poupança/investimento/cartão) com saldo calculado
automaticamente. account_id nullable em transactions. Widget patrimônio no
dashboard. Tela /contas. Seletor de conta nas transações manuais.

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

apps/api/internal/repository/account.go

@@ -0,0 +1,121 @@
+package repository
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"financeiro-carvalho/internal/model"
+)
+
+type AccountRepository struct {
+	pool *pgxpool.Pool
+}
+
+func NewAccountRepository(pool *pgxpool.Pool) *AccountRepository {
+	return &AccountRepository{pool: pool}
+}
+
+func (r *AccountRepository) List(ctx context.Context) ([]model.Account, error) {
+	rows, err := r.pool.Query(ctx, `
+		SELECT
+			a.id, a.name, a.type, a.initial_balance,
+			a.created_at::text, a.updated_at::text,
+			a.initial_balance
+				+ COALESCE(SUM(CASE WHEN t.type = 'income'  THEN t.amount ELSE 0 END), 0)
+				- COALESCE(SUM(CASE WHEN t.type = 'expense' THEN t.amount ELSE 0 END), 0)
+			AS balance
+		FROM accounts a
+		LEFT JOIN transactions t ON t.account_id = a.id
+		GROUP BY a.id
+		ORDER BY a.created_at
+	`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var out []model.Account
+	for rows.Next() {
+		var a model.Account
+		if err := rows.Scan(&a.ID, &a.Name, &a.Type, &a.InitialBalance, &a.CreatedAt, &a.UpdatedAt, &a.Balance); err != nil {
+			return nil, err
+		}
+		out = append(out, a)
+	}
+	return out, rows.Err()
+}
+
+func (r *AccountRepository) GetByID(ctx context.Context, id int) (*model.Account, error) {
+	var a model.Account
+	err := r.pool.QueryRow(ctx, `
+		SELECT
+			a.id, a.name, a.type, a.initial_balance,
+			a.created_at::text, a.updated_at::text,
+			a.initial_balance
+				+ COALESCE(SUM(CASE WHEN t.type = 'income'  THEN t.amount ELSE 0 END), 0)
+				- COALESCE(SUM(CASE WHEN t.type = 'expense' THEN t.amount ELSE 0 END), 0)
+			AS balance
+		FROM accounts a
+		LEFT JOIN transactions t ON t.account_id = a.id
+		WHERE a.id = $1
+		GROUP BY a.id
+	`, id).Scan(&a.ID, &a.Name, &a.Type, &a.InitialBalance, &a.CreatedAt, &a.UpdatedAt, &a.Balance)
+	if err != nil {
+		return nil, err
+	}
+	return &a, nil
+}
+
+func (r *AccountRepository) Create(ctx context.Context, in model.AccountInput) (*model.Account, error) {
+	var a model.Account
+	err := r.pool.QueryRow(ctx, `
+		INSERT INTO accounts (name, type, initial_balance)
+		VALUES ($1, $2, $3)
+		RETURNING id, name, type, initial_balance, created_at::text, updated_at::text
+	`, in.Name, in.Type, in.InitialBalance).
+		Scan(&a.ID, &a.Name, &a.Type, &a.InitialBalance, &a.CreatedAt, &a.UpdatedAt)
+	if err != nil {
+		return nil, err
+	}
+	a.Balance = a.InitialBalance
+	return &a, nil
+}
+
+func (r *AccountRepository) Update(ctx context.Context, id int, in model.AccountInput) (*model.Account, error) {
+	row := r.pool.QueryRow(ctx, `
+		UPDATE accounts SET name=$1, type=$2, initial_balance=$3, updated_at=NOW()
+		WHERE id=$4
+		RETURNING id, name, type, initial_balance, created_at::text, updated_at::text
+	`, in.Name, in.Type, in.InitialBalance, id)
+	var a model.Account
+	if err := row.Scan(&a.ID, &a.Name, &a.Type, &a.InitialBalance, &a.CreatedAt, &a.UpdatedAt); err != nil {
+		return nil, err
+	}
+	// recalculate balance
+	full, err := r.GetByID(ctx, a.ID)
+	if err != nil {
+		return nil, err
+	}
+	return full, nil
+}
+
+func (r *AccountRepository) Delete(ctx context.Context, id int) error {
+	_, err := r.pool.Exec(ctx, `DELETE FROM accounts WHERE id = $1`, id)
+	return err
+}
+
+func (r *AccountRepository) TotalPatrimony(ctx context.Context) (float64, error) {
+	var total float64
+	err := r.pool.QueryRow(ctx, `
+		SELECT COALESCE(SUM(
+			a.initial_balance
+				+ COALESCE((
+					SELECT SUM(CASE WHEN type='income' THEN amount ELSE -amount END)
+					FROM transactions WHERE account_id = a.id
+				  ), 0)
+		), 0)
+		FROM accounts a
+	`).Scan(&total)
+	return total, err
+}