refactor: restructure in entirety

internal/database/invoice.go

@@ -0,0 +1,99 @@
+package database
+
+import (
+	"billit/internal/models"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"time"
+)
+
+// GetNextInvoiceNumber generates the next invoice ID in format PREFIX/MMM-YYYY/XXX and increments the counter
+func (s *service) GetNextInvoiceNumber(userID string) (string, error) {
+	var prefix string
+	var counter int
+
+	// Get current prefix and counter
+	err := s.db.QueryRow(`SELECT COALESCE(invoice_prefix, 'INV'), COALESCE(invoice_counter, 0) FROM users WHERE id = ?`, userID).
+		Scan(&prefix, &counter)
+	if err != nil {
+		return "", err
+	}
+
+	// Increment counter
+	counter++
+
+	// Update counter in database
+	_, err = s.db.Exec(`UPDATE users SET invoice_counter = ? WHERE id = ?`, counter, userID)
+	if err != nil {
+		return "", err
+	}
+
+	// Generate formatted invoice ID: PREFIX/MMM-YYYY/XXX
+	now := time.Now()
+	humanReadableID := fmt.Sprintf("%s/%s-%d/%03d", prefix, now.Month().String()[:3], now.Year(), counter)
+
+	return humanReadableID, nil
+}
+
+// CreateInvoice stores an invoice with UUID and human-readable ID for a user
+func (s *service) CreateInvoice(id string, humanReadableID string, data interface{}, userID string) error {
+	jsonData, err := json.Marshal(data)
+	if err != nil {
+		return err
+	}
+	_, err = s.db.Exec(`INSERT INTO invoices (id, human_readable_id, data, user_id) VALUES (?, ?, ?, ?)`, id, humanReadableID, string(jsonData), userID)
+	return err
+}
+
+// GetInvoice retrieves an invoice by ID for a user
+func (s *service) GetInvoice(id string, userID string) (*models.Invoice, error) {
+	var inv models.Invoice
+	err := s.db.QueryRow(`SELECT id, COALESCE(human_readable_id, ''), data, user_id, created_at FROM invoices WHERE id=? AND user_id=?`, id, userID).
+		Scan(&inv.ID, &inv.HumanReadableID, &inv.Data, &inv.UserID, &inv.CreatedAt)
+	if err == sql.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &inv, nil
+}
+
+// GetAllInvoices retrieves all invoices for a user
+func (s *service) GetAllInvoices(userID string) ([]models.Invoice, error) {
+	rows, err := s.db.Query(`SELECT id, COALESCE(human_readable_id, ''), data, user_id, created_at FROM invoices WHERE user_id=? ORDER BY created_at DESC`, userID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var invoices []models.Invoice
+	for rows.Next() {
+		var inv models.Invoice
+		if err := rows.Scan(&inv.ID, &inv.HumanReadableID, &inv.Data, &inv.UserID, &inv.CreatedAt); err != nil {
+			return nil, err
+		}
+		invoices = append(invoices, inv)
+	}
+	return invoices, nil
+}
+
+// GetRecentInvoices returns the most recently generated invoices for a user
+func (s *service) GetRecentInvoices(userID string, limit int) ([]models.Invoice, error) {
+	rows, err := s.db.Query(`SELECT id, COALESCE(human_readable_id, ''), data, user_id, created_at FROM invoices WHERE user_id=? ORDER BY created_at DESC LIMIT ?`, userID, limit)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var invoices []models.Invoice
+	for rows.Next() {
+		var inv models.Invoice
+		if err := rows.Scan(&inv.ID, &inv.HumanReadableID, &inv.Data, &inv.UserID, &inv.CreatedAt); err != nil {
+			return nil, err
+		}
+		invoices = append(invoices, inv)
+	}
+	return invoices, nil
+}