first commit

parser/parser.go

@@ -0,0 +1,77 @@
+// Package parser extracts cycling distances from free-text Discord messages.
+package parser
+
+import (
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+const miToKM = 1.60934
+
+var (
+	// Matches: 25km, 25.5 km, 25,5km, 25KM, 25 kilometers, 25 kilometres
+	kmPattern = regexp.MustCompile(
+		`(?i)\b(\d+(?:[.,]\d+)?)\s*(?:km|kms|kilometer|kilometers|kilometre|kilometres)\b`,
+	)
+
+	// Matches standalone "k" used in cycling context: "did a 100k", "50k ride"
+	// Only match when followed by a word boundary and a non-unit word (ride, loop, etc.)
+	// or preceded by cycling verbs.
+	kPattern = regexp.MustCompile(
+		`(?i)\b(\d+(?:[.,]\d+)?)\s*k\b`,
+	)
+
+	// Matches: 25mi, 25 mi, 25 miles, 25mile
+	miPattern = regexp.MustCompile(
+		`(?i)\b(\d+(?:[.,]\d+)?)\s*(?:mi|mile|miles)\b`,
+	)
+)
+
+// ParseKM extracts the first distance found in text and returns it in KM.
+// Returns 0, false if no distance could be parsed.
+func ParseKM(text string) (float64, bool) {
+	if km, ok := firstMatch(kmPattern, text, 1.0); ok {
+		return km, true
+	}
+	if km, ok := firstMatch(miPattern, text, miToKM); ok {
+		return km, true
+	}
+	// "k" alone is ambiguous; only accept it when the message looks cycling-related
+	if looksLikeCycling(text) {
+		if km, ok := firstMatch(kPattern, text, 1.0); ok {
+			return km, true
+		}
+	}
+	return 0, false
+}
+
+func firstMatch(re *regexp.Regexp, text string, multiplier float64) (float64, bool) {
+	m := re.FindStringSubmatch(text)
+	if m == nil {
+		return 0, false
+	}
+	// Normalise comma decimal separator
+	numStr := strings.ReplaceAll(m[1], ",", ".")
+	v, err := strconv.ParseFloat(numStr, 64)
+	if err != nil {
+		return 0, false
+	}
+	return v * multiplier, true
+}
+
+var cyclingKeywords = []string{
+	"ride", "rode", "cycl", "bike", "biked", "biking", "cycle",
+	"zwift", "strava", "trainer", "gravel", "mtb", "road", "spin",
+	"century", "loop", "route", "segment", "climb", "climbing",
+}
+
+func looksLikeCycling(text string) bool {
+	lower := strings.ToLower(text)
+	for _, kw := range cyclingKeywords {
+		if strings.Contains(lower, kw) {
+			return true
+		}
+	}
+	return false
+}