feat: add inventory repository for query logic

backend/internal/repository/postgres_inventory.go

@@ -0,0 +1,196 @@
+package repository
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/forfarm/backend/internal/domain"
+)
+
+type postgresInventoryRepository struct {
+	conn Connection
+}
+
+func NewPostgresInventory(conn Connection) domain.InventoryRepository {
+	return &postgresInventoryRepository{conn: conn}
+}
+
+func (p *postgresInventoryRepository) fetch(ctx context.Context, query string, args ...interface{}) ([]domain.InventoryItem, error) {
+	rows, err := p.conn.Query(ctx, query, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var items []domain.InventoryItem
+	for rows.Next() {
+		var i domain.InventoryItem
+		if err := rows.Scan(
+			&i.ID,
+			&i.Name,
+			&i.Category,
+			&i.Type,
+			&i.Quantity,
+			&i.Unit,
+			&i.DateAdded,
+			&i.Status,
+			&i.CreatedAt,
+			&i.UpdatedAt,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	return items, nil
+}
+
+func (p *postgresInventoryRepository) GetByID(ctx context.Context, id string) (domain.InventoryItem, error) {
+	query := `
+		SELECT id, name, category, type, quantity, unit, date_added, status, created_at, updated_at
+		FROM inventory_items
+		WHERE id = $1`
+
+	items, err := p.fetch(ctx, query, id)
+	if err != nil {
+		return domain.InventoryItem{}, err
+	}
+	if len(items) == 0 {
+		return domain.InventoryItem{}, domain.ErrNotFound
+	}
+	return items[0], nil
+}
+
+func (p *postgresInventoryRepository) GetWithFilter(ctx context.Context, filter domain.InventoryFilter, sort domain.InventorySort) ([]domain.InventoryItem, error) {
+	var query strings.Builder
+	args := []interface{}{}
+	argPos := 1
+
+	query.WriteString(`
+		SELECT id, name, category, type, quantity, unit, date_added, status, created_at, updated_at
+		FROM inventory_items
+		WHERE 1=1`)
+
+	if filter.Category != "" {
+		query.WriteString(fmt.Sprintf(" AND category = $%d", argPos))
+		args = append(args, filter.Category)
+		argPos++
+	}
+
+	if filter.Type != "" {
+		query.WriteString(fmt.Sprintf(" AND type = $%d", argPos))
+		args = append(args, filter.Type)
+		argPos++
+	}
+
+	if filter.Status != "" {
+		query.WriteString(fmt.Sprintf(" AND status = $%d", argPos))
+		args = append(args, filter.Status)
+		argPos++
+	}
+
+	if !filter.StartDate.IsZero() {
+		query.WriteString(fmt.Sprintf(" AND date_added >= $%d", argPos))
+		args = append(args, filter.StartDate)
+		argPos++
+	}
+
+	if !filter.EndDate.IsZero() {
+		query.WriteString(fmt.Sprintf(" AND date_added <= $%d", argPos))
+		args = append(args, filter.EndDate)
+		argPos++
+	}
+
+	if filter.SearchQuery != "" {
+		query.WriteString(fmt.Sprintf(" AND name ILIKE $%d", argPos))
+		args = append(args, "%"+filter.SearchQuery+"%")
+		argPos++
+	}
+
+	if sort.Field == "" {
+		sort.Field = "date_added"
+		sort.Direction = "desc"
+	}
+
+	validSortFields := map[string]bool{
+		"name":       true,
+		"category":   true,
+		"type":       true,
+		"quantity":   true,
+		"date_added": true,
+		"status":     true,
+		"created_at": true,
+	}
+
+	if validSortFields[sort.Field] {
+		query.WriteString(fmt.Sprintf(" ORDER BY %s", sort.Field))
+		if strings.ToLower(sort.Direction) == "desc" {
+			query.WriteString(" DESC")
+		} else {
+			query.WriteString(" ASC")
+		}
+	}
+
+	return p.fetch(ctx, query.String(), args...)
+}
+
+func (p *postgresInventoryRepository) CreateOrUpdate(ctx context.Context, item *domain.InventoryItem) error {
+	now := time.Now()
+	item.UpdatedAt = now
+
+	if item.ID == "" {
+		item.CreatedAt = now
+		query := `  
+			INSERT INTO inventory_items 
+			(id, name, category, type, quantity, unit, date_added, status, created_at, updated_at)  
+			VALUES (gen_random_uuid(), $1, $2, $3, $4, $5, $6, $7, $8, $9)
+			RETURNING id`
+		return p.conn.QueryRow(
+			ctx,
+			query,
+			item.Name,
+			item.Category,
+			item.Type,
+			item.Quantity,
+			item.Unit,
+			item.DateAdded,
+			item.Status,
+			item.CreatedAt,
+			item.UpdatedAt,
+		).Scan(&item.ID)
+	}
+
+	query := `  
+		UPDATE inventory_items 
+		SET name = $1,
+			category = $2,
+			type = $3,
+			quantity = $4,
+			unit = $5,
+			date_added = $6,
+			status = $7,
+			updated_at = $8
+		WHERE id = $9
+		RETURNING id`
+
+	return p.conn.QueryRow(
+		ctx,
+		query,
+		item.Name,
+		item.Category,
+		item.Type,
+		item.Quantity,
+		item.Unit,
+		item.DateAdded,
+		item.Status,
+		item.UpdatedAt,
+		item.ID,
+	).Scan(&item.ID)
+}
+
+func (p *postgresInventoryRepository) Delete(ctx context.Context, id string) error {
+	query := `DELETE FROM inventory_items WHERE id = $1`
+	_, err := p.conn.Exec(ctx, query, id)
+	return err
+}