feat: add filter on price range

WIP

Signed-off-by: Julien Riou <julien@riou.xyz>

filter_range.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"regexp"
+
+	log "github.com/sirupsen/logrus"
+)
+
+// RangeFilter to store the pattern to match product model and price limits
+type RangeFilter struct {
+	model *regexp.Regexp
+	min   float64
+	max   float64
+}
+
+// NewRangeFilter to create a RangeFilter
+func NewRangeFilter(regex string, min float64, max float64) (*RangeFilter, error) {
+	var err error
+	var compiledRegex *regexp.Regexp
+
+	log.Debugf("compiling model filter regex")
+	if regex != "" {
+		compiledRegex, err = regexp.Compile(regex)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return &RangeFilter{
+		model: compiledRegex,
+		min:   min,
+		max:   max,
+	}, nil
+}
+
+// Include returns false when a product name matches the model regex and price is outside of the range
+// implements the Filter interface
+func (f *RangeFilter) Include(product *Product) bool {
+	if f.model == nil {
+		return true
+	}
+	if f.model.MatchString(product.Name) && product.Price < f.min || product.Price > f.max {
+		log.Debugf("product %s excluded because price for the model is outside of the range [%.2f-%.2f]", product.Name, f.min, f.max)
+		return false
+	}
+	log.Debugf("product %s included because price range filter is not applicable", product.Name)
+	return true
+}