init push

internal/shared/pkg/metricparse/metricparse.go

@@ -0,0 +1,74 @@
+// Package metricparse extracts a numeric value from the free-text engine/metric strings
+// used across FM reports (e.g. "GPC/N1 63.2"). The same parser MUST be used both when
+// aggregating totals and when deriving a single report's "today" contribution, otherwise
+// prev = total - today would not reconcile.
+package metricparse
+
+import (
+	"regexp"
+	"strconv"
+	"strings"
+	"unicode"
+)
+
+// numberToken matches a signed decimal number (integer or fractional).
+var numberToken = regexp.MustCompile(`[-+]?\d*\.?\d+`)
+
+// Parse returns ParseString(*v), or 0 when v is nil.
+func Parse(v *string) float64 {
+	if v == nil {
+		return 0
+	}
+	return ParseString(*v)
+}
+
+// ParseString pulls the numeric VALUE out of a metric label string:
+//
+//	"GPC/N1 63.2" -> 63.2   "PTC/N2 61.8" -> 61.8   "63.2" -> 63.2
+//	"63,2" -> 63.2          "  -5 "       -> -5      "N1" -> 0 (label only)
+//
+// It ignores digits fused to a label letter (the "1" in "N1", the "2" in "N2") by skipping
+// any number immediately preceded by a letter, and prefers a token that carries a decimal
+// point when several stand-alone numbers are present.
+func ParseString(s string) float64 {
+	s = strings.TrimSpace(s)
+	if s == "" {
+		return 0
+	}
+	// Normalize a decimal comma ("63,2") to a dot when it is the sole separator.
+	if !strings.Contains(s, ".") {
+		if i := strings.IndexByte(s, ','); i > 0 && i+1 < len(s) &&
+			isASCIIDigit(s[i-1]) && isASCIIDigit(s[i+1]) {
+			s = s[:i] + "." + s[i+1:]
+		}
+	}
+
+	locs := numberToken.FindAllStringIndex(s, -1)
+	candidates := make([]string, 0, len(locs))
+	for _, loc := range locs {
+		// A value is never glued to a preceding letter; that only happens for labels
+		// like N1/N2. Real values start the string or follow a space/slash/colon/etc.
+		if loc[0] > 0 && unicode.IsLetter(rune(s[loc[0]-1])) {
+			continue
+		}
+		candidates = append(candidates, s[loc[0]:loc[1]])
+	}
+	if len(candidates) == 0 {
+		return 0
+	}
+
+	chosen := candidates[0]
+	for _, c := range candidates {
+		if strings.Contains(c, ".") {
+			chosen = c
+			break
+		}
+	}
+	n, err := strconv.ParseFloat(chosen, 64)
+	if err != nil {
+		return 0
+	}
+	return n
+}
+
+func isASCIIDigit(b byte) bool { return b >= '0' && b <= '9' }