interfaces: refactor

interfaces/05-log-parser/refactor-notes/refactor-02/result.go

@@ -0,0 +1,53 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+const fieldsLength = 4
+
+// result stores the parsed result for a domain
+type result struct {
+	domain, page    string
+	visits, uniques int
+	// add more metrics if needed
+}
+
+// parseResult from a log line
+func parseResult(line string) (r result, err error) {
+	fields := strings.Fields(line)
+	if len(fields) != fieldsLength {
+		return r, fmt.Errorf("wrong input: %v", fields)
+	}
+
+	r.domain = fields[0]
+	r.page = fields[1]
+
+	r.visits, err = strconv.Atoi(fields[2])
+	if err != nil || r.visits < 0 {
+		return r, fmt.Errorf("wrong input: %q", fields[2])
+	}
+
+	r.uniques, err = strconv.Atoi(fields[3])
+	if err != nil || r.uniques < 0 {
+		return r, fmt.Errorf("wrong input: %q", fields[3])
+	}
+
+	return r, nil
+}
+
+// addResult to another one
+func addResult(r, other result) result {
+	r.visits += other.visits
+	r.uniques += other.uniques
+	return r
+}